Percutaneous Endoscopic Interlaminar Approach: Medial Foraminal Decompression in Treating Lumbar Disc Herniation or Spinal Stenosis

Background: The technique of transforaminal endoscopic spine surgery is being widely used for lumbar degenerative diseases. But the interlaminar endoscopic surgery, which is more familiar and easier to be operated for spine surgeons, is more easily applied by traditionally trained surgeons. Objective: We propose the technique of percutaneous endoscopic medial foraminal decompression through interlaminar approach for the treatment of lumbar disc herniation (LDH) and spinal stenosis (LSS), and to explore the safety and efficacy of using this technique clinically. Methods: Thirty-two LDH and eleven LSS patients received medial foraminal decompression surgery with 22.6 ± 7.9 months follow-up. Through interlaminar space, we are able to perform discectomy and lateral recess decompression to decompress the medial foraminal area. Clinical efficacy was assessed by calculating the scores of VAS, SF-36, and lumbar disease JOA and ODI respectively at preoperative, postoperative and the discharge period, 3-6 months postoperatively and the final follow-up time point when patients were considered having received maximum surgical benefit. Follow-up time period varied because of the patients' follow-up logistics in China serving a large referral area made it difficult for rural patients to return at established intervals for the study. Results: For both LDH and LSS patients, the observational indexes of the follow-up time points showed significant differences compared with those preoperatively (P<0.01). Surgical results were assessed according to JOA scores: 22 cases were excellent, 16 cases were good, and 5 cases were fair by modified MacNab criteria. The satisfaction rate of PEMFD was 88.37% during the follow-up period with the improvement of daily life quality. One patient had postoperative radiation calf pain and foot numbness, and another one had the dorsal remnant of the dural sac without symptom. Conclusion: The treatment for LDH and LSS with medial foraminal decompression is safe and effective with minimal tissue trauma, less surgical morbidity to the lumbar canal, with full decompression of nerve roots and the cauda equina. It is more similar to traditional open surgery and easier to achieve adequate canal decompression,