Does the Increase in Spine Surgery Reflect an Increase in Disease?

1. Does the Increase in Spine Surgery Reflect an Increase in Disease? Sohail K. Mirza, MD MPH Professor, Department of Orthopedics and Joint Professor, Department of Neurological Surgery University of Washington

2. NASS Format X UW Tech Transfer (Synthes) X X X X X X X Depuy, Surgical Dynamics, Synthes (to UW Dept. of Orthopedics) X X X X X Depuy, Synthes (to Dept of Orthop) X X

3. Disclosure • I hold the University of Washington Surgical Dynamics Endowed Chair for Spine Outcomes Research (approx $90k in 2006). • I receive royalties for surgical drills licensed by Synthes Spine through UW Office of Technology Transfer (approx. $16k in 2006). • UW Department of Orthopedics receives spine fellowship support, research support, and endowments from Synthes Spine and Depuy Spine. I work with the spine fellows and am involved with two of the research projects supported by these funds. • I prepared all the slides. Sohail K. Mirza, MD, MPH Professor, Department of Orthopedics and Sports Medicine and Department of Neurological Surgery, University of Washington Harborview Medical Center, Box 359798 325 Ninth Avenue Seattle, WA 98104 Email: mirza@u.washington.edu Tel: 206 731 3658 Fax: 206 731 3227

4. Does the increase in spine surgery reflect an increase in disease? no

5. Back Pain 1,865,196 results on 5/17/2002 707,000,000 results on 6/ 5/2007 26,100,000 results on 1/15/2008

6. New Technologies Resolution of pedicle screw litigation New posterior fixation devices New anterior fixation devices Cages Bone graft substitutes Bone morphogenetic proteins Minimally invasive spine surgery Computer-assisted surgery Artificial discs

7. New Clinical Knowledge: RCTs • Fusion results in better pain and function outcome in patients with spondylolisthesis. • Fusion with instrumentation results in a higher fusion rate. • Instrumentation is associated with a higher complication rate. • Artificial disc replacement may avoid complications of fusion.

8. Normal Degeneration

9. Biochemical Changes • Water content • Proteoglycan content • Chondroitin to sulfate ratio • Collagen network

10. Collagen Repetitive Sequence (GLY – X – Y ) X: proline Y: hydroxyproline Triple helix Tryptophan substitution?

11. Ala-KokkoScience 1999JAMA 2001 Spine 2002 Col9A2: Glutamine  Tryptophan Disc disease 6/157 (vs. 0/174 controls) COL9A3: Arginine  Tryptophan Disc disease 12% (vs. 5% controls) Trp allele  3X risk for disc disease

12. Association with Collagen IX Tryptophan Alleles Matsui, Mirza, Eyre JBJS-B 2004

13. Association with Collagen IX Tryptophan Alleles

14. Spinal Stenosis with Spondylolisthesis

17. Potential Physiological Basis for Disc-associated Back Pain • Initiation of a chemotactic response • Vascular ingrowth • Increased sensory innervation • Endplate cartilage defects • Inflammation

18. Variation

19. Ratio of Back Surgery Rates Deyo, Mirza CORR 2006

20. Variation in Lumbar Fusion Rates Per 1000 Medicare Enrollees 2002-2003 Weinstein, Lurie et al Spine 2006

21. Deyo, Mirza CORR 2006

22. Variation in Lumbar Fusion Rates Rate Per 1000 Medicare Enrollees Weinstein, Lurie et al Spine 2006

23. Variation in Lumbar Surgery Rates LaminectomyFusion Variation in Regional Rates8X20X Weinstein, Lurie et al Spine 2006

24. Causes of Variation • Lack of scientific evidence • Financial Incentives and Disincentives • Clinical Training and Professional Opinion • New technology Weinstein, Lurie et al Spine 2006

25. Growth

26. Procedure Comparisons (2001) Deyo, Nachemson, Mirza NEJM 2004

27. Annual Number of Operations in U.S. Data from National Inpatient Sample, HCUP/AHRQ Deyo, Nachemson, Mirza NEJM 2004

28. Inpatient Medicare Reimbursement Weinstein, Lurie et al Spine 2006

29. Inpatient Medicare Reimbursement 19922003 Rate of Lumbar Fusion 30 per 100k 110 per 100k Spending for Lumbar Fusion $75 million $482 million Percent Spending for Fusion 14% 47% Weinstein, Lurie et al Spine 2006

30. Deyo, Mirza et al Spine 2005

31. Deyo, Mirza et al Spine 2005

32. Deyo, Mirza et al Spine 2005

33. Deyo, Mirza et al Spine 2005

34. Deyo, Mirza et al Spine 2005

35. Deyo, Mirza et al Spine 2005

36. Office Visits for Back Pain Deyo, Mirza, Martin Spine 2006

37. National Health Interview Survey 2002 Deyo, Mirza, Martin Spine 2006

38. National Health Interview Survey 2002 Deyo, Mirza, Martin Spine 2006

39. National Health Interview Survey 2002 Deyo, Mirza, Martin Spine 2006

40. US Prevalence of Back Pain Deyo, Mirza, Martin Spine 2006

41. US Prevalence of Back Pain Deyo, Mirza, Martin Spine 2006

42. Potential Financial Conflicts of Interest

44. Favorable Results in Industry-Sponsored Research SponsorOdds Ratio95% CI Sponsor of study 3.6 2.6 to 4.9 For-profit organizations 5.3 2.0 to 14.4 Manufacturer of drugs 8.0 1.1 to 53.2 Spinal device manufacturer 3.3 2.4 to 4.5 Jacobs, Galante, Mirza, Zdeblick JBJS 2006

45. Favorable Results Field Industry-fundedIndependent Spine 73% 44% Hip 93% 37% Knee 75% 20%

46. “Surgeons have often touted procedures that ultimately proved to be disappointing.” April 8, 2002

47. April 8, 2002 “Trisha Bryant assumed that the procedures her surgeon recommended were necessary and had been validated by research. I, too, made that assumption….If Trisha had explored the medical literature, however, she would have discovered that every aspect of her case– the interpretation of the MRI scan, the diagnosis of spinal instability, the rationale for fusing vertebrae, the impending discography– was controversial…”

48. April 8, 2002 “… within the surgical profession there’s a curious gap between rhetoric and reality.” “Spinal instability is routinely given as a diagnosis to these patients with chronic lower-back pain. It is a term used to justify an operation. And it is a great diagnosis, because it can’t be directly disproved.” Surgeon who performs two to three spinal fusions a week. “Each approach to diagnosis and treatment is essentially a franchise, and there are too many franchises battling.” Seth Waldeman Pain Medicine, HSS

49. Conclusions • Biological basis for “discogenic back pain” is not known. • Rates of lumbar fusion for chronic back pain have increased without increase in prevalence of back pain. • Investigator-sponsor financial conflicts are common.