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Comparing the Effectiveness of Nonsurgical Treatments for Lumbar Spinal Stenosis in Reducing Pain and Increasing Walking Ability
Michael J. Schneider, DC, PhD1,2, Carlo Ammendolia3, Donald Murphy4,5, Ronald Glick6, Sara Piva1, Elizabeth Hile7, Dana Tudorascu8 , Sally C Morton9
1 Associate Professor, Department of Physical Therapy, University of Pittsburgh, Pittsburgh, Pennsylvania 2 Associate Professor, Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
3 Assistant Professor, Institute of Health Policy, Management and Evaluation, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada 4 Director of Primary Spine Care Services, Care New England Health System, Providence, Rhode Island 5 Clinical Assistant Professor, Department of Family Medicine, Alpert Medical School of Brown University, Providence, Rhode Island 6 Assistant Professor, Departments of Psychiatry and Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania 7 Assistant Professor, College of Allied Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 8 Assistant Professor, Department of Internal Medicine and Geriatric Psychiatry Neuroimaging Lab, University of Pittsburgh, Pittsburgh, Pennsylvania 9 Dean of Science, Virginia Tech, Blacksburg, Virginia
Original Project Title: A Comparison of Non‐Surgical Treatment Methods for Patients with Lumbar Spinal StenosisPCORI ID: 587 HSRProj ID: 20142228 ClinicalTrials.gov ID: NCT01943435
_______________________________ To cite this document, please use: Schneider M, Ammendolia C, Murphy D,et al. 2019. Comparing the Effectiveness of Nonsurgical Treatments for Lumbar Spinal Stenosis in Reducing Pain and Increasing Walking Ability. Washington, DC: Patient‐Centered Outcomes Research Institute (PCORI). https://doi.org/10.25302/2.2019.CER.587
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Table of Contents
ABBREVIATIONS ..................................................................................................................... 3
ABSTRACT ................................................................................................................................ 4
BACKGROUND ......................................................................................................................... 5
PARTICIPATION OF STAKEHOLDERS IN RESEARCH STUDY DESIGN .......................................... 7
METHODS .............................................................................................................................. 11
Study Design .................................................................................................................................. 11 Sample Size ................................................................................................................................... 11
Inclusion/Exclusion Criteria ........................................................................................................... 12
Recruitment .................................................................................................................................. 13
Randomization .............................................................................................................................. 14
Interventions .................................................................................................................................. 15
Study Outcome Measures ............................................................................................................. 17
Blinding ......................................................................................................................................... 21
Study Setting .................................................................................................................................. 21
Follow-up ...................................................................................................................................... 22
Missing Data .................................................................................................................................. 25
Ancillary Qualitative Study ............................................................................................................ 25
RESULTS ................................................................................................................................ 26
Participant Flow ............................................................................................................................ 26
Baseline Data ................................................................................................................................ 28
Results of Primary Analyses of Primary and Secondary Aims (Linear Mixed Models) ................. 48
Results of Analyses for Exploratory Aim 1 ..................................................................................... 43
Results of Analyses for Exploratory Aim 2 (Heterogeneity of Treatment Effect ........................... 48
Patient Global Index of Change and Satisfaction ........................................................................... 52
DISCUSION ............................................................................................................................ 62
Context for Study Results in Context ............................................................................................. 62
Uptake of Study Results and Generalizability of Findings ............................................................. 66
Subpopulation Considerations ...................................................................................................... 69
Study Limitations .......................................................................................................................... 69
Future Research ............................................................................................................................ 71
CONCLUSION ......................................................................................................................... 72
REFERENCES .......................................................................................................................... 74
APPENDIX ............................................................................................................................. 79
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Abbreviations
LSS Lumbar Spinal Stenosis MC Medical Care GE Group Exercise MTE Manual Therapy and Individualized Exercise SSS Swiss Spinal Stenosis Questionnaire SPWT Self-paced Walking Test ESI Epidural Steroid Injection NASS North American Spine Society UPMC University of Pittsburgh Medical Center PGIC Patient Global Index of Change ABI Ankle Brachial Index PCORI Patient-centered Outcomes Research Institute MET Metabolic Equivalent IMMPACT Initiative on Methods, Measurement and Pain
Assessment in Clinical Trials CI Confidence Interval OR Odds Ratio SAT Patient Satisfaction PCP Primary Care Practitioner OA Osteoarthritis BMI Body Mass Index MCDI Modified Co-morbidity Disease Index TSK Tampa Scale for Kinesiophobia ABC Activities Specific Balance Confidence Scale RAND GH General Health RAND P Pain RAND SF Social Functioning RAND EF Energy/Fatigue RAND EW Emotional Well-being RAND PF Physical Functioning RAND RLE Role Limitations due to Emotional Problems RAND RLP Role Limitations due to Physical Health SW SenseWear FU Follow-up PROMIS Patient Reported Outcomes Measurement
Information System SPPB Short Physical Performance Battery CEQ Credibility/Expectancy Questionnaire MRI Magnetic resonance Imaging CT Computed Tomograph PT Physical Therapy RCT Randomized Clinical Trial
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ABSTRACT Background: Lumbar spinal stenosis (LSS) is a highly prevalent condition among older adults and the
most frequent indication for spinal surgery in patients older than the age of 65. In this past decade the
fastest growth in lumbar surgery in the United States has occurred in older adults with LSS, and the rate
of complex fusion procedures has significantly increased. These operations are associated with
significant health care costs, risks, complications, and rehospitalization rates. Yet, evidence is lacking for
the effectiveness of the various nonsurgical treatment options offered to patients with LSS. This study
was designed to help bridge this evidence gap.
Objective: Compare the clinical effectiveness of 3 common nonsurgical approaches to the
management of patients with LSS: (1) medical care (MC) provided by a physiatrist; (2) nonspecific group
exercise classes (GE) provided by certified exercise instructors; or (3) a combination of manual therapy
and individualized exercises (MTE) provided by chiropractors and physical therapists.
Methods: Randomized controlled clinical trial of 259 patients with LSS. Patients were
community-dwelling older adults (≥ 60 years of age) recruited from the Pittsburgh metro area. We
confirmed diagnosis of LSS by both diagnostic imaging (MRI or CT) and symptoms of neurogenic
claudication. Participants were randomized into 1 of the 3 groups described above and treated for a
total of 6 weeks. Participants in the GE and MTE groups had a total of 12 treatment sessions; those in
the MC group had a total of 3 treatment sessions. The primary outcome measures were self-reported
pain/function measured by the Swiss Spinal Stenosis (SSS) questionnaire and walking performance
measured by the Self-paced Walking Test (SPWT). The secondary outcome measure was daily physical
activity measured by accelerometry. We took outcome measures at baseline as well as 2 months and 6
months from baseline. The primary end point was at 2 months. The primary analysis used linear mixed
models to compare changes in each outcome measure between the groups. The secondary analysis was
a comparison of the proportion of responders (≥ 30% change) in each outcome measure by group, using
the chi-square test.
Results: No serious adverse events were reported in any of the groups. At 2 months, there was a
statistically significantly greater reduction in adjusted mean SSS score (range = 12-55) in the MTE group
compared with MC (2.1; 95% CI, 0.3-3.9) or GE (2.4; 95% CI, 0.6-4.3). The minimum clinically important
difference (MCID) for the SSS is 3.02 points; therefore the between-group SSS differences were not
5
clinically significant. The adjusted mean differences in SPWT scores at 2 months favored MTE compared
with MC (135.1; 95% CI, –17.2-287.4) or GE (46.2; 95% CI, –110.9-203.4), but these between-group
SPWT differences were not statistically significant. GE showed significantly greater improvement in
adjusted mean physical activity at 2 months compared with MC (30.5; 95% CI, 3.1-57.9), but clinical
significance is unknown due to the lack of an established MCID for physical activity. The MTE group had
significantly more SSS (20%) and SPWT (65.3%) responders at 2 months compared with MC (7.6%;
48.7%) or GE (3%; 46.2%) (P = 0.002 and P = 0.04, respectively). We prespecified responders as those
participants who showed ≥ 30% improvement from baseline on the measured outcome. At 6 months,
there were no longer significant between-group differences on any outcome measures. There was a
general trend toward short-term improvement in SSS and physical activity that was not sustained over
time; however, all groups maintained their improvements in walking performance (SPWT) at 6 months.
Study Limitations: There were a greater of proportion of GE dropouts immediately after randomization
and a potential attention bias due to the greater amount of individualized attention given to the MTE
group.
Conclusion: The combination of manual therapy and individualized exercise led to
significantly greater improvement in SSS and SPWT at 2 months, whereas group exercise led
to significantly greater improvement in physical activity at 2 months. The clinical significance of
these short-term improvements is unknown.
BACKGROUND Lumbar spinal stenosis (LSS) is a highly prevalent condition among older adults. Radiographic and clinical
data from the Framingham cross-sectional study report a 30% prevalence of degenerative LSS in this
population.1 A degenerative disease of the spine, LSS is often associated with significant functional
limitation of walking and disability.2 LSS has an associated risk of falling that is comparable to that found
in patients with severe knee osteoarthritis.3,4
A review of the literature reveals that the bulk of previous published clinical trials for LSS have
focused on 2 main areas of research: (1) comparisons of epidural injections, and (2) comparisons of
spine surgery with nonsurgical treatments such as physical therapy. The literature on these 2 topic areas
has generated conflicting results, which can be confusing to patients and providers. The largest epidural
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steroid injection (ESI) study to date involved the randomization of 400 patients with central LSS to
receive ESI with glucocorticoids plus lidocaine, or ESI with lidocaine alone.5 The results showed no
additional benefit in the glucocorticoid injection group in short-term reduction of physical disability or
leg pain.5 A systematic review and meta-analysis was published about the use of ESI for radiculopathy
and spinal stenosis.6 This review concluded that ESI for radiculopathy was associated with immediate
reductions in pain and function, but the effect sizes were small and not sustained. Limited evidence
suggested that there was little or no effectiveness of ESI for LSS.
The North American Spine Society (NASS) has published a clinical guideline for the diagnosis
and treatment of degenerative LSS.7 The only 2 interventions recommended as evidence
based and effective were ESI and surgical decompression. The NASS guideline concluded that
there was insufficient evidence to make a recommendation for or against the use of these
commonly utilized nonsurgical treatments for LSS: pharmacological treatments, physical therapy,
exercise, or spinal manipulation. Yet the favorable recommendation by NASS for ESI is
contradicted by recently published reviews concluding that the body of evidence for the
effectiveness of ESI is of low quality.8,9
Most of the clinical trials about LSS to date have focused on comparing patients who undergo
spine surgery with those who do not. Several randomized trials have concluded that patients
with severe LSS do better with surgical decompression, compared with nonsurgical
treatments.10-13 However, these surgical procedures are associated with significant costs, risks,
and complications as well as high rehospitalization rates.14-16 The largest clinical trial to date
compared surgical versus nonsurgical care, and concluded that patients with LSS treated
surgically had greater improvement in pain and function.17 However, the results from this same
trial also showed that about a third of the patients in the nonsurgical group had significant
improvements in pain and function lasting up to 4 years.18 A more recently published trial
randomized patients with LSS to surgical decompression or physical therapy treatment, finding
that both groups showed the same amount of improvement in physical function at 2
years.19
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Many large gaps in evidence remain about the effectiveness of nonsurgical treatment
options for the management of LSS. Several published systematic reviews of the LSS literature
highlight the gaps in evidence about nonsurgical treatments for LSS.12,20-26
A Cochrane systematic review of multiple nonsurgical treatment options for LSS identified
21 randomized clinical trials; however, the authors were unable to find moderate- or high-
quality evidence for any specific treatment option.21 The most recent Cochrane systematic
review on surgical versus nonsurgical treatments for LSS found a severe lack of high-quality
research performed to date.20 This led the authors to conclude, “We have very little
confidence to conclude whether surgical treatment or a conservative approach is better for
lumbar spinal stenosis. . . . We can provide no new recommendations to guide clinical
practice.”20
To help bridge this evidence gap, we designed a randomized trial to explore the comparative
clinical effectiveness of 3 common nonsurgical management approaches for patients with LSS:
(1) medical care provided by a physiatrist; (2) community-based group exercises provided by
fitness instructors; and (3) manual therapy/individualized exercises provided by chiropractors
and physical therapists. The primary aim was comparing the safety and effectiveness of these 3
interventions on pain and physical function, measured by a self-reported outcome and a
performance-based outcome. The secondary aim was to compare the changes in physical
activity between these 3 groups, measured by accelerometry.
PARTICIPATION OF STAKEHOLDERS IN RESEARCH STUDY DESIGN In formulating our original research questions, we started by identifying gaps in the current
evidence. The principal investigator (MS) and coinvestigator (CA) previously published 2
systematic reviews of the literature, which revealed large gaps in the evidence for many of the
commonly used conservative nonsurgical treatment methods used for patients with LSS.21,22
As noted previously, the evidence gap is very clear: The clinical guidelines for treatment of
LSS published by the North American Spine Society find inconclusive evidence for the
effectiveness of physical therapy, medications, exercise, and manipulation.10 Yet these are
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commonly utilized nonsurgical treatments for LSS—and are actually mandated by the local
University of Pittsburgh Medical Center (UPMC) Health Plan before spine surgery can be
authorized.27
We designed this trial to provide clinically relevant evidence to help fill this gap and to inform
the choices confronting clinicians and patients with LSS when faced with the decision about
nonsurgical treatment. There is also a paucity of evidence that takes into account which clinical
outcomes are important to patients. This is consistent with the goal of all patient-centered
outcomes research to determine which treatment works best, for whom, and under what
circumstances.28
We designed this study with input from a variety of stakeholders, including patients
with LSS, community senior center directors, clinicians who treat patients with LSS, and a
medical director from our local UPMC Health Plan. We developed a formal study protocol and
research design only after taking into consideration input we received from our stakeholders.
We developed the medical care protocol with input from physician stakeholders, and the
manual therapy/exercise protocol with input from physical therapists and
chiropractors.
We conducted group discussions at local community senior centers and asked patients with LSS
for their perspectives about which clinical outcomes were most important to them. Most
patients told us that living with a chronic degenerative condition that caused daily pain caused
many challenges. However, most patients told us that their biggest concern was the inability to
walk for any prolonged distance. They related stories about how their walking impairment
affected their ability to perform normal activities of daily living, such as shopping or walking to or
from a bus stop. This information helped us to decide on our use of outcome measures for our
study. We decided to include the self-paced walking test as an objective measure of walking
performance, in addition to our primary outcome of a self- reported measure of pain and
function.
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We also learned from our focus group participants that many of them were using community
senior centers as an alternative to receiving physical therapy or chiropractic care associated
with attending 2 to 3 physical therapy or chiropractic sessions per week for several weeks. They
were essentially substituting group exercise at community centers for individualized exercise at
chiropractic or physical therapy clinics, chiefly because they could not afford the cost of the
multiple copays associated with clinic-based care.
We also met with the directors of 2 large community centers who confirmed these patients’
perspectives. The fitness instructors had told them that many older adults in their group
exercise classes said that they were attending the classes as a substitution for physical therapy
and chiropractic care. This was concerning to center directors, because the purpose of these
group exercise classes was to promote general fitness; they were not intended for therapeutic
purposes. These directors also brought up the importance of knowing whether patients with
LSS could safely participate in the group exercise setting.
The research team had originally envisioned a 2-arm trial comparing medical care with a
combination of manual therapy and clinic-based individualized exercises; however, after
listening to our patient and community center stakeholders, we expanded the study design into
a 3-arm trial that included community-based exercise as an additional comparator arm. This
aligns well with the PCORI methodological standard RQ-5, which recommends the comparator
treatments be chosen to reflect viable treatment options for patients and avoiding the use of a
“no treatment” control group. We feel confident that each of our 3 comparator arms represents
a “real-world” management option that is commonly used by patients with LSS, which should
enhance the generalizability of our findings. We have published a summary of our research
protocol in an open-access peer reviewed journal.29
SPECIFIC AIMS (as presented in the original research application) The study was a pragmatic comparative effectiveness trial designed as a 3-group randomized
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clinical trial. The main goal of this study was to provide research evidence that could better
inform the choices between these 3 types of nonsurgical treatment options for patients
with LSS. The 3 comparison groups in this trial were the following:
• Group 1: Usual medical care*
• Group 2: Community-based group exercise classes
• Group 3: Clinic-based manual therapy and individualized exercise
*Note: In the design phase of this study, we interviewed primary care physicians and asked them
about how they managed patients with LSS. They told us that they commonly followed a 2-step approach:
Step 1: oral medications and advice to stay active; Step 2: referral for epidural injection. Therefore,
we considered this 2-step approach to be reflective of “usual medical care.” However, the
physician providing the medical care in our trial was board certified in physical medicine and
rehabilitation. Although we basically followed the same 2-step approach, we allowed him to
follow a more pragmatic and tailored approach (described in more detail later). This led to the
recognition that the words “usual medical care” were no longer the best terminology to describe
this intervention group. Therefore, we decided to delete the adjective “usual” and simply use
the term medical care in this report and future publications.
Primary Aim: To compare the clinical outcomes between these 3 interventions using 2
validated primary outcome measures of pain and physical function: Swiss Spinal Stenosis (SSS)
questionnaire (self-report measure) and Shuttle Walk Test* (performance-based measure).
• Hypothesis: LSS subjects in Groups 1 and 2 will demonstrate greater improvement in
self-reported pain/function and walking performance compared with Group 3.
