Description

Lumbar spinal fusion (arthrodesis) is a surgical technique that involves fusing 2 or more lumbar vertebrae using local bone, autologous bone taken from the iliac crest of the individual, allogeneic donor bone, or bone graft substitutes.

Criteria

Lumbar spinal fusion may be considered medically necessary for any one of the following conditions:

• Spinal stenosis with both of the following:
  • Any one of the following:
    • Associated spondylolisthesis demonstrated on plain x-rays; or
    •  Spinal instability demonstrated on imaging studies; or
    • Spinal instability is anticipated due to need for bilateral or wide decompression with facetectomy or resection of pars interarticularis; and
  • Either of the following
    • Neurogenic claudication or radicular pain that results in significant functional impairment in an individual who has failed at least 3 months of conservative care and has documentation of central/lateral recess/or foraminal stenosis on magnetic resonance imaging or other imaging, or
    • Severe or rapidly progressive symptoms of motor loss, neurogenic claudication, or cauda equina syndrome
•  Severe, progressive idiopathic scoliosis with either of the following:
  • Cobb angle greater than 40°
  • Spinal cord compression with neurogenic claudication or radicular pain that results in significant functional impairment in an individual who has failed at least 3 months of conservative care
• Severe degenerative scoliosis (i.e., lumbar or thoracolumbar) with a minimum Cobb angle of 30°, or significant sagittal imbalance (e.g., sagittal vertical axis >5 cm), and with any one of the following:
  • Documented progression of deformity with persistent axial (nonradiating) pain and impairment or loss of function unresponsive to at least 1 year of conservative therapy
  • Persistent and significant neurogenic symptoms (claudication or radicular pain) with impairment or loss of function, unresponsive to at least 1 year of conservative nonsurgical care
  • Severe or rapidly progressive symptoms of motor loss, neurogenic claudication, or cauda equina syndrome
• Isthmic spondylolisthesis, when all of the following are present:
  • Congenital (Wiltse type I) or acquired pars defect (Wiltse type II), documented on x-ray; and
  • Persistent back pain (with or without neurogenic symptoms), with impairment or loss of function
• Recurrent, same-level disc herniation, at least 3 months after previous disc surgery, when all of the following are present:
  • Recurrent neurogenic symptoms (radicular pain or claudication) or evidence of nerve root irritation, as demonstrated by a positive nerve root tension sign or positive femoral tension sign or a corresponding neurologic deficit
  • Impairment or loss of function
  • Unresponsive to at least 3 months of conservative nonsurgical care or with severe or rapidly progressive symptoms of motor loss, neurogenic claudication, or cauda equina syndrome
  • Neural structure compression and instability documented by imaging at a level and side corresponding to the clinical symptoms
• Pseudarthrosis, documented radiologically, when all of the following are present:
  • No less than 6 months after initial fusion
  • With persistent axial back pain, with or without neurogenic symptoms, or with severe or rapidly progressive symptoms of motor loss, neurogenic claudication, or cauda equina syndrome
  • Impairment or loss of function, in an individual who had experienced significant interval relief of prior symptoms
• Instability due to fracture, dislocation, infection, abscess, or tumor when extensive surgery is required that could create an unstable spine
• Iatrogenic or degenerative flatback syndrome with significant sagittal imbalance; when fusion is performed with spinal osteotomy or interbody spacers
• Adjacent-level disease when all of the following are present:
  • Persistent back pain (with or without neurogenic symptoms) with impairment or loss of function that is unresponsive to at least 3 months of conservative therapy
  • Eccentric disc space collapse, spondylolisthesis, acute single-level scoliosis, or lateral listhesis on imaging
  • Symptoms and functional measures correlate with imaging findings

Conservative nonsurgical therapy for the duration specified should include the following:

• Use of prescription strength analgesics for several weeks at a dose sufficient to induce a therapeutic response
• Analgesics should include anti-inflammatory medications with or without adjunctive medications such as nerve membrane stabilizers or muscle relaxants; and
• Participation in at least 6 weeks of physical therapy (including active exercise) or documentation of why the individual could not tolerate physical therapy; and
• Evaluation and appropriate management of associated cognitive, behavioral, or addiction issues; and
• Documentation of individual compliance with the preceding criteria.

“Severely restricted functional ability” should generally include loss of function and/or documentation of inability or significantly decreased ability to perform normal daily activities of work, school, or at-home duties.

Persistent debilitating pain is defined as:

• Significant level of pain on a daily basis defined on a visual analog scale as a score greater than 4; and
• Pain on a daily basis that has a documented impact on activities of daily living despite optimal conservative nonsurgical therapy as outlined above and appropriate for the individual.

