Surgical Treatment And Prognosis Of Thoracic Ossification Of Ligamentum Flavum And Thoracic Ossification Of Posterior Longitudinal Ligament

Background and Objectives:Thoracic Spinal stenosis is a group of clinical syndromes caused by the decrease of the effective volume of the thoracic spine and the compression of the thoracic spine or nerve root due to one or more causes.Thoracic ossification of ligamentum flavum and thoracic ossification of posterior longitudinal ligament are common causes of thoracic spinal canal stenosis.Surgical decompression is the only effective method for the treatment of symptomatic thoracic spinal stenosis.Compared with the cervical and lumbar lesions,the diagnosis and treatment of thoracic spinal canal stenosis is more challenging.The operation process is more risky,accompanied with more complications.The overall curative effect of surgery for thoracic spinal canal stenosis is inferior to cervical spondylosis or lumbar spinal stenosis.The purpose of this study was to summarize the clinical features of thoracic spinal canal stenosis,to explore the operative strategy,to analyze the operative effect and the factors influencing the prognosis,so as to improve the diagnostic level and operative effect of thoracic spinal canal stenosis.Methods:(1)87 cases of thoracic ossification of the ligamentum Flavum underwent surgical treatment were included.The baseline-,imaging-and surgery-related factors were collected.The effectiveness of laminectomy and prodictors of prognosis were assessed.The value of imaging findings in predicting the exisetence of dural ossification was analyzed.(2)35 cases of thoracic ossification of the posterior longitudinal ligament were included.The baseline-,imaging-and surgery-related factors were collected.Effectiveness of different surgical methods was compared.Prodictors of prognosis were analyzed.(3)The thoracic parameters were measured and the operative strategies of circumferential decompression through a single posterior approach were discussed.Results:(1)The patients were averagely aged 55.75±10.16,and included 49 males and 38 females.The mean duration of disease was 23.08±26.87 months,The average JOA score of patients was significantly elevated from 6.69±1.356(preoperative)to 9.55±1.24(mean recovery rate 67.76%)at the final follow-up visit.Multivariate regression analysis suggested that the duration of preoperative symptoms and the residual ratio of sagittal diameter were independent predictors of prognostic factors.The "tram-track sign" and "Comma sign" were predictive factors of dural ossification.(2)35 cases of thoracic ossification of the posterior longitudinal ligament were included in the study,including 13 males and 22 females.The mean JOA average elevated from 6.43±1.08(preoperative)to 8.14±1.00(mean recovery rate 55.00%)at the final follow-up visit.The recovery rate of neurological function was 54.27%in the circumferential decompression group,and 56.83%in the posterior decompression group.There was no significant difference in curative effect between the two groups.Regression analysis suggested that the duration of preoperative symptoms was an independent predictor of prognosis.(3)Circumferential decompression through posterior transpedcicular approach can expand surgery vision and enlarge the scope of operation.Conclusions:(1)laminectomy is an effective method for the treatment of thoracic ossification of the ligamentum flavum.Duration of preoperative symptoms and residual ratio of sagittal diameter were independent predictors of prognostic factors.The "tram-track sign" and "Comma sign" were predictive factors of dural ossification.(2)There was no statistically significant difference in curative effect between circumferential decompression group and posterior decompression group.Ossification-Kyphosis angle and residual rate of the anteroposterior canal diameter can be used as a index for selecting surgery.Duration of preoperative symptoms was independent predictors of prognostic factors.(3)Circumferential decompression through posterior transpedcicular approach is an effective method and can be indicated for thoracic ossification of the posterior longitudinal ligament at 3 consecutive levels or fewer.