Carey John P, Migliaccio Americo A, Minor Lloyd B
Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.
Otol Neurotol. 2007 Apr;28(3):356-64. doi: 10.1097/01.mao.0000253284.40995.d8.
To characterize semicircular canal function before and after surgery for superior semicircular canal dehiscence (SCD) syndrome.
Prospective unblinded study of physiologic effect of intervention.
Tertiary referral center.
Patients with SCD syndrome documented by history, sound- or pressure-evoked eye movements, vestibular-evoked myogenic potential testing, and high-resolution multiplanar computed tomographic scans.
Nineteen subjects with SCD had quantitative measurements of their angular vestibulo-ocular reflexes (AVOR) in response to rapid rotary head thrusts measured by magnetic search coil technique before and after middle fossa approach and repair of the dehiscence. In 18 subjects, the dehiscence was plugged; and in 1, it was resurfaced.
The AVOR gains (eye velocity/head velocity) for excitation of each of the semicircular canals.
Vertigo resulting from pressure or loud sounds resolved in each case. Before surgery, mean AVOR gains were normal for the ipsilateral horizontal (0.94 +/- 0.07) and posterior (0.84 +/- 0.09) canals. For the superior canal to be operated on, AVOR gain was 0.75 +/- 0.13; but this was not significantly lower than the gain for the contralateral superior canal (0.82 +/- 0.11, p = 0.08). Mean AVOR gain decreased by 44% for the operated superior canals (to 0.42 +/- 0.11, p < 0.0001). There was a 13% decrease in gain for the ipsilateral posterior canal (p = 0.02), perhaps because plugging affected the common crus in some cases. There was a 10% decrease in gain for excitation of the contralateral posterior canal (p < 0.0001), which likely reflects the loss of the inhibitory contribution of the plugged superior canal during head thrusts exciting the contralateral posterior canal. Mean AVOR gain did not change for any of the other canals, but two subjects did develop hypofunction of all three ipsilateral canals postoperatively.
Middle fossa craniotomy and repair of SCD reduce the function of the operated superior canal but typically preserve the function of the other ipsilateral semicircular canals.
描述上半规管裂综合征（SCD）手术前后的半规管功能。
干预生理效应的前瞻性非盲法研究。
三级转诊中心。
通过病史、声音或压力诱发的眼动、前庭诱发肌源性电位测试以及高分辨率多平面计算机断层扫描记录确诊为SCD综合征的患者。
19例SCD患者在中颅窝入路和修复骨裂前后，采用磁搜索线圈技术对快速旋转头部推力时的角前庭眼反射（AVOR）进行了定量测量。18例患者堵塞了骨裂；1例患者进行了骨裂表面修复。
每条半规管兴奋时的AVOR增益（眼速度/头速度）。
在每种情况下，由压力或大声响引起的眩晕均得到缓解。术前，同侧水平半规管（0.94±0.07）和后半规管（0.84±0.09）的平均AVOR增益正常。对于要手术的上半规管，AVOR增益为0.75±0.13；但这并不显著低于对侧上半规管的增益（0.82±0.11，p = 0.08）。手术的上半规管平均AVOR增益下降了44%（降至0.42±0.11，p < 0.0001）。同侧后半规管增益下降了13%（p = 0.02），可能是因为在某些情况下堵塞影响了总脚。对侧后半规管兴奋时增益下降了10%（p < 0.0001），这可能反映了在头部推力刺激对侧后半规管时，堵塞的上半规管抑制作用的丧失。其他半规管的平均AVOR增益没有变化，但有两名患者术后同侧三条半规管均出现功能减退。
中颅窝开颅手术和SCD修复可降低手术上半规管的功能，但通常可保留同侧其他半规管的功能。
