A 70-Year-Old Man With Back, Buttock, and Thigh Pain

Correct Answer: C

We diagnosed the patient with lumbar spinal stenosis (LSS), a common condition among an older, active population. Indeed, LSS is now the most frequent cause of spinal surgery in people older than 65 years of age.¹

To confirm an LSS diagnosis, the clinician should obtain either a computed tomography scan or magnetic resource imaging (MRI) confirmation for anatomic narrowing and stenosis of the lumbar spinal canal, and/or its neuroforaminal areas.² The typical symptoms and signs of LSS include:

• Pain or discomfort in the lower back, but even more so in the buttocks, posterior thighs, and into lower areas of the leg with walking
• Significant pain or discomfort upon standing with prompt relief immediately with sitting and improvement with lumbar flexion (bending forwards at the waist)
• Subjective feeling of leg weakness or fatigue
• Weakness of muscle groups, tingling or sensory loss, and wide-based gait²

A variety of scoring systems are available for LSS. These scoring systems take clinical findings and convert them into point systems with thresholds indicating the presence of LSS.² The presenting patient displays:

• High-risk age
• Pain while in the process of standing
• Sitting relieves pain or the pain decreases when performing lumbar flexion maneuvers
• Posterior leg pain with walking
• Good peripheral circulation (since vascular claudication is a main differential for LSS)
• Absence of a positive straight leg raising with an increase in pain (as a typical disc herniation causes this symptom and is a major differential for LSS as well)
• Loss of Achilles tendon reflex

Based on a clinical diagnostic support tool, where a score of 7 or greater increased the likelihood of the clinical syndrome of LSS, our patient scored 16 out of a maximum 17 points. Our patient also scored an 8 out of 10 in questionnaire-based score, wherein 5 or greater is positive for LSS.²

Patient follow-up. An MRI of the spine demonstrated radiologic evidence for LSS in the L4 – L5 – S1 region. A program of nonsteroidal anti-inflammatory drugs (NSAIDs) and physical therapy for 3 to 4 months has been initiated. There was improvement at 6 weeks from baseline Oswestry Disability index score of 31% to 40% to a current score of between 18% to 22% depending on the day, with 0% to 20% indicating “minimal disability” and 20% to 40% meaning “moderate disability".³ Many of the manifestations other than pain, such as foot/ankle weakness and plantar numbness, have resolved or significantly improved. As of this writing, the patient will continue nonsurgical therapy and is prepared to try spinal injections if needed after 4 months. He is quite hesitant to undergo back surgery if there is no significant worsening of his current status.

Discussion. LSS is thought to be an acquired degenerative condition in most patients wherein a combination of lumbar intervertebral disc degeneration and arthritic changes in the lumbar vertebrae (osteophyte formation of the bodies and posterior facets) result in circumferential narrowing of the spinal canal. The reduced space and the presence of periodic arthritic inflammation causes pressure on the nerve roots of the spinal nerves and cauda equina.¹

Another useful clinical parameter is the Oswestry back pain disability questionnaire, commonly used to measure functional disability, which uses 10 easily quantifiable questions to create a numerical score for low back functional outcomes.³

Management options for LSS range from very conservative (modified rest, NSAIDs) through intermediate (epidural steroid injections), to open spinal surgery (laminectomy or spinal fusions). There’s agreement that absent major motor deficit or full-blown cauda equina syndrome involving bowel and bladder, a course of several months of nonsurgical therapy should be implemented prior to the more aggressive alternatives. Patients who choose nonsurgical interventions should avoid impact activities like jogging or lifting weights but can perform lumbar flexion exercises and general conditioning with regular twice weekly visits to a physical therapist along with NSAIDs and/or acetaminophen as needed.

The next level of care is the use of spinal epidural injections. The literature is quite mixed regarding its use, with studies showing response rates as low as 32% and as high as 71% with endpoints of pain relief and avoidance of surgery^.2 There is general acceptance that such injections are a reasonable next step in LSS for short-term symptom relief.

Regarding the role of surgery, the data is somewhat conflicted. In one study, Weinstein and colleagues compared outcomes between 289 patients, randomized to surgery, (mostly laminectomy) and 365 patients randomized to observation and found “significantly more improvement in all primary outcomes” including bodily pain and physical function, as measured by either the 36-Item Short Form Survey or the far less complex and more useful modified Oswestry Disability Index.⁴ Subsequent review of this Spine Patient Outcomes Research Trial (SPORT) opined that the degree of bidirectional crossover, in which 33% of patients randomized to surgery did not undergo surgery and 43% randomized to observation had surgery, rendered intention to treat analysis “uninterpretable.”⁵ Further, the SPINE trial and others, which found better pain relief with patients having surgery did not have standardized nonoperative regimens in the observation groups, introduces the possibility of less attention bias to the control group.

