Koos W T, Day J D, Matula C, Levy D I
Department of Neurosurgery, University of Vienna, Austria.
J Neurosurg. 1998 Mar;88(3):506-12. doi: 10.3171/jns.1998.88.3.0506.
The authors studied the relationships between tumor size, location, and topographic position relative to the intact facial nerve bundles in acoustic neurinomas to determine the influence of these factors on hearing preservation postoperatively. Consistent topographic relationships were found.
Four hundred fifty-two patients with acoustic neurinoma treated via a retrosigmoid approach were analyzed with respect to hearing preservation and facial nerve function. One hundred fifteen tumors were identified as small and were categorized as Grades I and II. Patients with Grade I tumors, that is, purely intracanalicular lesions, all had good hearing preoperatively, defined by a less than 50-dB pure tone average and 50% speech discrimination score. All 14 Grade I tumors were removed, resulting in preservation of the patient's hearing by these criteria. There were no particular topographic anatomical relationships associated with these tumors that affected hearing preservation. Grade II tumors, defined as those protruding into the cerebellopontine angle without contacting the brainstem, were found in 101 patients and were divided by size into two grades: IIA (< 1 cm) and IIB (1-1.8 cm). In 90 patients with Grade IIA tumors, 72 (89%) of 81 who had preserved hearing preoperatively maintained it postoperatively, and in the 11 patients with Grade IIB tumors, six of whom had good hearing preoperatively, four (67%) had preserved hearing postoperatively. Six morphological types were identified based on their neurotopographic relationships to the elements of the vestibulocochlear nerve.
Hearing preservation postsurgery by tumor type was as follows: 1A, 92%; 1B, 88%; 1C, 100%; 2A, 83%; 2B, 92%; and 3, 57%. Combined, this represents a hearing preservation rate of 87% after surgical treatment of Grade II acoustic neurinomas. Full nerve function was maintained in 88% of patients with anatomically preserved facial nerves in both Grade I and II tumors. The remaining 12% of patients retained partial function of the facial nerve. Two patients in the series lost anatomical integrity of the nerve due to surgery.
作者研究了听神经瘤的肿瘤大小、位置以及相对于完整面神经束的局部位置之间的关系，以确定这些因素对术后听力保留的影响。发现了一致的局部关系。
对452例经乙状窦后入路治疗的听神经瘤患者的听力保留情况和面神经功能进行了分析。115个肿瘤被确定为小肿瘤，并分为I级和II级。I级肿瘤患者，即纯内耳道病变患者，术前听力均良好，定义为纯音平均听阈小于50dB且言语辨别得分50%。所有14个I级肿瘤均被切除，按照这些标准患者听力得以保留。这些肿瘤不存在影响听力保留的特定局部解剖关系。II级肿瘤定义为突入桥小脑角但未接触脑干的肿瘤，在101例患者中发现，并按大小分为两个级别：IIA（<1cm）和IIB（1 - 1.8cm）。在90例IIA 级肿瘤患者中，术前听力保留的81例中有72例（89%）术后仍保留听力，在11例IIB级肿瘤患者中，术前听力良好的6例中有4例（67%）术后保留了听力。根据它们与前庭蜗神经各成分的神经局部关系确定了六种形态类型。
按肿瘤类型划分的术后听力保留情况如下：1A，92%；1B，88%；1C，100%；2A，83%；2B，92%；3，57%。综合起来，这代表II级听神经瘤手术治疗后的听力保留率为87%。I级和II级肿瘤中，面神经解剖结构保留的患者中有88%维持了完全神经功能。其余12%的患者保留了部分面神经功能。该系列中有2例患者因手术失去了神经的解剖完整性。
