Surgery Section - Lumbar Spine Surgery

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Conditions that may necessitate surgery of the lumbar spine include infection, tumor, vertebral fracture, cauda equina syndrome, spondylolysis with or without spondylolisthesis, herniated disc, lumbar spinal stenosis, axial pain and sciatica. If the initial evaluation does not reveal the possible presence of an underlying serious condition, such as fracture from major trauma or osteoporosis, tumor, infection, or cauda equina syndrome, which would indicate the need for additional diagnostic testing, the appropriate treatment is usually conservative.

Spondylolisthesis is the slippage of all or part of one vertebra onto another. The term is derived from the Greek spondylous, meaning "vertebra", and olithesis, meaning "to slip or slide down a slippery incline." Spondylolisthesis has a number of etiologies: congenital, also known as dysplastic spondylolisthesis; isthmic, resulting from a lesion in the pars interarticularis; degenerative spondylolisthesis resulting from long-standing intersegmental instability; postsurgical due to partial loss of discogenic support; posttraumatic usually due to acute fracture of the bony hook other than the pars; and, pathologic due to local bone disease.

Lumbar spinal stenosis (LSS) represents a degenerative condition of the spinal canal that develops as the lower spine narrows and deteriorates with the normal wear and tear of aging. This deterioration may lead to compression of the nerves of the lower back, causing pain in the lower back, as well as pain, loss of sensation and weakness in the legs. LSS is generally characterized by a dull, intermittent pain in the lower back that comes on with walking or standing, and radiates to the buttocks and into one or both legs. In severe cases patients can lose strength and motor function in the legs as well as bladder or bowel control.

The individual lumbar nerves and sacral nerves join to form the cauda equina, or "horse's tail" at the termination of the spinal cord, or conus medullaris. The conus medullaris usually overlies the body of L1. Compression of these nerve roots results in loss of function. Cauda equina syndrome has been described as a complex of symptoms and signs consisting of low back pain, unilateral or bilateral sciatica, motor weakness of the lower extremities, sensory disturbance, and loss of visceral function (i.e., bowel and bladder function) together with saddle anesthesia.

Sciatica is pain radiating down the legs in a sciatic nerve distribution. Symptoms are generally secondary to mechanical pressure and inflammation of the nerve roots. This may be due to a herniated disc or other mechanical pressure (e.g., from bone, or from muscle spasm surrounding the sciatic nerve within the pelvis -- "pyriformis syndrome" is a common example). Because of the varied causes, sciatica alone is not a good indicator of nerve root compression.

Herniated disc is protrusion of the cartilaginous material between the vertebra. Herniated disc is classified depending on the degree of herniation:

• In protruded (bulging) disc the central mass of the disc has fissures intruding into the ruptured inner fibers of the annulus. The peripheral fibers are still intact but generally allow the disc to bulge. Presumably the bulge is large enough to cause mechanical pressure on the adjacent nerve root.
• In an extruded disc (ruptured contained disc) the nuclear material has also penetrated the outer fibers of the annulus, but the prolapsed tissue is connected to the central part of the disc and the posterior longitudinal ligament is intact.
• In a sequestered disc the ligament is now ruptured, and one or more fragments of the herniated mass are extruded into the spinal canal. The sequestered disc tissue may migrate caudally, cranially, or laterally into the foramen.

Surgery is sometimes performed to decompress the affected nerves of the lower back in cases of lumbar spine stenosis, herniated disc and spondylolisthesis.

Fusion of the interdiscal space following decompression is done to provide support to an unstable area. Spine fusion of any type is generally performed when well-defined instabilities can be identified, in patients undergoing laminectomy and have spondylolisthesis, or patients with adult scoliosis. Performing fusion with primary discectomy may not be indicated. The determination of instability can often easily be made from radiographs and CT myelography or MRI scans in cases of trauma, infection, tumor, and deformity. However, potential instability of degenerative origin can be anticipated when required decompression will leave the motion segment significantly compromised, especially in cases of preexisting instability in the sagittal, coronal, or combined planes. Controversy exists as to indications for fusion in cases of painful motion segments of discogenic origin.

