Background The treatment strategies for multilevel thoracic ossification of the posterior longitudinal ligaments (T-OPLL) were rarely reported. The aim of this study was to investigate the clinical outcomes and complications of circumferential decompression for multilevel T-OPLL and compare two different methods in the management of the OPLL (resection or floating).

Methods Data of sequentially treated patients who received surgical treatment for thoracic spinal stenosis caused by multilevel T-OPLL from January 2005 to February 2012 were retrospectively reviewed. Based on the surgical approaches applied, the patients were divided into two groups. Group A consisted the patients who received posterior decompression and group B consisted the patients who received circumferential decompression via the posterior approach. Group B was further divided into two subgroups: subgroup 1 (the resection group) where the OPLL was completely resected and subgroup 2 (the floating group) where the OPLL was floated.

Results A total of 49 patients were included in the study. Fourteen patients with single posterior decompression were included in group A and 35 patients who received circumferential decompression were included in group B. In group B, 29 patients had complete resection of the ossified posterior longitudinal ligaments, while the other six underwent a flotation procedure. The follow-up data were available in 39 patients. Mean JOA scores improved from 5.4 ± 1.8 to 7.5 ± 2.8 in group A and from 3.7 ± 1.8 to 7.9 ± 2.4 in group B. The main complications included cerebrospinal fluid (CSF) leakage and postoperative neurologic deterioration (ND). Twenty-three of the 25 cases with postoperative CSF leakage achieved a complete recovery at the last follow-up and 12 of the 15 cases with ND achieved some neurological improvement at the last follow-up.

Conclusions Circumferential decompression via the posterior approach is an effective surgical method for thoracic spinal stenosis caused by multilevel OPLL of the thoracic spine. Patients who receive complete resection of the ossified posterior longitudinal ligaments may have better recovery rate than the “floating” group.