Biportal Endoscopic Posterior Thoracic Laminectomy for Thoracic Spondylotic Myelopathy Caused by Ossification of the Ligamentum Flavum: Technical Developments and Outcomes

Abstract

Objective: Advanced biportal endoscopic surgery techniques can be used to treat thoracic myelopathy secondary to ossification of the ligamentum flavum (OLF). This case series elaborates on a feasible biportal endoscopic technique for thoracic OLF removal and evaluates clinical and radiological outcomes.Methods: A biportal endoscopic posterior thoracic laminectomy was performed to remove the thoracic OLF. Surgical techniques have evolved from inside-out piecemeal removal methods to outside-in <i>en bloc</i> removal methods. Preoperative computed tomography was performed to analyze dural ossification and OLF types. Intraoperative videos were reviewed to observe dural ossification and to determine the surgical method. Neurological outcomes were assessed using the Japanese Orthopaedic Association (JOA) score.Results: Clinical symptoms and neurological function improved markedly after surgery (JOA score, preoperative: 12.6 ± 1.0, final follow-up: 15.6 ± 1.2). The mean operation time per segment was not short (106.6 ± 38 minutes). At early experience stages, inside-out piecemeal decompression was used and it caused intraoperative spinal cord injury. However, outside-in <i>en bloc</i> decompression technique did not induce neural complications. Postoperative segmental instability and correlated mechanical back pain were not observed.Conclusion: The biportal endoscopic posterior thoracic approach is an attractive surgical option to treat thoracic spondylotic myelopathy secondary to OLF. Piecemeal inside-out decompression can induce irreversible spinal cord injury, especially in the early experience stages. Outside-in decompression is more efficient and safer than inside-out pattern procedures by minimizing dural manipulation. Nonetheless, this technique is technically demanding and should only be performed in selected patients after acquiring abundant experience with endoscopic spine surgeries.

Safety and efficacy of one-hole split endoscope technique for surgical treatment of thoracic ossification of the ligamentum flavum

“…Nevertheless, FESS approaches have shown some new issues including limitations due to the coaxial approach in a single hole endoscope, a steep learning curve, and necessitating surgeons to possess extensive experience in endoscopic surgery. The UBE technique has also been described as a surgical method for addressing thoracic spondylotic myelopathy resulting from ossification of the ligamentum flavum 12 , 13 . Differing from FESS technique, the UBE technique deploys the endoscope and surgical instruments through two separate incisions, providing a larger operating space and partly reducing operational complexity.…”

“…However, these procedures are limited because of the steep learning curves in FESS, and controversies remain regarding approach selection, surgical instruments, and decompression strategies. Unilateral biportal endoscope (UBE) approaches have also shown good outcomes in treating TOLF 12 , 13 . However, two incisions should be made on the skin to make surgical window in UBE technique, and this may lead to more surgical trauma.…”

Lumbar Endoscopic Unilateral Laminotomy With Bilateral Decompression Surgery in Severe Lumbar Stenosis Under Electrophysiological Monitoring-Focused on Full-Visualized Trephine/Osteotome

“…As we all know, the outside-in technique was most accepted in the LE-ULBD surgery [ 23 ], whose procedure involves removal of bony structure including the lamina, articular facet joint first, then the entire LF en bloc or piecemeal to expose the dura and nerve root. However, the outside-in technique has disadvantages including uncertain removal border, dura tear and nerve injury.…”

Overview and Prevention of Complications During Biportal Endoscopic Thoracic Spine Surgery

“…The indications and contraindications for thoracic laminectomy by UBE are as follows [7][8][9]: (1) thoracic OLF and (2) thoracic spinal stenosis. The contraindications of thoracic laminectomy by UBE are as follows: (1) soft or calcified disc herniation, (2) severe ossified posterior longitudinal ligament, (3) spinal column instability, and (4) high-grade deformity.…”