*Note: We substituted the Self-paced Walking Test (SPWT) for the Shuttle Walk Test and notified
PCORI of this change before we began recruitment. This change in our choice of walking
performance measure occurred for 2 reasons. First, the developer of the SPWT consulted with
us about our research design and presented evidence about the reliability and accuracy of the
SPWT. Secondly, feedback from focus groups with stenosis patients indicated that the SPWT was
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a more patient-centered outcome that replicated real-life walking performance.
Secondary Aim: To compare changes in physical activity between these 3 treatment groups
using the SenseWear Armband (real-time activity measure).
•Hypothesis: Subjects in Groups 1 and 2 will demonstrate a greater change in physical
activity compared with Group 3.
Exploratory Aim 1: To explore relationships between 6-month attrition rates, number of
adverse events, adherence rates, number of falls, and cointerventions across treatment groups.
• Hypothesis: For all 3 treatment groups there will be a low incidence of adverse events and
similar treatment adherence rates. The 6-month attrition rate, number of falls, and
cointerventions will be lower in Groups 1 and 2 compared with Group 3.
Exploratory Aim 2: To explore treatment effects and responses by subgroup.
• Hypothesis: A group of baseline physical, psychosocial, and demographic measures
will be associated with treatment response and nonresponse in each group.
METHODS Methodological Standards Study Design This was a 3-arm, randomized controlled trial that compared the clinical effectiveness of group
exercise with manual therapy/individualized exercise, and each of these interventions with
medical care. The study was approved by the University of Pittsburgh Institutional Review
Board (PRO 12120422) and registered on ClinicalTrials.gov (NCT 01943435).
Sample Size
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We based sample-size estimation on hypothesized changes in our primary outcome
measure, the SSS questionnaire. We originally calculated a total sample size of 180 subjects with
an anticipated dropout rate of 15%, which would give us a final sample size of N = 150. This
would give us 80% power to detect a difference as small as 3.6 points (with a SD of 6.1) on the
total 12-item SSS score (30). In addition, this sample size also yields sufficient power to fit a
regression model that detects a statistical difference in the proportion of variability explained.
More specifically, a sample size of 150 achieves 81% power to detect an R-square of 5%
attributed to 2 independent variables (representing treatment) and assuming the control
variables account for an additional 20% of the variability. Due to an early unanticipated success
in enrollment and supplemental PCORI funding, we were able to continue recruitment for an
additional 6 months and achieve a larger final sample size (N = 259). We performed no interim
data analysis after reaching our original sample size of N = 180; we conducted only a single final
data analysis using data from the final sample size of N = 259.
Inclusion/Exclusion Criteria Participants were required to have been previously diagnosed with LSS by a physician and to
supply an MRI or CT report in which the radiologist confirmed the presence of anatomical
narrowing of the central canal, lateral recess, and/or foramen. We also confirmed the presence
of the following clinical signs of LSS: leg symptoms worsened by walking/relieved by sitting,
symptoms worsened by lumbar extension/relieved by flexion, and leaning forward on a
shopping cart while walking to relieve leg pain. To be eligible for the study, participants were
also required to (1) be aged 60 or older, (2) be able to read and write English, (3) be able to
walk at least 50 feet without an assistive device, (4) have a limitation of walking due to LSS, (5)
be able to engage in mild exercise, and (6) be willing to be randomized.
We excluded patients who (1) had a history of metastatic cancer, (2) had previous surgery for LSS
or lumbar fusion, (3) had cauda equina symptoms, (4) had a known history of severe peripheral
artery disease or exhibited an Ankle-Brachial index of < 0.8, (5) were told by a physician that they
should not engage in physical exercise, (6) had severe hypertension (systolic > 200 or diastolic >
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110), (7) could not complete a self-paced walking test for any reason other than symptoms
related to LSS, or (8) had a history of a neurological or neurodegenerative disease other than LSS
that affected their ability to walk.
Recruitment We used several strategies to recruit potentially eligible research participants from the general
population of older adults in the Pittsburgh metro area. The principle investigatorand research
coordinator set up informational booths and attended local community health fairs that were
targeted to older adults. Trifold informational brochures were produced and placed in the
waiting rooms of many primary care clinics affiliated with UPMC. We also produced a full-page
advertisement that we ran regularly in the Pittsburgh Senior News, a free monthly newspaper
with a circulation of 20 000 that is available in public venues such as major supermarkets in the
Pittsburgh region.
Our 2 most productive recruitment methods were the use of the University of Pittsburgh
Clinical and Translational Science Institute (CTSI) research registry and a series of direct
postcard mailings to the general public. The CTSI research registry is a voluntary database of
more than 100 000 patients who consented to be contacted for potential participation in
research studies. We also produced an oversize color postcard with information about our
study, an conducted a targeted direct mailing to Pittsburgh residents ≥ 60 years of age, living
within a 5- mile radius of our research facilities. Appendix B is a list of our direct mailings by ZIP
code and number of residents, which totaled more than 60 000 mailings over a period of 2
years.
Our recruitment strategies were extremely successful; we achieved our goal of enrolling 180
research participants about 6 months ahead of schedule—by June 1, 2015. Because of this
unanticipated early recruitment success, our program officer strongly suggested that we
continue recruitment for as long as possible to increase our total sample size. We were
subsequently awarded supplemental funding by PCORI, which allowed us to increase our final
sample size from N = 180 to N = 259 subjects. We achieved this new recruitment milestone by
14
the end of November 2015. In order maintain statistical integrity, we did not conduct any
interim data analysis after reaching our original recruitment goal of N = 180 subjects. We
conducted all analyses only after reaching the final total of N = 259 subjects.
We conducted a 2-phase screening process with those patients who contacted us expressing
interest in our research study (n = 710). The first phase consisted of a telephone screening
designed to filter out patients who clearly did not meet our inclusion criteria—for
example those who were younger than the age of 60 years or did not have MRI evidence of LSS.
Only those patients who passed the phone screening process (n = 298) were scheduled for the
second phase, a baseline physical examination at our research clinic. We designed this
examination to further screen out patients who had physical problems that could not be
established with a phone screen, including abnormal ankle brachial index, abnormally high blood
pressure, inability to walk 50 feet without an assistive device, or stopping the self-paced walking
test for reasons other than LSS (eg, chest pain, shortness of breath).
Randomization Randomization occurred immediately after the baseline screening examination confirmed that
the patient was eligible to participate in the trial. We used a computerized adaptive allocation
randomization algorithm to balance the 3 groups on 3 important baseline variables: (1)
SSS score, (2) SPWT score, and (3) age. We based the randomization scheme
on a minimization algorithm proposed by Stigsby and Taves.30 The approach is to use a rank-
based method to balance on multiple baseline prognostic factors.
All self-report questionnaires were converted into electronic format and completed by patients
on iPads. Research staff entered data from the baseline physical examination into iPads . All data
entered into the iPads were encrypted and transferred wirelessly to a secure central database,
where the randomization algorithm automatically processed the data and created the group
assignment. Within a few minutes of completing the baseline examination and self-report
questionnaires, our research assistant received an email from the research coordinator with the
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group assignment. Each participant was informed about which intervention they would be
receiving, and the research assistant scheduled his or her first appointment. This electronic
system of randomization automated the concealment of allocation sequence and eliminated the
need for double data entry.
Interventions The medical care arm of the study involved 3 visits to a physical medicine physician over 6
weeks—1 initial evaluation and 2 follow-up office visits. We designed a pragmatic treatment
protocol that was based chiefly on prescription of oral medications and epidural injections.
The physician reviewed each patient’s currently prescribed medications for LSS and was
permitted to modify/prescribe any of the following oral medications:
Nonsteroidal antiinflammatories: ibuprofen, celecoxib, diclofenac, or misoprostol
• Adjunctive analgesics: acetaminophen or gabapentin
• Antidepressant agents: nortriptyline, duloxetine, sertraline, trazodone, or mirtazapine
In addition to prescribing any of the above oral medications, the physician had the option of
referring participants for epidural steroid injections (ESIs) at 2 cooperating pain clinics in
Pittsburgh. Indications for ESI referral included inadequate pain relief with oral medications,
severe neurogenic claudication, or positive nerve tension signs. The clinical protocol was
pragmatic; the physician was allowed to tailor his recommendations to each patient’s individual
needs while staying within the parameters of the medications listed above, with the option of
recommending ESI when considered appropriate. The principle of shared-decision making was
used for all suggested medications and ESIs; in other words, research participants had an open
discussion with the physician about his recommendations and were not coerced into receiving
any prespecified regime of medications or injections. In addition to oral medications and/or
spinal injections, all subjects were given advice to stay active and to perform 2 home exercises:
hip-flexor stretching and prone, lumbar-extension stretching (yoga cobra pose). In addition, they
were encouraged to walk as much as possible despite their walking limitations.
16
The community-based group exercise arm of our trial involved attendance by the research
participants in supervised group exercise classes for older adults. These classes were held at 2
local senior community centers in Pittsburgh. Participants could choose to attend exercise
classes at either community center, based on convenience of location. The centers were
responsible for setting up the participants’ memberships, enrolling them in the group exercise
classes, and providing the approved schedule of classes for the study.
Participants were asked to attend 2 exercise classes per week for 6 weeks, for a total of 12
exercise classes. Each class was about 45 minutes in length and was taught by certified fitness
instructors who were experienced with supervising exercise classes for older adults. The
intensity and difficulty level of the exercise classes ranged from very easy to medium. The
pragmatic nature of our trial allowed for participants to self-select the level of exercise
class based on their perception of their fitness level. Community center staff monitored
attendance at each class, compiled this information into monthly spreadsheets, and sent them
to our research team. Although the reports were sent monthly, they had details about daily
class attendance.
The clinic-based manual therapy/individualized exercise arm of the trial involved treatment
provided by chiropractors and physical therapists at the Physical Therapy Clinical and
Translational Research Center at the University of Pittsburgh. Participants were
treated 2 times per week for 6 weeks; each treatment session lasted about 45 minutes. The
clinicians followed a pragmatic treatment protocol that consisted of 3 basic interventions:
(1) warm-up procedure using a stationary bicycle; (2) manual therapy procedures that included
lumbar distraction mobilization, hip-joint mobilization, side-posture lumbar and/or sacroiliac-
joint mobilization, and sciatic/femoral nerve mobilization; and (3) individualized exercise
procedures with instruction in spinal-stabilization exercises and stretching exercises to be
completed at home. Each subject was assessed by physical examination for which specific
muscles required stretching and which other muscles required strengthening. The treating
chiropractor or physical therapist then developed an individualized program of
17
stretching/strengthening exercises for each patient; this was in contrast with the nonspecific
nature of the group exercise classes and general exercise instructions given to all patients by
the physician. Appendix A provides a detailed list of all the manual therapy and therapeutic
exercise procedures utilized in our treatment protocol for this arm of the study.
Study Outcome Measures Our primary subjective outcome measure of self-reported pain/function was the SSS
questionnaire,31 which is a validated patient self-report of pain and physical function. We used
the 12-item version of this form, which has 2 subscales; a 7-item Symptom Severity subscale
and a 5-item Physical Function subscale. The SSS has been shown to possess adequate
psychometric properties for use with LSS patients, with a minimal clinically important
difference (MCID) of 3.02 points for the total 12-item SSS score, which is 0.36 and 0.10 points
per item for the Symptom Severity and Physical Function subscales, respectively.32 The primary
objective outcome measure of walking performance was the distance walked (meters) during
the SPWT, which is a validated measure of walking performance in patients with LSS.33 The
SPWT has been shown to be highly reproducible with a test–retest intraclass correlation
coefficient (ICC) of 0.98 34. No MCID has been established for the SPWT.
We selected these outcome measures based on feedback received from our patient and
clinician stakeholders. Patients with LSS who participated in our community group discussions
told us that their general concerns were about their level of pain and function; they had a
specific concern about the distance they could walk before needing to sit down. The SSS was an
obvious choice for a self-reported measure of pain and function, because it contains both
Symptom Severity and Physical Function subscales and was validated for use within the LSS
population.
We decided to use the SPWT as our objective measure of walking performance instead of the
Shuttle Walk Test, because the SPWT more closely resembles the way LSS patients
walk in real-life settings.34 Performed on level ground, the SPWT instructs patients to walk at
18
their normal pace and to continue walking until their symptoms rise to a level that they must sit
down and rest. A physical therapist walks behind the patient, measures the distance walked in
meters, and records the total time walked in minutes. The developer of the SPWT consulted
with our research team about the specific details of conducting this pragmatic test of walking
performance.
We also used the SenseWear armband (BodyMedia Inc) to record physical activity for our
secondary outcome measure.35,36 This small, wireless accelerometer is worn over the triceps
muscle. It combines information from skin temperature and a biaxial accelerometer, enabling
the device to estimate energy expenditure from activities that do not require ambulation.
Physical activity measured by the SenseWear has compared well with reference standards such
as doubly labeled water (ICC: 0.48 to 0.81) 35, 36 and indirect calorimetry (ICC: 0.11 to 0.92).37-41
After finishing the testing procedures at baseline, subjects were fitted with the Sensewear
armband and instructed to wear the monitor for 7 days. Data from the activity monitor were
inspected to ensure they were sufficient, which we defined as at least 4 days with 10 hours of
physical activity data per day.42-44 Subjects without sufficient data were asked to wear the
portable monitor for an additional week prior to starting study-related interventions. We used
the same procedures to collect physical activity data at the follow-up examinations.
We also obtained several other self-reported measures using validated instruments widely
employed in rehabilitation trials. A patient global index of change (PGIC) and treatment
satisfaction (SAT) questionnaire were given to our research participants at the follow-up
examinations. The PGIC asked patients to rate their level of “overall status change since first
beginning treatment” on a 7-point scale, ranging from “very much worse” (–3) to “very much
better” (+3). The SAT questionnaire asked patients to rate their level of satisfaction with the
treatment on a 6-point scale, ranging from “extremely dissatisfied” (–3) to “extremely satisfied”
(+3).
We used a modified comorbidity disease index45 to gather self-reported information about
19
the number of comorbid medical conditions that were diagnosed in addition to LSS. We used a
Falls History Form to ask questions about the number of falls over the past year and level
of current fear of falling.46 The Activities Specific Balance Confidence scale47 was administered
to assess participants’ level of confidence about not losing balance during routine activities of
daily living. We used the 10-item Oswestry Low Back Pain Disability Index48 and the 11-item
Tampa Scale for Kinesiophobia49 to assess self-reported disability from back pain and fear of
movement, respectively. We screened for depressive symptoms utilizing the short-form version
of the Patient Reported Outcomes Measurement Information System (PROMIS) depression
scale.50 Last, we used a 6-item treatment expectancy and credibility questionnaire specifically
modified for use in patients with chronic low back pain.51 Table A provides a summary of all
outcome measures and the times at which they were collected during the trial.
In addition to these self-reported measures, a research physical therapist performed some
physical examination procedures at baseline to capture additional clinical data. This therapist
recorded range of motion of the lumbar spine as well as that of the hip and knee joints, and
palpation of these structures was performed for local tenderness. Tests for balance and
mobility included a modified version of the Short Physical Performance Battery52: 4-meter gait
speed, timed chair stands, and timed single-leg standing. Blood pressure measurements were
taken on all participants, as well as height and weight for calculation of body mass index.
20
Table A. Outcome Measures and Other Information Gathered at Baseline and Follow-up
•
•
Table X: Timeline of Outcome Measures
Measure Baseline Mid 2 o treatment Follow-up 6 mo
Follow-up
Primary Outcomes
Self-report = SSS • • • •
Performance-based = SPWT • • Secondary Outcome
Physical activity • Real-time activity = SWA*
•
Exploratory Outcomes
Falls history • • •
Activities Balance Confidence Scale (ABC)
• • •
Oswestry • • • •
Side effects, adverse events
• • •
Cointerventions~ •
RAND-36 • • •
SPPB • • •
PGIC • •
Satisfaction • •
Other Variables
Demographics •
Comorbidities (MCDI) •
Baseline history and physical exam
•
Psychosocial Measures
Fear (TSK) •
Depression (PROMIS) •
Expectancy (CEQ) •
~Cointerventions include new medications, injections, hospitalizations, surgery, chiropractic care, physical therapy, or acupuncture treatment.
*Note about SWA: At baseline and follow-up assessments, the SenseWear Armband was be given to all subjects to take home and wear continuously for 1 week.
Abbreviation Key: SSS = Swiss Spinal Stenosis questionnaire SPWT = Self-paced Walking Test SWA = SenseWear Armband; ABC = Activities Balance Confidence Scale RAND-36 = RAND 36-item Health Survey SPPB = Short Physical Performance Battery; PGIC = Patient Global Index of Change; MCDI = Modified Comorbidity Disease Index; TSK = Tampa Scale for Kinesiophobia; PROMIS = Patient Reported Outcomes Measurement Information System; CEQ = Credibility/Expectancy Questionnaire
21
We also used a portable Doppler unit and sphygmomanometer to record the Ankle Brachial
Index (ABI). The ABI is a highly sensitive and specific screening test for peripheral artery disease
and lower leg vascular claudication.53,54 Any patient with an ABI below 0.8 was excluded
from participating in our study, because of the possibility of vascular rather than neurogenic
claudication. We also excluded patients with severe high blood pressure, using the American
College of Sports Medicine criteria (systolic > 200 or diastolic > 110).
