LAUSR

BACKGROUND Discontinuous thoracic ossification of the ligamentum flavum (TOLF) is diagnosed according to the number and distribution of involved segments seen on magnetic resonance images. When TOLF causes thoracic myelopathy, surgical intervention for these lesions becomes unavoidable. However, there are few reports on the outcomes of surgery for discontinuous TOLF. METHODS The study included 26 patients of mean age 55.0 years who underwent simultaneous (n=16) or staged (n=10) decompression of discontinuous TOLF between July 2006 and June 2016. Final neurological status was evaluated using the modified Japanese Orthopaedic Association (JOA) score. The surgical data and incidence of complications were compared. The mean follow-up duration was 73.3 months. RESULTS There was no between-group difference in number of levels decompressed or the amount of intraoperative blood loss. There was a significant improvement in the JOA score from 4.0 before surgery to 8.0 postoperatively, with an average recovery rate of 58.3%. The JOA recovery rate was significantly better in the staged group than in the simultaneous group (68.4% vs. 52.0%, P<0.05). However, the incidence of complications was similar between the staged and simultaneous groups, including for dural tear (1 vs. 6, P=0.19), cerebrospinal fluid leak (4 vs. 6, P=1.00), and transient neurological deterioration (0 vs. 2, P=0.51). CONCLUSIONS The surgical outcome of staged decompression for discontinuous TOLF seems to be better than that of simultaneous decompression. The complication rates of these two strategies are similar.