Linder Thomas, Schlegel Christoph, DeMin Nicola, van der Westhuizen Stephan
Department of Otorhinolaryngology, Head and Neck Surgery, Kantonsspital Luzern, Luzern, Switzerland.
Otol Neurotol. 2009 Jan;30(1):41-7. doi: 10.1097/MAO.0b013e31818be812.
The functional outcome of ossiculoplasties in chronic ear and lateral cranium base surgery depends on the presence of a ventilated middle ear space and is guided by the existence or absence of ossicular remnants. In patients with poorly ventilated middle ears, after multiple previous operations, missing stapes suprastructure, or after partial temporal bone resection for tumor removal, restoration of conductive hearing is not possible. The direct placement of a vibrating floating mass transducer (FMT) onto the round window membrane with obliteration of the surgical cavity is a new option.
Starting in January 2006, five patients underwent a subtotal petrosectomy to control their chronically discharging ear, to remove residual cholesteatoma, or to revise previous incompletely exenterated cavities. Four patients underwent a simultaneous placement of a Vibrant Soundbridge (VSB) onto the round window membrane; one patient had a staged reconstruction after initial Bone-Anchored Hearing Aid rehabilitation. In all operations, the external ear canal and the eustachian tube were closed, and the cavity was obliterated using abdominal fat.
Preoperative and postoperative pure tone audiograms were analyzed in respect to deterioration of inner ear function, aided and unaided (hearing aid, VSB, and Bone-Anchored Hearing Aid) speech audiograms were compared to verify improvements in communication skills, functional gains were calculated at comfortable level settings, and postoperative computed tomographic scans were used to exclude recurrent disease and to confirm the position of the FMT onto the round window membrane. Patient's satisfaction was measured using a standardized questionnaire.
All patients were very satisfied daily users of their middle ear implant and had complete eradication of their middle ear pathology. Bone conduction worsened at 2 kHz, with preservation of inner ear function in the other frequencies. Whereas none of the patients had any unaided speech discrimination before the surgery at conversational levels, all patients obtained 95 to 100% correct monosyllabic scores at 70 to 80 dB using the VSB. The functional gain was highest at higher frequencies.
Patients with combined hearing loss undergoing subtotal petrosectomy with complete fat obliteration of the middle ear and mastoid area can be safely rehabilitated, placing the FMT of a VSB onto the round window membrane, either at the time of primary surgery, or as a staged secondary procedure.
慢性中耳及外侧颅底手术中听骨成形术的功能结果取决于中耳腔是否通气，并且受听骨残余物的存在与否所引导。在中耳通气不良的患者中，经过多次先前手术、镫骨上部结构缺失，或为切除肿瘤而进行部分颞骨切除术后，恢复传导性听力是不可能的。将振动式浮动质量传感器（FMT）直接放置在圆窗膜上并封闭手术腔是一种新的选择。
从2006年1月开始，5例患者接受了颞骨次全切除术，以控制其慢性耳流脓、清除残留胆脂瘤或修正先前未完全清除的腔隙。4例患者同时将听觉骨桥（VSB）放置在圆窗膜上；1例患者在初次骨锚式助听器康复后进行了分期重建。在所有手术中，外耳道和咽鼓管均被封闭，并用腹部脂肪封闭腔隙。
分析术前和术后纯音听力图以了解内耳功能的恶化情况，比较佩戴和未佩戴（助听器、VSB和骨锚式助听器）时的言语听力图以验证沟通能力的改善情况，在舒适水平设置下计算功能增益，并使用术后计算机断层扫描排除复发性疾病并确认FMT在圆窗膜上的位置。使用标准化问卷测量患者的满意度。
所有患者都是中耳植入物的日常使用者，对其非常满意，并且中耳病变已完全根除。骨导在2kHz时变差，其他频率的内耳功能得以保留。术前所有患者在对话水平下均无言语辨别能力，而使用VSB时，所有患者在70至80dB时单音节得分的正确率均达到95%至100%。功能增益在较高频率时最高。
接受颞骨次全切除术且中耳和乳突区完全用脂肪封闭的混合性听力损失患者，可通过在初次手术时或作为分期二次手术将VSB的FMT放置在圆窗膜上而安全地实现听力康复。