Blinding
Blinding of the treating clinicians and research participants was not possible, because both
group were obviously aware of the intervention they were giving or receiving. We attempted to
minimize bias by having an independent physical therapist perform all baseline physical
examinations and follow-up reassessments. Our primary outcome measures (SSS) were a
patient-report questionnaire and an objective outcome measure of walking performance
(SPWT), conducted in a manner to minimize examiner bias. Participants were instructed to walk
as far as they could until they needed to sit down and rest. The physical therapist observing the
subjects was not permitted to coach or provide any encouragement; he simply recorded the
total distance and time walked. Because the SenseWear armband is worn at the subject’s
home, the exploratory measure of physical activity was also not subject to examiner bias; data
are uploaded directly from the device.
Study Setting
All treatments were provided at no charge to the participants or their insurance carriers. The
medical care was provided by a physical medicine physician at his outpatient clinical practice
setting. Participants who attended the group exercise classes were given complimentary access
to those classes or a temporary membership to a local community center. A chiropractor or a
physical therapist in a research-based physical therapy clinic at the University of Pittsburgh
treated participants in the manual therapy arm. All locations were chosen because of their real-
22
world settings.
Follow-up
For all 3 arms of the study, the respective interventions were completed over a 6-week period.
Participants returned for 2 follow-up research examinations, at 2 months (2 weeks
after completion of care) and 6 months (4 months after completion of care).
Analytical and Statistical Approaches
The analysis of our primary aim consisted of a between-groups comparison of the changes in
the primary subjective (SSS) and objective (SPWT) outcomes from baseline values to 2 months
(primary end point). The analysis of our secondary aim was a comparison of the between-group
changes in the average amount of physical activity from baseline to 2 months. We defined our
measure of physical activity as the average number of daily minutes spent in light, moderate, or
vigorous physical activity (> 1.5 metabolic equivalents of task [METs]). We also performed these
same analyses comparing the data obtained at 6 months with the baseline measures. Due to
the constraints of our 3-year PCORI contract, we could not obtain any results beyond 6 months.
We also performed a series of secondary responder analyses for each of the outcome measures
associated with our primary and secondary aims. We accomplished this by dichotomizing all
subjects into either “responders” or “nonresponders” based on the prespecified threshold of a
minimum 30% improvement in outcome from baseline. We performed separate responder
analyses for each of the 3 outcome measures (SSS, SPWT, and physical activity), comparing the
proportions of responders at 2 months and 6 months.
We summarized the outcomes and all baseline characteristics with descriptive statistics,
separated by treatment group. We used linear mixed models as the primary analytic method to
assess the significance of treatment for each group, while adjusting for the three baseline
randomization balancing variables: SSS, SPWT, and age. We followed a modified intention-to-
treat principle: All participants who were randomized (N = 259) were included in the analysis,
23
using linear mixed models to account for missing data. We verified the normality assumptions
for the outcome variables for the simple analysis as well the assumptions for the multiple
regression models on the change scores.
For our primary and secondary aims, we also performed a series of secondary responder
analyses using dichotomous outcomes, consistent with the recommendations published by the
Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT).55,56
Per IMMPACT recommendations, we defined treatment responders as those who achieved at
least a 30% improvement in the outcome measure of interest, which is considered “moderate
improvement.” We believe that a 30% improvement in symptoms and/or functional
performance is a clinically important change over 2 months, considering that LSS is a chronic
degenerative disease that tends to deteriorate over time. Our analyses compared the
proportions of subjects considered “responders” by treatment group on these measures—SSS,
SPWT, and physical activity. We assessed differences in the proportion of
responders/nonresponders between the groups using chi-square and Fisher exact tests.
Our first exploratory aim was to explore 6-month attrition and adherence rates, number of falls,
adverse events, and cointerventions. We defined adherence as any participant who did not
drop out after randomization and attended at least 2 of the 3 scheduled medical care visits, or
at least 9 of the 12-scheduled group exercise or manual therapy sessions. We defined attrition
as any participant who did not drop out after randomization and received at least 1 treatment
but who did not show up for the follow-up research examination. At baseline, participants were
asked, “Have you fallen any time during the past year? If yes, how many times did you fall?” At
the 6-month follow-up evaluation, participants were asked, “Have you fallen any time between
now and when you finished your study intervention? If yes, how many times did you fall?”
We defined a serious adverse event as any unanticipated health care problem, directly related
to a study intervention, that caused the participant to seek medical care outside of the study.
We asked all research participants to neither seek any new type of health care nor start any
24
new exercises outside of the study until after their 2-month follow-up evaluation. Therefore,
we asked participants only about which cointerventions they had utilized during the period
between their 2-month and 6-month follow-up evaluations. We summarized these exploratory
outcomes with descriptive statistics of their respective counts and rates, separated by
treatment group. The analysis for this aim consisted of omnibus chi-square tests for the
differences in the rates or proportions of each outcome across the 3 groups.
Our second exploratory aim was to explore potential baseline predictors of treatment
response. We first performed univariate analyses to test for possible associations between
baseline characteristics and response, based on the criterion of responders being defined as
those participants who demonstrated ≥ 30% change on either the SSS or SPWT. We used 2-
sample t-tests for continuous variables and chi-square tests for categorical variables to test
the association between responders and nonresponders and each variable of interest. We
decided a priori that statistical significance would be set at P < 0.10 for variables to be included
in the multivariable logistic regression model. We used the same responder–nonresponder
dichotomous variables for SSS, SPWT, and physical activity created for the secondary responder
analyses associated with our primary and secondary aims.
We then used logistic regression models to test the association between responders and non
responders, treatment groups, and other variables of interest. We put the variables that we
found significant using univariate procedures (P < 0.10) in a multivariable logistic regression
model, and applied a backward elimination procedure. The level of significance for removal
was P < 0.10.
We evaluated heterogeneity of treatment effects by testing the interaction between treatment
and 8 baseline variables using multiple logistic regression models, with responder status as the
dependent variable. These 8 variables were age, sex, body mass index, comorbidities, race,
kinesiophobia, knee osteoarthritis, and depression. We dichotomized age at < 75 years versus ≥
75 years. Se split comorbidities, depression, and the other continuous variables at their
25
respective medians. We considered baseline variables as potential moderators of treatment
effect due to our experience in other studies and the published literature. We compared the P
value for the interaction between the moderator and the treatment variable to 0.05. Regardless
of significance, we presented between-treatment group comparisons as odds ratios and
stratified 95% confidence intervals by the potential moderator. Finally, we explored with
descriptive statistics and responder analyses the between-group differences in Patient Global
Index of Change and Treatment Satisfaction at 2 months and 6 months.
Missing Data
To account for any missing data, we used linear mixed-effects models to study treatment
differences over time for the primary and secondary outcomes. We used a compound
symmetry structure for the correlation structure and the Kenward-Roger approximation
method for the degrees of freedom.57 Linear mixed-effects models use all available data; if a
subject had a measurement at 1 time point and the rest of the data were missing, then that
subject was still used in the analysis. Therefore, these mixed models included data from all
participants who had a baseline examination and were randomized (N = 259).
Ancillary Qualitative Study
Although not part of our original research design, we were able to include an ancillary
qualitative study that involved focus-group discussions with participants from each of the 3
intervention arms. These discussions were recorded, transcribed, coded, and analyzed for
themes using qualitative software. The results of this ancillary qualitative study are available as
a supplemental report upon request, as they will be published separately from the main results
of this trial.
26
RESULTS
Participant Flow
Figure 1 provides a CONSORT participant flow diagram.58 We screened 710 people over the
phone and excluded 412 for not meeting the minimum inclusion criteria; 298 people were
brought into our research facility for a baseline physical examination screening to assess their
eligibility for participation in the trial. Informed consent was obtained from all potentially
eligible patients. A total of 259 people met our inclusion criteria, were enrolled, and were
randomized. A total of 19 enrolled participants dropped out after randomization and never
attended any of the intervention sessions, with a larger number of drop-outs in the group
exercise arm (N = 12). We included in our analysis only those patients who attended at least 1
intervention session.
27
Figure 1. CONSORT flow diagram
Baseline Screening Examination
Assessed for eligibility (n=298)
(n=197)
Excluded as ineligible (n=39)
Abnormal ankle-brachial index (n=12)
Extremely high blood pressure (n=1)
Could not walk without need for an
assistive device (n=2)
Stopped self-paced walking test for
reason other than stenosis (n=24)
2-month follow up exam (n=79)
Lost to follow up (n=5)
2-month follow up exam (n=67)
Lost to follow up (n=5)
2-month follow up re-exam (n=80)
Lost to follow up (n=4)
Phone Screens (n=710)
Allocated to Medical Care (n=88)
thdrew after randomization (n=4)
Received Medical Care (n=84)
Allocated to Group Exercise (n=84)
Withdrew after randomization (n=12)
Received Group Exercise (n=72)
Allocated to Manual Therapy (n=87)
Withdrew after randomization (n=3)
Received Manual Therapy (n=84)
Randomized (n=259)
-month follow up exam (n=67)
Lost to follow up (n=12)
6-month follow up exam (n=59)
Lost to follow up (n=8)
6-month follow up exam (n=65)
Lost to follow up (n=15)
Did not meet minimum inclusion criteria (n=412)
28
Baseline Data
Table 1 contains the baseline demographic and clinical characteristics of our participants, both
by study total and assigned treatment group. The randomization process worked well;
no significant differences existed between the groups on any demographic or clinical
characteristics. The average age of our participants was 72.4 years (SD = 7.8), with a range of
60-92 years. Many of our participants reported comorbid osteoarthritis of the hip (16.6%)
and/or knee (31.7%), with an average body mass index of 31.0 (SD = 6.6). We achieved good
racial and socioeconomic diversity, with our research participants represented by 21.6%
African American, 47.1% without a college degree, and 51.4% with an annual income below
$40 000.
Our participants had an average of 4.7 (SD = 2.2) medical comorbidities: arthritis (85%);
cataracts (52%); emotional problems (34%); hearing problems (31%); and joint replacement
(30%). As listed in Table 1, the 2 most common types of arthritis reported by our participants
were hip osteoarthritis (16.6%) and knee osteoarthritis (31.7%). At baseline, our participants
had an average SSS Symptom Severity subscore of 20.3 (SD = 4.3; range = 7-35) and walked an
average of 455.3 meters (SD = 480.0) during the SPWT.
Physical activity was recorded from the SWA device, which captures data in terms of METs. One
MET is defined as 1 Kcal/kg/hour and is roughly equivalent to the energy cost of sitting quietly.
The amount of METs expended can be used to create general activity categories as follows:
sedentary = ≤ 1.5 METs; light = > 1.5-3.0 METs; moderate = ≥ 3.0 to 6.0 METs; and vigorous = ≥
6.0 METs. Our subjects were very sedentary, spending an average of about 18 hours per day
(1095.3 ± 150.3 mins/day) in activities ≤ 1.5 METs. They spent less than 3 hours per day (165.5 ±
129.7 mins/day) performing activities >1.5 METs. Table B provides a comparison of the baseline
