A Modified Percutaneous Endoscopic Technique to Remove Extraforaminal Disk Herniation at the L5-S1 Segment

OBJECTIVE: To introduce a modified percutaneous endoscopic lumbar diskectomy (PELD) technique to remove extraforaminal disk herniation at the L5-S1 segment, including the technical essentials and preliminary results. METHODS: The geometric parameters of the transverse process, facet joint, and sacrum (IFS) space based on imaging examination were measured in 100 common patients. The technical essentials, including working cannula placement and disk removal involved in the technique, were described. Ten cases (7 men and 3 women) with extraforaminal disk herniation at L5-S1 were surgically treated with the PELD technique through the TFS space from June 2015 to March 2017. RESULTS: The maximum diameter of the TFS space varied from 2.73 to 11.81 mm (6.84 +/- 2.01 mm) on the left and 3.00 to 10.47 mm (7.02 +/- 2.05 mm) on the right. The distance of possible skin entry points from midline varied from 33.28 to 84.18 mm, and the distance of external iliac vessels to skin varied from 70.05 to 119.14 mm. All 10 patients who underwent the modified PELD technique were back to previous activities in 1 month. Visual analog scale (VAS) or Oswestry Disability Index (ODI) scores reduced to 2.5 +/- 2.0 or 25.4 +/- 10.8 from 7.5 +/- 1.3 or 75.2 +/- 13.3, respectively, 1 day after operation. At 30 days after the operation, the VAS score was 1.0 +/- 0.6 and ODI score was 10.2 +/- 3.2. No neurologic deficit or surgical site infection occurred. CONCLUSIONS: We introduced a modified PELD technique to remove extraforaminal disk herniation at the L5-S1 segment. This technique was less invasive, effective, and safe. We also summarized a detailed protocol to identify and remove the herniated disk for nerve protection.