Development of hand-guided measurement device of stapes mobility using the micromachining technique

听骨链由锤骨、砧骨和砧骨组成，在听觉力学中起着重要的作用。如果听小骨的某一部分变得固定，就会发生听力损失。为了提高听力水平，固定部分被替换为假体。这种手术被称为“鼓室成形术”。在鼓室成形术中，评估患者的踝关节活动度是非常重要的，因为它关系到听力水平改善的预后。本研究以Wada等人的方法为基础，研制了一种可用于临床测量的踝关节活动度测量装置。(2000)是通过组装一个小型力传感器和一个高精度的致动器而开发的，并通过测量豚鼠的距骨活动度来评估其临床适用性。可以得出以下结论：1.通过使用小型电容力传感器和带有柔性线圈杆和钢丝的液压微机械手，实现了装置的小型化。由于这项技术，在不影响敏感度和重复性的情况下，在手术中可以测量到距骨的移动度。豚鼠正常距骨的等效刚度为17±3N/m(N=5)。与耳硬化症症状相对应的正常和人工固定之间的僵硬程度有明显区别。因此，本研究开发的新仪器将有助于诊断胫骨固定。

The ossicular chain, consisting of the malleus, incus and stapes, plays an important role in auditory mechanics. If some part of the ossicles becomes fixed, hearing loss occurs. In order to improve the level of hearing, the fixated part is replaced with a prosthesis. This surgery is called "tympanoplasty." It is important to evaluate the stapes mobility during the tympanoplasty, because it affects the prognosis of improvement of the hearing level. However, objective measurement of stapes mobility has not yet to be achieved.In this study, an apparatus which is clinically useful for measuring the stapes mobility based on the method of Wada et al. (2000) was developed by assembling a small-sized force sensor and a high-precision actuator, and its clinical applicability was evaluated by measuring stapes mobility in the guinea pig. The following conclusions can be drawn.1. Miniaturization of the apparatus was realized by the use of a small-sized capacitive force sensor and a hydraulic micromanipulator with a flexible coil rod and wires. Owing to this technology, the stapes mobility is measurable during surgery without impairing the sensitivity and repeatability.2. The equivalent stiffness of the normal stapes in guinea pigs was 17±3 N/m (N = 5).3. The difference between the stiffness of the normal stapes and that of the artificially fixed stapes which corresponds to the symptom of otosclerosis was clearly distinguished. Therefore, the new apparatus developed in this study would be helpful for diagnosing stapes fixation.