動眼神経麻痺に併発した異常連合現象を利用した斜視手術

Surgery for oculomotor nerve palsy with misdirection syndrome

　患眼の内直筋と眼瞼挙筋の間の異常連合現象のみられる3症例の外傷性動眼神経不全麻痺を対象に，内直筋のともむき筋に対してcounterpalsyを起こさせるように健眼の外直筋の後転に内直筋の切除を併用し健眼を故意に内転させた。その結果，外斜偏位の減少とともに眼瞼下垂の改善が得られ，さらにきわめて狭い範囲であるが両眼単一視視野が認められた。これらの結果から眼瞼下垂の改善は健眼で固視する際にcounterpalsyにより過剰なインパルスが健眼の外直筋に伝達され，同量のインパルスがHeringの法則に従い患眼の内直筋とこれと異常連合する眼瞼挙筋に伝わり眼瞼が挙上すると推察した。

We treated 3 cases of traumatic oculomotor palsy with misdirection syndrome. We performed recession and resection to induce adduction of the sound eye. It was our intention to cause counter palsy in the yoke muscle of paretic medial rectus of the affected eye. All the cases showed marked reduction in exodeviation and blepharoptosis after surgery. They regained binocular single vision withprismatic corrections for residual deviations. It appeared that the surgery on the sound eye resulted in trasmission of excessive innervation to the pa-retic medial rectus in accordance to the equal inner-vation law of Hering. Stimulus of the levator muscle via misdirection from the medial rectus would have led to disappearance of blepharoptosis.