More recent studies evaluated surgical vs non-surgical treatment in 169 patients with some degree of high crossover between groups. Investigators in this study provided a fixed, standardized, professional, nonoperative PT regimen and found similar results in the surgical, decompression, and PT groups for pain, relief, and physical function.6 Specifically measured were physical function and neurogenic symptoms (e.g. Oswestry Disability scores PT vs surgery 40.2 vs 42.6 at baseline; 33.1 vs 33.5 at 10 weeks; 28.5 vs 27.2 at 26 weeks; 29.5 vs 29.2 at 52 weeks and 27.0 vs 25.2 at 2 years).⁶ An interesting addition to the literature then added an evaluation of “real life, physical activity“ using “functional objective markers of functional improvement“ using the short physical performance battery, and the self-paced walking test demonstrated that, despite a lot of “improvement“ when filling out the subjective “short form 36“ and even the Oswestry disability Index, objective actual measurements of bona fide, measurable “real life” functional capacity in LSS patients - balance, gait, speed, and ambulation distance - did not significantly change after decompression surgery at 6 months.⁷

Put in this context, LSS surgery is not as definitively indicated and efficacious as, for example, cholecystectomy for gallbladder disease. Additionally, 3 to 4 weeks is too short of an interval to see results from nonsurgical measures before proceeding to more aggressive surgical options.  Therefore, Answer D is incorrect.

Answer A, microdiscectomy, is the preferred option for herniated discs lasting more than 4 months, and while this surgical procedure is a major advance in efficacy, safety, and long-term results in such cases⁸, the presented patient’s clinical findings support LSS rather than herniated disc. Additionally, radiologic findings would exclude or confirm a disc herniation in any event.

What’s the Take Home? LSS is a common, chronic condition and it is the most frequent cause for spinal surgery in the Medicare (older than age 65 years) population. Specific diagnosis requires the presence of both clinical and imaging criteria demonstrating encroachment and stenosis of the lumbar spinal canal. However, the presumptive diagnosis can be suggested by classical clinical findings, including age older than 65 years; pain in lower back and even more so in bilateral buttock, thigh, and gluteal areas; prompt pain relief with sitting and exacerbation when standing up; neurogenic claudication; and neurologic symptoms such as plantar and toe tingling and numbness, leg and ankle weakness, and reflex losses. Easily applied prediction rules and point schemes are available to aid diagnosis. Because LSS is a chronic condition and only slowly progressive, if at all, a time interval before proceeding to aggressive treatments is possible. While enthusiasm and positive results dominated the surgical literature a decade ago, more recent studies have shown little meaningful difference at 2 to 3 years between surgery and conservatively treated groups. Therapy decisions need to be critically discussed between patient and physician and position with patient choice being important and dogma and uncertainty being avoided.

References

1. Djurasovic M, Classman SD, Carreon LY and Dimar JR. Contemporary management of symptomatic lumbar spinal stenosis. Orthop Clin N Am. 2010;41:183-191
2. Suai P, Rainville J, Kalichman L and Katz JN. Does this older adult with lower extremity pain have the clinical syndrome of lumbar spinal stenosis? JAMA. 2010; 304: 2628-2637
3. Fairbank JT, Pynsent PB. The Oswestry disability index. Spine. 2000; 25: 2940-2953
4. Weinstein JN, Tosteson TD, Lurie JD et al. Surgical versus nonsurgical therapy for lumbar spinal stenosis. N Eng J Med. 2008; 358:784-810
5. Katz JN. Editorial surgery for lumbar spinal stenosis: Informed patient preference should weigh heavily. Ann Int Med. 2015;162:518-519
6. Delitto A, Piva SR, Moore CE, et al. Surgery versus nonsurgical treatment for lumbar spinal stenosis. Ann Int Med. 2015;162:465-473.
7. Smuck M, Meuremi A, Zheng P, et al. Objective measurement of function following lumbar spinal stenosis decompression reveals improved function capacity with stagnant real-life physical activity. Spine J. 2018;18:15-21.
8. Bailey CS, Rasoulinejad P, Taylor D et al. Surgery versus conservative care for persistent sciatica lasting 4-12 months. N Eng J Med. 2020;382:1093-1102.