腰椎椎間孔巨大神経鞘腫の腹膜鏡下摘出術

Laparoscopic Resection of a Giant Lumbar Foraminal Schwannoma

Ⅰ．はじめに

　神経鞘腫は有髄神経を構成するシュワン細胞由来の良性腫瘍であるが，腰椎椎間孔神経鞘腫は後腹膜腔に巨大病変を呈するケースが稀に存在する^11,13)．傍脊柱筋アプローチなど後方からの限られた術野では，巨大化した後腹膜腔の腫瘍成分を摘出するのは容易ではない^5,13)．われわれは，巨大化したダンベル型（Eden type Ⅳ）の腰椎椎間孔神経鞘腫に対し，前方から経腹膜法で腹腔鏡下に後腹膜腔の腫瘍成分を摘出し，残存した後方成分を二期的に傍脊柱筋アプローチで摘出した結果，良好な経過をたどった1例を経験した．腹腔鏡下アプローチの利点につき，文献的考察を加えて報告する．

　Lumbar foraminal schwannomas occasionally present as giant lesions in the retroperitoneal cavity. Here, we report a case of a L5 giant foraminal schwannoma that was laparoscopically excised. A 26-year-old man visited our hospital with the complaint of numbness of the left leg that had persisted for 2 years. Magnetic resonance imaging scans revealed a dumbbell tumor originating from the left L5/L6 intervertebral foramen. The tumor mass in the retroperitoneum extended to 6 cm and was buried in the iliopsoas, pressing superiorly on the L4 nerve root. During the surgical procedure, the ventral portion of the tumor was first excised outside the intervertebral foramen, using the anterior approach to laparoscopically enter the retroperitoneum. Postoperatively, the left leg pain disappeared. The residual tumor in the posterior portion was resected microsurgically with the Wiltse paraspinal approach. The tumor was a schwannoma originating from the dorsal ramus of the L5 nerve root. Postoperatively, the patient resumed ambulation and was discharged with no exacerbation of the neurological symptoms.