"Cave-in" decompression under unilateral biportal endoscopy in a patient with upper thoracic ossification of posterior longitudinal ligament: Case report.

Background: Thoracic ossification of the posterior longitudinal ligament (TOPLL) requires surgery for spinal cord decompression. Traditional open surgery is extremely invasive and has various complications. Unilateral biportal endoscopy (UBE) is a newly developed technique for spine surgery, especially in the lumbar region, but rare in the thoracic spine. In this study, we first used a different percutaneous UBE "cave-in" decompression technique for the treatment of beak-type TOPLL.

Methods: A 31-year-old female with distinct zonesthesia and numbness below the T3 dermatome caused by beak-type TOPLL (T2-T3) underwent a two-step UBE decompression procedure. In the first step, the ipsilateral lamina, left facet joint, partial transverse process, and pedicles of T2 and T3 were removed. In the second step, a cave was created by removing the posterior third of the vertebral body (T2-T3). The eggshell-like TOPLL was excised by forceps, and the dural sac was decompressed. All procedures are performed under endoscopic guidance. A drainage tube was inserted, and the incisions were closed after compliance with the decompression scope a C-arm. The patient's preoperative and postoperative radiological and clinical results were evaluated.

Results: Postoperative CT and MR films conformed complete decompression of the spinal cord. The patient's lower extremity muscle strength was greatly improved, and no complications occurred. The mJOA score improved from 5 to 7, with a recovery rate of 33.3%.

Conclusion: UBE spinal decompression for TOPLL showed favorable clinical and radiological results and offers the advantages of minimal soft tissue dissection, shorter hospital stays, and a faster return to daily life activities.