OBJECTIVETo investigate the clinical effects of 360 degree circular decompression and transpedicle screw fixation to treat the ossification of thoracic posterior longitudinal ligament by posterior approach.

METHODSFrom December 2009 to November 2013, 18 patients with ossification of thoracic posterior longitudinal ligament ossification were treated with 360 degree circle decompression and transpedicle screw fixation by posterior approach. There were 8 males and 10 females,ranging in age from 32 to 67 years old, with an average of 51 years old. Four patients were accompanied with ligamentum flavum ossification. Longitudinal ossifications in 5 cases were located in the upper thoracic vertebra and 13 cases in the middle and lower thoracic vertebra. Five cases were typical type, 4 cases were segmental type, 6 cases were continuous type and 3 cases were mixed type. All the patients had the posterior spinal canal decompression combined with longitudinal ligament resection, interbody fusion with bone graft and internal fixation surgeries. The operation time,blood loss and complications were recorded. JOA score were applied to evaluate the neurological function recovery pre-surgery, 2 days post-surgery and the latest follow-up. The surgery effects were evaluated by Epstein-Schwall method.

RESULTSThe operation time ranged from 3 to 6 hours (mean, 4.2 hours). The blood loss ranged from 800 to 4 000 ml (mean, 1 800 ml). All the patients were followed up, and the duration ranged from 6 months to 3 years, with a mean of 1.8 years. The JOA score increased from preoperative 4.30 ± 2.60 to 7.60 ± 2.40 2 days after surgery, and 7.80 ± 1.90 at the latest follow-up (t = 4.61, P < 0.001). The JOA scores between 2 days after surgery and the latest follow-up had no significant differences (t = 0.28,P = 0.78). The neurological recovery rate was 74% 2 days after surgery and 71% at the latest follow-up. There were 4 cases got an excellent result,10 good,3 fair and 1 poor according to Epstein-Schwall evaluation method. Four patients had cerebrospinal fluid leakage, 3 patients had intercostal nerve paralysis or pain, and 1 patient had superficial incision infection. The neurological function in 3 patients became worse in the second day posteratively , and among them, 2 patients were recovered at the latest follow-up and 1 patient had no changes. All the patients got fusion of bone graft and no internal fixation loosening and fractures occurred.

CONCLUSION360 degree circular decompression and transpedicle screw fixation can resect different types of thoracic longitudinal ligament ossification, and can achieve a good clinical effect.