Extraforaminal microscopic assisted percutaneous nucleotomy for foraminal and extraforaminal lumbar disc herniations.

Background: Foraminal and extraforaminal lumbar disc herniations are uncommon. The main presentation is radicular pain related to the exiting nerve root at the affected level. Different approaches for surgical intervention have been described.

Purpose: This study aimed to evaluate the clinical outcome, complications recurrence, and reoperation rate of extraforaminal microscopic-assisted percutaneous nucleotomy, with literature review focusing on complications and recurrence rate.

Study Design: This is a prospective cohort study done in a high-flow spine center in Germany.

Patient Sample: Between October 2012 and October 2015, 76 patients (35 women and 41 men) with foraminal or extraforaminal lumbar disc prolapse were operated on.

Outcome Measures: The following were the outcome measures: (1) self-report measures: Visual Analogue Scale (VAS) for leg pain and back pain; (2) physiological measures: standing plain X-rays (anterioposterior, lateral, and dynamic views); and (3) functional measures: Oswestry Disability Index (ODI) (validated German version) and Odom's criteria.

Methods: All patients were operated upon with trans-tubular extraforaminal microscopic-assisted percutaneous nucleotomy (EF-MAPN) technique. Preoperative clinical and neurologic evaluations were done. The mean follow-up period was 38 months (range 12-54). The study has not received funding for research from any organization. All authors do not have any conflict of interest.

Results: The mean age was 54 years. The most commonly affected level was L4/L5 (34 patients). The mean preoperative VAS for leg pain was 7.6 (3-10), which improved to 1.4 (0-4) postoperatively. The average operative time was 57.5 minutes. There were no intraoperative complications. One patient had temporary postoperative quadriceps weakness (L4 radiculopathy) that was completely improved at 3 months' follow-up. Another patient had deep venous thrombosis after discharge. Two patients had recurrences that necessitated another operation within the first 6 months postoperatively. Both were followed up for 1 year without a second recurrence.

Conclusion: Trans-tubular percutaneous extraforaminal microscopic-assisted nucleotomy is effective for foraminal and extraforaminal disc herniations. It is a muscle-splitting minimally invasive approach with minimal morbidity. Complications, recurrence, and reoperation rate are not different compared with microsurgical open or endoscopic techniques.