Downward Laminotomy Technique for Hidden Zone Foraminal Disk Herniations: Technical Notes and Preliminary Results.

Abstract

Hidden zone foraminal herniations are among the more rare forms of herniations. As exploration is difficult, and there is a close relationship between the nerve root and pedicle, many surgical approaches have been proposed. The aim of this study was to describe downward laminotomy as a new approach to these herniations. A downward laminotomy technique was used in 5 cases with hidden zone foraminal disk herniation with no extension to the intervertebral disk space. The herniated disk fragment was located at L4-L5 in 4 cases and at L3-L4 in 1 case. Mean visual analog scale scores reduced from preoperative 8.2 to 2.1 postoperatively. The allodynia was resolved in two months. It was concluded that downward laminotomy provides a safe, less risky, and minimally invasive approach to hidden zone foraminal disk herniations.