Development of a new sialendoscopic sialolithectomy system using a shape-memory alloy

本研究的目的是开发一种适合于实际应用的形状记忆合金非手术内窥镜肛门取石术系统，并将其应用于临床。我们与日本ACTMENT株式会社合作，使用镍钛超弹性形状记忆合金镍钛研制了一种篮形钳。它有三根直径为0.16毫米的镍钛合金丝，形状足以接住帆石。但篮形钳子外径为0.78 mm，直径过大，不能插入鼻内窥镜的工作通道。因此，今后应对篮形钳子进行改进，使其外径变得越来越小。我们还研制了两种细小的唾液内窥镜，可通过舌下隆突的开口将其引入颌下导管。一种是外径1.1 mm的唾液内窥镜(德国POLYDLAGNOST GmbH)，具有6000像素光纤，并具有插入篮钳和灌溉通道的工作通道。同时研制了一种外径小于0.4 mm、可插入工作通道的唾液内窥镜专用超细筐钳。另一种是外径1.2 mm的腮腺内窥镜(日本Fibertech株式会社)，使用1600像素光纤和0.75内径的工作通道，其中可以插入1.9F篮钳(美国波士顿科学公司)。使用这些新开发的涎镜系统，我们成功地摘除了2例患者的颌下腺涎石。然而，我们的系统有问题；我们的系统不能去除直径较大的涎石，而不是直径较大的唾液管。我们认为我们需要开发一种涎镜碎石术系统，以确保取出不同大小的结石。

The purpose of this study was to develop a new non-surgical endoscopic sailolithectomy system suitable for practical use with a shape-memory alloy and to apply it to the clinical use.We developed a basket forceps with the collaboration of ACTMENT Co. Ltd. (Japan) using nitinol, which is a superelastic shape-memory alloy of nickel and titanium. It has three nitinol wires of 0.16mm diameter memorized an adequate shape to catch the sailolith. However, the outer-diameter of basket forceps is 0.78mm, and the diameter is too large to insert the working channel of the sialendoscopy. Therefore, we should improve the basket forceps to reduce the outer diameter smaller and smaller than the present one in the future.We also developed two types of fine sialendoscope, which could be introduced to the submandibular duct through the opening of sublingual caruncula. One is a sialendoscope of 1.1-mm outer-diameter (POLYDLAGNOST GmbH, Germany) with 6000-pixels optic fibers, and it has a working channel to insert a basket forceps and an irrigation channel. At the same time, we developed an ultrafine basket forceps specialized in the sialendoscope with less than 0.4mm outer-diameter, which can be inserted into the working channel. The other is a sialendoscope of 1.2-mm outer-diameter (FiberTech Co., Ltd., Japan) with 1600-pixels optic fibers and a working channel of 0.75 inner-diameter, in which a 1.9F basket forceps (Boston Scientific Corporation, USA) can be inserted.Using these newly developed sialendoscopy systems, we successfully removed sialoliths of the submandibular gland of two patients. However, our systems have the problem ; our systems do not enable to remove the sialolith with the larger diameter rather than the diameter of the salivary duct. We consider that we need to develop a sialendoscopic lithotripsy system to ensure the removal of various size of sailolith.