Percutaneous endoscopic lumbar discectomy for extreme lateral lumbar disc herniation.

Background: Far lateral disc herniation (FLDH) constitutes a minor portion of the total discectomy workload for spine surgeons. So far, there is still a debate about the term "extreme lateral," and in general, it describes the intra - and extraforaminal position of the disc herniation. We present a surgical treated case series in which the disc herniation on the lumbar spine was still ventral of the exiting nerve root far outside of the foramen. Methods: Study Design and Patient Characteristics: retrospective analysis of 14 surgical treated patients. Surgical Technique: In all patients, the so-called foraminal retreat maneuver (percutaneous endoscopic lumbar discectomy) was performed. A foraminoscope with a 15° optic orientation and a nonbeveled working sleeve were used in all cases. The aforementioned technique represents a modification of the "inside-out" endoscopic surgery on the lumbar spine. Results: We treated 11 male and 3 female patients with an average age of 67 years and 66 years, respectively. Except for one, 13 patients presented with clear monoradicular symptoms accompanied by mild-to-moderate neurological deficits. In 11 cases, the disc herniation exhibited cranial migration; two were at the disc level, and in another case, caudal migration was observed. Immediate pain relief and significant improvement of neurological symptoms occurred in all patients. Two patients developed neuropathic pain, which improved after conservative treatment within 6 weeks following the procedure. No recurrence was observed in this case series. Conclusion: Patients suffering from extreme lateral lumbar disc herniation were found to be significantly older. Furthermore, there is a higher tendency toward male patients and cranial migration of the herniation. The described and modified inside-out technique, along with a 15° optic, allows for clear identification of the exiting nerve root and safe removal of the displaced disc herniation far outside of the spinal canal and foramen. No complications occurred in this small series, and the development of neuropathic pain appears to be relatively common.