Spine Surgery, Drum Tower Hospital, Nanjing University, CHINA
Xu SUN, MD, Lei-Lei XU, MS, Feng ZHU, MD, Qi DING, MS,
Zezhang ZHU, MD, Bin WANG, MD, Bang-ping QIAN, MD,
Yang YU, MD, Yong QIU, MD
from Spine Surgery, the Affiliated Drum Tower Hospital of Nanjing
University Medical School, Nanjing, China
Accuracy and safety of pedicle screw
placement in adult lumbar spine with
and without scoliosis:
a case-control study
QF # 73
Adult lumbar scoliosis
Pedicle screw based constructs
Advantage: Stabilize three columns of
the spine
# 4787, M 49ys
For scoliosis,
pedicle screw placement involves
increased risk of perforation
Aorta
#10019,F, 23 y, Congenital
Anterior perforations
at L2, L4 and L5.
A systemic review of all prospective studies
until 2010
Accuracy (%of the screws fully
contained in pedicles)
69 to 94%, free-hand
28 to 85%, fluoroscopy,
81 to 92%, fluoroscopy-
navigation
89 to 100% with CT navigation
Gelalis ID, et al. Eur Spin J , 2012
Accurately
placed
Lateral
perforated
Medial
perforated
Anterior
perforated
Endplate
perforated
Currently available data in terms of pedicle screw accuracy in
adults with or without lumbar scoliosis were from multiple centers,
with varied techniques and experiences.
The purpose was to compare the accuracy
and safety of lumbar pedicle screw placement
by one team in scoliosis adults versus non-
scoliosis adults,
and to shed light on the malpositioning pattern
of pedicle screws as well as the possible risk
factors of screw misplacement.
Purpose
Patients and Methods
Scoliosis Non-scoliosis
N=65 (M/F, 17/48) N=127 (M/F, 68/59)
Age : 30-68 yr Age : 31-69 yr
Lumbar idiopathic
scoliosis, degenerative
scoliosis
Degenerative lumbar
stenosis, and Grade I
degenerative
spondylolisthesis
Placement: Using free-hand technique
Post-Op CT: To assess screw positions #5629 F, 59y
#8352 F, 46y
Classification of screw positions
Safety: Medial breach ≤ 2
mm, breach ≤ 4 mm of
lateral or anterior wall
without aorta impingement.
Potential risk: Medial
breach ≥ 2 mm, breach ≥ 4
mm of lateral or anterior
wall , or with aorta
impingement
Modi NH, et al. Euro Spine J, 2008;
Upendra BN, et al. Spine, 2008;
Gertzbein SD, et al. Spine ,1990,
Grade Screw position
0 Fully contained within
the cortex
1 Cortical breach ≤ 2mm
2 Cortical breach of
2 to 4mm
3 Cortical breach of
4 to 6mm
4 Cortical breach ≥ 6mm
Accuracy: w/o cortical
breach (Grade 0)
Group Scoliosis Non-
scoliosis Stat.
No. of Pts 65 127
Average age 39 yr 45 yr P > 0.05
Screws 457 546
Accuracy of screws 89.5% 91.9% Chi-sq = 0.086,
P = 0.769
Rate of screw penetration 48 (10.5%) 44 (8.1%) Chi-sq = 1.482,
P = 0.223
Complications:
Dural tear occurred in 5 patients.
NO vascular injury. No neurological deficits.
Results
Distribution of screw
positions in both groups
At potential risk
Safely placedAccurately placed
0
100
200
300
400
500
600
8 4
48 44
409 502
0%
50%
100%
0%
50%
100%
0%
50%
100%
Accurately
Penetrated
Misplacement pattern in
Scoliosis pts
High accuracy and safety of pedicle screw placement
can be achieved in adult lumbar scoliosis,
comparable to those without scoliosis.
Surgeons should carefully determine the length and
direction of pedicle screw during placement in severe
scoliosis, in the apical region as well as on the
concave side.
Conclusion
Disclosures
Xu SUN
Lei-Lei XU
Feng ZHU
Qi DING
Zezhang ZHU
Bin WANG
Bang-ping QIAN
Yang YU
Yong QIU
Authors No Relationships
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d. Speakers’ Bureau
e. Other Financial Support