Percutaneous full endoscopic posterior decompression of thoracic myelopathy caused by ossification of the ligamentum flavum

Abstract

Purpose Ossification of ligamentum flavum (OLF) is the leading cause of progressive thoracic myelopathy (TM) in East Asian countries. Surgical decompression is the general treatment for TM. This study investigated the application of percutaneous full endoscopic posterior decompression (PEPD) for the treatment of thoracic OLF. Methods Eighteen patients with TM were treated by PEPD under local anaesthesia. Patients had an average age of 59.1 years and single-level lesions mostly at the lower thoracic vertebrae. Computed tomography and magnetic resonance imaging were used to classify the OLF. The pre-and postoperative neurological statuses were evaluated using the American Spinal Injury Association (ASIA) sensory and motor score, modified Japanese Orthopaedic Association (mJOA) score and Frankel grade. Results OLF for all patients was classed as lateral, extended, and enlarged types without comma and tram track signs. Decompression was completed, and a dome-shaped laminotomy was performed through limited laminectomy and flavectomy. Dural tears in 2 patients were the only observed complication. The average score of ASIA sensory and motor, mJOA, as well as the Frankel grade improved significantly after surgery at an average follow-up time of 17.4 months. The average recovery rate (RR) was 47.5% as calculated from the mJOA scores. According to RR, 10 cases were classified as good, 4 cases fair, and 4 cases unchanged. Conclusions For patients with thoracic OLF at a single level and lateral, extended, and enlarged types without comma and tram track signs, it is safe and reliable to perform PEPD, which has satisfactory clinical results.Graphical abstract These slides can be retrieved under Electronic Supplementary Material.

Surgical results and prognostic factors following percutaneous full endoscopic posterior decompression for thoracic myelopathy caused by ossification of the ligamentum flavum

“…In addition, thoracic kyphosis might be influenced by changes in back extensor strength in particular, and providing strong, natural extrinsic support for the spine seems to be important for decreasing the incidence of spinal deformities 33 . Percutaneous endoscopic surgeries minimize damage to the paraspinal muscles, facet joints, lamina and posterior ligamentous complexes 15 . We believe that OLF patients who undergo PEPD without fusion may have a much lower risk of kyphosis, and we will continue to conduct a control study to verify this point.…”

“…OLF was classified into lateral, extended, enlarged, fusion, and tuberous types based on axial CT as well as round and beak types based on sagittal MRI 19,20 . Fusion and tuberous types of OLF were excluded based on the surgical difficulties in endoscopic decompression 15 . In addition, patients with ventral compression (thoracic disc herniation, ossification of the posterior longitudinal ligament), concomitant cervical or lumbar lesions and severe cardiopulmonary disease were also excluded.…”

“…The ipsilateral lesion was treated in the same manner. The whole procedure utilized the technique of "over-the-top" decompression 15 . Finally, the dural sac was exposed, and pulsation of the dural sac improved (Fig.…”

“…2h). Notably, tight DA/DO should be maintained but completely isolated from the surrounding LF to avoid a dural tear 15 . After complete decompression, the cannula was removed, and the incision was closed without the use of a suction drain.…”

“…To the best of our knowledge, all the published studies on prognostic factors in OLF patients have been based on traditional open surgery. However, MIS has been advantageous in treating OLF with satisfactory surgical results 12,[15][16][17] . This study investigated the prognostic factors following MIS and was based on the retrospective analysis of OLF patients who underwent percutaneous full endoscopic posterior decompression (PEPD).…”