[Treatment of migrated lumbar intervertebral disc herniation by percutaneous spinal endoscopy through bone tunnel]

To investigate the clinical effect of percutaneous endoscopic lumbar discectomy (PELD) through bone tunnel in the treatment of migrated lumbar intervertebral disc herniation.

The clinical data of 42 patients with migrated lumbar intervertebral disc herniation treated through PELD techniques were retrospectively analyzed from October 2015 to December 2018. There were 26 males and 16 females, aged from 39 to 71 years old with a mean of(58.55±7.16) years. There were 7 cases where the affected segment was L_3,4, 24 cases of L_4,5, and 11 cases of L₅S₁. According to modified free nucleus pulposus classification, 3 cases of type A1, 6 cases of type A2, 8 cases of type B1, 8 cases of type B2, 6 cases of type C1, and 11 cases of C2. Among these 42 cases, 22 patients were treated with transpedicular approach (transpedicular approach group), 6 cases were type A2, 6 cases were type B2 and 10 cases were type C2, and 20 cases with translaminar approach(translaminar approach group), 3 cases were type A1, 8 cases were type B1, 6 cases were type C1, 2 cases were type B2 and 1 case was type C2. The operation time, intraoperative and postoperative complications of the two groups were recorded, and the pain visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to assess the improvement of the clinical symptoms before surgery, immediately after surgery, and 12 months after surgery, and the modified Macnab evaluation system was used to evaluate the clinical efficacy.

The operative time was from 69 to 105 min with a mean of (88.29±9.85) min;and no intraoperative complications such as neurovascular injury or dural tear were occurredin all patients. One case in the transpedicular approach group was changed to general anesthesia and translaminar approach due to local anesthesia intolerance. All the patients were followed up from 13 to 34 months, with a mean of (13.71±3.56) months. VAS and ODI were significantly improved in two groups immediately after surgery and 12 months after surgery (P<0.05). According to modified Macnab criteria, 27 cases obtained excellent results, 11 good, 3 fair, and 1 poor. There were no postoperative complications such as lumbar fractures and postoperative infections in the follow-up patients.

For migrated intervertebral disc herniation, the modified nucleus pulposus classification can be used to estimate the precise target before operation, and the reasonable bone tunnel approach can be selected to obtain good results.