1. COMPARISON OF OUTCOMES IN PLIF SURGERY IN RELATION TO PATHOLOGY Manoj Krishna Chandra Bhatia Raymond Pollock Spinal Unit, University Hospital of North Tees, Stockton-on-Tees. UK. www.spinalunit.org

2. There are few effective treatment alternatives available for Post-discectomy syndrome There are few effective treatment alternatives available for Post-discectomy syndrome Braverman et al, Archives of Physical Medicine and Rehabilitation 82(5), 691-93, 2001 May

3. Only 34 % improvement in post-discectomy patients having surgery Only 34 % improvement in post-discectomy patients having surgery North et al Neurosurgery, 28(5); 685-690, 1991 May

4. Do patients with Postlaminectomy or Postdiscectomy surgery have poorer outcome as compared to other groups after revision surgery? Do patients with Postlaminectomy or Postdiscectomy surgery have poorer outcome as compared to other groups after revision surgery?

5. PATIENT SAMPLE Prospective study Prospective study 154 Patients 154 Patients 85 Female, 69 Male 85 Female, 69 Male Mean Age - 44.3 years (Range 12-81) Mean Age - 44.3 years (Range 12-81) Minimum follow-up- 2 years Minimum follow-up- 2 years All failed conservative treatments All failed conservative treatments

6. PATIENT SAMPLE Degenerative Disc Disease-114 Degenerative Disc Disease-114 Post discectomy syndrome- 30 Post discectomy syndrome- 30 Spondylolysis/listhesis- 10 Spondylolysis/listhesis- 10

7. Principles of PLIF/TLIF Surgery Remove Pain Generators- Disc/Facet Remove Pain Generators- Disc/Facet Free Neural Structures Free Neural Structures Restore Normal Loading through Disc Restore Normal Loading through Disc

8. OUTCOME MEASURES USED Oswestry Disability Index Oswestry Disability Index Visual Analog Scale for Back Pain Visual Analog Scale for Back Pain Visual Analog Scale for Leg Pain Visual Analog Scale for Leg Pain

9. Statistical Methods Normality of data set checked Normality of data set checked Paired t test –in each group Paired t test –in each group ANOVA used to test difference between the mean improvements of the 3 groups ANOVA used to test difference between the mean improvements of the 3 groups

10. CHANGES IN ODI

11. Improvement in ODI DDD Group 22.5( p=0.00) Post-discectomy group 22.2( p= 0.00) Spondylolisthesis group 34.7(p=0.00) No statistical difference between the 3 groups( p=0.494)

12. CHANGES IN VAS FOR LBP

13. Improvement in VAS Back Pain DDD Group 4.0( p=0.00) Post-Discectomy Group 3.2( p=0.01) Spondylolisthesis Group 3.9 ( 0.00) No statistical significant difference between the 3 groups(0.38)

14. CHANGE IN VAS FOR LEG PAIN

15. Improvements in VAS Leg Pain DDD Group 3.7( p=0.00) Post-discectomy Group 2.2( p=0.01) Spondylolisthesis Group 3.3(p=0.05) No statistical difference between the 3 groups(p=0.639)

16. Summary PLIF surgery results in clinical and statistically significant improvements in patients with DDD, Post-discectomy syndrome, and Spondylolisthesis PLIF surgery results in clinical and statistically significant improvements in patients with DDD, Post-discectomy syndrome, and Spondylolisthesis There was no statistical difference between these 3 groups in the amount of improvement There was no statistical difference between these 3 groups in the amount of improvement

17. Trends Leg pain improvement in post-discectomy group, though significant, is less than other groups Leg pain improvement in post-discectomy group, though significant, is less than other groups ODI improvement in spondylolisthesis group is more than other groups ODI improvement in spondylolisthesis group is more than other groups

18. Discussion Challenges current thinking that patients with post-discectomy syndrome do poorly after surgery( and nothing can be done for them) Challenges current thinking that patients with post-discectomy syndrome do poorly after surgery( and nothing can be done for them) Suggests that improvements in the post- discectomy group are comparable to primary surgery Suggests that improvements in the post- discectomy group are comparable to primary surgery

19. Discussion Literature suggests type of surgery influences outcome, with repeat decompression the least beneficial Literature suggests type of surgery influences outcome, with repeat decompression the least beneficial PLIF addresses all the pathology in the motion segment PLIF addresses all the pathology in the motion segment

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