Fusion and repeat discectomy following single level open lumbar discectomies. Survival analysis

Dr John MortimerMr Chris Hoffman

CCDHB and TBI Health group

Sciatica = Leg Dominant Pain

• Patients referred for surgical review

• History of back and then leg-dominant pain

• Severe disability – unable to work and sleep

• Associated neurological disturbance

• Conservative care• Nortriptyline for sleep disturbance

• CT guided steroid injection

• NSAIDS/Opiates prn

• Physiotherapy

Failure of Resolution

• Indications for discectomy

• Leg dominant (CBI pattern 3) pain

• Positive tension signs – SLR to reproduce Leg Dominant Pain

• Concordant MRI scan – Disc prolapse at relevant level/side

• When should we operate?

• Must do - Cauda Equina Syndrome (rare)

• Should do - Progressive neurology (rare)

• Could do - Aim to reduce long term pain/disability

• Window of opportunity to intervene – 3 to 12 months

Surgical Goals

• Resolution of leg pain • Reduction in back pain• Preventing further disability

• Goal of surgery• Discectomy removes the displaced fragment• Removes the irritation/pressure on the relevant nerve

• Surgical technique• Cannot repair any nerve damage• Cannot repair the annular defect

• Problem of recurrent prolapse and/or chronic back pain• Conservative care initially• Repeat discectomy (fragment only)• Complete discectomy and spinal fusion

Aims and Methods

• To describe the rates of reoperation following single level lumbar discectomies by one surgeon between 2000-2016

• To describe the complication rates

• To describe the prevalence and association of patient factors and MRI reported disk disease on the incidence of repeat same level discectomy and lumbar fusions

Aims and Methods

• Inclusion

• Single level primary discectomy for MRI proven disk prolapse L1-S1

• No previous discectomy or fusion of any level

• Exclusion

• > one level discectomy

• Any previous spinal surgery

• Decompression for reasons other than HNP

• Any other combination of surgery fusion

Aims and Methods

• Single surgeon database 1998-2016 (Mana Orthopaedics)

• Private practice medical records

• MRI reports

• ACC coding

• ACC surgical request report - ARTP’s

• Operation notes

• Hutt, Wairarapa & Wellington Hospital medical records

• Pacific Radiology Records (PACS)

Aims and Methods

• Patient risk factors• Age• Gender• Level• Disk morphology type• Single level DDD versus multi level DDD• Duration of symptoms

• Outcomes• Indication for surgery – recurrent leg, leg/back or back pain• Patient undergoing same-level discectomy• Patient undergoing discectomy and lumbar fusion• Patient undergoing lumbar fusion• Time to repeat surgery• All complication/Deaths/ re-admission <30days

Cohort demographics

522 patients

M:F 6:4

Age Mean 44

Std. 14.1

Symptom Med. 37 wk

duration IQR 20-69

0 10 20 30 40 50 60 70 80 90

<2 weeks 2 to 6weeks

6 weeksto 3

months

3 to 6 6 monthsto 1 year

1- 2 years 2 to 5 5 to 10 >10

Cohort demographics

37%

53%

7% 3%

Disk morphology

central para-central foraminal Far Lateral

48%

45%

5% 2%

Level

L5-S1 L4-5 L3-4 L2-3

Survival without re-operation

no re-op80%

1 or more20%

34 per 1000 person-years

Surgery for Pain

45%

37%

18%

Repeat Diskectomy +fusion

Repeat Discectomy

Fusion

Recurrent Leg Dominant pain

• MRI with isolated recurrence

• 8.0 %

• 12 per 1000-person-years

• Mean age 44.6yr

• M:F 48 : 52

• Med. Symptom duration 46.5 wk

• Single : multi-level disease 60 : 40

• Mean time to re-operation 1.0 yr

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Post-Op time (Years)

R² = 0.90

Rate of repeat discectomy leg pain

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Post-op (yr)

Isolated Repeat Discectomy survival

Recurrent Leg and Back pain

• MRI shows prolapse and further degeneration

• 5.0 %

• 3.3 per 1000-person-years

• Mean age 44

• M:F 65 : 35

• Med. Symptom duration 39 wk

• Single : multi-level disease 87 : 13

• Mean time to re-operation 1.5 yr

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Time (yr)

Rate of Discectomy + Fusion

R² = 0.94

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Survival Fusion + Discectomy

Fusion for back pain

• Back dominant pain

• Failed conservative care

• MRI with local progression of disc degeneration

• 3.6%

• 2.3 per 1000-person-years

• Mean age 43.6yr

• M:F 42 : 58

• Med. Symptom duration 37 wk

• Single : multi-level disease 82 : 18

• Mean time to re-operation 3.9 yr

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Time (yr)

Rate of isolated fusion for back pain

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Survival – Isolated fusion for back pain

Demographic risk factors

Isolated discectomy Fusion + discectomy Isolated fusion

Age 1.02 p=0.64 1.01 p=0.90 0.998 p=0.98

Duration 0.617 p=0.57 0.802 p=0.57 0.966 p=0.97

Gender M:F 0.624 p=0.14 1.10 p=0.68 0.474 p=0.15

Single Level Disk diseasevs

Multi-Level Disk Disease

Isolated discectomy Fusion + discectomy Isolated fusion

Single v Multiple Disk

0.670 p=0.21 1.25 p=0.10 2.09 p=0.29

Flaws and future

• Subjective markers of patient outcomes influenced by surgically candidacy and surgical decision making

• Doesn’t objectively measure pre or post op leg/back pain and quality of life measures (SF-36, ODI)

• Loss to F/U

• Next Step: Spine Surgery Registry• Prospective collection of Patient outcomes – VAS, EQ5D and ODI

• Revision procedures recorded on registry