characteristics of all participants who completed their assigned treatment and those for whom
we had missing data. This table shows that those who withdrew after randomization were
mostly similar with minor exceptions (e.g. marital status).
29
Table B: Baseline characteristics for all participants with and without complete data at each time point. For categorical variables, “F” indicates p-
value from Fisher’s exact test and no “F” indicates p-value from chi-square test. Continuous variable p-values from Wilcoxon rank sum test.
Baseline
Randomized: N=259
2 month follow-up
Received treatment: N=240
6 month follow-up
Received treatment: N=240
Started Tx
(n=240)
Withdrew –
no tx
(n=19)
Completed
2mo FU
(n=225)
Missing
2mo FU
(n=15)
Completed
6mo FU
(n=191)
Missing 6mo
FU
(n=49)
Categorical
Measure Category
n (%) n (%) p-
value
p-
value
p-value
Sex Male 113(47.1%) 9(47.4%) 0.98 107(47.6%) 6(40.0%) 0.57 89(46.6%) 24(50.0%) 0.77
Female 127(52.9%) 10(52.6%) 118(52.4%) 9(60.0%) 102(53.4%) 25(51.0%)
Race White 184(76.7%) 17(89.5%) 0.47F 172(76.4%) 12(80.0%) 1.00F 151(79.1%) 33(67.4%) 0.15F
Black 54(22.5%) 2(10.5%) 51(22.7%) 3(20.0%) 38(19.9%) 16(32.7%)
Other 2(0.8%) 0(0.0%) 2(0.9%) 0(0.0%) 2(1.1%) 0(0.0%)
Hispanic Yes 0(0.0%) 0(0.0%) 1.00F 0(0.0%) 0(0.0%) 1.00F 0(0.0%) 0(0.0%) 1.00F
No 240(100.0%) 19(100.0%) 225(100.0%) 15(100.0%) 191(100.0%) 49(100.0%)
Married Yes 120(50.0%) 5(26.3%) 0.05 116(51.6%) 4(26.7%) 0.06 104(54.5%) 16(32.7%) 0.01
No 120(50.0%) 14(73.7%) 109(48.4%) 11(73.3%) 87(45.6%) 33(67.4%)
Education LE 8th
grade or
>8th grade
but not HS
grad
10(4.2%) 0(0.0%) 0.31 10(4.4%) 0(0.0%) 0.62 8(4.2%) 2(4.1%) 0.68
30
Baseline
Randomized: N=259
2 month follow-up
Received treatment: N=240
6 month follow-up
Received treatment: N=240
Started Tx
(n=240)
Withdrew –
no tx
(n=19)
Completed
2mo FU
(n=225)
Missing
2mo FU
(n=15)
Completed
6mo FU
(n=191)
Missing 6mo
FU
(n=49)
Categorical
Measure Category
n (%) n (%) p-
value
p-
value
p-value
HS grad to
some
college
106(44.2%) 6(31.6%) 100(44.4%) 6(40.0%) 87(45.6%) 19(38.8%)
College
grad or
higher
124(51.7%) 13(68.4%) 115(51.1%) 9(60.0%) 96(50.3%) 28(57.1%)
Household
income
$20K or
less
46(19.2%) 6(31.6%) 0.25 44(19.6%) 2(13.3%) 0.43F 32(16.8%) 14(28.6%) 0.07
$20,001-
$40,000
74(30.8%) 7(36.8%) 67(29.8%) 7(46.7%) 57(29.8%) 17(34.7%)
$40K or
more
120(50.0%) 6(31.6%) 114(50.7%) 6(40.0%) 102(53.4%) 18(36.7%)
Current
Smoker
Yes 15(6.3%) 0(0.0%) 0.61F 15(6.7%) 0(0.0%) 0.61F 12(6.3%) 3(6.1%) 1.00F
No 225(93.8%) 19(100.0%) 210(93.3%) 15(100.0%) 179(93.7%) 46(93.9%)
Tobacco Use Yes, I
currently
smoke
15(6.3%) 0(0.0%) 0.55F 15(6.7%) 0(0.0%) 0.81F 12(6.3%) 3(6.1%)
31
Baseline
Randomized: N=259
2 month follow-up
Received treatment: N=240
6 month follow-up
Received treatment: N=240
Started Tx
(n=240)
Withdrew –
no tx
(n=19)
Completed
2mo FU
(n=225)
Missing
2mo FU
(n=15)
Completed
6mo FU
(n=191)
Missing 6mo
FU
(n=49)
Categorical
Measure Category
n (%) n (%) p-
value
p-
value
p-value
No, I have
never
smoked
102(42.5%) 11(57.9%) 96(42.7%) 6(40.0%) 80(41.9%) 22(44.9%)
No, I used
to smoke,
but quit
119(49.6%) 8(42.1%) 110(48.9%) 9(60.0%) 95(49.7%) 24(49.0%)
Other/Miss
ing
4(1.7%) 0(0.0%) 4(1.8%) 0(0.0%) 4(2.1%) 0(0.0%)
Predominant
Pain
Legs 43(17.9%) 3(15.8%) 0.63F 42(18.7%) 1(6.7%) 0.53F 39(20.4%) 4(8.2%) 0.12
Low Back 145(60.4%) 10(62.6%) 135(60.0%) 10(66.7%) 113(59.2%) 32(65.3%)
Equal 52(81.7%) 6(31.6%) 48(21.3%) 4(267%) 39(20.4%) 13(26.5%)
Qualitative
description
of leg pain
Pain 114(47.5%) 7(36.8%) 0.37 108(48.0%) 6(40.0%) 0.55 96(50.3%) 18(36.7%) 0.09
Neurologic 126(52.5%) 12(63.2%) 117(52.0%) 9(60.0%) 95(49.7%) 31(63.3%)
Hip OA Yes 39(16.3%) 4(21.1%) 0.53F 35(15.6%) 4(26.7%) 0.28F 32(16.8%) 7(14.3%) 0.68
No 201(83.8%) 15(79.0%) 190(84.4%) 11(73.3%) 159(83.3%) 42(85.7%)
32
Baseline
Randomized: N=259
2 month follow-up
Received treatment: N=240
6 month follow-up
Received treatment: N=240
Started Tx
(n=240)
Withdrew –
no tx
(n=19)
Completed
2mo FU
(n=225)
Missing
2mo FU
(n=15)
Completed
6mo FU
(n=191)
Missing 6mo
FU
(n=49)
Categorical
Measure Category
n (%) n (%) p-
value
p-
value
p-value
Knee OA Yes 74(30.8%) 8(42.1%) 0.31 71(31.6%) 3(20.0%) 0.56F 59(30.9%) 15(30.6%) 0.97
No 166(69.2%) 11(57.9%) 154(68.4%) 12(80.0%) 132(69.1%) 34(69.4%)
Started Tx
(n=240)
Withdrew
– no tx
(n=19)
Completed
2mo FU
(n=225)
Missing 2mo
FU
(n=15)
Completed
6mo FU
(n=191)
Missing 6mo
FU
(n=49)
Continuous
Measure
Mean ± SD Mean ± SD p-
value
Mean ± SD Mean ± SD p-value Mean ± SD Mean ± SD p-value
Age 72.3 ± 7.8 73.5 ± 8.2 0.47 72.3 ± 7.6 71.4 ± 10.7 0.30 72.8 ± 7.7 70.2 ± 8.0 0.02
BMI 31.0 ± 6.6 31.4 ± 7.6 0.86 30.7 ± 6.3 35.5 ± 9.2 0.03 30.6 ± 6.3 32.6 ± 7.5 0.12
Treatment
Expectancy_A
35.4 ± 11.8 31.0 ± 13.3 0.17 35.6 ± 11.9 31.8 ± 9.0 0.10 35.6 ± 12.1 34.5 ± 10.7 0.36
Treatment
Expectancy_B
42.8 ± 8.9 39.3 ± 9.5 0.10 43.0 ± 8.9 39.5 ± 8.8 0.11 43.1 ± 8.9 41.3 ± 9.0 0.15
Treatment
Expectancy_C
39.4 ± 10.5 35.5 ± 10.9 0.16 39.6 ± 10.3 35.6 ± 13.2 0.22 39.8 ± 10.3 37.7 ± 11.3 0.16
33
Started Tx
(n=240)
Withdrew
– no tx
(n=19)
Completed
2mo FU
(n=225)
Missing 2mo
FU
(n=15)
Completed
6mo FU
(n=191)
Missing 6mo
FU
(n=49)
Continuous
Measure
Mean ± SD Mean ± SD p-
value
Mean ± SD Mean ± SD p-value Mean ± SD Mean ± SD p-value
Depression T-
Score
47.6 ± 8.9 51.3 ± 7.5 0.08 47.4 ± 8.8 50.4 ± 10.1 0.24 47.1 ± 8.9 49.2 ± 8.9 0.13
MCDI (comorbidities)
4.7 ± 2.2 5.1 ± 1.6 0.18 4.6 ± 2.2 5.7 ± 1.9 0.03 4.5 ± 2.2 5.4 ± 2.3 0.01
TSK (kinesiophobia) 25.6 ± 4.7 25.7 ± 4.8 0.97 25.6 ± 4.8 26.5 ± 2.7 0.50 25.5 ± 5.0 26.0 ± 3.3 0.91
ABI (Ankle-Brachial
Index)
(min of right/left)
1.1 ± 0.2 1.0 ± 0.1 0.15 1.1 ± 0.2 1.0 ± 0.2 0.42 1.1 ± 0.2 1.1 ± 0.2 0.76
Vibration
(max of
right/left)
33.0 ± 14.7 27.5 ± 16.1 0.15 32.9 ± 14.7 33.2 ± 15.7 0.90 33.0 ± 14.6 32.6 ± 15.1 0.81
Single Leg
Standing(seconds)
13.0 ± 16.3 16.2 ± 21.3 0.72 13.5 ± 16.7 6.4 ± 7.6 0.13 13.4 ± 16.4 11.5 ± 16.0 0.27
Gait Speed (meters/second)
0.9 ± 0.2 0.9 ± 0.2 0.29 0.9 ± 0.2 0.9 ± 0.2 0.17 0.9 ± 0.2 0.9 ± 0.2 0.86
Oswestry
Disability Index
38.3 ± 12.7 38.7 ± 14.1 0.89 38.2 ± 12.7 39.5 ± 13.5 0.43 37.9 ± 12.9 39.6 ± 12.1 0.49
Falls Score 0.7 ± 1.2 0.8 ± 1.7 0.75 0.7 ± 1.2 0.9 ± 0.8 0.11 0.7 ± 1.3 0.7 ± 0.8 0.28
ABC Score (activities, balance, confidence)
69.4 ± 21.2 62.6 ± 22.9 0.22 69.4 ± 21.2 68.4 ± 22.5 0.94 69.4 ± 21.0 69.1 ± 22.3 0.96
34
Started Tx
(n=240)
Withdrew
– no tx
(n=19)
Completed
2mo FU
(n=225)
Missing 2mo
FU
(n=15)
Completed
6mo FU
(n=191)
Missing 6mo
FU
(n=49)
Continuous
Measure
Mean ± SD Mean ± SD p-
value
Mean ± SD Mean ± SD p-value Mean ± SD Mean ± SD p-value
RAND_GH 59.8 ± 18.2 56.7 ± 16.4 0.50 60.7 ± 17.8 46.0 ± 19.0 0.00 61.0 ± 18.1 54.7 ± 17.7 0.04
RAND_P 38.3 ± 21.3 33.9 ± 27.7 0.37 38.6 ± 21.4 33.5 ± 19.2 0.27 39.1 ± 20.9 35.1 ± 22.4 0.34
RAND_SF 47.8 ± 10.2 45.1 ± 15.5 0.83 47.8 ± 10.1 47.5 ± 11.8 0.88 48.4 ± 9.9 45.4 ± 11.0 0.10
RAND_EW 76.7 ± 16.3 71.1 ± 17.8 0.19 77.2 ± 15.8 68.0 ± 21.0 0.07 77.8 ± 15.7 72.3 ± 17.7 0.04
RAND_EF 50.5 ± 18.8 40.8 ± 20.2 0.05 51.3 ± 18.6 37.7 ± 18.1 0.01 51.4 ± 18.9 46.7 ± 18.0 0.15
RAND_PF 45.9 ± 20.3 43.9 ± 22.4 0.85 46.5 ± 20.2 37.7 ± 20.5 0.09 46.5 ± 20.1 43.6 ± 21.0 0.41
RAND_RLE 40.8 ± 43.4 40.7 ± 46.5 0.99 40.1 ± 43.6 51.1 ± 41.5 0.37 38.6 ± 43.3 49.7 ± 43.1 0.08
RAND_RLP 74.0 ± 35.1 70.8 ± 34.6 0.53 73.4 ± 35.2 81.7 ± 34.7 0.31 73.6 ± 35.7 75.5 ± 33.3 0.97
SPWT_Total Time (mins)
7.6 ± 6.9 7.3 ± 6.9 0.88 7.7 ± 6.9 5.9 ± 7.0 0.14 7.7 ± 6.8 7.2 ± 7.4 0.19
SPWT_Total
Distance (meters)
457.8 ± 482.1 423.3 ±
463.3
0.67 465.4 ± 483.2 343.8 ± 465.7 0.12 464.9 ± 480.0 430.2 ± 494.3 0.29
SSS_Total 31.4 ± 5.9 33.2 ± 6.5 0.24 31.3 ± 5.9 33.1 ± 6.4 0.27 31.2 ± 5.9 32.3 ± 5.9 0.16
SSS_Symptom_
Severity
20.2 ± 4.3 21.3 ± 4.0 0.33 20.2 ± 4.4 21.0 ± 4.1 0.45 20.0 ± 4.4 21.0 ± 4.0 0.14
SSS_Physical_
Function
11.2 ± 2.5 11.9 ± 3.0 0.21 11.1 ± 2.4 12.1 ± 2.8 0.22 11.1 ± 2.4 11.3 ± 2.8 0.66
35
Started Tx
(n=240)
Withdrew
– no tx
(n=19)
Completed
2mo FU
(n=225)
Missing 2mo
FU
(n=15)
Completed
6mo FU
(n=191)
Missing 6mo
FU
(n=49)
Continuous
Measure
Mean ± SD Mean ± SD p-
value
Mean ± SD Mean ± SD p-value Mean ± SD Mean ± SD p-value
Physical Activity (mins/day)
(Sedentary ≤1.5
METs)
1096.2 ± 145.0 1076.6 ±
220.8
0.79 1094.0 ±
146.7
1133.9 ±
111.0
0.45 1097.1 ± 143.7 1092.7 ±
151.5
0.90
Physical Activity (mins/day)
(Light, Moderate
>1.5 METs)
169.5 ± 130.3 115.7 ±
101.4
0.13 173.1 ± 131.0 110.0 ± 106.1 0.06 175.4 ± 130.1 145.9 ± 130.1 0.10
Leg Pain Intensity 5.1 ± 3.0 5.1 ± 3.1 0.88 5.1 ± 3.0 4.9 ± 3.9 0.96 4.9 ± 3.0 5.5 ± 3.2 0.21
Back Pain
Intensity
6.5 ± 2.6 6.3 ± 2.3 0.47 6.5 ± 2.6 7.1 ±
3.0
0.22 6.3 ± 2.6 7.3 ± 2.4 0.01
35
Table 1. Baseline demographic and clinical characteristics, by study total and each treatment group. For
categorical variables, “F” indicates P value from Fisher exact test and no “F” indicates P value from chi-square
test. For continuous variable P values from Wilcoxon rank sum test. For continuous variables, P values from
Kruskal-Wallis test.
Total
(N = 259)
Medical
Care
(n = 88)
Group
Exercise
(n = 84)
Manual
Therapy
(N = 87)
Categorical Measure Category N (%) n (%) n (%) n (%) P Value
Sex Male 122 (47.1%) 42 (47.7%) 45 (53.6%) 35 (40.2%) 0.22
Race White 201 (77.6%) 68 (77.3%) 66 (78.6%) 67 (77.0%) 1.00F
Black 56 (21.6%) 19 (21.6%) 18 (21.4%) 19 (21.8%)
Other 2 (0.8%) 1 (1.1%) 0 (0.0%) 1 (1.1%)
Hispanic Yes 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 1.00F
Married Yes 125 (48.3%) 40 (45.5%) 43 (51.2%) 42 (48.3%) 0.75
Education LE eighth grade or >
eighth grade but not HS
grad
10 (3.9%) 1 (1.1%) 4 (4.8%) 5 (5.7%) 0.46F
HS grad to some college 112 (43.2%) 37 (42.0%) 35 (41.7%) 40 (46.0%)
College grad or higher 137 (52.9%) 50 (56.8%) 45 (53.6%) 42 (48.3%)
Household income $20K or less 52 (20.1%) 15 (17.0%) 15 (17.9%) 22 (25.3%) 0.69
$20 001-$40 000 81 (31.3%) 29 (33.0%) 27 (32.1%) 25 (28.7%)
$40 000 or more 126 (48.6%) 44 (50.0%) 42 (50.0%) 40 (46.0%)
Current smoker Yes 15 (5.8%) 7 (8.0%) 2 (2.4%) 6 (6.9%) 0.25
Hip OA Yes 43 (16.6%) 14 (15.9%) 14 (16.7%) 15 (17.2%) 0.97
Knee OA Yes 82 (31.7%) 32 (36.4%) 21 (25.0%) 29 (33.3%) 0.26
Qualitative description
of leg pain Pain 121(46.7%) 44(50.0%) 36(42.9%) 41(47.1%) 0.64
Neurologic
(numbness,
heaviness, tingling,
weakness)
138(53.3%) 44(50.0%) 48(57.1%) 46(52.9%)
Predominant pain Legs 46(17.8%) 15(17.1%) 16(19.1%) 15(17.2%) 0.97
Low back 155(59.9%) 55(62.5%) 49(58.3%) 51(58.6%)
Equal 58(23.4%) 18(20.5%) 19(22.6%) 21(24.1%)
Leg pain intensity Mean ± SD 5.06 ± 3.02 5.16 ± 3.36 5.14 ± 2.76 4.87 ± 2.92 0.66
Back pain intensity Mean ± SD 6.52 ± 2.57 6.80 ± 2.59 6.23 ± 2.41 6.53 ± 2.69 0.17
36
Table 1 (cont’d)
Total (N = 259)
Medical
Care
(n = 88)
Group
Exercise
(n = 84)
Manual
Therapy
(N = 87)
Continuous Measure Mean ± SD Mean ± SD Mean ± SD Mean ± SD P Value
Age 72.4 ± 7.8 72.0 ± 7.4 72.9 ± 8.1 72.1 ± 8.1 0.78
BMI 31.0 ± 6.6 31.2 ± 6.3 30.8 ± 6.5 31.2 ± 7.1 0.56
Treatment expectancy_A 35.1 ± 11.9 35.5 ± 11.5 36.5 ± 11.7 33.3 ± 12.5 0.23
Treatment expectancy_B 42.5 ± 9.0 42.5 ± 8.8 42.2 ± 9.4 42.9 ± 8.8 0.92
Treatment expectancy_C 39.1 ± 10.6 39.7 ± 10.9 39.5 ± 10.2 38.2 ± 10.7 0.47
Depression T score 47.8 ± 8.9 48.3 ± 8.2 48.3 ± 9.1 46.8 ± 9.3 0.31
MCDI (comorbidities) 4.7 ± 2.2 4.9 ± 2.2 4.4 ± 2.2 4.7 ± 2.1 0.29
TSK (kinesiophobia) 25.6 ± 4.7 26.1 ± 4.4 25.3 ± 4.9 25.5 ± 4.9 0.53
ABI (Ankle-Brachial Index)
(min of right/left) 1.0 ± 0.2 1.1 ± 0.2 1.0 ± 0.1 1.0 ± 0.2 0.36
Vibration
(max of right/left) 32.6 ± 14.8 32.0 ± 15.2 31.9 ± 14.5 33.8 ± 14.9 0.53
Single leg standing (seconds) 13.2 ± 16.7 11.9 ± 16.6 13.6 ± 17.0 14.3 ± 16.7 0.21
Gait speed (meters/second) 0.9 ± 0.2 0.9 ± 0.2 1.0 ± 0.2 0.9 ± 0.2 0.59
Oswestry Disability Index 38.3 ± 12.8 38.1 ± 11.9 38.7 ± 13.5 38.1 ± 13.2 0.94
Falls score 0.7 ± 1.2 0.7 ± 1.1 0.6 ± 0.9 0.9 ± 1.5 0.73
ABC score
(activities, balance, confidence) 68.9 ± 21.4 67.6 ± 22.5 69.1 ± 21.1 70.1 ± 20.5 0.85
RAND_GH 59.5 ± 18.1 60.8 ± 17.2 57.4 ± 17.6 60.3 ± 19.3 0.44
RAND_P 38.0 ± 21.7 40.3 ± 20.5 36.7 ± 19.7 36.8 ± 24.7 0.40
RAND_SF 47.6 ± 10.6 46.4 ± 10.5 47.3 ± 11.9 49.0 ± 9.4 0.14
RAND_EW 76.3 ± 16.4 75.8 ± 17.4 75.7 ± 15.1 77.3 ± 16.7 0.56
RAND_EF 49.8 ± 19.0 50.2 ± 18.1 49.4 ± 18.5 49.7 ± 20.6 0.99
RAND_PF 45.8 ± 20.4 44.8 ± 20.6 45.1 ± 19.9 47.5 ± 20.8 0.63
RAND_RLE 40.8 ± 43.6 42.4 ± 43.7 42.6 ± 45.5 37.5 ± 41.9 0.72
RAND_RLP 73.7 ± 35.0 75.9 ± 36.0 72.0 ± 33.7 73.3 ± 35.5 0.49
SPWT total time (mins) 7.6 ± 6.9 8.1 ± 7.7 7.1 ± 6.1 7.5 ± 6.9 0.99
37
Total (N = 259)
Medical
Care
(n = 88)
Group
Exercise
(n = 84)
Manual
Therapy
(N = 87)
Continuous Measure Mean ± SD Mean ± SD Mean ± SD Mean ± SD P Value
SPWT total distance (meters) 455.3 ± 480.0 482.2 ± 529.1 433.4 ± 421.2 449.2 ± 485.2 0.91
SSS total 31.5 ± 6.0 31.4 ± 5.8 31.6 ± 6.0 31.7 ± 6.1 0.91
SSS Symptom Severity 20.3 ± 4.3 20.1 ± 4.4 20.4 ± 4.2 20.5 ± 4.4 0.80
SSS Physical Function 11.2 ± 2.5 11.3 ± 2.5 11.2 ± 2.6 11.2 ± 2.5 0.87
Physical activity (mins/day)
(sedentary = ≤ 1.5 METs) 1095.3 ± 150.3 1087.9 ± 152.8 1097.4 ± 159.7 1100.5 ± 138.3 0.81
Physical activity (mins/day)
(light, moderate = > 1.5 METs) 165.5 ± 129.7 167.4 ± 130.1 157.0 ± 125.5 172.0 ± 133.4 0.80
38
Results of Primary Analyses of Primary and Secondary Aims (Linear Mixed Models)
Table 2 provides the results from the primary analyses of all outcome measures related to the
primary and secondary aims. The results are organized into 3 sections within the table: (1)
group means at each time point; (2) unadjusted within-group changes from baseline; and (3)
adjusted between-group differences from baseline. The models for the between-group analyses
were adjusted for the baseline randomization variables used to balance the groups; these
included baseline SSS, SPWT, and age.
