AJCC April 2000

When Do Patient's with Lower Back Problems Need Surgery?

by Gregg J. Carb, D.C. & Al Ueda, D.C.

Chiropractic Doctors of all kinds see a lot of lower back pain cases. Surveys we’ve all read in the past show that lower back pain is one of the most frequent reasons for a patient to initiate a visit to the chiropractor. A significant number of lower back pain cases treated in chiropractic offices involve radiation of pain into the leg(s), and a certain fraction of those cases will appropriately require surgery. For the benefit of patient management, and for that matter risk management, the indications for considering surgical consultation in lower back pain and lumbar radiculopathy cases are reviewed in this article. Additionally, Dr. Carb will share some personal experiences with lumbar spine surgery.

From the Literature

In a study1 of 513 patients evaluated at 3 months after surgery for lumbar discectomy, stepwise logistic regression showed six clinical variables as independently predictive of a good outcome: absence of back pain, absence of a work-related injury, radicular distribution pain extending to the foot, leg pain on SLR, absence of back pain on SLR, and reflex asymmetry. Sensory deficits predicted good outcomes only in those patients with the best pre-surgical prognoses based on the above variables. Age, motor deficit and obesity did not correlate with outcome. In conclusion, patients with the purest radicular syndromes had the best results, and those with the least evidence of radiculopathy the poorest.

A prospective study2 evaluated the appropriateness of surgical indications for herniated lumbar intervertebral disc or spinal stenosis in 328 patients, and measured outcomes on one year follow-up. The criteria used to assess appropriateness were formulated using a method developed by the RAND Corporation. Two-thirds of the patients fit into seven clinical criteria that involved: pain in the lower limb, imaging suggestive of discal hernia or spinal stenosis, major (progressive weakness / + contralateral SLR) or minor (asymmetric reflex / sensory deficit / + ipsilateral SLR / sciatica) neurological findings, and activity restriction ranging from 2 weeks to 6 weeks. In all, indications for 126 patients were considered inappropriate, the vast majority because a) preoperative duration of conservative treatment was too short, or b) insufficient duration of severe activity restriction before surgery. A significant difference between the level of appropriateness and outcome was not found. This study was conducted in Switzerland where rates for lumbar spine surgery are lower than the U.S. due to more careful patient selection. Based on the above clinical criteria, the majority of patients fit into highly suggestive of radiculopathy. It is not surprising that appropriateness and outcomes were not necessarily related, particularly in view of the reasons most cases were considered inappropriate.

According to AHCPR guidelines,3 within the first 3 months of acute low back symptoms, surgery is considered only when serious spinal pathology or nerve root dysfunction obviously due to a herniated lumbar disc is detected. A disc herniation, characterized by protrusion of the central nucleus pulposus through a defect in the outer annulus fibrosis, may trap a nerve root causing irritation, leg symptoms and nerve root dysfunction. The presence of a herniated lumbar disc on an imaging study, however, does not necessarily imply nerve root dysfunction. Studies of asymptomatic adults commonly demonstrate intervertebral disc herniations that apparently do not entrap a nerve root or cause symptoms.

Therefore, nerve root decompression can be considered for a patient if all of the following criteria exist: sciatica is both severe and disabling, symptoms of sciatica persist without improvement for longer than 4 weeks or with extreme progression, there is strong physiologic evidence of dysfunction of a specific nerve root with intervertebral disc herniation confirmed at the corresponding level and side by findings on an imaging study.

Patients with acute low back pain alone, without findings of serious conditions or significant nerve root compression, rarely benefit from a surgical consultation. Many patients with strong clinical findings of nerve root dysfunction due to disc herniation recover activity tolerance within 1 month; no evidence indicates that delaying surgery for this period worsens outcomes. With or without an operation, more than 80 percent of patients with obvious surgical indications eventually recover. Surgery seems to be a luxury for speeding recovery of patients with obvious surgical indications but benefits fewer than 40 percent of patients with questionable physiologic findings.

