Lower Back Pain

1. Lower Back Pain Does the evidence support a surgical solution? Jennifer Holliday, MS4 August 24, 2007

2. Lower back pain (LBP) is a common complaint • 80% of persons in the US have had LBP at some point in their lives • Back pain results in more lost productivity than any other medical condition • Most patients who seek treatment are treated medically • However, many people also receive surgery – 4% of US persons will have spinal surgery at some point in their lives • Most patients who present to primary care with LBP have pain that cannot be attributed to a specific dz or spinal pathology (ie non-specific low back pain)

3. Most Common Indications for Spinal Surgery for LBP • Lumbar disc herniation • Lumbar spinal stenosis • I will discuss both of these

4. Lumbar Disc Herniation • Epidemiology • Most often between 30-50 years of age, M:F 2:1 • Usually in otherwise healthy people • At L4-L5 and L5-S1 level • Risk factors include male sex, obesity, smoking, occupations that involve prolonged sitting, repetitive twisting motions • Pathophysiology • Age leads to degenerative changes that may result in herniation of nucleus pulposus or annulus fibrosis beyond the intervertebral disc space, into spinal canal • Pain from mechanical and biochemical irritation of adjacent nerve roots

5. Lumbar Disc Herniation, Cont. • Symptoms • LBP brought on by heavy exertion, repetitive bending, twisting, heavy lifting • May begin in lower back and radiate to sacroiliac region and buttocks • Can radiate down posterior thigh • Pain can often be elicited by palpating different parts of spine including facet joints, longitudinal ligaments and vertebral periosteum • May have radicular pain extending below the knee following the dermatome of the involved nerve root • Pain is relieved by rest • More severe cases may have weakness, paresthesias, cauda equina syndrome

6. Lumbar Disc Herniation, Cont. • Physical Exam • Depends on level of herniation • Positive results on straight-leg raise • Reflex, sensory, motor deficits • Point tenderness over spinous process at level of disc involved • Diagnosis • Plain radiographs may be necessary to rule out other etiologies of pain such as infection, tumors or other anomalies • MRI is the image of choice

7. Clinical Findings of Common Lumbar Disc Herniations From Townsend: Sabiston Textbook of Surgery, 17th Ed.

8. Diagnosis of Lumbar Disc Herniation • MRI– here can see bulge of disc into spinal canal

9. Therapy of Lumbar Disc Herniation • Medical, non-surgical therapies • Brief bed rest (2 days) • NSAIDs • Exercise and PT • Epidural steroid injections • Surgical Therapy

10. So, surgery? Advertisement from The Center in Bend, Oregon.

11. Surgery for Lumbar Disc Herniation • If non-surgical treatment fails, surgery can be considered • Persistent disabling symptoms after 4-6 weeks of non-surgical therapies • Surgery will neither stop the pathological process that allowed the herniation to occur nor restores it back to a normal state • Types of surgical procedures • Open disc excision • Microlumbar disc excision

12. Evidence • Randomized trials comparing surgery to non-surgical management for lumbar disc herniation with persistent radiculopathy indicate that patients who undergo surgery improve faster, but outcomes appear similar within two years

13. Regional Variation in Surgery Rates • From 1996-1997, 44,088 patients w/ lumbar disc herniation in Medicare-eligible population had spinal surgery • Rate of surgery varied from 0.24/1000 persons in York, PA to 1.96/1000 persons in Boise, ID • National avg was 0.64/1000 • Geographic variation in rates appears to correlate with MRI use

14. Ratio of Rates of Surgery for Lumbar Disc Herniation Check us out!

15. Early Study Leading to Guidelines on Management of Acute Low Back Pain From Weber H. 1982 Lumbar disc herniation. A controlled, prospective study with ten years of observation. Spine. 1983;8:131-40. As cited in Birkmeyer NJ and JN Weinstein. Medical versus surgical treatment for low back pain: evidence and clinical practice. Effective Clinical Practice: September/October 1999.

16. Lumbar Spinal Stenosis • Can refer to ≥ 1 of the following: • Narrowing of intraspinal canal • Narrowing of lateral recess • Narrowing of neural foramen • Etiologies: • Spondylosis (degenerative arthritis affecting the spine) is MOST COMMON cause • Other acquired causes: space-occupying lesions, traumatic and postoperative causes, skeletal diseases • Congenital causes: dwarfism, spinal dysraphism

17. Lumbar Spinal Stenosis Cont. • Pathophysiology • Mechanical compression and ischemia of nerve roots is most accepted etiology of pain • Is either direct from mechanical compression or indirectly from intrathecal pressure, which increases as canal area is reduced • Clinical Presentation • Neurogenic claudication – pain exacerbated by walking, standing, relieved by sitting or lying • Sx include discomfort, sensory loss, leg weakness which are usually bilateral

18. Lumbar Spinal Stenosis, Cont. • Physical Exam: • Neurologic exam often normal • DTRs can be diminished, esp. distally • May have focal weakness/sensory loss in distribution of spinal nerve roots • Diagnosis • Plain films can sometimes be helpful, but • MRI is modality of choice • Criteria to define stenosis vary, and should be interpreted in clinical context, as spinal stenosis can be a frequent incidental finding.

