Yong Raymund L, Westerberg Brian D, Dong Charles, Akagami Ryojo
Division of Neurosurgery, Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
J Neurosurg. 2008 Jan;108(1):105-10. doi: 10.3171/JNS/2008/108/01/0105.
Tumor size is likely to be a major determinant of hearing preservation after surgery for vestibular schwannoma. Findings in some large case series have not supported this concept, possibly due to variation in the technique used for tumor measurement. The authors sought to determine if the length of tumor-cochlear nerve contact was predictive of hearing outcome in adults undergoing resection of a vestibular schwannoma.
Patients who underwent a hearing-preserving approach for resection of a vestibular schwannoma at one institution by a neurosurgeon/neurotologist team between 2001 and 2005 were screened. Patients with American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) Class A or B hearing preoperatively were included. Magnetic resonance images were reviewed and used to calculate the length of tumor-cochlear nerve contact. Tumors were also measured according to AAO-HNS guidelines.
Thirty-one patients were included, 8 (26%) of whom had hearing preservation. Univariate analysis revealed that extracanalicular length of tumor-cochlear nerve contact (p = 0.0365), preoperative hearing class (p = 0.028), I-V interpeak latency of the brainstem auditory evoked potential (p = 0.021), and the interaural I-V interpeak latency difference (p = 0.018) were predictive of hearing outcome. Multivariate analysis confirmed the predictive value of extra-canalicular length of contact and preoperative hearing class (p = 0.041 and p = 0.0235, respectively).
Vestibular schwannomas with greater lengths of tumor-cochlear nerve contact increase a patient's risk for hearing loss after surgery with attempted hearing preservation. Involvement of the internal auditory canal produces a constant risk of hearing loss. Data from the experience of a single surgical team can be used to estimate the probability of good hearing outcome for any given patient with serviceable hearing and a vestibular schwannoma.
肿瘤大小可能是前庭神经鞘瘤手术后听力保留的主要决定因素。一些大型病例系列研究的结果并不支持这一概念，这可能是由于肿瘤测量技术的差异所致。作者试图确定肿瘤与耳蜗神经接触的长度是否可预测接受前庭神经鞘瘤切除术的成年患者的听力结果。
对2001年至2005年间在某机构由神经外科医生/神经耳科医生团队采用听力保留方法切除前庭神经鞘瘤的患者进行筛查。纳入术前美国耳鼻咽喉头颈外科学会（AAO-HNS）A级或B级听力的患者。回顾磁共振图像并用于计算肿瘤与耳蜗神经接触的长度。肿瘤也根据AAO-HNS指南进行测量。
纳入31例患者，其中8例（26%）听力得以保留。单因素分析显示，肿瘤与耳蜗神经接触的外耳道外长度（p = 0.0365）、术前听力分级（p = 0.028）、脑干听觉诱发电位的I-V峰间潜伏期（p = 0.021）以及双耳I-V峰间潜伏期差（p = 0.018）可预测听力结果。多因素分析证实了外耳道外接触长度和术前听力分级的预测价值（分别为p = 0.041和p = 0.0235）。
肿瘤与耳蜗神经接触长度较长的前庭神经鞘瘤会增加患者在尝试保留听力的手术后听力丧失的风险。内耳道受累会持续存在听力丧失的风险。来自单个手术团队经验的数据可用于估计任何给定的有可用听力的前庭神经鞘瘤患者获得良好听力结果的概率。
