Date Published: January 24, 2012
Publisher: Hindawi Publishing Corporation
Author(s): Praveen K. Yalamanchili, Michael J. Vives, Saad B. Chaudhary.
Cervical spondylotic myelopathy is a progressive disease and a common cause of acquired disability in the elderly. A variety of surgical interventions are available to halt or improve progression of the disease. Surgical options include anterior or posterior approaches with and without fusion. These include anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, cervical disc replacement, laminoplasty, laminectomy with and without fusion, and combined approaches. Recent investigation into the ideal approach has not found a clearly superior choice, but individual patient characteristics can guide treatment.
Cervical degenerative disease, or cervical spondylosis, is an age-related change affecting the cervical spinal column. Radiographic evidence of cervical spondylosis can be found in 85% of individuals over sixty years of age . Certain occupations and activities that place increased loads on the head may have a predisposition for cervical degenerative disease. Cervical myelopathy is a clinical syndrome that may result from cervical spondylosis. When cervical myelopathy is a result of spondylosis, it is referred to as cervical spondylotic myelopathy (CSM).
The anterior surgical options can be used for both single level and multilevel disease. The anterior approach is generally favored with soft disc herniations, concomitant severe axial neck pain, kyphosis, and with 1-2 levels of involvement (Figure 1).
The posterior surgical options are generally utilized for multilevel compression, such as in cases of congenital stenosis, older patients with advanced multilevel spondylosis, and certain cases of ossification of the posterior longitudinal ligament (OPLL) [21, 22]. The posterior approach relies on decompression through both direct removal of offending posterior structures and indirectly, through spinal cord translation posteriorly . Therefore when spinal cord compression is from anterior structures, patients should have maintenance of lordosis or correctable kyphosis to permit adequate indirect decompression . Posterior approaches utilize a midline approach through the posterior cervical skin and musculature followed by subperiosteal dissection of the selected levels. Extent of dissection laterally over the facets is dependent on whether a concomitant fusion is to be performed.
Recently a systematic review sponsored by the American Association of Neurological Surgeons (AANS)/the Congress of Neurological Surgeons (CNS) was performed to develop evidence-based guidelines for choosing among the available surgical options for treatment of CSM . The National Library of Medicine and Cochrane Databases were queried using MeSH headings and keyword regarding anterior and posterior surgery and CSM. An evidentiary table was assembled to summarize the quality of evidence from I to III (lowest). Recommendations were formulated containing degree of strength based on Scottish Intercollegiate Guidelines. Most of the manuscripts were found to be Class III. The results of the paper were that ACDF, ACCF, laminoplasty, laminectomy, and laminectomy with fusion all yielded similar near term functional improvements for CSM. Laminectomy without fusion, however, is associated with late deterioration. Another recent systematic review of retrospective cohort studies showed that ACCF, ACDF, laminoplasty, and laminectomy and fusion yielded similar neurologic recovery . The major differences between the groups were the associated complications. Therefore it appears that, given the available literature, the choice of surgical approach will be more dependent on the individual patient factors described previously than the superiority of any one surgical option. This clinical equipoise has been the motivating factor for interest in pursuing a prospective randomized clinical trial and for the distinction of CSM as one of the national health research priorities for comparative effectiveness research by the Institute of Medicine (Medicine Io; Initial National Priorities for Comparative Effectiveness Research; http://www.iom.edu/. Accessed May 31, 2011).
Cervical spondylotic myelopathy is a progressive disease that often requires surgical intervention. A variety of surgical options exist, including anterior and posterior approaches with and without fusion. Evidence-based review has not clearly shown one technique to be clinically superior to another. Therefore decision-making will depend on individual patient factors and associated approach-related complications. Factors to consider include location of cord compression, number of levels involved, sagittal alignment, instability, associated axial neck pain, and risk factors for pseudoarthrosis.