单侧和对称性双侧获得性滑车神经麻痹患者的歪头试验

Background: The head-tilt phenomenon (difference between the vertical deviati ons with an ipsilateral and contralateral headtilt by 45 deg. each) occurring in patients with a superior oblique palsy has traditionally been explained by the lacking contraction of the superior oblique muscle within the synkinetic movemen t of ocular counterrolling. However, using a computer model, Robinson showed that the superior oblique palsy itself causes only a relatively small head-tilt ph enomenon. Adaptive mechanisms amplifying the otolith reflex were suggested to ex plain the increase of the head-tilt phenomenon in the course of time. In order to reduce the abnormal head posture required for binocular vision, the otolith r eflex would be amplified, accepting the greater vertical deviation when the head is tilted to the paretic side [23]. Question: If the head-tilt phenomenon were solely caused by the lacking contraction of the superior oblique muscle, it sho uld be greater in bilateral than in unilateral superior oblique palsies. If an a daptive mechanism were acting to reduce the abnormal head posture, the head-til t phenomenon should not be greater, and could even be smaller in bilateral than in unilateral superior oblique palsy, because in bilateral (symmetric) trochlear nerve palsies the vertical deviation at straight gaze is already small or absen t without adaptation. Patients and Methods: We have carried out a retrospective comparison of 10 patients with bilateral symmetric superior oblique palsies and 10 patients with unilateral superior oblique palsy. In all cases, the palsy was acquired and had been present for at least 1 year. Results: The patients with bi lateral superior oblique palsy had a head-tilt phenomenon ranging from 0 to 7 d egrees (median, 2 deg.). The patients with unilateral superior oblique palsy had a head-tilt phenomenon between 2 and 13 degrees (median, 8 deg.). The differen ce was significant (p=0.0117). Conclusions: The head-tilt phenomenon is smaller in long-standing bilateral symmetric superior oblique palsies than in long-st anding unilateral superior oblique palsy. This finding supports the hypothesis t hat in unilateral superior oblique palsy, an adaptive mechanism augments the hea d-tilt phenomenon by an amplification of the otolith reflex. However, we presum e that the amplification of the otolith reflex is only a side effect of the adap tive change of the vertical fusional vergence tonus and thus the price of the im proved vertical fusion, rather than a compensatory mechanism.

先天性上斜肌不全麻痹手术前后Bielschowsky歪头试验的变化

目的 探讨先天性上斜肌不全麻痹手术前、后Bielschowsky歪头试验的变化。 方法根据患眼原在位的垂直斜视度数 ,按照麻痹性斜视的手术原则 ,采用常规手术方式 ,减弱麻痹肌的直接拮抗肌和配偶肌 ,即减弱患眼的下斜肌和对侧眼的下直肌 ,治疗 38例单眼先天性上斜肌不全麻痹患者。手术前、后采用三棱镜遮盖法定量进行Bielschowsky歪头试验 ,检查患者原在位和头部向双侧倾斜时患眼的垂直斜视度数。以头部向患眼侧倾斜时患眼的垂直斜视度数高于头部向健眼侧倾斜时患眼的垂直斜视度数的数值≥ 5 0 △ 为Bielschowsky歪头试验阳性。结果 术前全部患眼的垂直斜视度数原在位为 3 0 △ ～ 2 5 0 △ ,平均为 11 0 △ ;头部向患眼侧倾斜时为 15 0 △ ～ 4 0 0 △ ,平均为 2 3 0 △ ;头部向健眼侧倾斜时为 0 0 △ ～ 10 0 △ ,平均为 2 5 △ ,Bielschowsky歪头试验均为阳性。术后全部患眼原在位的垂直斜视度数为 0 0 △ ～ 5 0 △ ,平均为 2 0 △ ;4例患者Bielschowsky歪头试验转为阴性 ,34例仍为阳性 (89 5 % )。结论 采用减弱患眼下斜肌和对侧眼下直肌方法治疗先天性上斜肌不全麻痹 ,术后患者Bielschowsky歪头试验的转阴率较低。以其作为手术疗效的评价标准值得探讨。

下斜肌截除术

下斜肌截除术(Partial myectomy of inferior oblique,myectomy of io)是White(1942)设计的一种简便易行而且效果确实的下斜肌减弱手术,其适应症为各种原因所造成的下斜肌功能过强(原发性和继发性)。自1979年至1988年的10年间,我们对继发性下斜肌功能过强进行此种手术45例。