三角部腫瘍に対するHigh parietal paramedian approach—Technical nuances and Case review

High Parietal Paramedian Approach for Tumors in the Trigone of the Lateral Ventricle:Technical Nuances and Case Review

Ⅰ．はじめに

　側脳室三角部腫瘍に対するHigh parietal approachは一般的なアプローチであるが，適応疾患が限られるため，頻用されるものではない．われわれは，術前画像の情報を活用し，脳皮質切開部の決定と三角部までの侵入経路の確保の方法，腫瘍摘出の順序・摘出中の注意などの点に配慮して摘出に臨んでいる．本稿では，われわれの摘出方法と9例の治療結果について紹介し，アプローチの妥当性を検討する．

　The aim of this paper was to introduce and validate our high parietal paramedian approach for tumors in the trigone of the lateral ventricles.

　This study included nine tumors found in the trigone region and treated surgically in our institute.

　The approach of this method is described here. First, the central sulcus and post-central gyrus were identified by the electrodes after opening of the dura mater. Corticotomy was performed in the rearward area of the post-central gyrus 25mm within the midline and 20mm along the length, to avoid the damage to the primary sensory area and arcuate fasciculus. A round-shaped spatula was used to protect the surrounding brain tissue. The tumors were excised from medial portion because the feeding supply is usually derived from the medial and deep choroid plexus. As vital structures, including the optic radiation, thalamus, posterior horn of the internal capsule, and fornix, exist around the trigone, gentle dissection from the ventricle wall is needed. The hematoma was removed last to avoid obstructive hydrocephalus, and a drainage tube was left in the ventricle.

　Total gross resection of all the tumors was performed, and an approximate blood loss of 50-445ml（average 134.3ml）was recorded. None of the patients had permanent neurological deficit, and those with visual defects recovered postoperatively.

　Preservation of the visual and high brain function is an important consideration in the treatment strategy for tumors in the trigone of the lateral ventricle. The high parietal paramedian approach is a versatile and prominent approach that helps preserve these functions.