Regression of Anterior Disk-Osteophyte Complex Following Cervical Laminectomy and Fusion for Cervical Spondylotic Myelopathy.

Abstract

A retrospective case-control study. To investigate whether posterior cervical laminectomy and fusion modifies the natural course of anterior disk-osteophyte complex in patients with multilevel cervical spondylotic myelopathy. Dorsal migration of the spinal cord is the main purported mechanism of spinal cord decompression following cervical laminectomy and fusion but other potential mechanisms have received scant attention in the literature. This study was conducted to investigate whether cervical laminectomy and fusion affects the size of anterior disk-osteophyte complex. The medical records and radiographic imaging of 44 patients who underwent cervical laminectomy and fusion for cervical spondylotic myelopathy between 2006 and 2013 were analyzed. The size of the anterior disk-osteophyte complex was measured preoperatively and postoperatively on MR images taken at an interval of >3 months apart. A control group consisted of 20 nonoperatively treated advanced cervical spondylosis patients. Patients in the control met the same inclusion and exclusion criteria and also had sequential magnetic resonance imaging (MRI) taken at an interval of >3 months apart. The nonoperative and operative groups were statistically similar in the pertinent patient demographics and characteristics including sex, age, time to second MRI, size of anterior disk-osteophyte complex on baseline MRI, mean number of levels affected, and percentage of patients with T2 signal change. As expected the mJOA scores were significantly lower in the operative versus nonoperative cohort (13.6 vs. 16.5, P<0.01). A significant decrease in the size of anterior disk osteophyte was observed in the operative group postoperatively (P<0.01). In comparison, there was no statistically significant change in the size of the anterior disk-osteophyte complex in the control group (P>0.05). The magnitude of the change in disk size between the 2 groups was statistically significant (P<0.01). The findings of this study suggest that regression of anterior disk-osteophyte complex occurs following cervical laminectomy and fusion, and likely provides another mechanism of spinal cord decompression.