Thoracic myelopathy secondary to ossified ligamentum flavum and dural ossification – A series of 19 cases and review of literature
Interdisciplinary Neurosurgery: Advanced Techniques and Case Management
Objective: Thoracic myelopathy has gradually risen to be a prominent diagnosis in patients with persistent upper back pain, bladder symptoms and spastic paraparesis. Often encountered, these conditions pose a serious dilemma to neurosurgeons with respect to surgical planning, timing of surgery, prognosis and possible complications and outcome assessment. In view of these queries and to clarify the indications of when to intervene the following study has been undertaken. To analyze the clinical presentation, radiological features, clinical implications and surgical nuances and outcomes in patients with single and multiple level dorsal canal ossified ligamentum flavum (D-OLF) and associated dural ossification (DO). Patients and methods: Nineteen patients with the diagnosis of thoracic myelopathy (TM) were identified between January 2012 and March 2017. All patients were treated surgically, with decompressive laminectomies, in a single tertiary care center in Southern India. mJOA was calculated preoperatively and assessed postoperatively and a mean mJOA was calculated to assess the significance in neurological improvement. The data was collected from the medical records department and various factors were analyzed, using SPSS software, for correlation. Results: Mean age of our group was 50.84 years with a range of 29 to 71 years. It comprised of 11 males and 8 females. All patients had features of myelopathy. Surgery did have a positive effect on neurological improvement (p = 0.001) in all patients except one. Dural ossification had correlation with pre op and post op urinary disturbances with p value of 0.02. (Mann Whitney Test for 2 independent variables used). A total of ten patients had urinary symptoms pre operatively, out of which six patients showed postoperative improvement at the end of one year. Four of these patients continued to have symptoms, two patients were on Clean Intermittent Catheterisation (CIC), and one patient had features of hesitancy and frequency. Preoperative bladder dysfunction was a strong predictor for continued bladder dysfunction at the end of 1 year (p < 0.004). Conclusions: All patients with D-OLF and or DO presented with myelopathic features. MRI with concurrent CT spine helps to delineate dural ossification from D-OLF and helped to rule out other differentials. The classical “tram track” and “comma sign” is well noted in CT spine and helps to plan surgical approach and anticipate probable complications. Patients with concurrent D-OLF and DO and long segment pathology had increased risk of intraoperative dural tears and postoperative CSF leaks. These subset of patients had a peaked incidence of bladder involvement or non-improvement of existing bladder dysfunction, postoperatively. Patients with D-OLF and DO seemed to do better after surgical decompression. Surgery should be offered once diagnosis is confirmed on imaging, as all patients in out study, except one, showed postoperative neurological improvement. Our study concluded that patients with prolonged preoperative symptoms persisted to have them even after surgery. Patients with concurrent D-OLF and DO showed more significant improvement, postoperatively, in terms of mJOA – postop with a p = 0.002 as compared to patients with D-OLF alone. We recommend that each case be treated individually and treatment should be planned appropriately, based on the radiology and levels involved, keeping in mind the preoperative symptoms and their duration.
Kumar, Vinod; Nair, Rajesh Parameshwaran; Kongwad, Lakshman I.; and Ramachandran, Girish Menon, "Thoracic myelopathy secondary to ossified ligamentum flavum and dural ossification – A series of 19 cases and review of literature" (2019). Open Access Archive. 756.