胸腰椎部に発生した脊髄硬膜外嚢腫の1治験例

A CASE OF EXTRADURAL CYST IN THORACO-LUMBAR REGION

はじめに

　脊髄に発生する嚢腫には，皮様嚢腫，寄生虫（echino—coccus）による嚢腫，髄膜嚢腫がある。1934年Elsbergら^5）が約250例の脊髄腫瘍のなかから3例の硬膜外嚢腫と2例の硬膜内嚢腫を見付けた。3例の硬膜外嚢腫は，いずれも髄膜嚢腫で，彼らは他家の同様な1症例を加え，計4例を脊髄硬膜外嚢腫として報告し，その成因を先天性髄膜憩室または先天性の硬膜欠損部よりのクモ膜ヘルニアと推定した。この論文が発表されてから，報告例は漸次増加し，1968年にはCloward^3）が集めえた報告例，計92例について，詳細な統計的観察を加えて発表するに至つた。

　しかし，Clowardの論文には本邦例は含まれていない。著者らの調べえた範囲では，本邦では8例の報告があるに過ぎない^{8）9）12）13）14）}。この疾患の発生頻度は，全脊髄腫瘍の約1％で，稀な疾患である。最近著者らは胸腰椎部に発生した1例を経験したので，これを報告する。

A case of extradural cyst in thoraco-lumbar region was reported. Sixteen year-old boy had occasional headache for last 8 months except 2 months of spontaneous remission. This headache was increased and accompanied with nausea and vomiting when he was tired after labor. For the last 2 months, walking difficulties appeared with headache, but these symptoms were improved by recumbency. The cerebrospinal fluid test revealed a high pressure of 420 mm H₂O, which raised up to 500mm H₂O by Queckenstedt's test. The cerebrospinal fluid proteins were 2 fractions in Nissl-Esbach's test and the cell counts were 11/3. Carotid angiogram showed no evidence of intra-cranial space occupying lesions. The air was unintentionally injected into the cyst on the at-tempted pneumoencephalography at the lumbar level. Plain radiographs of the thoraco-lumbarspines showed a well-marked widening of the inter-pedicular distances and deep concave erosion of the posterior surface of the vertebral bodies from D-12 to L-3. Descending myelography was per-formed. The downward flow of Myodil was obstructed at the level of D-11. Below this level, the contrast medium tended to collect in the pockets lying dorsolateral to the spinal cord.

Laminectomy was carried out from D-11 to L-2. The cyst was found to be completely extradural and extended laterally into intervertebral foramina along the nerve roots. The cyst was filled with a clear colorless fluid, practically identical with the cerebrospinal fluid. The dorsal wall of the cyst was excised, but the ventral wall had so tightly fused with the dura that it was remained. Leakage of the fluid was found at the point near the left pedicle of D-12 and the opening was closed with sutures. Histological examination revealed that the cyst wall was composed of collagenous fibers.

No neurological deficit was found except slight hypesthesia over the segment of S-1 of the left side after operation. He returned to his previous job, and continues to work during the follow-up period of about 3 years.