Personal Experience With Surgery

About eleven years ago, I had an L5 diskectomy and partial facetectomy for an 8mm extruded disc. The nucleus of the L5 disc had expelled centrally behind the L5 vertebral body into the vertebral canal and also left into the intervertebral foramen. This caused unresolved moderate lower back and left leg pain, and slight calf muscle wasting for several months. The purpose of the surgery was to decompress the L5 and S1 roots by removing the extruded disc material and shaving the articular facet about 10% to open the intervertebral space for exit of the L5 nerve root.

Earlier this year, I re-injured the lumbosacral region performing a heavy leg press exercise. The next day I was bending over to adjust the last patient of the day and experienced very intense, immediate left upper gluteal/hip and lower leg/foot burning pain. There was no position that could relieve the pain. Only an ambulance ride to the hospital and administration of Demerol, Ativene, and Morphine partially relieved it. This is called severe, intractable, and unrelenting radicular pain.

An MRI was obtained which showed no frank disc herniation but rather large bone spurring – “ Impression: Postoperative changes at L5/S1 with a left-sided posterolateral osteophyte slightly elevating the S1 root and probably impinging the medial aspect of the foramina on that side.” (Figure 1 A & B plain films). That made perfect sense to me because Valsalva was negative but both lumbar flexion (tension on the nerve root) and extension (compression on the nerve root) greatly increased the hip and leg pain. At the time of the first injury to the disc a decade ago, with the large herniation, Valsalva was strongly positive as was Crossed Straight Leg Raise (pain down the involved leg when performing a SLR on the well side).

Click Below:

Figure 1A Figure 1B Figure 2

An L5 epidural was performed a few days later. This procedure is conducted under fluoroscopic control with delivery of Marcaine and Depo-Medrol (steroid) by injection, inserted adjacent to the L5 nerve root (Figure 2). Because the procedure is done with the patient in a prone position for proper imaging, thereby creating extension of the lumbosacral joint, and the injected material is a space-occupying, non-compressible fluid, my already irritable L5 nerve root became even more unhappy. Caution any patients undergoing this procedure with radiating symptoms that are aggravated by extension.

After failure of the nerve root block, or with the passage of time, to improve my condition in any capacity, I opted for surgical intervention. At this point, the findings were achy/burning pain just below the crest of the ilium medially and in the lateral calf, numbness/ burning across the dorsum of the left foot distally, and weakness of the foot and toe extensors (functional drop foot). The operative plan was to trace the nerve root from its emergence from the spine and remove any bony or soft-tissue impediments. During the procedure scar tissue was identified in the epidural space, the L5 nerve root was found deviated cephalad by an underlying large osteophyte and associated disc protrusion, which itself was extending laterally far enough to impress the dorsal sensory ganglion. A hemilaminotomy provided a posterior approach to the nerve root, medial facetectomy and foraminotomy, along with resection of the posterolateral disc / osteophyte fully decompressed the nerve root. RESULTS: Post-operative weight-bearing ability and proximal hip region pain improved 80% within a few weeks, distal sensory and motor disturbances have been slower to respond - nerve regeneration takes time.

Impressions

In patients where radiating leg pain is much worse than lower back pain (or lower back pain is absent), that’s a bad sign. Crossed straight leg raise is also a bad sign. When patients have truly severe radicular pain unrelieved by rest or any position (particularly with motor weakness or reflex asymmetry), you can take the guidelines for one month of conservative care and extended activity restriction prior to surgery and shove them. The literature reviewed points to surgery as an appropriate tool for the neurological decompression of spinal nerves in great distress. This gives the neurosurgeon a very specific operative target and goal. Surgery is generally or wholly inappropriate, without extensive conservative care and the passage of time, for mechanical back pain and questionable nerve root involvement. It is good chiropractic practice to be able to quickly identify those lower back problem patients in need of a good neurosurgeon. Those grateful patients should eventually return for chiropractic care to address the mechanical issues leading to the serious neural compromise.

References

1. Abramovitz J, Neff S. Lumab disc surgery: results of the Prospective Lumbar Discectomy Study of the Joint Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. Neurosurgery 1991; 29:2.

2. Larequi-Lauber T et al. Appropriateness of indications for surgery of lumbar disc hernia and spinal stenosis. Spine 1997; 22:2.

3. Acute Low Back Problems in Adults. Clinical Practice Guidelines. U.S. Department of Health and Human Services. AHCPR Publication No. 95-0642; 1994.