At 2 months, there was a statistical significantly greater reduction in adjusted mean SSS score
(range = 12-55) in the manual therapy and individualized exercises (MTE) group compared with
the medical care (MC) group (2.1; 95% CI, 0.3-3.9) and the group exercise classes (GE) group
(2.4; 95% CI, 0.6-4.3). The MCID for the SSS is 3.02 points; therefore, the adjusted between-
group SSS differences were not clinically significant. There was also improvement in the
adjusted mean SPWT score at 2 months in the MTE group compared with MC (135.1; 95% CI, –
17.2-287.4) and GE (46.2; 95% CI, –110.9-203.4), but these adjusted between-group SPWT
differences were not statistically significant. GE showed a statistically significantly greater
improvement in adjusted mean physical activity at 2 months compared with MC (30.5; 95% CI,
3.1-57.9), but clinical significance is unknown due to the lack an established MCID for physical
activity. The linear mixed models did not reveal any significant adjusted between-group
changes in any of the outcome measures at 6 months.
Results of Secondary Analyses of Primary and Secondary Aims (Responder Analyses) Table 3a
presents the results of the omnibus test of 3-way comparisons of proportions of responders in
each treatment arm at 2 months and 6 months. We performed 3 sets of responder analyses, 1
related to each of the primary and secondary outcome measures (SSS, SPWT, and physical
activity [PA]).
39
Table 2. Primary and secondary outcome measures: unadjusted within-group changes from baseline (outcome to baseline) and adjusted* between-group differences in improvement from baseline.
Outcome, Mean ± SD Baseline 2 Months 6 Months
SSS: Total Score (range = 12-55)
Medical care 31.3 ± 5.8
(n = 84)
29.1 ± 6.9
(n = 79)
29.3 ± 6.8
(n = 67)
Group exercise 31.6 ± 6.0
(n = 72)
29.8 ± 5.7
(n = 67)
29.4 ± 6.7
(n = 59)
Manual therapy 31.6 ± 6.1
(n = 84)
27.2 ± 2.9
(n = 80)
28.4 ± 6.7
(n = 65)
SPWT: Total Distance Walked (meters)
Medical care 482.2 ± 529.1 616.6 ± 620.8 683.3 ± 723.3
Group exercise 433.4 ± 421.2 651.5 ± 639.7 688.3 ± 680.3
Manual therapy 449.2 ± 485.2 698.6 ± 662.7 723.5 ± 781.5
SW: Minutes per Day in Light/Moderate Activity (> 1.5 METs)
Medical care 167.4 ± 130.1 148.0 ± 116.8 159.1 ± 128.3
Group exercise 157.0 ± 125.5 170.1 ± 142.5 155.3 ± 113.1
Manual therapy 172.0 ± 133.4 176.1 ± 135.1 161.9 ± 129.7
Unadjusted Within-group Differences, Outcome to Baseline; Mean ± SD
SSS: Total Score 2 Months 6 Months
Medical care –2.0 ± 5.5 –1.5 ± 5.7
Group exercise –1.7 ± 5.2 –2.2 ± 7.1
Manual therapy –4.1 ± 5.9 –2.6 ± 6.1
SPWT: Total Distance Walked (meters)
Medical care 130.5 ± 478.7 165.4 ± 634.7
Group exercise 219.2 ± 413.0 278.7 ± 512.8
Manual therapy 267.8 ± 507.8 256.6 ± 642.0
SW: Minutes per Day in Light/Moderate Activity (> 1.5 METs)
Medical care –23.1 ± 85.3 –24.5 ± 85.5
Group exercise 4.3 ± 64.8 0.4 ± 75.9
Manual therapy –6.0 ± 76.0 –30.4 ± 85.6
40
Outcome, Mean ± SD Baseline 2 Months 6 Months
Adjusted* Between-group Differences, Outcome to Baseline; Mean (95% CI)
SSS: Total
Group exercise – medical care 0.3 (–1.5, 2.2) –0.6 (–2.5, 1.4)
Manual therapy – medical care –2.1 (–3.9, –0.3) ^
^P = 0.02
–1.2 (–3.1, 0.7)
Group exercise – manual therapy 2.4 (0.6, 4.3) ^
^P = 0.01
0.6 (–1.4, 2.6)
SPWT: Total Distance Walked (meters)
Group exercise – medical care 87.0 (–75.2, 249.2) 91.5 (–77.9, 260.8)
Manual therapy – medical care 129.7 (–27.2, 286.6) 81.0 (–84.3, 246.2)
Group exercise – manual therapy –42.7 (–205.4, 120.0) 10.5 (–159.4, 180.5)
SW: Minutes per Day in Light/Moderate Activity (> 1.5 METs)
Group exercise – medical care 30.5 (3.1, 57.9) ^
^P = 0.03
23.1 (–6.4, 52.5)
Manual therapy – medical care 18.7 (–7.6, 45.0) –4.6 (–33.1, 23.8)
Group exercise – manual therapy 11.8 (–15.6, 39.1) 27.7 (–1.9, 57.3)
Notes: SPWT = Self-Paced Walking Test; SSS = Swiss Spinal Stenosis score; SW = SenseWear . *Models were adjusted for baseline randomization variables (SSS, SPWT, age). ^ P < 0.05
41
Table 3a. Responder Analysis: 3-way Comparisons of Responders in Each Group After Dichotomizing Within-person
Change in Outcomes (Omnibus Chi-square Test)
Medical Care Group Exercise Manual Therapy P Value
Baseline to 2 Months N (%) N (%) N (%)
≥ 30% reduction in SSS total score 6 (7.6%)
[n = 79]
2 (3.0%)
[n = 66]
16 (20.0%)
[n = 80]
0.002
≥ 30% increase in SPWT total distance walked 37 (48.7%)
[n = 76]
30 (46.2%)
[n = 65]
49 (65.3%)
[n = 75]
0.04
≥ 30% increase in average number of minutes
per day in activity > 1.5 METs
16 (21.3%)
[n = 75]
18 (29.0%)
[n = 62]
21 (28.4%)
[n = 74]
0.51
Baseline to 6 Months
≥ 30% reduction in SSS total score 7 (10.5%)
[n = 67]
7 (11.9%)
[n = 59]
10 (15.4%)
[n = 65]
0.68
≥ 30% increase in SPWT total distance walked 30 (45.5%)
[n = 66]
30 (50.8%)
[n = 59]
32 (49.2%)
[n = 65]
0.82
≥ 30% increase in average number of minutes
per day in activity > 1.5 METs
12 (19.7%)
[n = 61]
14 (27.5%)
[n = 51]
13 (22.0%)
[n = 59]
0.61
Table 3b. 2-way Comparisons of Manual Therapy and Medical Care, Baseline to 2 Months
Medical Care Manual Therapy P Value
≥ 30% reduction in SSS total score 6 (7.6%) 16 (20.0%) 0.02
≥ 30% increase in SPWT total distance walked 37 (48.7%) 49 (65.3%) 0.04
≥ 30% increase in physical activity (> 1.5 METs) 16 (21.3%) 21 (28.4%) 0.32
Table 3c. 2-way Comparisons of Manual Therapy and Group Exercise, Baseline to 2 Months
Group Exercise Manual Therapy P Value
≥ 30% reduction in SSS total score 2 (3.0%) 16 (20.0%) 0.002
≥ 30% increase in SPWT total distance walked 30 (46.2%) 49 (65.3%) 0.02
≥ 30% increase in physical activity (> 1.5 METs) 18 (29.0%) 21 (28.4%) 0.93
42
Table 3d. 2-way Comparisons of Medical Care and Group Exercise, Baseline to 2 Months
Medical Care Group Exercise P Value
≥ 30% reduction in SSS total score 6 (7.6%) 2 (3.0%) 0.23
≥ 30% increase in SPWT total distance walked 37 (48.7%) 30 (46.2%) 0.76
≥ 30% increase in physical activity (> 1.5 METs) 16 (21.3%) 18 (29.0%) 0.30
Table 3e. 2-way Comparisons of Manual Therapy and Medical Care, Baseline to 6 Months
Medical Care Manual Therapy P Value
≥ 30% reduction in SSS total score 7 (10.5%) 10 (15.4%) 0.40
≥ 30% increase in SPWT total distance walked 30 (45.5%) 32 (49.2%) 0.67
≥ 30% increase in physical activity (> 1.5 METs) 12 (19.7%) 13 (22.0%) 0.75
Table 3f. 2-way Comparisons of Manual Therapy and Group Exercise, Baseline to 6 Months
Group Exercise Manual Therapy P Value
≥ 30% reduction in SSS total score 7 (11.9%) 10 (15.4%) 0.57
≥ 30% increase in SPWT total distance walked 30 (50.8%) 32 (49.2%) 0.86
≥ 30% increase in physical activity (> 1.5 METs) 14 (27.5%) 13 (22.0%) 0.51
Table 3g. 2-way Comparisons of Medical Care and Group Exercise, Baseline to 6 Months
Medical Care Group Exercise P Value
≥ 30% reduction in SSS total score 7 (10.5%) 7 (11.9%) 0.80
≥ 30% increase in SPWT total distance walked 30 (45.5%) 30 (50.8%) 0.55
≥ 30% increase in physical activity (> 1.5 METs) 12 (19.7%) 14 (27.5%) 0.33
43
We defined a responder as any participant who showed at least a 30% improvement in his or
her outcome measure from baseline to time point of analysis (2 months or 6 months). There
was a significant between-group difference at 2 months for SSS (P = 0.002) and SPWT (P = 0.04),
but not for physical activity (P = 0.51). We found no significant between-group differences at 6
months for any of the 3 outcomes.
We also performed additional analyses of all 2-way comparisons between groups. Tables 3 b-d
present the between-group comparisons at 2 months, and Tables 3 e-g show the results at 6
months. At 2 months, there was a significantly greater proportion of SSS responders in the
manual therapy arm (20.0%) compared with the group exercise (3.0%) and medical care (7.6%)
arms. There was also a significantly greater proportion of SPWT responders at 2 months in the
manual therapy arm (65.3%) compared with the group exercise (46.2%) and medical care
(48.7%) arms. However, these between-group differences in SSS and SPWT outcomes were no
longer significant at 6 months. There were no significant between-group differences in the
proportions of physical activity responders at either 2 months or 6 months. The proportions of
responders by group are also depicted visually with bar graphs in Figure 2 (2 months) and
Figure 3 (6 months).
Results of Analyses for Exploratory Aim 1
Table 4 lists the rates of anticipated unpleasant side effects and serious adverse events
reported by our participants at the 2-month follow-up evaluation. We defined anticipated
unpleasant side effect as any postintervention symptom that was minor and transient in nature
(≤ 2 days duration). There was a significantly greater (P < 0.001) proportion of musculoskeletal
side effects (transient muscle and joint soreness) reported by the participants in the group
exercise and manual therapy arms. Participants in the medical care arm reported a significantly
greater proportion of transient nonmusculoskeletal side effects. Fortunately, there were no
serious adverse events to report from any participant in any of the 3 treatment arms of this
trial.
44
Table 5 provides a tabulation of the number of falls reported by participants at baseline and at
the 6-month follow-up. We found no significant between-group differences in the number of
falls reported at either time point. Table 6 summarizes the adherence and attrition rates for
each treatment arm at 3 different time points. Although group sizes were balanced at baseline,
a significantly greater proportion of subjects dropped out of the group exercise arm after
randomization and never attended any group exercise class. There were no significant
between- group differences in adherence rates for those participants who attended at least 1
intervention session. The adherence rates were above 90% for each of the 3 intervention
groups. There were no significant between-group differences in attrition rates for the 2- or 6-
month follow-up evaluations.
45
Figure 2. Responder analysis of main outcomes: bar graph of the proportions of responders by group.
Responders are defined as patients who had at least a 30% improvement in their outcome measure at 2 months as compared with baseline. Significant between-group differences (P < 0.05).
Figure 3. Responder analysis of main outcomes: bar graph of the proportions of responders by group. Responders
are defined as patients who had at least a 30% improvement in their outcome measure at 6 months as compared
with baseline. No significant between-group differences.
90
80
70
60
50
40
30
20
10
65.3
28.4
7.6 3.0
SSS Total SPWT Total Distance
Responders at 2 MONTHS (≥30% improvement from baseline)
Sensewear
Medical Care Group Exercise Manual Therapy
Per
cen
t o
f R
esp
on
de
rs
46
Table 4. Reported adverse events and anticipated unpleasant side effects, study total and by treatment group at 2
months (2 weeks after end of intervention). Categories are not mutually exclusive or hierarchical because
participants could report more than 1 side effect. No serious adverse events were reported by any participant in
any of the 3 intervention arms.
Anticipated Side Effects
and
Adverse Events
Total
N =
226
Medical
Care
n = 79
Group
Exercise
n = 67
Manual
Therapy
n = 80
P Value
Muscle soreness 71 (29.6%) 5 (6.0%) 22 (31.9%) 44 (54.3%) 0.001
Joint soreness 52 (21.7%) 1 (1.2%) 11 (15.9%) 40 (49.3%) 0.001
Gastrointestinal 6 (7.2%) 6 (7.2%) 0 0 0.004
Drowsiness 5 (6.0%) 5 (6.0%) 0 0 0.01
Dry mouth 4 (4.8%) 4 (4.8%) 0 0 0.04
Headache 3 (3.6%) 3 (3.6%) 0 0 0.11
Fluid retention 3 (3.6%) 3 (3.6%) 0 0 0.11
Dizziness 4 (1.7%) 2 (2.4%) 1 (1.4%) 1 (1.2%) 1.00
Joint swelling 2 (2.5%) 0 0 2 (2.5%) 0.33
Insomnia 2 (2.4%) 2 (2.4%) 0 0 0.33
Off balance feeling 1 (1.4%) 0 1 (1.4%) 0 0.30
Anxiety 1 (1.2%) 1 (1.2%) 0 0 1.00
Increased BP 1 (1.2%) 1 (1.2%) 0 0 1.00
Mood swings 1 (1.2%) 1 (1.2%) 0 0 1.00
Weight gain 1 (1.2%) 1 (1.2%) 0 0 1.00
Falling 1 (1.2%) 1 (1.2%) 0 0 1.00
Serious adverse events
(study related and requiring outside
medical treatment)
0
0
0
0
1.00
47
Table 5. Number of Falls Reported at Baseline and at 6-month Follow-up Evaluation
All
Subjects Medical
Care Group
Exercise Manual Therapy
Number of participants at baseline N = 259 n = 88 n = 84 n = 87 P Value
Number of Falls (during 1 year prior to baseline)
n (%)
n (%)
N (%)
n (%)
0 150 (57.9%) 52 (59.1%) 49 (58.3%) 49 (56.3%) 0.93 1 73 (28.2%) 24 (27.3%) 27 (32.1%) 22 (25.3%) 0.77
2 20 (7.8%) 8 (9.1%) 4 (4.8%) 8 (9.2%) 0.41
≥ 3 16 (6.2%) 4 (4.5%) 4 (4.8%) 8 (9.2%) 0.36
Number of participants at 6 months N = 191 n = 67 n = 59 n = 65 P Value
Number of Falls (between end-of-care and 6 months)
n (%)
n (%)
n (%)
n (%)
0 107 (56.0%) 35 (52.2%) 38 (64.4%) 34 (52.3%) 0.30
1 53 (27.7%) 17 (25.4%) 15 (25.4%) 21 (32.3%) 0.60
2 17 (8.9%) 10 (14.9%) 3 (5.1%) 4 (6.2%) 0.10
≥ 3 13 (6.8%) 4 (6.0%) 3 (5.1%) 6 (9.2%) 0.62
Table 6. Attrition (drop-out) and treatment adherence rates by group at 2- and 6-month follow-up evaluations.
Treatment adherence was defined as attending ≥75% of treatment or exercise sessions.
All
Subjects Medical
Care Group
Exercise Manual Therapy
Number of participants randomized at baseline
N = 259
n = 88
n = 84
n = 87
P Value
Attrition after randomization (received no intervention)
19 (7.3 %)
4 (4.5%)
12 (14.3%)
3 (3.4%)
0.02
Attrition at 2 months (primary end point for analysis)
33 (12.7%)
9 (10.2%)
17 (20.2%)
7 (8.0%)
0.09
Attrition at 6 months 68 (26.3%) 21 (23.9%) 25 (29.8%) 22 (25.2%) 0.79
Adherence to 6-week intervention (subjects who did not drop out after
randomization)
230 (95.8%)
84 (98.8%)
68 (94.4%)
78 (92.9%)
0.76
Table 7 provides a tabulation of the various cointerventions reported by participants who
completed 6 weeks of each treatment at the 6-month follow-up evaluation. A significantly
48
lower proportion of group exercise participants (49%) were exercising at home as compared
with those in either the medical care (72%) or manual therapy (77%) arms. However, a
significantly greater proportion of group exercise (48%) participants were engaged in
community-based exercises, compared with 18% and 23% of those in the medical care or
manual therapy arms, respectively.
Results of Analyses for Exploratory Aim 2 (Heterogeneity of Treatment Effect)
Our second exploratory aim explored potential baseline associations and predictors of
treatment response for SSS and SPWT in each of the 3 treatment groups (heterogeneity of
treatment effect). We used both simple univariate tests of association (chi-square) and
multivariable logistic regression for predictors of treatment effect. The results of the
unadjusted univariate analysis of baseline characteristics and responder status are displayed in
Table 8. We found significant differences between mean SSS and SPWT scores for the
responders and nonresponders with respect to their association with age and falls score.
The results of the multivariable logistic regression models of responders and nonresponders at
2 months are displayed in Tables 9a and 9b. The MTE group showed a higher rate of SSS
response (20%) compared with either the GE group (3%) or the MC group (7.6%). Using the MC
group as the reference group, the MTE group had greater odds of being SSS responders (OR 3.5;
95% CI, 1.2-9.6), and the GE arm had lower odds of being responders (OR 0.4; 95% CI, 0.08-2.1).
