Objective: To evaluate the efficacy and safety of Smith-Petersen osteotomy (SPO) assisted by releasing disk space from posterior approach for thoracolumbar kyphosis. Methods: A review was conducted on 8 patients (3 males and 5 females) with thoracolumbar kyphosis were treated with SPO assisted by releasing disk space from posterior approach at Department of Orthopaedics, Peking University Third Hospital from June 2016 to September 2017. The age was 56.5 years (range:18-71 years). There were 3 cases of Scheuermanns kyphosis, 2 cases of degenerative kyphosis, 1 case of proximal junctional kyphosis (PJK) after lumbar surgery, and 2 cases of kyphosis after thoracolumbar laminectomy. The paired t test was used for statistical analysis in thoracolumbar kyphosis angle, osteotomy segment kyphosis angle, sagittal vertical value (SVA), visual analogue score (VAS), Oswestry dysfunction index (ODI) before and after surgery. Statistical difference was confirmed with P<0.05. Results: Osteotomy level included 2 cases in T_11-12, 3 cases in T₁₂-L₁, 3 cases in L_1-2. The average operation time was 339 min (range: 247-416 min), bleeding volume was 1 275 ml (range: 500-2 500 ml). The mean follow-up time was 16.5 months (range: 12-24 months). The average thoracolumbar kyphosis angle was 59.9° (range: 40°-73°) pre-operation, 9.5°(range:-5.1°-20°) post-operation and 13.5°(range:-1.3°-28°) at the latest follow-up. It made an average correction with 46.4°and corrective rate with 78.0%. The osteotomy segment kyphosis angle was 37.9° (range: 26°-46°) pre-operation, -1.3° (range:-11°-13°) post-operation making an 39.2° open-up angle, and 2.0° (range:-13.5°-13°) at the latest follow-up. Lumbar lordosis was 47.5° (range: 2°-76°) pre-operation, 41.2°(range:15°-62°) post-operation and 36.9°(range:15°-58°) at the latest follow-up. SVA was 54 mm(range:-34 mm-149 mm) pre-operation and 39 mm(range:-3 mm-119 mm) at the latest follow-up. VAS score of low back pain was 6.3(range:0-9) pre-operation and 3.0(range:0-6) at the latest follow-up. ODI score was 21.9(range: 0-42) pre-operation and 11.0(range: 0-26) at latest follow-up. Comparing to pre-operation value, there were statistical difference in the thoracolumbar kyphosis angle(t= 8.547, P=0.000), osteotomy segment kyphosis angle(t=9.739, P=0.000), VAS(t=3.077, P=0.018), ODI(t=5.800, P=0.001) at the latest follow-up. There was no neuropathic complication in all patients. Cerebrospinal fluid leakage occurred in 2 cases with spinal surgery history, and recovered after symptomatic treatment. Conclusions SPO assisted by releasing disk space from posterior approach could safely achieve effective correction of rigid thoracolumbar kyphosis deformity within 40°.

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.