A novel "de-tension"-guided anterior decompression strategy- thoracic anterior controllable antedisplacement fusion (TACAF) for multilevel ossification of posterior longitudinal ligament in thoracic spine: a retrospective study with at least 2-year follow-up

Purpose To propose a novel surgical strategy-thoracic anterior controllable ante-displacement fusion (TACAF) to treat mT-OPLL, and investigated its safety and efficacy. Methods Between January 2019 and December 2021, a total of 49 patients with thoracic myelopathy due to mT-OPLL were surgically treated with TACAF were retrospectively reviewed. Patients’ demographic data, radiological parameters, and surgery-related complications, m-JOA and VAS scores, thoracic kyphosis (TK), kyphosis angle in fusion area (FSK), thoracic curvature, spinal cord curvature and curvature of curved rod in surgical region, diameter and area of the spinal cord at the most compressed level were included. Results All patients acquired satisfactory recovery of neurological function and overall complication rate is low at the final follow up. The mean m-JOA of the two groups respectively was 3.74±2.05, 3.67±1.95 before surgery, and 9.97±0.83, 9.80±0.68at the final followed up, with the recovery rate of 84.26±14.20,82.79±10.35%, as to VA Scores. the mean FSK was 34.50±4.46,35.33±3.44before surgery, and was restored to 20.97±5.70,22.93±6.34at the final followed up respectively, as to mean TK. (P<0.05). Spinal cord curvature was improved from 34.12±3.59,33.93±3.45before surgery to 19.47±3.53,18.80±3.17at the final follow-up respectively, as to thoracic curvature (P<0.05), and In addition, the area and diameter of the spinal cord was also significantly improved at the final follow up (all P<0.05). The curvature of the thoracic pulp and thoracic vertebra is closely related to the curvature of the rod. There was no statistically significant difference in the incidence of the pelvis and the slope value of the sacrum. Conclusions This strategy provides a novel solution for the treatment of mT-OPLL with favorable recovery of neurological function, the tension of spinal cord, and less complications.