Spinal Cord Swelling After Surgery in Cervical Spondylotic Myelopathy: Relationship With Intramedullary Gd-DTPA Enhancement on MRI.

Abstract

This is a prospective multicenter study. Postoperative spinal cord swelling has been reported in patients with cervical spondylotic myelopathy. In the cases of the spinal cord swelling, the involvement in the intramedullary gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) enhancement on magnetic resonance imaging (MRI) was referred. The prevalence and clinical relevance of postoperative spinal cord swelling and its relationship with intramedullary Gd-DTPA enhancement in patients with cervical spondylotic myelopathy were investigated. A total of 683 consecutive patients with cervical spondylotic myelopathy who underwent laminoplasty were examined. T1, T2, and Gd-DTPA-enhanced MRI were performed before surgery. Patients with intramedullary Gd-DTPA enhancement were allocated to the enhancement group. Fifty consecutive cases who did not exhibit intramedullary Gd-DTPA enhancement were allocated to the nonenhancement group. Both groups underwent MRI examinations at 1 month and 1 year after surgery. The prevalence of spinal cord swelling in the enhancement group (26%) was significantly higher than that in the nonenhancement group (4%) (P=0.0038). At 1 year after surgery, spinal cord swelling had resolved in all patients in the nonenhancement group, while it persisted in 3 of 13 patients (23%) in the enhancement group. On multiple regression analysis, intramedullary Gd-DTPA enhancement rather than the spinal cord swelling showed a significant influence in terms of recovery of the Japanese Orthopedic Association score. Surgical outcomes of patients with postoperative swelling should be evaluated separately according to the presence or absence of intramedullary Gd-DTPA enhancement on MRI. Spinal cord swelling associated with intramedullary Gd-DTPA enhancement was indicative of poor prognosis.