Posterior approach laminectomy combined with localized resection of ossified posterior longitudinal ligament and dekyphosis for multilevel ossification of the posterior longitudinal ligament in the thoracic spine / 中华骨科杂志

ABSTRACT

Objective To investigate the safety and effectiveness of posterior approach laminectomy combined with localized resection of ossified posterior longitudinal ligament and dekyphosis for multilevel ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine.Methods Thirty-one cases of thoracic multilevel OPLL was treated with this new technique between August of 2012 and August of 2016.Twenty-nine among the 31 cases were successfully followed up more than two years.Among these 29 cases,9 were male and the other 20 were female,with an average age of 48.5±7.1 years.The average segment number of OPLLwas 6.5±2.2 (range,3-11).The average segment number of laminectomy was 7.9±2.5 (range,4-13).There were 26 cases combined with ossification of the ligamentum flavum (OLF).Posterior approach laminectomy combined with localized resection of OPLL and dekyphosis for multilevel OPLL in the thoracic spine was applied to all cases.Firstly,en-bloc laminectomy was performed to all the segments of OPLL.Then the nearest segment of ossification to the kyphotic apex and the most stenotie level was selected and limitedly resected.Finally,wedge-shaped osteotomy was conducted to decrease the kyphosis.The outcomes including recovery rate of myelopathy and the radiological changes were recorded during the post-operative follow-up.Single group pre and post analysis was conducted by using paired t-test.Results Twenty-seven cases underwent one-level circumferential decompression,and the other two case underwent two-level localized resection of the ossified posterior longitudinal ligament.The average operation time was 245.2±75.1 min (range,131-423 min).The average blood loss was 1 307.9±1 457.7 ml(range,300-6 000 ml).The average follow-up time was 40.2± 14.9 months (range,25-69 months).The kyphotic angle of the stenotic segments decreased 11.4°±3.5° averagely after the surgery,from pre-operative 28.7°±9.6° to post-operative 17.3°±8.6°.The decreased kyphotic angle was 7.4°±3.1 ° at the final follow-up with an average kyphotic angel of 22.3°± 10.3°.The average length of the resected ossified posterior longitudinal ligament was 11.3±3.9 mm,and the average shortening length of the spinal column was 5.0±3.0 mm (range,0.4-13.8 mm).The pre-operative Japanese Orthopedic Association (JOA) score was 4.3±2.2 averagely (range,1-9),and the final JOA score increased to 9.3±2.3 (rang,3-11).The average recover rate was 85.7％ (range,-100％ to 100％),and the rate of excellent or good was 89.7％.Among the 29 cases,6 cases occurred post-operative transient deterioration and regained a satisfactory recovery eventually;one case occurred post-operative paraplegia and never recovered;19 cases occurred post-operative cerebrospinal fluid leakage and healed under conservative treatment.Conclusion For the thoracic multilevel OPLL,one-stage posterior approach laminectomy combined with localized resection of the ossified posterior longitudinal ligament and dekyphosis can significantly improve the outcomes of the myelopathy with low rate of post-operative paraplegia.Therefore,this new surgery technique is a safe and effective treatment for multilevel OPLL in thoracic spine.