Surgery Section - Surgery for Degenerative Diseases of the Cervical Spine

IMPORTANT REMINDER

Regence Medical Policies are developed to provide guidance for members and providers regarding coverage in accordance with contract terms. Benefit determinations are based in all cases on the applicable contract language. To the extent there may be any conflict between the Medical Policy and contract language, the contract language takes precedence.

PLEASE NOTE: Contracts exclude from coverage, among other things, services or procedures that are considered investigational or cosmetic. Providers may bill members for services or procedures that are considered investigational or cosmetic. Providers are encouraged to inform members before rendering such services that the members are likely to be financially responsible for the cost of these services.

Description

Degenerative changes of the cervical spine are common in both symptomatic and asymptomatic adults. By age 50 years, degeneration is evident on plain radiographs in more than 50% of asymptomatic people. The clinical problem is to determine what if any relationship these degenerative changes have with a patient's symptoms.

Imaging studies will show whether structural abnormalities correlate with the patient's signs and symptoms. Standard radiographs are anteroposterior (AP) views of both the upper and lower cervical spine, a lateral view that should include all the cervical vertebrae and the cervical vertebrae and the cervical thoracic junction, and oblique presentations.

Generally, there are two reasons for obtaining imaging studies in addition to plain radiographs: to localize a surgically correctable lesion, and to assess conditions when a diagnosis other than degenerative disease is suspected.

Myelography is used in evaluating cervical radiculopathy and myelopathy.

CT provides excellent visualization of the osseous structure of the spine but when used alone does not distinguish neural elements from other soft tissue. When combined with intrathecal contrast, the relationship between neural elements and bone is improved. However, visualizing non-enhanced soft tissue such as disc material and a compressed nerve root is difficult. CT is valuable in trauma and in conditions such as tumors and infections in which definition of bone is required.

MRI is now the most commonly used advanced imaging technique for evaluation of patients with neck pain believed to result from degenerative changes. The advantages of MRI are that it provides a complete view of the vertebrae, intervertebral discs, subarachnoid space, nerve roots, and the spinal cord, including intraspinal cord anatomy. As with standard radiographs, a high percentage of asymptomatic people have abnormal cervical MRI scans; therefore, these studies cannot be used alone but must be correlated with a patient's symptoms.

Surgery of the Cervical Spine
Interbody bone grafting in the lower cervical spine is usually combined with anterior cervical decompression and/or instrumentation. Bone grafting techniques include use of autologous iliac crest graft and allogeneic grafts that have been freeze-dried, fresh frozen or irradiated. Several clinical studies have reported a significantly higher rate of graft collapse with allograft material used for fusion. The fusion rate between the two graft materials is not statistically significantly different, however, the possible allograft instability in the long term is more likely to result in a pseudoarthrosis which may require additional surgery. Autologous iliac bone grafts are accompanied by postoperative discomfort at the harvest site. However, studies have shown that continued donor site pain was not a long term problem.

Internal fixation for traumatic instability of the cervical spine is a standard of care. A number of studies have documented the biomechanical advantage of adding wires, plates or screws to an arthrodesis of an unstable spinal injury. Because of the success of internal fixation for traumatic disorders, it has been proposed that anterior or posterior plates and screws or cages for degenerative cervical spine disorders be considered. Due to the lower fusion rate with multiple-level fusions, stutt-graft fusions, and in persons with osteopenic bone in particular, the addition of instrumentation is proposed.

However, to date prospective studies have not been conducted which address the addition of instrumentation to a decompression and fusion procedure of the cervical spine for degenerative cervical disease. For this reason the addition of instrumentation to cervical spine surgery for degenerative disorders is not routinely recommended.

Policy/Criteria

1. The degenerative cervical disease conditions for which patients are referred for surgery include cervical disc herniation, spondylotic radiculopathy, spondylitic myelopathy, spinal stenosis, and spondylolisthesis. The indications for surgery in degenerative conditions focus on arm pain or on neurologic impairment and include one of the following:
   1. Persistent or recurrent arm pain not responsive to a minimum of 12 weeks* of non-surgical treatment along with confirmatory imaging studies consistent with clinical findings (radiographs, CT, myelogram, or MRI). Non-surgical treatment includes physical therapy, isometric exercises, aerobic conditioning, flexibility exercises, and progressive conditioning exercises. The critical aspects of rehabilitation for degenerative cervical spine disorders include the following:
      1. PT - ultrasound, electric stimulation, heat, and ice for pain control
      2. PT and at home - manual techniques and exercises to improve range of motion
      3. PT and at home - passive, active assistive, and active resistive exercises
      4. PT - instructions in posture, movement, and body mechanics
   2. Progressive arm weakness along with confirmatory imaging studies consistent with clinical findings (radiographs, CT, myelogram, or MRI).
   3. Static neurologic deficits associated with radicular pain along with confirmatory imaging studies consistent with clinical findings (CT scan, myelogram or MRI).

   *It is reasonable to consider surgical intervention after 4 to 6 weeks if the patient's symptoms are severe and functionally incapacitating.

2. Surgery for degenerative diseases of the spine include interbody fusion with autologous iliac bone graft, with or without discectomy. Studies have shown that autologous iliac crest bone is the preferred graft material. Allogeneic or donor bone graft material provides a similar fusion rate, but a significantly higher rate of graft collapse as autologous bone. Allogeneic bone graft for cervical spine arthrodesis may be medically necessary for patients with osteopenic bone, previous iliac bone graft donation, or other sound medical reason making the patient a poor candidate for autologous iliac bone harvesting.
3. Internal fixation devices for the cervical spine include titanium screw plates, wires, rods, and cages. Internal fixation or instrumentation of the cervical spine is generally only medically necessary with bone graft fusion when further stabilization of the area is required. Instrumentation is not medically necessary with single level autologous or allogeneic bone graft fusions or most two-level fusions. The addition of internal fixation devices (instrumentation) may be medically necessary for cervical spine surgery in the following instances:
   1. Tumor resection from the cervical vertebrae
   2. Fracture of the cervical vertebrae
   3. Chronic inflammation causing vertebral destruction
   4. Kyphotic deformity of the cervical spine
   5. Degenerative cervical spine disease with more than one level of cervical spine fusion

Cross References

Lumbar Spine Surgery, Regence Medical Policy Manual, Surgery, Policy No. 101

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

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

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