Summary. The microendoscopic discectomy (MED) technique has been one of the promising surgeries for lumbar disc herniation in the last few years. The purpose of this study is to report the feasibility of a minimally invasive technique for extraforaminal lumbar disc herniation. Ten patients with extraforaminal lumbar disc herniation (one at L3-4, four at L4-5, and five at L5-S1) underwent MED using the METRx system. A tubular retractor was inserted posterolaterally adjacent to the caudal base of the transverse process at the level of the affected disc. The nerve root was carefully distinguished from its surrounding tissues, and then the herniated disc was excised. The mean length of the preoperative clinical course was 7 months. The pain in the lower extremity was relieved in all patients. The clinical results in the MED group were the same as those in the open surgery group. Endoscopic herniotomy requires much less extensive muscle dissection than open surgery. The MED technique for extraforaminal lumbar disc herniation can be performed safely and effectively. There is a learning curve to this procedure
