Technical consideration of transforaminal endoscopic spine surgery for central herniation

Introduction: Lumbar disc prolapse is most common between 30 and 50 years of age and is associated with severe disability and pain. It commonly occurs at L4/5 and L5/S1. Transforaminal endoscopic discectomy is an emerging technique for treatment of degenerative disc disease. Literature has shown clinical outcomes, comparable to classical open and micro lumbar discectomy. Central disc herniations in lumbar spine pose technical challenge for transforaminal endoscopic decompression due to its location. Existing techniques to access central herniations and ventral epidural space have trajectory related challenges due to the proximity of the retroperitoneal space and abdominal organs and technically difficult for the less experienced surgeon. Materials and Methods: Thirty patients – 19 males and 11 females – with central, multifocal, central-paracentral disc herniations in the lumbar spine operated in 2015 and 2016 were considered in this study. All patients underwent selective endoscopic discectomy under monitored care anesthesia and local anesthesia with modification of the classical technique, medialization of annulotomy, undercutting the nonarticular part of superior articular process (foraminotomy) and use of articulating and long jaw instruments either alone or in combination. Results: In all the thirty patients, we were able to achieve adequate decompression with neurological recovery. All patients improved in their neurological status. Postoperatively, visual analog scale dropped from 7.8 to 1.8 and ODI dropped from 73.46% to 32. 90% of the patients reported excellent and good results. One patient had recurrent herniation and was treated with transforaminal surgery. One patient had persistent back pain and reported poor outcome. Three patients underwent medial branch block for facet joint pain followed by medial branch rhizotomy and reported excellent and good results. Conclusion: Transforaminal endoscopic spine surgery with modifications as described above to reach the dorsal part of the disc in the midline and to access ventral epidural space is safe and effective.