The MTE group also showed a higher rate of SPWT response (65.3%) compared with either the
GE group (46.2%) or the MC group (48.7%). The MTE group had greater odds of being SPWT
responders (OR 2.1; 95% CI, 1.1-4.0) when compared with the MC reference group. The GE
group had about the same odds (OR 0.95; 95% CI, 0.5-1.9) of being SPWT responders as the MC
reference group. We also found a significant association between age and responder status;
younger patients were more likely to be SSS and SPWT responders regardless of group
assignment. Falls score was associated only with SSS responder status, with responders more
likely to report fewer falls at 6 months.
49
Table 7. Cointerventions reported by participants from end-of-care to 6-month follow-up. Note that these data
are derived only from those participants who attended the 6-month follow-up visit.
Cointerventions
(between end-of-care and 6 months)
Total
N = 191
Medical
Care
n = 67
Group
Exercise
N = 59
Manual
Therapy
n = 65
P Value
Exercising at home 127 (66.5) 48 (71.6%) 29 (49.2%) 50 (77.0%) 0.003
Exercising in community setting 55 (28.8%) 12 (17.9%) 28 (47.5%) 15 (23.1%) 0.001
Physical therapy 22 (11.5%) 6 (9.0%) 10 (16.9%) 6 (9.2%) 0.29
Chiropractic 21 (11.0%) 12 (17.9%) 5 (8.5%) 4 (6.2%) 0.07
Added use of assistive device 21 (11.0%) 6 (9.0%) 5 (8.5%) 10 (15.4%) 0.38
Spinal injections 19 (9.9%) 5 (7.5%) 7 (11.9%) 7 (10.8%) 0.69
Added/increased pain meds 19 (9.9%) 6 (9.0%) 7 (11.9%) 6 (9.2%) 0.84
Spine surgery 4 (2.1%) 2 (3.0%) 1 (1.7%) 1 (1.5%) 1.00
Stopped/decreased pain meds 3 (1.6%) 2 (3.0%) 0 (0.0%) 1 (1.5%) 0.78
50
Table 8. Univariate analyses of baseline characteristics and responder status, for the SPWT and SSS outcome
measures. SPWT = Self-paced Walking Test; SSS = Swiss Spinal Stenosis symptom severity score.
SPWT Total Di
N = 216
stanc e SSS Total
N = 225
Responder
(n = 116)
Nonrespo
nder (n =
100)
Responder
(n = 24)
Nonrespo
nder (n =
201)
Characteristic
(categorical measures) n (%) n (%) P Value n (%) n (%) P Value
Sex, no. of female 59 (50.9%) 57 (57.0%) 0.37 15 (62.5%) 103 (51.2%) 0.30
Race, no. African American 31 (26.7%) 19 (19.0%) 0.18 8 (33.3%) 43 (21.4%) 0.19
Marital Status, no. of married 64 (55.2%) 48 (48.0%) 0.29 15 (62.5%) 101 (50.3%) 0.26
Education, no. of college grad or higher 61 (52.6%) 46 (46.0%) 0.33 16 (66.7%) 99 (49.3%) 0.11
Household Income, no. making $40 000 or more
57 (50.4%) 45 (45.0%) 0.43 12 (50.0%) 94 (47.5%) 0.82
Diagnosis of hip OA, no. with yes 20 (17.2%) 15 (15.0%) 0.66 3 (12.5%) 32 (15.9%) 0.66
Diagnosis of knee OA, no. with yes 38 (32.8%) 30 (30.0%) 0.66 9 (31.0%) 62 (31.6%) 0.95
Characteristic
(continuous measures) Mean ± SD Mean ± SD P Value Mean ± SD Mean ± SD P Value
Age, years 71.3 ± 7.7 73.7 ± 7.3 0.02 69.2 ± 6.9 72.7 ± 7.6 0.03
BMI, kg/m2 30.5 ± 6.6 30.9 ± 5.8 0.66 32.5 ± 6.7 30.5 ± 6.2 0.15
Depression T score 47.5 ± 9.2 47.1 ± 8.5 0.71 47.4 ± 10.5 47.4 ± 8.6 1.00
Comorbidities 4.5 ± 2.2 4.7 ± 2.2 0.44 5.00 ± 2.7 4.5 ± 2.2 0.34
Kinesiophobia (TSK) 25.2 ± 4.6 25.9 ± 5.1 0.25 25.2 ± 5.2 25.6 ± 4.8 0.66
Ankle Brachial Index 1.0 ± 0.1 1.1 ± 0.2 0.69 1.0 ± 0.1 1.05 ± 0.2 0.76
Vibration 31.7 ± 15.1 34.2 ± 14.2 0.22 30.8 ± 16.0 33.2 ± 14.5 0.44
Single leg standing 13.6 ± 16.3 12.9 ± 17.0 0.75 17.0 ± 18.2 13.0 ± 16.5 0.27
SPPB gait speed 1.1 ± 0.3 1.2 ± 0.4 0.17 1.0 ± 0.2 0.9 ± 0.2 0.68
Fall score 0.8 ± 1.4 0.5 ± 0.8 0.04 0.3 ± 0.6 0.8 ± 1.2 0.002
Balance score (ABC) 70.3 ± 21.3 67.5 ± 21.4 0.34 76.3 ± 20.7 68.6 ± 21.2 0.09
Tables 9a and 9b. Multivariable logistic regression models (using backward stepwise elimination) of
study participants who responded and who did not respond to intervention based on the SSS and SPWT
at 2 months. SSS Swiss Spinal Stenosis; SPWT = Self-Paced Walking Test. Medical care is the reference
group.
Table 9a. SSS: Primary outcome measure (N=225 participants) at 2 months.
Parameter Odds Ratio 95% Confidence Limits p-value
Intercept -- -- -- 0.11
Treatment Type
Group Exercise 0.41 0.08 2.14 0.049
Manual Therapy 3.45 1.24 9.64 0.001
Age 0.92 0.86 0.98 0.016
Falls score 0.46 0.22 0.95 0.037
Table 9b. SPWT: Secondary outcome measure (N=216 participants) at 2 months.
Parameter Odds Ratio 95% Confidence Limits p-value
Intercept -- -- -- 0.02
Treatment type
Group Exercise 0.95 0.49 1.86 0.17
Manual Therapy 2.08 1.07 4.04 0.01
Age 0.96 0.92 0.99 0.02
51
52
To assess if any baseline variables were moderating the relationship between treatment and
responders and nonresponders, we tested the interaction between treatment and each of
several variables using multiple logistic regression models, with SSS and SPWT responder status
as the outcome. We chose the variables based on their biologically plausible relevance to LSS
and the clinical experience of the investigators. Tables 10 and 11 depict the results of these
moderator analyses for the SSS and SPWT outcomes, respectively. We found no significant
moderators associated with the SSS scores; however, Table 11 shows that baseline depression
(P = .06) and the number of comorbidities (P = .06) were 2 variables that showed a trend
toward significance as potential moderators of SPWT outcome. Age, sex, race, body mass index,
fear avoidance, and knee osteoarthritis were not associated with responder status. The
treatment effect of manual therapy versus medical care appears to be stronger among patients
with depression scores above the median and comorbidity scores below it. The P value for
these interactions was 0.06; although not reaching 0.05, it suggests a potential interaction and
moderating effect. While we were not powered for these stratified analyses, these results
warrant further investigation in future studies, given their clinical plausibility of being potential
treatment moderators.
Patient Global Index of Change and Satisfaction
The results of additional exploratory analyses of the PGIC and SAT scores obtained at 2 months
and 6 months are presented in tables. Descriptive statistics of the item ratings and proportions
of responders/nonresponders for PGIC scores are presented in Tables 12a and 12b; those for
SAT scores are presented in Tables 13a and 13b. The manual therapy arm showed the highest
level of PGIC and SAT scores at both time points, followed by group exercise and medical care.
53
Table 10. Analysis of hypothesized moderators at baseline with treatment response for SSS as the dependent
variable (primary outcome measure). R = responder; NR = nonresponder; SSS = Swiss Spinal Stenosis (total score).
P value is for the interaction term, from a Wald chi-square test for interaction.
Moderator
R
(n)
NR
(n) Effect
Odds
Ratio
95% CI
Lower
95% CI
Upper P Value
Age 24 201 Group exercise versus manual therapy age < 75 0.070 0.009 0.558
0.43
Group exercise versus medical care age < 75 0.291 0.031 2.701
Manual therapy versus medical care age < 75 4.167 1.260 13.783
Group exercise versus manual therapy age ≥ 75 0.397 0.038 4.105
Group exercise versus medical care age ≥ 75 0.548 0.046 6.489
Manual therapy versus medical care age ≥ 75 1.380 0.211 9.014
Sex 24 201 Group exercise versus manual therapy male 0.160 0.018 1.449
0.83
Group exercise versus medical care male 0.333 0.033 3.362
Manual therapy versus medical care male 2.083 0.458 9.480
Group exercise versus manual therapy female 0.113 0.014 0.926
Group exercise versus medical care female 0.437 0.043 4.419
Manual therapy versus medical care female 3.870 0.998 15.013
BMI 24 201 Group exercise versus manual therapy BMI < 30 0.162 0.019 1.413
0.91 BMI = body
mass index
Group exercise versus medical care BMI < 30 0.423 0.037 4.877
Manual therapy versus medical care BMI < 30 2.605 0.492 13.796
Group exercise versus manual therapy BMI ≥ 30 0.104 0.012 0.873
Group exercise versus medical care BMI ≥ 30 0.400 0.042 3.786
Manual therapy versus medical care BMI ≥ 30 3.846 1.091 13.563
Comorbidities 24 201 Group exercise versus manual therapy MCDI < 4 0.117 0.000 0.681
0.99
MCDI = Modified Co-morbidity Disease Index
Group exercise versus medical care MCDI < 4 0.355 0.000 3.034
Manual therapy versus medical care MCDI < 4 2.706 0.386 31.596
Group exercise versus manual therapy MCDI ≥ 4 0.218 0.022 1.093
Group exercise versus medical care MCDI ≥ 4 0.687 0.059 5.078
Manual therapy versus medical care MCDI ≥ 4 3.146 0.856 14.506
54
Moderator R
(n)
NR
(n)
Effect Odds
Ratio 95% CI
Lower 95% CI
Upper P Value
Kinesiophobia 24 201 Group exercise versus manual therapy TSK < 26 0.147 0.017 1.266
0.44 TSK = Tampa Scale for Kinesiophobia
Group exercise versus medical care TSK < 26 0.234 0.025 2.217
Manual therapy versus medical care TSK < 26 1.591 0.423 5.981
Group exercise versus manual therapy TSK ≥ 26 0.108 0.013 0.901
Group exercise versus medical care TSK ≥ 26 0.672 0.058 7.737
Manual therapy versus medical care TSK ≥ 26 6.242 1.260 30.924
Race 24 201 Group exercise versus manual therapy not black 0.095 0.012 0.760
0.90
Group exercise versus medical care not black 0.280 0.030 2.589
Manual therapy versus medical care not black 2.962 0.888 9.882
Group exercise versus manual therapy black 0.171 0.018 1.678
Group exercise versus medical care black 0.607 0.050 7.415
Manual therapy versus medical care black 3.542 0.586 21.397
Knee Osteoarthritis 24 201
Group exercise versus manual therapy no knee OA 0.080 0.010 0.644 0.37
OA = osteoarthritis Group exercise versus medical care no knee OA 0.490 0.043 5.582
Manual therapy versus medical care no knee OA 6.140 1.288 29.270
Group exercise versus manual therapy knee OA 0.280 0.030 2.648
Group exercise versus medical care knee OA 0.417 0.042 4.085
Manual therapy versus medical care knee OA 1.488 0.354 6.263
Depression 24 201 Group exercise versus manual therapy T score < 48.2 0.130 0.000 0.695
0.13 T score; from PROMIS short form
Group exercise versus medical care T score < 48.2 0.156 0.000 0.896
Manual therapy versus medical care T score < 48.2 1.171 0.287 5.173
Group exercise versus manual therapy T score ≥ 48.2 0.172 0.017 0.938
Group exercise versus medical care T score ≥ 48.2 2.516 0.126 153.683
Manual therapy versus medical care T score ≥ 48.2 14.652 1.845 678.035
55
Table 11. Analysis of hypothesized moderators at baseline with treatment response for SPWT as the dependent
variable (secondary outcome measure). R = responder; NR = nonresponder; SPWT = Self-paced Walking Test.
P value is for the interaction term, from a Wald chi-square test for interaction.
Moderator R (n)
NR (n)
Effect Odds Ratio
95% CI Lower
95% CI Upper
P Value
Age 24 201 Group exercise versus manual therapy – age < 75 0.455 0.194 1.063
0.75
Group exercise versus medical care – age < 75 0.793 0.354 1.775
Manual therapy versus medical care – age < 75 1.744 0.769 3.960
Group exercise versus manual therapy – age ≥ 75 0.423 0.132 1.361
Group exercise versus medical care – age ≥ 75 1.231 0.362 4.181
Manual therapy versus medical care – age ≥ 75 2.909 0.926 9.135
Sex 24 201 Group exercise versus manual therapy – male 0.688 0.254 1.863
0.46
Group exercise versus medical care – male 1.000 0.390 2.561
Manual therapy versus medical care – male 1.455 0.537 3.941
Group exercise versus manual therapy – female 0.290 0.110 0.762
Group exercise versus medical care – female 0.740 0.282 1.942
Manual therapy versus medical care – female 2.555 1.066 6.126
BMI 24 201 Group exercise versus manual therapy – BMI < 30 0.526 0.215 1.292
0.86 BMI = body
mass index
Group exercise versus medical care – BMI < 30 0.936 0.373 2.350
Manual therapy versus medical care – BMI < 30 1.778 0.701 4.506
Group exercise versus manual therapy – BMI ≥ 30 0.357 0.124 1.033
Group exercise versus medical care – BMI ≥ 30 0.757 0.279 2.050
Manual therapy versus medical care – BMI ≥ 30 2.118 0.833 5.390
Comorbidities 24 201 Group exercise versus manual therapy – MCDI < 4 0.356 0.093 1.359
0.060 MCDI = Modified
Co-morbidity Disease Index
Group exercise versus medical care – MCDI < 4 2.311 0.724 7.375
Manual therapy versus medical care – MCDI < 4 6.500 1.640 25.76
Group exercise versus manual therapy – MCDI ≥ 4 0.397 0.169 0.932
Group exercise versus medical care – MCDI ≥ 4 0.520 0.224 1.210
Manual therapy versus medical care – MCDI ≥ 4 1.308 0.610 2.809
56
Moderator R
(n)
NR
(n)
Effect Odds Ratio
95% CI Lower
95% CI Upper
P Value
Kinesiophobia 24 201 Group exercise versus manual therapy – TSK < 26 0.306 0.114 0.820
0.35 TSK = Tampa
Scale for Kinesiophobia
Group exercise versus medical care – TSK < 26 0.532 0.197 1.436
Manual therapy versus medical care – TSK < 26 1.742 0.646 4.697
Group exercise versus manual therapy – TSK ≥ 26 0.672 0.260 1.741
Group exercise versus medical care – TSK ≥ 26 1.359 0.547 3.376
Manual therapy versus medical care – TSK ≥ 26 2.022 0.827 4.947
Race 24 201 Group exercise versus manual therapy – not black 0.351 0.160 0.768
0.40 Group exercise versus medical care – not black 0.765 0.356 1.646
Manual therapy versus medical care – not black 2.181 1.033 4.608
Group exercise versus manual therapy – black 1.091 0.252 4.714
Group exercise versus medical care – black 1.600 0.387 6.620
Manual therapy versus medical care – black 1.467 0.376 5.723
Knee Osteoarthritis
24
201 Group exercise versus manual therapy – no knee OA 0.373 0.165 0.843
0.37
OA = osteoarthritis Group exercise versus medical care – no knee OA 1.048 0.470 2.335
Manual therapy versus medical care – no knee OA 2.812 1.236 6.395
Group exercise versus manual therapy – knee OA 0.714 0.200 2.549
Group exercise versus medical care – knee OA 0.750 0.219 2.574
Manual therapy versus medical care – knee OA 1.050 0.348 3.167
Depression 24 201 Group exercise versus manual therapy – T score < 48.2 0.826 0.323 2.112
0.06 T score; from
PROMIS short form Group exercise versus medical care – T score < 48.2 0.895 0.339 2.360
Manual therapy versus medical care – T score < 48.2 1.083 0.443 2.645
Group exercise versus manual therapy – T score ≥ 48.2 0.180 0.059 0.549
Group exercise versus medical care – T score ≥ 48.2 0.917 0.367 2.287
Manual therapy versus medical care – T score ≥ 48.2 5.092 1.717 15.103
57
Table 12a. Patient Global Index Change, Baseline to 2 Months
Treatment Type
Medical Care Group Exercise Manual Therapy
PGIC item ratings –3 0 0 0
–2 2 1 1
–1 10 4 3
0 27 13 8
+1 19 26 30
+2 14 16 29
+3 7 4 8
Total n per group 79 64 79
n (%) n (%) n (%)
Nonresponders ≤ 0
Responders ≥ 1
39 (49)
40 (51)
18 (28)
46 (72)
12 (15)
67 (85)
PGIC Question: “Since I first started treatment in this research study, my overall status is . . .” Nonresponders: –3 = very much worse; –2 = much worse; –1 = minimally worse; 0 = no change.
