Cervical myelopathy caused by c3-c4 spondylosis in elderly patients - A radiographic analysis of pathogenesis

Study Design. A radiographic analysis of elderly patients with cervical spo ndylotic myelopathy, particularly those with involvement of the C3-C4 level . Objectives. To elucidate the potential contributors to the higher incidence of pathology at C3-C4 in the elderly. Summary of Background Data. In this study, the elder patients showed a grea ter predilection for involvement of the C3-C4 lesion compared with their yo unger counterparts. No previous study has addressed C3-C4 pathology in elde rly patients. Methods. This study included 18 patients, 10 men and 8 women, with cervical spondylotic myelopathy caused by C3-C4 disorders (group I). For the purpos e of comparison, 18 younger patients (less than 50 years of age) with myelo pathy (group II) and 30 volunteers over the age of 65 (group III) were also investigated. Mean age at admission was 73.5 years for group 1, 42.4 years for group II, and 73.4 years for group III. Radiographic analysis, using s tatic and dynamic radiographs, was performed to evaluate the morphologic fe atures. Results. The mean spinal canal diameter for groups I and II was significant ly smaller than that for group Ill. Group I exhibited greater C2-C7 lordosi s. The aged population, group I and group III, showed greater C3-C4 angulat ion associated with C4 forward inclination in neutral standing position as compared with younger patients. Regarding dynamic factors, group I showed t he largest segmental motion at C3-C4, and, conversely, the smallest mobilit y at the lower segments, with significant differences. Conclusions. Using radiographic analysis, morphologic features that predisp ose patients to disorders of the C3-C4 motion segment were evaluated. These features included 1) greater C3-C4 angulation associated with age-related postural change and 2) hypermobility at the C3-C4 segment compensating for decreased mobility at the lower segments.