Per Pedicel-Ligament Flavum Tunnel Outside-In Foraminoplasty for T -T Discectomy under a Percutaneous Endoscope.

Objective: To describe the effectiveness of T -T discectomy and per pedicel-ligament flavum tunnel outside-in foraminoplasty protocols under percutaneous endoscope.

Methods: This retrospective study from September 2017 to June 2019 comprised 10 patients (mean age was 64.7 years, with 7 men and 3 women) with symptomatic thoracic disc herniation. Patients who had 12 months of follow-up and no cervical and lumbar spine surgery or trauma during the follow up period were included in the study. Patients underwent surgery at different levels: 3 patients for T -T and 7 patients for T -T . Percutaneous endoscopic thoracic discectomy was performed following under-vision foraminoplasty, which was based on lower pedicel-ligament flavum tunnel detection. Patients who presented with symptomatic soft disc herniation of the thoracic spine and did not respond to conservative treatments were included. Patients with calcified disc herniation or concomitant ossification of the posterior longitudinal ligament were excluded. The surgery involves four steps: (i) facet joint reaching procedures; (ii) sliding the working sleeve caudally to attach the pedicel, rotating the scope to detect the lower border of the superior articular process, the pedicel, and the lower pedicel-ligamentum flavum tunnel (PEFT) under vision, respectively; (iii) milling the superior articular process under vision; and (iv) finding and removing the disc protrusion after the posterior longitudinal ligament is resected. Patient outcomes were evaluated using vision analog scale scores, Oswestry disability index scores, and Japanese Orthopaedic Association scores. The VAS scores, Oswestry disability index scores, and Japanese Orthopaedic Association scores before and after the operation were compared by t-test for statistical analysis. MRI, CT, and plain X-rays were performed in of all the patients before and after surgery.

Results: The patient was usually able to stand and walk approximately 2 h after the surgery. During the 12-month follow-up, all patients showed a significant improvement in pain. Postoperative thoracic MRI examination of all patients showed full decompression of the spinal cord and no residual pressure. Postoperative back pain and nerve root pain were significantly alleviated in all patients, and spinal cord function was significantly restored. The mean visual analog scale scores of patients postoperation were significantly better than those of patients preoperation (6.10 ± 1.37 vs 1.80 ± 0.79, P < 0.05). The mean ODI scores of patients postoperation were better than those of patients preoperation (13% ± 2.36% vs 55% ± 9.20%, P < 0.05). The mean JOA scores increased from 3.2 ± 0.75 to 9.3 ± 0.64. The JOA improvement rate was 79.6% ± 5.1%. There was 1 patient who had transient intercostal neuralgia.

Conclusion: Following pedicel-ligament flavum tunnel outside-in foraminoplasty protocols, T -T discectomy is relatively safe when conducted under percutaneous endoscope.