Clinical Characteristics and Surgical Outcome of Revision Surgery in Patients with Cervical Ossification of the Posterior Longitudinal Ligament

OBJECTIVE: To investigate the clinical characteristics and surgical outcome of revision surgery after first surgical decompression of cervical ossification of posterior longitudinal ligament. METHODS: A retrospective analysis was performed of 913 patients who underwent surgical decompression of cervical ossification of posterior longitudinal ligament from 1998 to 2012. Of these patients, 35 underwent revision surgery. Neurologic and surgical outcomes, radiologic findings, surgical procedures, and complications were evaluated. Indications for revision surgery were compared between early (<= 24 months after the first surgery) and delayed (>24 months after the first surgery) revision surgery. RESULTS: There was a higher prevalence of male patients with revision surgery (89%) compared with patients without revision surgery (71.2%, P = 0.033). Preoperative Japanese Orthopaedic Association score was significantly lower in patients with revision surgery (11.5 vs. 12.7, P < 0.01). Visual analog scale score for neck pain was improved both without revision surgery (from 3.0 to 2.1, P < 0.001) and with revision surgery (from 3.0 to 2.2, P < 0.001) patients. Symptomatic residual stenosis was a more frequent cause of revision surgery in early revision surgery than in delayed revision surgery (75% vs. 25%, P < 0.001). In delayed revision surgery, growth of ossification of posterior longitudinal ligament (50%) was the primary cause of revision surgery. CONCLUSIONS: Clinical outcomes (Japanese Orthopaedic Association and visual analog scale scores) of revision surgery are similar to the outcomes of patients who did not require revision surgery. Residual stenosis after the index surgery is the most common indication for early revision surgery. To avoid early revision surgery, surgeons should carefully consider achieving circumferential decompression of the spinal canal during initial surgery.