Extensive Posterior Fusion for Cervical Spondylotic Myelopathy

Abstract

The degenerative process of cervical spondylosis through acquired narrowing of the vertebral canal or segmental hypermobility of the vertebral column, either singularly or in combination, may increase to injurious levels the mechanical stresses acting upon the spinal cord or supportive vasculature. Determination of the most efficacious treatment for the individual case, therefore, requires evaluation of the relative importance of each possible causative mechanism. In the majority of cases, vertebral column narrowing acquired by laminal or ligamentous thickening or by osteophyte growth is usually predominant at lower cervical levels, whereas severe degrees of hypermobility or subluxation are more common at upper cervical levels, especially in patients with rheumatoid arthritis [4]. The longterm success of many routine surgical procedures with patients possessing this combination of mechanical abnormalities is frequently compromised by poor general health, advanced age, poor quality of bone and difficulty in maintaining immobilization. The failure to achieve fusion in the unstable cervical segments may result in a greater degree of spinal cord compromise through increased instability or accentuation of abnormal vertebral column curvature. A successful fusion may also be complicated by the additional strain upon adjoining vertebral column segments which have been previously compromised by degenerative changes or laminectomy and, therefore, accelerate instability at the adjoining unfused segments. Within this group of relatively high-risk surgical candidates who demonstrated subluxations of the upper cervical segments (C1–C3) associated with neighboring vertebral canal narrowing of the lower cervical segments (C4–C7), we have achieved significant resolution of myelopathy through a single-staged extensive stabilization of the entire cervical vertebral column.

This research has been supported in part by Veterans Administration Merit Review no. 1655–03P.