Pedicle screws, spine cages, wires, and other instrumentation used as an adjunct to fusion is recommended when the affected area shows evidence of instability or has had additional destabilizing procedures, such as a discectomy or facetectomy. Spinal fusion is generally not necessary for a routine decompressive laminectomy for lumbar stenosis. The association of improved clinical outcome with instrumentation and fusion in patients with degenerative disease has not been established by randomized controlled trials comparing instrumentation to older methods using bone grafts alone. There is clear evidence that failure of fusion seems to result in a poor surgical outcome. It is also well-documented that instrumentation improves the fusion rate. However, It is not yet known whether the addition of instrumentation improves long-term health outcomes.

Policy/Criteria

1. Acute Low Back Pain
1. If the initial evaluation of low back pain, with a focused medical history and physical examination, does not reveal the possible presence of an underlying serious condition, such as an acute herniated disc with significant neurologic deficits, cauda equina syndrome, or fracture which would indicate the need for additional diagnostic testing, the appropriate treatment would usually be conservative. This may include:
   1. Limited activity restriction, with return to normal activities as soon as possible
   2. Medications such as acetaminophen, NSAIDs, muscle relaxants, or opioids
   3. Patient education about back problems
   4. Reassurance to the patient that recovery is expected.
2. If the patient does not improve within 2 weeks*, appropriate treatment may include:
   1. A review of the history and physical findings
   2. Reassurance to the patient that recovery is expected
   3. Support for returning to work or required daily activities
   4. Muscle conditioning exercises
   5. Trial of a lumbar support
   6. A/P lateral x-rays or flexion-extension xrays
3. If the patient does not improve within 6 weeks*, there may be a need for more definitive diagnostic measures. These may include:
   1. CBC, ESR, MRI, CT and CT myelography, electrodiagnostic studies, bone scan,
   2. EMG (may include SEP after age 50)
   3. Consultation with surgeon about appropriate imaging studies to define the pain generator(s).
   4. Additional physical examination to identify physiologic or anatomic evidence which would indicate nerve root compression

*Time periods may be waived depending on findings indicating clinical urgency

2. Chronic Low Back Pain
1. Presurgical Review

   In patients whose low back pain persists longer than 6 weeks* and there is a specific problem which has been defined by the physiologic evidence and imaging studies, a presurgical review should include the following:

1. Thorough education of member regarding treatment alternatives, benefits and risks.
2. Evidence of an active rehabilitation program to include, on average, 4 to 6 visits of supervised physical therapy to gain understanding and knowledge to manage chronic back pain and a trial of a regular low-impact aerobic exercise program.
3. The discussion concerning surgical treatment options should include short- and long-term outcomes.
4. In order for surgery to be considered medically necessary, there should be an identified specific mechanical problem causing the prolonged pain or urgent neurologic deficit/hazard and the surgery must be appropriate to correct the problem.

*Time periods may be waived depending on findings indicating clinical urgency.

Note: There is not consensus among spinal surgeons about the most appropriate treatment approach to many cases where surgery is one option. The importance of a well-informed patient participating in the decision for surgery is paramount. Prior review (or retrospective review if preauthorization has not been obtained) will be conducted according to the medical necessity criteria stated in this policy, and coverage may be denied if criteria are not met. Offering an education opportunity to the member is an option for the Regence health plan, and may or may not be available.

3. Surgical Options

In order for any of the following surgical options to be considered medically necessary, the procedure must be recommended by the treating surgeon.