19. MRI of Lumbar Spinal Stenosis Narrowing of spinal canal

20. Lumbar Spinal Stenosis, Cont. • Treatment • Conservative, non-surgical tx should precede surgical tx • PT • NSAIDs, analgesics • Epidural steroid injections

21. Surgery? • Usually recommended after non-surgical options have not worked • May be beneficial in patients w/ persistent symptoms • Procedures • Decompressive laminectomy with/without fusion/discectomy • Outcomes reported by patients better initially after surgery vs. non-intervention comparison group, however at longer term follow-up, outcomes are comparable and significant differences are difficult to demonstrate

22. Regional Variation in Surgery Rates • For 1996-1997, 58,556 patients w/ spinal stenosis in Medicare-eligible population had spinal surgery • Rate of surgery for spinal stenosis varied 12-fold, from 0.29/1000 persons in Johnson City, TN to 3.34/1000 persons in Bend, OR

23. Ratio of Rates of Surgery for Spinal Stenosis Again, check us out.

24. What explains these regional variations? • Lack of consensus among clinicians about indications for surgical procedures • For example, rates of surgery for hip fractures vary little by geographic region • This is because there is little ambiguity regarding diagnosis and treatment of this problem • Physicians differ in their definitions of failure of non-surgical therapy, thresholds for radiologic definitions of disease and in how they interpret patient symptoms and physical exam findings • Clinical decisions are also driven by patient preferences • Rigorous newspaper ads promoting surgery as solution to pain will influence this • Wide degree of variation reflects clinical uncertainty and is attributable to lack of high-quality evidence

25. Lack of Evidence! • Sparse data on efficacy of non-invasive interventions in patients with spinal stenosis or lumbar disc herniation • Many confounding variables in studies that do exist, such as factors contributing to patients’ choice of treatment, expectations of results from treatment and perception of symptoms • Studies comparing surgery to “usual care” may not be adequate comparison, as a more appropriate comparison may be a comprehensive rehabilitation program • Therefore most studies with findings of surgical benefits compared to usual care are not necessarily useful to clinicians

26. Example of Difficult Comparison • Weinstein et al. (2006) • Prospective observational cohort study of surgical candidates with lumbar disc herniation • Outcome measure: patient-reported improvements in disability index • Showed small but statistically significant differences in favor of discectomy compared with “usual care.” • However large number of patients crossed over between assigned groups, which precludes any conclusions about comparative effectiveness • Take-home point: nonrandomized comparisons of self-reported outcomes are subject to potential confounding and must be interpreted cautiously

27. Examples of Existing Quality Studies • Brox et al. (2003) • Blind, randomized study of 64 patients comparing lumbar instrumented fusion with cognitive intervention and exercises in patients with chronic low back pain and disc degeneration • Main outcome measure of disability index showed equal improvement in both groups • However, small sample size and again, patient reported outcome measure

28. Take-Home Points • Little evidence indicates that surgery is better than medical therapy for lumbar disc herniation and spinal stenosis • In evidence that does exist, short-term outcomes may be better for patients w/ persistent symptoms in the short-term after surgery • However, this difference attenuates w/ long-term follow-up • The above trends in evidence data are true for both lumbar spinal stenosis and lumbar disc herniation • Across geographic regions in the US, there is an 8-fold variation in rates of surgery for lumbar disc herniation and a 12-fold variation in surgery rates for spinal stenosis

29. Pearl of Wisdom for Future PCPs • Consider psychosocial characteristics of your patients before you consider methods of treatment • Such as: willingness to return to work, willingness to rehabilitate according to recommended plan post-op • If the alternative option to surgery for your patient is “usual care,” you might be better off referring patients with persistent symptoms to surgery • However, if you can access comprehensive services involving exercise, behavior therapy, etc., these should be used prior to surgical referral

30. Frustrating Conclusion • We need more evidence! • We need better data on when to do surgery • We need less advertising by surgeons with obvious financial benefit

31. Thank You • Roger Chou, MD, who provided me with his research on similar topics at the Oregon Evidence-based Practice Center

32. References Birkmeyer NJ and JN Weinstein. Medical versus surgical treatment for low back pain: evidence and clinical practice. Effective Clinical Practice: September/October 1999. Brox JI et al. Randomized clinical trial of lumbar instrumented fusion and cognitive intervention and exercises in patients with chronic low back pain and disc degeneration. SPINE 2003 28(17):1913-1921. Canale: Campbell’s Operative Orthopaedics, 10th Ed. Lumbar Disc Disease. Chou, R. Treatment of subacute and chronic low back pain. Pending publication on UpToDate at www.utdol.com. Fairbank J et al. Randomised controlled trial to compare surgical stabilisation of the lumbar spine with an intensive rehabilitation programme for patients with low back pain: the MRC spine stabilisation trial. BMJ, doi:10.1136/bmj.38441.620417.BF (published 23 May 2005). Jordan J et al. Herniated lumbar disc. BMJ Clinical Evidence 2005;12:1118. Townsend: Sabiston Textbook of Surgery, 17th Ed. Weinstein JN et al. Surgical vs nonoperative treatment for lumbar disk herniation. JAMA 2006;296(20):2451-2459.