涙嚢鼻腔吻合術における骨窓形状

Anatomical background for bony opening in dacryocystorhinostomy

　涙嚢鼻腔吻合術（DCR）において篩骨蜂巣への穿破を避ける骨窓の形状を検討するために，涙嚢窩と節骨蜂巣の位置関係を調べた。DCRの適応となった患者100例100側（男性28名，女性72名，45〜83歳，平均70.6歳）を対象に，眼窩のCT撮影をドイツ水平面に平行に行った。内眼角の高さとその5mm下方の高さとにおいて，涙嚢窩の前後径および前涙嚢稜から篩骨蜂巣前端までの長さを，それぞれ計測した。内眼角の高さでは涙嚢窩の前後径は7.9±1.0mm，前涙嚢稜から篩骨蜂巣前端までの長さは3.3±1.7mmであり，内眼角から5mm下方の高さでの各々の値は，8.3±1.1mm，5.4±2.6mmであった。篩骨蜂巣の前端は涙嚢窩の下方ほど後涙嚢稜寄りに位置し，骨窓の形成には後方へと広げる余地がある。

We evaluated the anatomical relationship between the lacrimal fossa and the ethmoidal sinus in order to determine the optimum site of bony opening in dacryocystorhinostomy (DCR). Orbital computed tomography (CT) was performed parallel to the eye-ear plane in 100 patiens prior to DCR. The series comprised 28 males and 72 fe-males. Their age ranged from 45 to 83 years, average 70.6 years. On CT sections, the anteroposterior diameter of the lacrimal fossa at the height of the medial canthus averaged 7.9±1.0 mm. The distance from the anterior lacrimal crest to the anterior extremity of the ethmoidal sinus averaged 3.3±1.7 mm. At the height 5 mm below the medial canthus, these values averaged 8.3±1.1 mm and 5.4±2.6 mm respectively. The findings show that the anterior proximity of the ethmoidal sinus is nearer to the posterior lacrimal crest when the DCR bony opening is located more inferiorly, al-lowing room for backward expansion of the bony opening in DCR surgery.