Lin Kuan-Liang, Chen Chang-Mu, Wang Shou-Jen, Young Yi-Ho
Departments of 1Otolaryngology and 2Surgery, National Taiwan University Hospital, Taipei, Taiwan; and 3Department of Otolaryngology, Catholic Cardinal Tien Hospital, Fu-Jen Catholic University, Taipei, Taiwan.
Ear Hear. 2014 Sep-Oct;35(5):571-6. doi: 10.1097/AUD.0000000000000046.
The maximum size of the vestibular schwannoma (VS) that is compatible with preservation of the function of the vestibular nerve in performing stereotactic radiosurgery remains unclear. This study utilized ocular vestibular-evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) test results to correlate with the size of VS.
Fifty patients with unilateral VS underwent audiometry, and caloric, oVEMP and cVEMP tests. Tumor size from magnetic resonance imaging was measured on the axial plane, and the relationships between tumor size and each test result were analyzed.
The pure-tone average from four frequencies did not significantly predict tumor size. Alternatively, oVEMP and cVEMP responses remained significant predictors for tumor size in the regression model, namely, tumor size (cm) = 0.62 × (oVEMP response) + 1.39 × (cVEMP response), where oVEMP and cVEMP responses were regarded as binary variables, in which 1 and 0 reflect abnormal and normal responses, respectively. This model explained 76% of the variance. Accordingly, the estimated VS size exhibiting abnormal oVEMPs and cVEMPs is >2.01 (0.62 +1.39) cm.
When VS size is <2.0 cm, preservation of the function of superior/inferior vestibular nerve indicated by the oVEMP/cVEMP test is achievable. Therefore, both oVEMP and cVEMP tests may serve as supplementary tools for determining treatment option in VS patients.
在进行立体定向放射外科手术时，与保留前庭神经功能相适应的前庭神经鞘瘤（VS）的最大尺寸仍不明确。本研究利用眼前庭诱发肌源性电位（oVEMP）和颈前庭诱发肌源性电位（cVEMP）测试结果与VS大小进行关联分析。
50例单侧VS患者接受了听力测定、冷热试验、oVEMP和cVEMP测试。在轴位平面上测量磁共振成像的肿瘤大小，并分析肿瘤大小与各项测试结果之间的关系。
四个频率的纯音平均听阈不能显著预测肿瘤大小。相反，在回归模型中，oVEMP和cVEMP反应仍然是肿瘤大小的显著预测指标，即肿瘤大小（厘米）=0.62×（oVEMP反应）+1.39×（cVEMP反应），其中oVEMP和cVEMP反应被视为二元变量，1和0分别反映异常和正常反应。该模型解释了76%的方差。因此，oVEMP和cVEMP均异常时估计的VS大小>2.01（0.62 +1.39）厘米。
当VS大小<2.0厘米时，通过oVEMP/cVEMP测试提示的保留上/下前庭神经功能是可以实现的。因此，oVEMP和cVEMP测试均可作为确定VS患者治疗方案的辅助工具。