Responders: +1 = minimally better; +2 = much better; +3 = very much better.
Table 12b. Patient Global Index Change, Baseline to 6 Months
Treatment Type
Medical Care Group Exercise
Manual Therapy
PGIC item ratings -3 0 1 1
-2 3 3 5
-1 12 7 7
0 19 12 4
1 22 19 28
2 9 12 16
3 2 5 4
Total n per group 67 59 65
n (%) n (%) n (%)
Nonresponders ≤ 0 34 (51) 23 (39) 17 (26)
Responders ≥ 1 33 (49) 36 (61) 48 (74)
PGIC Question: “Since I first started treatment in this research study, my overall status is . . .”
Nonresponders: –3 = very much worse; –2 = much worse; –1 = minimally worse; 0 = no change.
Responders: +1 = minimally better; +2 = much better; +3 = very much better.
58
Table 13a. Treatment Satisfaction, Baseline to 2 Months
Treatment Type
Medical Care Group Exercise Manual Therapy
Treatment satisfaction –3 0 2 1
item ratings –2 3 3 0
–1 9 2 3
+1 24 11 8
+2 27 32 26
+3 16 14 41
Total n per group 79 64 79
n (%) n (%) n (%)
Nonresponders ≤ 1
Responders ≥ 2
36 (46)
43 (54)
18 (28)
46 (72)
22 (15)
67 (85)
Satisfaction Question: “How satisfied are you with the treatment you received in this study”? Nonresponders: –3 = extremely dissatisfied; –2 = dissatisfied; –1 = somewhat dissatisfied.
Responders: +1 = somewhat satisfied; +2 = satisfied; +3 = extremely satisfied.
Table 13b. Treatment Satisfaction, Baseline to 6 Months
Treatment Type
Medical Care Group Exercise Manual Therapy
Treatment satisfaction –3 0 0 1
item ratings –2 5 0 0
–1 12 3 2
+1 15 9 6
+2 24 30 20
+3 11 17 36
Total n per group 67 59 65
n (%) n (%) n (%)
Nonresponders ≤ 1
Responders ≥ 2
22 (48)
35 (52)
12 (20)
47 (80)
9 (14)
56 (86)
Satisfaction Question: “How satisfied are you with the treatment you received in this study”? Nonresponders: –3 = extremely dissatisfied; –2 = dissatisfied; –1 = somewhat dissatisfied.
Responders +1 = somewhat satisfied; +2 = satisfied; +3 = extremely satisfied.
59
Missing Data
At our primary outcome end point of 2 months we had a total of 33 participants (12.7%) with
missing data. Participants from the group exercise arm had the largest proportion of missing
data at 2 months (20.2%) compared with the medical care (10.2%) and manual therapy (8%)
arms. One reason for missing data was that some subjects withdrew immediately after
randomization and did not receive any intervention. Significantly more participants withdrew
from the group exercise (14.3%) arm of our study than from the medical care (4.5%)
and manual therapy (3.4%) arms. Some subjects did not adhere to their assigned
intervention and withdrew at various times during the 6-week intervention period. Other
subjects completed their assigned intervention but failed to return for their 2- or 6-month
follow-up.
To account for missing data, we used linear mixed effects models to study treatment
differences over time using SSS and SPWT as the dependent variables in separate models.
These models included (1) unadjusted fixed effect of time, treatment, and treatment by time
interaction; (2) least square means by group over time; (3) differences between group means
over time; and (4) adjusted for covariates of interest. The linear mixed models borrow
information pertaining to the relationships in the outcome at multiple time points such that
persons missing data at certain time points can still be used in the analysis.
For the SPWT models, the unadjusted linear mixed model included a fixed effect of time and
treatment. We tested the interaction between time and treatment and not found it to be
statistically significant (P > 0.05). We then adjusted the linear mixed model with main effect of
time and treatment for the covariates of interest previously used in our primary linear
regression models. We found no statistically significant differences between treatment groups
in any of the models involving SPWT. This is consistent with the results of our primary analysis.
For the linear mixed models involving the SSS as the dependent variable, the first model
included a fixed effect of time, treatment, and treatment by time interaction. The interaction
60
term was significant (P = 0.04), suggesting that the SSS score differed between treatment
groups over time. As with the SPWT models, we then performed an adjusted model with the
previously used covariates. The interaction between treatment and time remained significant,
even after adjusting for covariates of interest, suggesting differences in SSS group means over
time adjusted for covariates of interest. Table 14 provides a summary of all missing data for
each outcome measure and each time point.
61
Table 14. Missing data for each outcome measure by assigned intervention group. See footnotes at bottom of
table for key to specific reasons for missing data.
Medical Care (n = 88)
Group Exercise (n = 84)
Manual Therapy (n = 87)
Missing Swiss Spinal Stenosis (SSS) data at 2 months
Average missing data rate = 13.2%
(across all 3 groups)
1n = 4 2n = 3 3n = 2
10.2% missing data
1n = 12 2n = 3 3n = 2 4n = 1
21.4% missing data
1n = 3 2n = 4 3n = 0
8% missing data
Missing Self-paced Walking Test (SPWT) data at 2 months
Average missing data rate = 16.7%
(across all 3 groups)
1n = 4 2n = 3 3n = 2
5n = 3
13.6% missing data
1n = 12 2n = 3 3n = 2 4n = 1 5n = 1
22.6% missing data
1n = 3 2n = 4 3n = 0
5n = 5
13.8% missing data
Missing SenseWear data at 2 months
Average missing data rate = 18.5%
(across all 3 groups)
1n = 4 2n = 3 3n = 2
6n = 6
17% missing data
1n = 12 2n = 3 3n = 2 4n = 1 6n = 3
25% missing data
1n = 3 2n = 4 3n = 0
6n = 5
13.8% missing data
Missing SSS data at 6 months
Average missing data rate = 26.3%
(across all 3 groups)
1n = 4 2n = 3 3n = 2 7n = 12
23.9% missing data
1n = 12 2n = 3 3n = 2 7n = 8
29.8% missing data
1n = 3 2n = 4 3n = 0 7n = 15
25.3% missing data
Missing SPWT data at 6 months
Average missing data rate = 26.7%
(across all 3 groups)
1n = 4 2n = 3 3n = 2 5n = 1 7n = 12
25.0% missing data
1n = 12 2n = 3 3n = 2 5n = 0 7n = 8
29.8% missing data
1n = 3 2n = 4 3n = 0 5n = 0 7n = 15
25.3% missing data
Missing SenseWear data at 6 months
Average missing data rate = 34%
(across all 3 groups)
1n = 4 2n = 3 3n = 2 6n = 5 7n = 12
29.5% missing data
1n = 12 2n = 3 3n = 2 6n = 8 7n = 8
39.3% missing data
1n = 3 2n = 4 3n = 0 6n = 7 7n = 15
33.3% missing data
1 Withdrew after randomization, lost to all follow-up (FU). 2 Withdrew during treatment, lost to all FU. 3 Completed care, lost to all FU. 4 Completed care and 6-month FU, but not 2-month FU. 5 Could not complete SPWT for reason other than stenosis. 6 Did not use SenseWear as instructed. 7 Completed care and 2-month FU, but not 6 months FU.
62
DISCUSSION
Context for Study Results
Our results were mixed with respect to confirming our specific aims and hypotheses. For our
primary aim, we hypothesized that participants in both the GE and MTE arms would show
better clinical outcomes in self-reported pain/function (SSS) and walking performance (SPWT)
compared with those randomized to the MC arm. However, we found that all 3 groups showed
modest reductions in SSS and improvement in SPWT at 2 months, but only the improvements in
SPWT were sustained at 6 months.
The results of our regression analyses for the primary outcomes of pain/function found a
statistically significant improvement in mean SSS scores in the MTE arm compared with the
other 2 arms; however, the magnitude of this effect has only marginal clinical significance
because the adjusted between-group differences did not exceed the MCID. The mean
unadjusted within-group improvement of 4.1 points in SSS score from baseline for MTE group
was only modest, considering that the MCID is 3.02 points. The greatest improvement in
walking performance was found in the manual therapy arm, although this was not statistically
significant when compared with the improvements found in the other 2 study arms. Also the
clinical significance of this magnitude of walking improvement in unknown, as there is no
established MCID for walking performance (SPWT).
Compared with those from the regression models, the results of the secondary responder
analyses for our primary outcomes may be more clinically relevant and easier to interpret. The
responder analyses revealed that there were significantly larger proportions of SPWT and SSS
responders in the manual therapy arm at 2 months as compared with either the group exercise
or medical care arms. However, the short-term results favoring the manual therapy
intervention arm at 2 months did not persist at 6 months. This may be explained in part by the
lack of any follow-up treatment, or “booster sessions,” after the initial 6-week intervention
period.
63
For our secondary aim, we hypothesized that participants in the GE and MTE arms would
demonstrate greater changes in PA compared with participants in the MC arm; however, we
found that only participants in the GE arm showed improvement in their level of PA, compared
with either of the other 2 arms. The GE arm showed significantly greater improvement in PA
compared with the MC arm at 2 months but not at 6 months. It was interesting to find that
both the MC and MTE arms showed less PA at 6 months, with only the GE arm participants
maintaining their baseline PA level. This is in direct contrast with the results showing an overall
improvement in walking performance in all 3 groups. This is not surprising, considering that
none of our research interventions provided a targeted treatment for improving PA. This
reinforces the fact that measures of physical performance (walking capacity) are different from
measures of overall physical activity (average time spent in activities > 1.5 METs). It may also
have been unrealistic in this age group to set a 30% increase in PA as the minimum threshold.
We also found some interesting results from our analyses of our first exploratory aim. One
unexpected finding was that a significantly greater number of participants randomized to GE
dropped out immediately after randomization, compared with the other 2 arms. Although no
significant difference in attrition (drop-out) rates existed between groups at 2 months or 6
months, participants who adhered to the GE intervention still had a higher number of
individuals fail to show for their follow-up examinations (Table 6). Feedback received from
those who dropped out of the GE arm after randomization indicated that lack of motivation to
exercise and transportation issues were the major barriers to attending group exercise classes.
However, for those participants who attended at least 1 intervention session, adherence rates
to the assigned interventions were excellent: above 90% in each of the study arms (Table 6). As
noted in the Results section, we did not have any serious adverse events in any of the 3
treatment groups (Table 4). The higher rate of transient musculoskeletal side effects in the GE
and MTE arms was expected due to the more physical nature of those interventions.
Conversely, the higher rate of gastrointestinal side effects in the MC arm was also expected and
64
anticipated as normal reactions to the oral medications prescribed by our research physician
(Table 4).
A little more than 40% of our participants in all 3 arms reported having experienced at least 1
fall in the past year, and this rate did not change significantly in any of the arms at 6 months
(Table 5). We also analyzed the type and number of cointerventions reported by our
participants between the 2- and 6-month follow-up. A significantly greater proportion of
participants from the manual therapy and medical care arms reported that they were doing
home-based exercises as compared with the group exercise arm. This can be explained by the
fact that in both of these intervention arms, participants were given instructions for home-
based exercises.
Conversely, a significantly greater number of participants in the group exercise arm reported
that they were exercising in a community setting as compared with the other 2 arms. This is
not surprising, considering that patients had become accustomed to a routine of exercising in a
group setting twice a week for 6 weeks, which may have led them into a new routine of
regular exercise. In addition, participants in our focus groups told us that they enjoyed the
socialization aspect of group exercise classes, which enhanced their motivation to continue
exercising in the community setting. A total of only 4 research participants (2.1%) reported
having spinal surgery at 6 months, with no significant differences in surgery rates between the
3 groups.
The largest RCT (SPORT trial) comparing surgical and nonsurgical treatments for LSS concluded
that patients treated with surgery had better results for up to 4 years following surgery.17,18
However, in this study there was no standardization of the interventions available to the
subjects who were not randomized to surgery. A secondary analysis of the SPORT trial data was
performed, which focused on the subset of patients in the nonsurgical arm who received
physical therapy (PT) treatment.59 This study showed that receiving PT within the first 6 weeks
after enrollment was associated with a lower rate of progression to surgery at 1-year follow-up.
65
Another RCT published after the SPORT trial compared surgical decompression and physical
therapy for LSS.19 This study showed that both surgical and nonsurgical approaches yielded
similar results on self-reported pain and function at 2 years.
Considering the high prevalence of LSS in older adults, there is a surprising lack of evidence
about the effectiveness of well-defined and standardized nonsurgical management approaches
for this common condition. The results of our study should be viewed in the context of the
results from these previous LSS trials. The secondary analysis of the SPORT trial concluded that
future research studies were needed to compare the safety and effectiveness of clearly defined
nonsurgical treatment protocols. Our study provides new evidence about the safety and
effectiveness of 3 well-defined nonsurgical interventions, which may help clinicians provide
patients with information about nonsurgical options that can then be discussed in a shared-
decision-making process. Our results also support the view that patients with LSS can show
some modest level of clinical improvement over time without surgical intervention.
It is also important to view the results of this study within the greater context of the current
nonsurgical management approach to patients with LSS. The guidelines from leading
professional organizations provide little or no guidance to clinicians or patients about which
nonsurgical methods might benefit patients with LSS. There also seems to be a general feeling
among patients and providers that nothing can be done to help a chronic degenerative
condition like LSS—that a slow decline in function is simply to be expected as part of the natural
progression of the condition. Although the natural history of LSS without any treatment or
intervention is not well known, it appears that many patients with LSS remain stable or improve
over time.60 Participants in our focus groups expressed frustration about how little information
was provided to them about viable nonsurgical treatment options by their primary care
physicians (PCPs). Many told us that their PCPs discouraged participation in group exercise
classes, physical therapy, and/or chiropractic care for 2 basic reasons: (1) fear of potential injury
and (2) lack of evidence for effectiveness.
The results of our study provide new evidence for the safety of community-based group
66
exercise classes as well as clinic-based manual therapy and individualized exercise provided by
physical therapists and chiropractors. There were no serious adverse events associated with
participation in either of these intervention groups. Although musculoskeletal side effects were
very common in these 2 groups, they were minor and transient. In fact, patients in our focus
groups said that they actually enjoyed feeling some muscle soreness after exercising in the
group setting or after having their physical therapy or chiropractic session; they interpreted
this soreness as a positive sign that their muscles and joints had been worked out. Our study
should provide physicians with some assurance that patients with LSS can safely participate in
group exercise classes and will not necessarily be harmed by physical therapists or
chiropractors.
With respect to effectiveness, although the amount of improvement in self-reported
pain/function was only short lived and modest, the magnitude of improvement in walking
performance was larger and sustained at 6 months in all 3 groups. Wide variability in our
walking performance data and no established MCID for the SPWT made it difficult to draw
conclusions about the clinical significance of the observed changes in mean distance walked;
however, at 6 months, the responder analysis showed that about half of the patients in all 3
groups were walking at least 30% farther than they were at baseline.
This finding suggests that although LSS is a chronic degenerative condition, patients can still
make some improvements in their physical function and should not be assumed to have a poor
or guarded prognosis. This should be an important component of shared decision making when
patients with LSS explore nonsurgical treatment options with their PCPs. That said, these
findings should be balanced with the amount of time and cost associated with each
intervention. Most patients would be required to make a copay for each of 12 physical therapy
or chiropractic visits, which would be 4 times costlier to the patient than making just 3 copays
with a physician. The cost of group exercise classes is free or just a few dollars each session at
most community centers.
Uptake of Study Results and Generalizability of Findings
67
The demographic makeup of our study participants (Table 1) is very similar and comparable to
the populations of LSS participants in the previously noted trials by Weinstein et al17,18 and
Delitto et al19 with respect to baseline age, BMI, medical comorbidities, and self-reported
levels of pain and function. The socioeconomic and racial diversity of our participants was
comparable to the general demographics of the urban Pittsburgh population, and thus our
results should be generalizable to most other major metropolitan urban populations in the
United States.
The pragmatic nature of this trial facilitates the implementation and uptake of our results by
many of our stakeholders. Our medical care protocol was straightforward and pragmatic.
Although administered by a physiatrist in our study, this approach to shared decision making
and tailoring medications to each individual patient could easily be implemented by most PCPs.
PCPs could also provide more referrals to chiropractors and physical therapists for nonsurgical
management of LSS; however, information obtained from focus groups of LSS patients revealed
that most PCPs are hesitant to refer their LSS patients to chiropractors and physical therapists,
citing lack of evidence for the safety and effectiveness of such interventions. To overcome this
barrier to the uptake of our study results, our research physiatrist will actively disseminate our
results at PCP grand rounds. We also plan to publish a commentary article about our medical
care protocol in a peer reviewed journal geared toward a PCP readership. In addition, our local
UPMC Healthplan stakeholders will assist us in developing an active dissemination and
implementation plan to increase the uptake of our study results, by increasing awareness
among PCPs who are network providers in this local health plan.
The findings from our group exercise arm are clearly generalizable to the real-world setting.
Most community centers that provide services to older adults offer some type of group exercise
class. We did not have to create any new group exercise protocol for our study; we simply
provided access to existing community-based group exercise classes. The cost of these classes is
minimal or free to most older adults as a benefit under major health insurance plans, which
removes the financial barrier to uptake of the study results. Our stakeholders include the
68
directors of 2 large community centers that service older adults in Pittsburgh. They agreed that
these findings should be disseminated widely to the other community centers in the Pittsburgh
metro area. They will also work with the PI on an active dissemination plan to push these study
results directly to their members and community-dwelling older adults residing in
neighborhoods near their centers.
