Radiologic Findings and Risk Factors of Adjacent Segment Degeneration after Anterior Cervical Discectomy and Fusion : A Retrospective Matched Cohort Study with 3-Year Follow-Up Using MRI

OBJECTIVE: The purpose of this study was to figure out the radiologic findings and risk factors related to adjacent segment degeneration (ASD) after anterior cervical discectomy and fusion (ACDF) using 3-year follow-up radiography, computed tomography (CT), and magnetic resonance image (MRI). METHODS: A retrospective matched comparative study was performed for 64 patients who underwent single-level ACDF with a cage and plate. Radiologic parameters, including upper segment range of motion (USROM), lower segment range of motion (LSROM), upper segment disc height (UDH), and lower segment disc height (LDH), clinical outcomes assessed with neck and arm visual analogue scale (VAS), and risk factors were analyzed. RESULTS: Patients were categorized into the ASD (32 patients) and non-ASD (32 patients) group. The decrease of UDH was significantly greater in the ASD group at each follow-up visit. At 36 months postoperatively, the difference for USROM value from the preoperative one significantly increased in the ASD group than non-ASD group. Preoperative other segment degeneration was significantly associated with the increased incidence of ASD at 36 months. However, pain intensity for the neck and arm was not significantly different between groups at any post-operative follow-up visit. CONCLUSION: The main factor affecting ASD is preoperative other segment degeneration out of the adjacent segment. In addition, patients over the age of 50 are at higher risk of developing ASD. Although there was definite radiologic degeneration in the ASD group, no significant difference was observed between the ASD and non-ASD groups in terms of the incidence of symptomatic disease.

Spinal Intramedullary Lipoma without Dysraphism

Spinal cord lipomas are commonly associated with spinal dysraphism. The lipomas without spinal dysraphism have been reported to be only 1% of all spinal cord lipomas. We report two cases of patients with spinal intramedullary lipomas without dysraphism. One patient was a 57-year-old man who had lower back pain and right-sided sciatica for 20 years. Magnetic resonance imaging (MRI) of the spine demonstrated an intradural mass occupying L1 to L2. The other patient was a 27-year-old woman who had back pain and gait disturbance for 5 months. MRI of the spine showed an elongated intradural mass occupying T7 to T9. Total laminectomy with partial resection of the lesions was performed on both patients. Pathological studies confirmed the diagnosis of spinal cord lipoma. They exhibited no dysraphism. Postoperatively, neurological symptoms improved in both patients.