Clinical Results And Prognostic Factors for Thoracic Myelopathy Caused by Ossification of Yellow Ligament after Surgical Treatment

ABSTRACT

STUDY DESIGN: Retrospective study. OBJECTIVES: We analyzed the clinical results of thoracic myelopathy caused by ossification of yellow ligament (OYL) and to explore prognostic factors after surgical treatment. SUMMARY OF LITERATURE REVIEW Thoracic myelopathy due to OYL is difficult to treat; surgery is considered as treatment of choice. However, studies of the clinical results and prognostic factors are few due to its rare presentation. MATERIALS AND METHODS: Twenty six patients who had surgery for thoracic myelopathy caused by OYL were evaluated from February 2002 to April 2012. We describe the analysis of the clinical results after surgery and prognostic factors. RESULTS: Modified Japanese orthopedic association (JOA) score was recorded in all patients by 5.7+/-1.3 points (range, 2-9 points) preoperatively, 7.8+/-1.7 points (range, 4-10 points) postoperatively, and 8.4+/-2.1 points (range, 5-11 points) at final follow-up. Hirabayashi recovery rate was recorded by 60.2+/-20.2% (range, 45.5-72.0%) postoperatively, 64.5+/-17.3% (range, 50.2-75.1%) at final follow-up. The Visual Analogue Scale (VAS) score was also improved by 7.6+/-1.8 points (range, 7-10 points) preoperatively, 4.5+/-1.3 points (range, 3-6 points) postoperatively, and 3.8+/-1.6 points (range, 2-5 points) at final follow-up. Both modified JOA score and VAS score improved significantly (p<0.05). In prognostic factor analysis, OYL type on CT axial image, duration of symptom, and preoperative severity of myelopathy was significant (p<0.05). CONCLUSION: We showed the effectiveness of surgery on patients who suffer from thoracic myelopathy caused by OYL and that OYL type identified by CT axial image, duration of symptom, and preoperative severity of myelopathy were significant prognostic factors.