海綿静脈洞部及び傍鞍部に進展した巨大下垂体腺腫に対するExtradural Temporopolar Approach

Extradural Temporopolar Approach for Giant Pituitary Adenomas Invading the Cavernous Sinus and Parasellar Regions

I．はじめに

　近年，神経画像診断の進歩，微小解剖の詳細な理解，microsurgeryの技術や術中ナビゲーション機器の発展により，頭蓋底外科の進歩はめざましく，海綿静脈洞内病変に対しても種々の手術方法が試みられており，その手術成績も著しく向上している^{1-5,7,9,12-14,17,18,21）}．Dolencら^4）のcombinedepi-and subdural approachを応用したextraduraltemporopolar approachは，上部脳底動脈や視交叉下部の病変に対する手術方法としてDayら^3）によって報告された．この手術方法の特徴は，海綿静脈洞外側壁硬膜を剥離することにより，側頭葉先端部の静脈を犠牲にせずに側頭葉を硬膜外から後方に圧排することができ，傍鞍部や視交叉周囲，上部脳幹前側面の病変に対し十分な視野が得られることである．

　そこでわれわれは，この手術方法を海綿静脈洞内から傍鞍部に進展した巨大下垂体腺腫の摘出に応用し，硬膜外及び硬膜内の両方から腫瘍摘出を行い，満足すべき結果を得たので，その有用性について報告する．

Objective: An extradural temporopolar approach has recently been used in the treatment of the parasel-lar, infrachiasmatic, or intracavernous regions. In this approach, the temporal (superficial) dural layer isseparated from the deep layer (inner cavernous membrane) to expose the cavernous sinus extradurally. Wereport our experiences with 5 cases in which a giant pituitary adenoma invading the cavernous sinus andparasellar regions was resected via the extradural temporopolar approach.

Patients and Methods: Between January 1995 and December 1997, 60 patients with pituitary adenomaswere operated on at Okayama University Hospital. The extradural temporopolar approach was used for 5patients who had a giant pituitary adenoma invading the cavernous sinus and parasellar regions. The 5 pa-tients were women aged from 32 to 62 years and presented with a visual dysfunction. Four patients hadhormonally non-functioning pituitary adenomas and one had a growth-hormone secreting pituitary adeno-ma.

Results: The operations resulted in 1 total, 3 subtotal and 1 partial removal. There was no operativemortality or major morbidity. Transient oculomotor palsy occurred in 2 cases postoperatively. Thisapproach provided excellent exposure of the tumor, relevant cranial nerves and arteries in and around thecavernous sinus through extradural retraction of the temporal lobe, allowing for sufficient resection of theintracavernous and parasellar portion of the tumor. Tumors invading the inferior portion of the clivus orthe contralateral cavernous sinus could not be removed through this approach.

Conclusion: Our findings suggest that the extradural temporopolar approach is useful for resection ofgiant pituitary adenomas invading the cavernous sinus and parasellar regions.