The findings from the manual therapy and individualized exercise protocol that we developed
for this study are very relevant to the chiropractic and physical therapy professions. Our results
show that utilization of this protocol is a safe and effective intervention for the nonsurgical
management of patients with LSS. Most of the individual procedures within our study protocol
are commonly utilized by chiropractors and physical therapists, making the results potentially
generalizable to clinicians in both professions, who are already familiar with at least some of
these procedures. However, very few physical therapists or chiropractors are currently
combining these individual procedures into a comprehensive “boot camp” approach, as we
utilized in our research protocol. We also discovered a potential barrier to the uptake of these
study results from focus groups and informal discussions; namely, that many chiropractors and
physical therapists lack confidence in their ability to provide effective treatment to patients
with LSS. They shared a collective belief that there was a lack of evidence for the safety and
effectiveness of the nonsurgical methods available to them.
To help overcome this barrier, the PI and coinvestigators are in the process of designing a
weekend-based continuing education course for chiropractors and physical therapists; in it we
will provide a review of the clinical examination, diagnosis, and treatment options for LSS. This
course will also include a hands-on workshop to provide skills and training in the combination
of procedures utilized in our research protocol. We believe that this active dissemination and
implementation strategy will lead to greater uptake of our study results by the chiropractic and
physical therapy professions, who will have greater confidence and skills in managing patients
with LSS. We also believe that this training will lead to a greater rate of referral to these
providers by PCPs.
69
Subpopulation Considerations As discussed in the Results section of this report, we explored the heterogeneity of treatment
effect by performing an analysis of baseline associations and predictors of treatment response.
We found a significant association between age and responder status: Younger patients were
more likely to be SSS and SPWT responders, regardless of group assignment. Falls score was
associated only with SSS responder status, with responders more likely to report fewer falls at 6
months. We did not find any significant moderators associated with either of our primary
outcome measures of self-reported pain/function (SSS) or walking performance (SPWT).
Baseline depression and number of comorbidities showed a trend (P = 0.06) toward significance
as possible moderators of SPWT outcome.
The treatment effect of manual therapy versus medical care appears to be stronger among
patients with depression scores above the median and comorbidity scores below it. Age, sex,
body mass index, fear avoidance, and knee osteoarthritis were not associated with responder
status. It is important to note that we were not sufficiently powered for these stratified
analyses; however, some of these associations warrant further investigation in future research
trials given their clinical plausibility as potential treatment moderators.
Study Limitations
There was large heterogeneity in the clinical response found in our study, and that while some
patients improved in each group and the interventions were shown to be safe, the overall levels
of response (improvement) were low. In addition, our study was unable to identify which
patient characteristics were predictive of treatment response. The large standard deviations
associated with the walking performance and physical activity data reflect the large variation in
the clinical status of patients with LSS. There is a need for further research in the area of
nonsurgical interventions and how they may have differential effects on various subgroups of
LSS patients.
70
Compared with either of the other intervention arms, a significantly greater proportion of
subjects withdrew from the group exercise arm immediately after randomization. This may
have created selection bias, in which those subjects who chose to accept randomization into
group exercise were more motivated toward physical activity than subjects in the other 2 arms
of the study. Increased motivation might be a confounding variable in those results showing
greater physical activity in this group at 2 months. Also, subjects who received the MTE
intervention spent about 45 minutes face to face with a physical therapist or chiropractor for 12
sessions. This increased personal attention might be a confounding variable in those results
showing greater short-term improvement in self-reported pain/function with MTE.
We also found some limitations in the use of the SPWT. We noticed a sense of boredom in
some of our subjects, which may have influenced their decision about when to stop the test
even if they could have walked farther. We also received feedback from participants in our
focus groups about how their walking performance could vary day to day, based on the
natural fluctuations of a chronic degenerative disease such as LSS. They also told us that in real
life, they had challenges with walking over uneven ground, steps, and curbs, which were not
part of the SPWT. Some participants had other medical problems that precluded them from
completing the SPWT, which led to some missing SPWT data at 2- and 6-month follow-ups.
However, subjects agreed that given the choice, the SPWT was still a better measure of their
true walking performance compared with other outcome measures such as the Shuttle Walk
Test or treadmill tests.
There were also some limitations with the use of the physical activity monitor. Although the
device was rather small and unobtrusive, it was still large enough that some subjects found it
uncomfortable to wear 24 hours per day for 7 consecutive days. As noted earlier, this led to the
situation in which we had missing physical activity data for a subset of research participants at
2- and 6-month follow-ups. Participants in our focus groups also gave us important feedback
about their perceptions of the challenges associated with measuring physical activity. They told
us that, similar to the challenges with measurements of walking performance, their level of
71
general physical activity varied by day and by week based on many factors other
than their LSS. Many subjects told us that they wanted to be able to walk farther at any 1
time but that they did not really desire to increase their overall level of physical activity.
This trial allowed for some discretion on the part of our medical care and manual therapy
providers to modify their clinical interventions based on each patient’s needs. The
heterogeneity in providing this care is a limitation that prevented us from assessing which
component(s) of these interventions may have moderated the treatment effects, reducing the
internal validity of the results; however, this heterogeneity is found in the real-
world setting and improves the external validity of these results.
Finally, in retrospect we realize that our original choice of the term usual medical care may not
have been the most accurate terminology. Patients in our focus groups who were randomized
to the medical care arm told us that our research physician gave them much more time and
attention than what they generally had received previously from their other physicians. Also
they told us how much they appreciated our physician’s thoroughness in reviewing all of their
medications, trying his best to minimize the dosages and number of medications and taking the
time to more fully explain all treatment options. In short, our “usual” medical care may have
been “unusual,” which may partly explain our research participants’ generally favorable
response to this intervention.
Future Research
One potential area for future research would be to compare the effectiveness of multimodal
“bundles” of different interventions, possibly with a factorial design. We designed this study as
a comparative effectiveness trial seeking the most effective of these 3 interventions;
however, in real clinical practice it might better serve patients if various combinations of these
interventions are utilized in a multimodal or sequential manner. It is possible that a
combination of 2 or 3 interventions used in our trial might have a synergistic or sequential
effect and provide LSS patients with more clinical benefit than any one individual intervention.
For example, patients with high levels of pain may get more benefit from manual therapy or be
72
more tolerant of exercise when concurrently managed by a physician with appropriate
medications or even an epidural steroid injection. Also, patients who are responding well to
chiropractic or physical therapy treatment might benefit from participating in concurrent group
exercise classes, and vice versa.
Another research question is whether it is more effective to provide “booster sessions,” or
periodic visits to a chiropractor or physical therapist spaced out over time, rather than in a
single bolus of treatment typically given within a 6-week intervention. In the focus groups,
participants told us that they realized LSS was a chronic disorder that could not realistically be
“cured” with 6 weeks of any intervention. They told us that they felt they would benefit from
more regular and periodic visits, or booster sessions, to a physical therapist or chiropractor as
a type of long-term management of their chronic degenerative condition. They also told us that
continuing with regular exercise over the long term was helpful in maintaining the short-term
benefits they gained during 6-week intervention period.
It would also be a novel concept to create more collaboration and coordination of care
between physical therapists, chiropractors, and the community centers that offer group
exercise classes for older adults. After completing an intensive course of individualized physical
therapy or chiropractic care, LSS patients could be transitioned to group exercise classes for
ongoing maintenance of their improved function. These are all testable hypotheses for future
clinical comparative effectiveness research studies.
CONCLUSION
Our study found that the combination of manual therapy and individualized exercise leads to
significantly greater short-term improvement in the primary outcome of pain/function at 2
months compared with either of the other 2 groups. Compared with medical care, group
exercise led to significantly greater improvement in the secondary outcome of physical activity at
2 months. The clinical significance of these short-term improvements and between-group
differences is uncertain. At 6 months, these short-term improvements in self-reported
73
pain/function and general physical activity were not sustained; however, all groups maintained
their within-group improvements in walking performance at 6 months. No serious adverse
events were reported in any of the treatment groups.
Concerns about the rising rates of opioid use and spine surgery in older adults make a
compelling case for the dissemination of research evidence about safe and effective alternative
treatment options for LSS. Previous trials have provided evidence only from comparisons of
surgical versus nonsurgical interventions. This has resulted in a serious evidence gap about
comparisons of different well-defined nonsurgical interventions with each other, rather than
with surgery. The results of our study provide evidence to help fill that gap.
It is simplistic to dichotomize all LSS patients into being either “surgical” or “nonsurgical”
candidates or to suggest that one general approach is clearly better than the other for every
patient. Because no single intervention appears to be superior for the long-term management of
LSS, consideration should be given to patient preference, clinical status, and medical
comorbidities within the context of shared-decision making. The interventions provided in our
study are well defined and pragmatic nonsurgical approaches that could be offered as options to
LSS patients in a stepped approach. More nonsurgical comparative effectiveness studies are
needed to provide additional evidence about the long-term management and prognosis of
patients with LSS.
74
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Appendix A: Manual therapy and individualized exercise
protocol implemented by the study chiropractors and physical
therapists.
All research participants randomized to this group will receive a combination of manual therapy and
exercise therapy from a licensed chiropractor or physical therapist. Each encounter will last a total of
about 45 minutes.
I. WARM-UP PROCEDURE
A. Stationary Bicycle: The warm-up period each visit will gradually be increased from 5 to 20 minutes
over the course of the 6-week treatment plan, depending on each individual’s exercise tolerance.
II. MANUAL THERAPY PROCEDURES
A. Prone Procedures
1. Lumbar Distraction Mobilization. This procedure will be performed in the prone position on a
special treatment table (Cox-Zenith Table) that allows for the caudal section to be distracted away
from the cephalad section, as well as, moved toward the floor and/or laterally. The clinician will
place the heel of one hand over the spinous process of each lumbar vertebra while the other hand
pushes on the caudal section of the table (or by using the attached “T”-bar), creating segmental
distraction and mobilization of each segment.
2. Hip Mobilization. All mobilizations will be Grade 4, taking the joint to full end-range position within
the subject’s tolerance. Apply static deep pressure over the gluteus medius, minimus and piriformis
muscles to loosen these soft tissues, while passively rotating the hip into internal, then external
rotation. Repeat 3 times, bilaterally. Mobilize each hip joint individually into extension by stabilizing
the pelvis/sacrum with the heel of one hand and lifting the subject’s thigh (with flexed knee) off the
table a few inches. The hip joint will be extended to end-range 3 times using contract-relax technique,
isometrically contracting the muscle to be stretched. Mobilize each hip joint individually into full
internal/external rotation 3 times using a contract-relax technique. Mobilize each hip joint
individually into full abduction 3 times using a contract-relax technique to stretch the adductors
muscles and allow for full hip abduction.
B. Side-Posture Procedures
1. Side Posture Mobilization. After completion of the prone procedures, the subject will be placed in
the side posture position, making sure to keep the subject’s lumbar spine in flexion. The clinician
then segmentally mobilizes the lumbar spine into rotation bilaterally, each segment 3 times.
2. Femoral Nerve Mobilization. Place subject in side-lying “slumped” position with cervical and
thoracic spine in flexion with head on a pillow. Perform with the intent of tensioning, the L1 through
L3 nerve roots. Each mobilization is performed 20 repetitions using two different positions. This is 2
sets of neural mobs for each leg, repeated bilaterally. The subject is shown these as self-
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mobilizations to be performed bilaterally at home on a daily basis.
a. Distal: Involved side up. Hold subject’s thigh and ankle. Hip is extended to
barrier, knee is flexed, rhythmic knee flexion. Repeat 20 times.
b. Proximal: Knee is flexed, hip is extended, rhythmic hip extension. Repeat 20 times.
C. Supine Procedures
Several manual therapy techniques will be performed with the subject lying in the supine position.
1. Individual Knee-to-Chest Mobilization. Flex the subject’s individual hip and knee toward the
chest with external rotation, using a contract-relax technique, one side at a time. Repeat 3
times.
2. Bilateral Knee-to-Chest Flexion Mobilization. Perform with both knees flexed and brought up
toward the chest, creating a flexion mobilization of the lumbar spine. Contract-relax technique
will be used to facilitate this stretch/mobilization.
3. Contralateral Knee-to-Chest Mobilization. Flex hip and knee toward opposite shoulder using
contract- relax technique to stretch piriformis.
4. Hamstring Stretch. Stretch the hamstrings using a straight leg raise procedure with
contract-relax technique.
5. Lumbar Hyperflexion. Bring both legs overhead with knees extended using contract-relax.
6. Rotational Lumbar Mobilization. Perform with the subject’s knees bent and feet flat on the
treatment table. Gently push on both knees laterally, and rotate the lumbar spine to end range
bilaterally, using contract-relax with twist and heels on table.
7. Sciatic Nerve Mobilization. Perform with the intent of tensioning the lumbosacral nerve roots,
L4, L5 and S1. Each mobilization is performed 20 repetitions using three different positions.
The participant is shown these as self-mobilizations to be performed bilaterally at home on a
daily basis.
a. Distal: Hip is flexed, knee extended, rhythmic ankle plantar/dorsi-flexion.
b. Intermediate: Hip is flexed, flexion/extension of the knee with ankle dorsiflexion.
c. Proximal: Ankle in dorsiflexion, knee extended, rhythmic hip flexion.
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III. HOME EXERCISES
The last 10 minutes of each session will be demonstration and review of home-based exercises and neural mobilizations with the subject. There is a specific series of home exercises that subjects will be prescribed sequentially over the course of the 6-week treatment program. These are described in a separate lumbar spinal stenosis exercise booklet created by Dr. Carlo Ammendolia. Note that some of the manual procedures listed above are duplicated on the exercise checklist as self-stretching techniques. Instruct the subject on each visit how to do the next exercise(s) and increased repetitions. Refer to the exercise booklet for details.
1. Stationary Bike - Start with 5 minutes of continuous cycling daily, with goal of increasing to 20 minutes daily within 6 weeks.
2. Lying on Back a. Knee-to-Chest
b. Knee-to-Opposite Chest
c. Double Knee-to-Chest
3. Sitting on Chair
a. Sit to Stand, then Stand to Sit, repeat
4. Nerve Flossing {Neuro-Mobilization)
a. Distal {Ankle)
b. Intermediate {Knee)
c. Proximal (Hip)
d. Sitting Forward - Flex body and arms toward floor
5. Lying on Side
a. Side Sit-up
b. Quadriceps stretch
c. Side Hip-lift
6. Lying on Stomach, pillow under pelvis
a. Torso Extension
b. Back Leg Extension
7. Lying on Back
a. Pelvic Tilt
b. Pelvic Twist
c. Half Sit-up
8. Standing
a. Standing pelvic tilt
b. Groin stretch
9. Walking
a. Walking with posterior pelvic tilt
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Appendix B: Spinal Stenosis Recruitment - Postcard Direct Mailings to selected zip codes within the
City of Pittsburgh (Nov 2013 – Sept 2015)
Month/Year Zip Code Quantity
November 2013 15217 (Squirrel Hill) 1,800 (split)
January 2014 15217 (Squirrel Hill) 1,800 (split)
January 2014 15206 (East Liberty) 3,676
March 2014 15221 (Regent Square) 2,550 (split)
May 2014 15221 (Regent Square) 2,550 (split)
June 2014 15224 (Bloomfield) 1,358
August 2014 15203 (South Side) 1,233
September 2014 15219 (Uptown, Hill District)
1,577
October 2014 15201 (Lawrenceville) 1,822
November 2014 15218 (Edgewood, Swissvale)
2,114
December 2014 15207 (Hazelwood) 1,746
January 2015 15212 (North Side, Brighton Heights)
2,000
February 2015 15227 (Hayes) 2,212 (split)
March 2015 15227 (Hayes) 2,212 (split)
March 2015 15217 (Squirrel Hill) 1,841 (split)
March 2015 15210 (Carrick) 1,699 (split)
March 2015 15217 (Squirrel Hill) 1,841 (split)
April 2015 15210 (Carrick) 1,699 (split)
April 2015 15227 (Hayes) 2,212 (split)
April 2015 15206 (East Liberty) 1,838 (split)
May 2015 15227 (Hayes) 2,212 (split)
May 2015 15206 (East Liberty) 1,838 (split)
June 2015 15213 (Oakland) 2,040
June 2015 15224 (Bloomfield) 1,358
July 2015 15232 (Shadyside) 1,018
July 2015 15207 (Hazelwood) 1,746
July 2015 15218 (Edgewood/Swissvale)
2,114
August 2015 15201 (Lawrenceville) 1,822
August 2015 15221 (East End) 2,559 (split)
August 2015 15221 (East End) 2,559 (split)
September 2015 15203 (South Side) 1,233
September 2015 15208 (Homewood) 1,575
September 2015 15219 (Uptown, Hill District)
1,577
TOTAL N = 61,593
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Copyright© 2019. University of Pittsburgh at Pittsburgh. All Rights Reserved.
Disclaimer:
The [views, statements, opinions] presented in this report are solely the responsibility of the author(s) and do not necessarily represent the views of the Patient-Centered Outcomes Research Institute® (PCORI®), its Board of Governors or Methodology Committee.
Acknowledgement:
Research reported in this report was [partially] funded through a Patient-Centered Outcomes Research Institute® (PCORI®) Award (587). Further information available at: https://www.pcori.org/research-results/2012/comparing-effectiveness-nonsurgical-treatments-lumbar-spinal-stenosis-reducing