Microsurgical decompression of thoracic spina1 ossification of ligamentum flavum through paruspinal approach using percutaneous tubular retractor system

CHEN Chunmei; WANG Rui; CAI Ranze; WANG Yinqing; WU Jianfeng; TU Songjie; SHI Songsheng

Abstract：Objective The clinical outcomes of microsurgical decompression of ossification of ligamentum flavum (OLF) in the thoracic spine through paruspinal approach using percutaneous tubular retractor system were analyzed.Methods A total of 11 patients with OLF admitted in the hospital between August 2009 and December 2016 were enrolled in the study.General anesthesia was performed by tracheal intubation,under the nerve electrophysiological monitoring,through the percutaneous micro channel unilateral vertebral approach.Under the microscope,firstly the opposite side of the spinal was exposed,the high speed grinding was carefully grinding and removing the calcified yellow ligament,and then the same side of the spinal was decompressed to achieve the bilateral decompression of spinal canal.Operative duration,blood loss volume,post-operative wound pain duration and hospital stay were analyzed.Creatine phosphokinase (CPK-MM) level was recorded at 1 d pre-operatively,and post-operatively at 1 d,3 d and 5 d.The pre-operative and post-operative scores of Japanese Orthopedic Association (JOA) and visual analogue scale (VAS) were analyzed respectively to evaluate the function status of spinal cord.CT three-dimensional reconstruction of thoracic spine was performed at 1 w post-operatively.Magnetic resonance imaging (MRI) plain scan of thoracic spine was conducted before operation,and at 1 w and 6 months after operation.Results Thoracic spinal decompression was achieved in all patients without the injuries of spinal cord or nerve root.The CT three-dimensional reconstruction showed that the minimally invasive incision did not affect the stability of the spine,and no doformity of the spine occurred during the follow-up period.No post-operative spinal instability was identified by CT three-dimensional reconstruction.Level of CPK-MM increased at post-operative 1 d and declined gradually,reached the pre-operative level at 7 d post-operatively.Post-operative scores of JOA and VAS were improved compared with those of pre-operation (P ＜0.05).All the patients were followed up for 6 to 23 months.The symptoms of all patients were improved.Conclusion Microsurgical resection of OLF using pereutaneous tubular retractorsystem through paraspinal approach can achieve a better recovery of neural functional and minimize the injuries of operation.This technique offers the advantages of mini-invasiveness,shorter hospital stay,rapid recovery and good post-operative spinal stability.