[Clinical application of percutaneous transforaminal endoscope-assisted lumbar interbody fusion]

To conclude of the technical notes of percutaneous transforaminal endoscope-assisted lumbar interbody fusion (PT-Endo-LIF), and to investigate its safety and efficacy for treatment of degenerative lumbar disease.

Twenty-four patients were treated by PT-Endo-LIF combined with posterior percutaneous pedicle screws fixation from October 2017 to April 2018. There were 16 males and 8 females, ranging in age from 39 to 72 years old, with a mean of (59.6±9.5) years old. There were 15 cases diagnosed with lumbar intervertebral disc herniation combined with degenerative disc, the other 9 cases were diagnosed as low level lumbar spondylolistheses w/o segmental instability. Single segmental fusion was performed for 22 cases(one for L₂,₃, 3 for L₃,₄ and 18 for L₄,₅) and 2 segmental fusion was performed for the other 2 cases (both for L₃,₄ and L₄,₅). PT-Endo-LIF was performed under local anesthesia with conscious sedation, followed by decompression through endoscopic technics. After that, end-plate preparation and autogenous bone and expandable cage implantation were performed. Finally, percutaneous screws and rod instrumentation were used. The visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical efficacy. The operation time, intraoperative bleeding volume, intraoperative and postoperative complications were recorded. All patients underwent X-ray, CT plain scan, three-dimensional reconstruction and MRI examination to evaluate the stability of the implants and fusion rate before 3 days and 1, 3, 6, 12 and 18 months after operation.

All patients were followed up, and the duration ranged from 12 to 18 months. The operation time of single-segment fusion was (192.3±22.7) min, and that of double-segment fusion was (272.5±24.7) min. The estimated intraoperative bleeding volume was less than 50 ml per segment, and no blood transfusion was performed in all patients. The VAS improved from preoperative 7.4±1.1 to postoperative 2.3±0.8 (t=-19.65, P<0.000 5). The ODI improved from preoperative (41.2±3.3)% to the final follow-up (12.3±2.5)%(t=-35.76, P<0.000 5). Postoperative complications occurred in 4 cases, and contralateral radicular symptoms occurred in 2 cases. After contralateral foraminoscopic decompression, the symptoms were completely alleviated. One case had neurological symptoms related to percutaneous screw placement, and the symptoms were alleviated after removal of the lateral screw rod internal fixation. The other cases had surgical incision infection and improved after debridement and suture. At the latest follow-up, no displacement or loosening of the fusion cage and screw rod system occurred in all patients, and 14 cases showed signs of fusion.

PT-Endo-LIF is a minimal invasive, safe and efficient surgical procedure for treatment of degenerative lumbar disease. Nevertheless, the long-term results still need to be confirmed by a multi-center and lagre sample follow-up study.