Lumbar spinal fusion is considered investigational if the sole indication is any one of the following conditions:

• Disc herniation
• Chronic nonspecific low back pain without radiculopathy
• Degenerative disc disease
• Initial discectomy/laminectomy for neural structure decompression

Lumbar spinal fusion is considered not medically necessary for any indication not addressed above.

Multiple-level lumbar spinal fusion is considered not medically necessary when the criteria listed above are not met for all levels.

Procedure Codes

Diagnosis Codes

Professional Statements and Societal Positions Guidelines

Practice Guidelines and Position Statements

North American Spine Society

The North American Spine Society (NASS; 2014) published coverage policy recommendations for lumbar fusion and made the following recommendations.

• In disc herniation who fulfill criteria for discectomy. The NASS recommends fusion for individuals who meet any of the following criteria:
  • Primary extraforaminal disc herniation is present at L5-S1, in which a far lateral approach is not feasible because of the presence of the iliac wings
  • Primary foraminal disc herniation for which facet resection is necessary to retrieve the disc, which will result in iatrogenic instability
  • Recurrent disc herniation
  • Primary disc herniation in the lumbar spine that is at the level of the spinal cord (i.e., low lying conus medullaris)
  • Lumbar spinal fusion is not recommended as an adjunct to primary excision of a central or posterolateral disc herniation at any level in the absence of instability or spondylolisthesis.
• In lumbar spinal stenosis who fulfill criteria for decompression. The NASS recommends fusion for individuals who meet any of the following criteria:
  • Dynamic instability is present, as documented by flexion-extension radiographs or comparison of a supine and upright image, defined as a difference in translational alignment between vertebrae greater than 2 mm between views
  • Spondylolisthesis (defined as at least 1-2 mm of anterolisthesis of the upper vertebra in relation to the lower vertebra) is present, either isthmic (i.e., secondary to a posterior arch stress fracture) or degenerative type
  • Cases in which decompression will likely result in iatrogenic instability, such as foraminal stenosis, during which greater than 50 percent of the facet joint will be removed to adequately decompress the exiting nerve root.*
  • Adjacent level disease, (e.g., stenosis) that has developed above or below a previous fusion
  • Recurrent stenosis (e.g., that which developed at a level that has been previously operated)

*For cases in which there is severe foraminal stenosis, adequate decompression often can require aggressive resection one or both facet joints at a particular level. Removal of an entire facet joint, even unilaterally, is generally thought to be a destabilizing event in the lumbar spine. While most cases of unilateral foraminal stenosis can be adequately decompressed with a nondestabilizing procedure, such as a foraminotomy, there are some cases in which the compression can be so severe and the orientation of the joint is such that achieving adequate decompression without producing iatrogenic instability can be difficult, if not dangerous to the underlying nerve root. This is a particular clinical scenario that would be exceedingly difficult to study that will likely not be addressed by a prospective, randomized trial (or other comparative trial for that matter). Recognizing this limitation in the evidence, that will likely persist, evidence-based medicine surgeons have made it clear that this should be reserved as a potential indication for fusion in the setting of stenosis without obvious signs of preoperative spondylolisthesis or instability.

• In individuals with pseudarthrosis in the lumbar spine. The NASS recommends fusion for individuals who meet all of the following criteria (a-d) or demonstrate presence of a gross failure of the instrumentation (e.g., pedicle screw breakage, screw loosening, curve/correction decompensation):
  • Mechanical low back pain that is approximately at the level of the pseudarthrosis, qualified as pain that can be somewhat positionally abated
  • A period of time following the index surgery during which the individual had symptomatic relief
  • Nonoperative care for at least 6 months
  • CT or plain films that are highly suggestive of nonunion at a lumbar segment at which a fusion had been previous attempted. These criteria include:
    • Lack of bridging bone
    • Dynamic motion noted on flexion-extension radiographs

Specific criteria were described for infection, tumor, traumatic injuries, deformity (e.g., scoliosis), stenosis, disc herniations, synovial facet cysts, discogenic low back pain, and pseudoarthrosis. NASS isolated situations where lumbar fusion would not be indicated: disc herniation in the absence of instability or spondylolisthesis; stenosis in the absence of instability; foraminal stenosis or spondylolisthesis; and discogenic low back pain.

Other 2014 guidelines from NASS addressed the diagnosis and treatment of degenerative lumbar spondylolisthesis. NASS gave a grade B recommendation to surgical decompression with fusion for the treatment of individuals with symptomatic spinal stenosis and degenerative lumbar spondylolisthesis to improve clinical outcomes compared with decompression alone. A grade C recommendation was given to decompression and fusion as a means to provide satisfactory long-term results for the treatment of individuals with symptomatic spinal stenosis and degenerative lumbar spondylolisthesis.

