How to Avoid Postoperative Remaining Ossification Mass in Anterior Controllable Antedisplacement and Fusion Surgery

OBJECTIVES: To retrospectively review the cases with ossification of the posterior longitudinal ligament (OPLL) treated with anterior controllable antedisplacement and fusion (ACAF). Patients with postoperative remaining ossification mass (PROM) are analyzed to figure out the causes and preventions of this problem. METHODS: A total of 115 patients were included. PROM was identified as remaining OPLL existed in the spinal canal other than included in the vertebral-OPLL complex on postoperative computed tomography. The Japanese Orthopaedic Association scoring system was used to evaluate the neurologic status. Surgery-related complications such as cerebrospinal fluid (CSF) leakage and spinal cord or nerve injury were all recorded. The patients with the PROM group and those without the PROM group were compared. RESULTS: There were 14 patients with wide-base OPLL (12.2%) and 10 patients (8.7%) with PROM among the 115 patients with OPLL. The 10 patients with PROM were all with wide-base OPLL. The average improvement rate of Japanese Orthopaedic Association score in patients without PROM was significantly larger than that in patients with PROM (69.5 ± 22.6% vs. 36.7 ± 22.0, P < 0.01). Incidence rate of postoperative CSF leakage and neural deterioration were significantly higher in patients with PROM than that in patients without PROM (CSF leakage, 40.0% vs. 5.9%; neural deterioration, 50.0% vs. 3.0%). No other complications were observed. CONCLUSIONS: The occurrence of PROM might cause complications and poor neural function recovery in patients treated with ACAF. Surgical techniques should be noted to avoid PROM in ACAF surgery.