1. Laminectomy with microdiscectomy may be considered medically necessary treatment for a herniated disc with accompanying radiculitis/radiculopathy and radicular pain which has not responded to non-surgical treatment as described. All patients should have MRI and/or CT myelogram evidence of a lesion corresponding to symptoms. Criteria for diagnosis of radicular syndrome include:
   1. Leg pain is predominant symptom
   2. Neurologic symptoms are specific (e.g., pain in a typical dermatomal distribution)
   3. Nerve tension signs occur: Straight leg raise less than 50% of normal; bowstring discomfort; crossover pain; or any combination of these
   4. Neurologic signs: sensory loss, or reflex alteration. Weakness and wasting may be surgical indications in and of themselves if correlated with imaging findings.
2. Decompression with or without discectomy may be considered medically necessary for Cauda equina syndrome.
3. Spinal fusion may be considered medically necessary for conditions that will result in mechanical instability of the spine, such as:
   1. Fractures
   2. Tumors
   3. Infection with two or three level involvement
   4. Adult scoliosis
   5. Isthmic spondylolisthesis
   6. Iatrogenic instability
   7. Degenerative spondylolisthesis with radiographically proven unstable olisthetic level or findings of radicular syndrome (see A through D above for criteria for radicular syndrome)
   8. Patients undergoing laminectomy and who have spondylolisthesis
   9. Disc herniation in patients with a large central disc herniation, where facet joint excision exceeds 50% or more bilaterally or complete excision of one facet is performed. Patients who are undergoing a subsequent surgery at the same disc segment that was operated on before may also be candidates for a fusion.
   10. Chronic, severe and significantly disabling low back pain from degenerative disc disease which has failed to respond to non-surgical measures (as described in No. 1 above), is of more than six months’ duration, and fusion is recommended by the treating surgeon.  Members who appear unlikely to benefit from surgery for psychological/motivational or other reasons may be poor candidates for surgery. Member should be thoroughly educated regarding alternatives, benefits and risks and demonstrate realistic expectations from surgery. Interbody fusions for chronic and disabling low back pain may be indicated at either one or two contiguous levels. Theoretically, these patients suffer from degenerative lumbar disc that creates microinstability which causes the low back pain. If the micromotion is eliminated through spine fusion, clinical symptoms may be reduced or eliminated. The surgical success results have been mixed, 60 to 70 percent improved, which are comparable to the natural history of improvement without surgery over the long term.
   11. Lumbar spinal stenosis when one of the following criteria are met:
       1. When decompression is performed in an area of segmental instability as manifested by gross movement on flexion-extension radiographs
       2. When the decompression coincides with an area of degenerative instability, as with scoliosis or spondylolisthesis
       3. When the decompression creates an iatrogenic instability by the disruption of the posterior elements where facet joint excision exceeds 50% bilaterally or complete excision of one facet is performed
       4. Patients with prior fusion who are currently undergoing adjacent laminectomy
4. Spinal instrumentation may be considered medically necessary as an adjunct to fusion in the following instances:
   1. Patients with lumbar spine trauma resulting in fracture
   2. Patients with local infection causing injury to the spine
   3. Following tumor excision of the lumbar spine
   4. Patients with isthmic spondylolisthesis
   5. Patients requiring multi-level fusions
   6. Adjacent to prior fusion
   7. Patients who are smokers
   8. Patients with degenerative conditions when one or both of the following criteria are met:
      1. The degenerative area shows evidence of instability on flexion-extension films
      2. The patient has had additional destabilizing procedures, such as a discectomy or facetectomy
5. Based on a lack of evidence from well-designed clinical trials, spine instrumentation is considered investigational as an adjunct to fusion for degenerative conditions that do not meet the criteria in III.D.8, including but not limited to the following:
   1. Grade 2 degenerative spondylolisthesis
   2. Spinal stenosis without nerve root impingement
6. Cage support may be considered medically necessary  in the following instances if supported by an independent second surgical option:
   1. Anterior cage support in grade 2 spondylolisthesis
   2. Posterior cage support in any case of spondylolisthesis

Cross References

Spinal Cord Stimulation for Treatment of Pain, Regence Medical Policy Manual, Surgery, Policy No. 45

Lysis of Epidural Adhesions Using Hypertonic Solutions and/or Epidural Catheters, Regence Medical Policy Manual, Surgery, Policy No. 94

Surgery for Degenerative Diseases of the Cervical Spine, Regence Medical Policy Manual, Surgery, Policy No. 103

Percutaneous Intradiscal Electrothermal Annuloplasty (IDET) and Percutaneous Intradiscal Radiofrequency Thermocoagulation, Regence Medical Policy Manual, Surgery, Policy No. 118

Artificial Intervertebral Disc, Regence Medical Policy Manual, Surgery, Policy No. 127

Decompression of Intervertebral Discs Using Laser (Laser Discectomy) or Radiofrequency Energy (Disc Nucleoplasty™), Regence Medical Policy Manual, Surgery, Policy No. 131

Facet Joint Injections, Regence Medical Policy Manual, Surgery, Policy No. 135

Lumbar Dynamic Stabilization, Regence Medical Policy Manual, Surgery, Policy No. 143

Percutaneous Discectomy, Regence Medical Policy Manual, Surgery, Policy No. 145

Interspinous Distraction Devices (Spacers), Regence Medical Policy Manual, Surgery, Policy No. 155

Trans-Sacral Lumbar Interbody Fusion, Regence Medical Policy Manual, Surgery, Policy No. 157

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