Surgical experience of Unilateral Laminectomy for Bilateral Decompression (ULBD) of ossified ligamentum flavum in the thoracic spine

Introduction: We describe a new surgical technique for the treatment of ossified ligamentum flavum (OLF) in the thoracic spine through unilateral laminectomy for bilateral decompression (ULBD). Methods: We reviewed the clinical data of 11 consecutive adult patients who had undergone ULBD for OLF between August 2004 and July 2008. Four patients underwent simultaneous decompressive surgery for cervical or lumbar lesions. The duration of symptoms was 25.4 months. Using clinical charts and mailed questionnaires, we evaluated the patients by pre- and postoperative Japanese Orthopaedic Association (JOA) scores and recovery rates. Results: The mean follow-up period was 10.09 months (range: 3-35 months). The average age was 54.5 years (range: 34-78 years). The mean preoperative JOA score was 6.6. This improved to 8.8 in the follow-up study. The recovery rate was 33.2 %. The cross-sectional area of the pre- and postoperative dural sac at the level of the stenosis was 57.56 mm² and 111.8 mm² respectively (p < 0.0001). There was no operation-related transfusion, and there was no evidence of postoperative instability in the follow-up examination. Conclusion: ULBD is a safe and effective nonfusion technique that provides a good surgically decompressed field. A potential increase in kyphosis following laminectomy can be avoided by this surgical technique, also it preserves the contralateral facet joint, the lamina and the midline ligament structures, while widening the spinal canal.