Percutaneous Endoscopic Approach for Highly Migrated Intracanal Disc Herniations by Foraminoplastic Technique Using Rigid Working Channel Endoscope

STUDY DESIGN: A retrospective analysis of 59 patients operated for excision of soft highly migrated intracanal lumbar disc herniations by percutaneous endoscopic foraminoplasty. OBJECTIVE: To describe a safe and effective percutaneous endoscopic technique for removal of migrated herniations and report the results on the basis of modified MacNab criteria. SUMMARY OF BACKGROUND DATA: Migrated herniations pose a great challenge even for experienced endoscopic surgeons. These herniations are hidden from the endoscopic view by anatomic barriers like hypertrophied facet, inferior pedicle and foraminal ligaments rendering percutaneous endoscopic transforaminal lumbar discectomy (PELD) by conventional approach, difficult with high failure rate. Foraminoplasty, which means enlargement of foramen by undercutting ventral part of superior-facet, upper border of inferior pedicle along with ablation of foraminal ligament, can help us to address this issue. METHODS: Fifty-nine patients with soft highly migrated herniations who underwent PELD with foraminoplasty under local anesthesia from January 2002 to June 2006 were analyzed retrospectively. Patients were evaluated by postoperative Visual Analog Scale for leg pain and Oswestry Disability Index scores. Outcomes were graded according to modified MacNab criteria. RESULTS: Mean follow-up was 25.4 months. Mean visual analog scale score for radicular pain improved from 8.01 to 1.56, and mean Oswestry disability Index improved from 61.6 to 10.76. Based on modified MacNab criteria, 91.4% of patients experienced satisfactory outcome. Three patients had persistent leg pain after surgery. One patient underwent a repeat-PELD on next day and the other after 1 month. Both were relieved of symptoms. Third patient was subjected to open discectomy after 25 weeks from the first operation and showed improvement. Two patients had recurrent herniation at same level after 6 months; 1 patient underwent repeat PELD, and the other underwent open discectomy. Both patients had good results. CONCLUSION: Foraminoplastic-PELD is safe and effective procedure for surgical treatment of soft migrated herniations. The results are comparable to results of open discectomy.