The 2011 NASS guidelines (updated in 2013) addressed multidisciplinary spine care for adults with a chief complaint of degenerative lumbar spinal stenosis. The guidelines indicated that the nature of the pain and associated individual characteristics should be more typical of a diagnosis of spinal stenosis than a herniated disc. NASS addressed whether the addition of lumbar fusion to surgical decompression improved surgical outcomes in the treatment of spinal stenosis compared with treatment by decompression alone. NASS gave a grade B recommendation (fair evidence) to decompression alone for individuals with leg predominant symptoms without instability.

The 2012 NASS guidelines (updated in 2014) addressed multidisciplinary spine care for the diagnosis and treatment of lumbar disc herniation with radiculopathy. The guidelines indicated that “there is insufficient evidence to make a recommendation for or against fusion for specific individual populations with lumbar disc herniation with radiculopathy whose symptoms warrant surgery. Recommendation: I (Insufficient Evidence).”

American Association of Neurological Surgeons and Congress of Neurological Surgeons

The 2014 guidelines from American Association of Neurological Surgeons and Congress of Neurological Surgeons addressed fusion procedures for the lumbar spine. These guidelines indicated that there was no evidence that conflicted with the recommendations formulated in the 2005 guidelines for fusion procedures for the lumbar spine (see Table 13).

Table 13. Guidelines on Fusion Procedures for the Lumbar Spine

DDD: degenerative disc disease; GOR: grade of recommendation; LOE: level of evidence.

The 2 associations also provided recommendations on:

• Assessment of functional outcome following lumbar fusion (part 2),
• Assessment of economic outcome (part 3),
• Radiographic assessment of fusion status (part 4),
• Correlation between radiographic outcome and function (part 5),
• Interbody techniques for lumbar fusion (part 11),
• Pedicle screw fixation as an adjunct to posterolateral fusion (part 12),
• Injection therapies (part 13),
• Brace therapy (part 14),
• Electrophysiologic monitoring (part 15),
• Bone growth extenders and substitutes (part 16), and
• Bone growth stimulators (part 17).

American Academy of Orthopaedic Surgeons

Information updated in 2015 by the American Academy of Orthopaedic Surgeons has indicated that the type of treatment required for idiopathic scoliosis in children and adolescents depends on the type and degree of the curve, child’s age, and number of remaining growth years until the child reaches skeletal maturity.

• Observation is appropriate when the curve is mild (<25°) or if the child is near skeletal maturity.
• The goal of bracing is to prevent scoliotic curves from worsening. Bracing can be effective if the child is still growing and has a spinal curvature between 25° and 45°. There are several types of braces, most being the underarm type.
• Surgery may be recommended if the curve is greater than 45° and the child is still growing. If the individual has reached skeletal maturity, surgery may still be recommended for scoliotic curves that exceed 50° to 55°. An implant made up of rods, hooks, screws, and/or wires is used to straighten the spine. Bone graft from the bone bank, or from the individual’s hip region, is also used to help the operated portion of the spine heal solid.
• At present, the main research focus in idiopathic scoliosis is an investigation into genetic factors as a cause of scoliosis.

National Institute for Health and Care Excellence

The National Institute for Health and Care Excellence (NICE; 2017) provided guidance on lateral interbody fusion for lumbar spine low back pain. NICE stated that lumbar fusion may be appropriate for “people with severe, life-limiting, chronic low back pain that does not respond to conservative treatments.” The evidence on lateral interbody fusion was considered “adequate in quality and quantity.” Also in 2017, NICE reexamined lumbar disc replacement and reported higher complication rates were found in individuals who underwent fusion. The conclusion was that disc replacement was not warranted and spinal fusion for nonspecific low back pain should only be performed as part of a randomized controlled trial.

International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT)

The International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) updated their guidelines on treatment of idiopathic scoliosis in 2018. In these guidelines, fusion is discussed in the context of other treatments, as an outcome measure indicating treatment failure.

U.S. Preventive Services Task Force Recommendations

Adolescent Idiopathic Scoliosis: The US Preventive Services Task Force updated their recommendations on screening for adolescent idiopathic scoliosis in 2018 and concluded that the current evidence is insufficient to assess the balance of benefits and harms of screening for adolescent idiopathic scoliosis in children and adolescents aged 10 to 18 years (I statement). The Task Force found no studies of surgical treatment in screening-relevant populations that met inclusion criteria.