Naros Georgios, Sandritter Joey, Liebsch Marina, Ofori Alex, Rizk Ahmed R, Del Moro Giulia, Ebner Florian, Tatagiba Marcos
Department of Neurosurgery, Eberhard Karls University, Tuebingen, Germany.
Department of Neurosurgery, University of Padova, Padova, Italy.
Front Neurol. 2017 Aug 3;8:378. doi: 10.3389/fneur.2017.00378. eCollection 2017.
Nearly two-thirds of patients with vestibular schwannoma (VS) are reporting a significantly impaired quality of life due to tinnitus. VS-associated tinnitus is attributed to an anatomical and physiological damage of the hearing nerve by displacing growth of the tumor. In contrast, the current pathophysiological concept of non-VS tinnitus hypothesizes a maladaptive neuroplasticity of the central nervous system to a (hidden) hearing impairment resulting in a subjective misperception. However, it is unclear whether this concept fits to VS-associated tinnitus. This study aims to determine the clinical predictors of VS-associated tinnitus to ascertain the compatibility of both pathophysiological concepts.
This retrospective study includes a group of 478 neurosurgical patients with unilateral sporadic VS evaluated preoperatively regarding the occurrence of ipsilateral tinnitus depending on different clinical factors, i.e., age, gender, tumor side, tumor size (T1-T4 according to the Hannover classification), and hearing impairment (Gardner-Robertson classification, GR1-5), using a binary logistic regression.
61.8% of patients complain about a preoperative tinnitus. The binary logistic regression analysis identified male gender [OR 1.90 (1.25-2.75); = 0.002] and hearing impairment GR3 [OR 1.90 (1.08-3.35); = 0.026] and GR4 [OR 8.21 (2.29-29.50); = 0.001] as positive predictors. In contrast, patients with large T4 tumors [OR 0.33 (0.13-0.86); = 0.024] and complete hearing loss GR5 [OR 0.36 (0.15-0.84); = 0.017] were less likely to develop a tinnitus. Yet, 60% of the patients with good clinical hearing (GR1) and 25% of patients with complete hearing loss (GR5) suffered from tinnitus.
These data are good accordance with literature about non-VS tinnitus indicating hearing impairment as main risk factor. In contrast, complete hearing loss appears a negative predictor for tinnitus. For the first time, these findings indicate a non-linear relationship between hearing impairment and tinnitus in unilateral sporadic VS. Our results suggest a similar pathophysiology in VS-associated and non-VS tinnitus.
近三分之二的前庭神经鞘瘤（VS）患者报告称，耳鸣导致其生活质量显著受损。VS相关性耳鸣归因于肿瘤的移位生长对听神经造成的解剖学和生理学损伤。相比之下，目前非VS耳鸣的病理生理学概念假设，中枢神经系统对（隐匿性）听力损伤产生适应性不良的神经可塑性，从而导致主观错误感知。然而，尚不清楚这一概念是否适用于VS相关性耳鸣。本研究旨在确定VS相关性耳鸣的临床预测因素，以确定两种病理生理学概念的兼容性。
这项回顾性研究纳入了一组478例接受神经外科手术的单侧散发性VS患者，术前根据不同临床因素，即年龄、性别、肿瘤侧别、肿瘤大小（根据汉诺威分类为T1-T4）和听力损伤（Gardner-Robertson分类，GR1-5），评估同侧耳鸣的发生情况，采用二元逻辑回归分析。
61.8%的患者术前有耳鸣症状。二元逻辑回归分析确定男性[比值比（OR）为1.90（1.25-2.75）；P = 0.002]、听力损伤GR3[OR为1.90（1.08-3.35）；P = 0.026]和GR4[OR为8.2l（2.29-29.50）；P = 0.001]为阳性预测因素。相比之下，T4期大肿瘤患者[OR为0.33（0.13-0.86）；P = 0.024]和完全听力丧失GR5患者[OR为0.36（0.15-0.84）；P = 0.017]发生耳鸣的可能性较小。然而，60%听力良好（GR1）的患者和25%完全听力丧失（GR5）的患者患有耳鸣。
这些数据与关于非VS耳鸣的文献高度一致，表明听力损伤是主要危险因素。相比之下，完全听力丧失似乎是耳鸣的负性预测因素。这些发现首次表明，在单侧散发性VS中，听力损伤与耳鸣之间存在非线性关系。我们的结果提示，VS相关性耳鸣和非VS耳鸣具有相似的病理生理学机制。
