Study design : A retrospective radiographic and medical record analysis of 36 patients.
Objectives : To describe the incidence and consequence of the distribution of sagittal plane motion, across the adjacent cervical moti: n segment, after cervical fusion. Furthermore, to find the cause of the progression of degenerative changes in intervertebral iscs adjacent to the fused segment.
Sumr iary of Literature Review : Anterior cervical fusion has been widely used in the treatment of degenerative cervical spine. An i.t creased incidence of degenerative disease may exist at the levels immediately adjacent to a cervical fusion. However, the frequency of these complications is probably overestimated, and their effect on clinical outcome remains unknown. Mate ials and Methods : From 1990 to 1996, 36 patients who underwent anterior cervical spine fusion for degenerative disorders sere reviewed retrospectively with an average follow up of 69 years. Lateral views in neutral position, in flexion, and in exteri ;ion of the preoperative cervical roentgenograms were analyzed in comparison with the last follow-up films in the range of m,: tion of the neck, and in the intervertebral angular mobility and anteroposterior displacement of the vertebral bodies, and finall, r to quantify the incidence of the spinal instability.
Resul is : Degenerative change in adjacent intervertebral level was observed in 16 of the 36 patients (44.40/6), above the fusion in 10, be ow the fusion in 4, and both above and below the fusion in 2 cases. In addition, degenerative change in adjacent intervertebral level was observed in 68% of cases of loss of lordosis of the fused segment, and degenerative change occurred more frequenr, y in younger patients to a statistically significant extent.
Cond rsions : Loss of lordosis of the fused segment and young age are two factors promoting degenerative changes in adjacent inter. ertebral levels after anterior cervical fusion.
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