Change in Morphology of Intramedullary T2-Weighted Increased Signal Intensity After Anterior Decompressive Surgery for Cervical Spondylotic Myelopathy

Study Design. Retrospective study. Objective. To study the change in morphology of T2-weighted (T2W) increased signal intensity (ISI) and its association with functional outcome after central corpectomy for cervical spondylotic myelopathy (CSM) and ossified posterior longitudinal ligament (OPLL). Summary of Background Data. There are limited data on change in T2W ISI morphology after anterior decompressive surgery. It is unclear whether change in T2W ISI carries prognostic significance in patients with CSM/OPLL. Methods. We reviewed patients who underwent central corpectomy for CSM/OPLL between 1996 and 2010, and underwent a follow-up magnetic resonance imaging (MRI) at 6 months or later postoperatively. T2W ISI on sagittal images was classified as type 0 no ISI; type 1, predominantly (>50%) faint with an indistinct border; and type 2, predominantly (>50%) intense with a sharp border. The length of T2W ISI and the presence of T1-weighted hypointensity were also recorded on preoperative and follow-up images. Functional outcomes as measured by the Nurick grade were correlated with change in morphology of MR signal changes. Results. Sixty-four patients (60 males, mean age = 50 +/- 1.1 yr) were reviewed. The mean follow-up duration was 29 +/- 3.5 months. The majority of patients (71.9%) had no change in the type of ISI at follow-up. The type of ISI improved in 13 patients (20.3%), and worsened in 5 patients (7.8%). The mean length of ISI was 26.2 +/- 3.4 mm preoperatively and 13.7 +/- 1.8 mm at follow-up in 53 patients (P = 0.002). Change in ISI grade or length was not associated with change in Nurick grade at follow-up (P = 0.74, P = 0.5). Conclusion. The type of T2W ISI does not change, but the length of T2W ISI decreases for the majority of patients undergoing anterior cervical decompression for CSM/OPLL. In our series, change in morphology of T2W ISI did not correlate with functional outcome as measured by Nurick grade.