Percutaneous Endoscopic Transforaminal Outside-In Outside Technique for Foraminal and Extraforaminal Lumbar Disc Herniations-Operative Technique

BACKGROUND: Different transforaminal endoscopic r eroaches have been developed for the surgical treatment of lumbar disc herniation: Kambin (intradiscal), Yeung (intraforaminal intradiscal), Ruetten (extreme lateral), transforaminal endoscopic surgical system (intraforaminal extradiscal) approach, and modifications. The operative technique for the treatment of foraminal and extraforaminal lumbar disc herniation through these surgical approaches has not been well described in reported studies. Moreover, each of these surgical approaches has limitations in the removal of migrated intra- or extraforaminal disc herniation. We have described, step by step, the operative technique of a modified percutaneous endoscopic transforaminal approach we have termed the "percutaneous endoscopic intra- and extraforaminal extradiscal approach or transforaminal outside-in outside [TOIO] approach" for the treatment of foraminal and extraforaminal lumbar disc herniation. METHODS: From 2012 to 2018, 48 patients had undergone the percutaneous endoscopic TOIO approach for symptomatic foraminal and extraforaminal lumbar disc herniation. The inclusion criteria were the same as the microdiscectomy criteria. The exclusion criteria included patients with severe foraminal stenosis and disc degeneration, listhesis, and scoliosis. The pre- and postoperative clinical data, radiographic findings, and surgical technique were investigated. RESULTS: No intraoperative complications developed. the patients showed progressive improvement of initial neurological deficits with complete recovery of motor weakness and L4, L5 hypoesthesia at 1 month postoperatively. One patient experienced persistent postoperative dysesthesia on the affected leg for similar to 1 month. CONCLUSION: The percutaneous endoscopic TOIO approach is a minimally invasive, safe, and efficacious surgical procedure for the treatment of lumbar foraminal and extraforaminal disc herniation. Proper patient selection is mandatory to ensure a satisfactory outcome.