Development of Destruction System for Renal, Ureteral and Biliary Calculi using Pin-hammer Microexplosion

爆炸有两种作用；由于冲击波能量的动态作用和由于爆轰产生的气体能量的静态作用。研制了一种以动力作用为主的爆破导管。迄今为止，使用该导管进行微爆炸膀胱结石成形术131例，成功率为100%。微爆炸碎石是目前治疗膀胱结石的最佳方法。但爆炸导管由于产生有害气体，不能用于输尿管、肾结石和胆道结石的破坏。为了解决这一问题，我们新开发了两种类型的碎石机；有针锤式和胶囊式。对这些碎石机的爆轰威力进行了测试。结果表明，采用针锤式碎石机较为合适。三硝基间苯二甲酸三毫克用于炸药。炸药、点火系统和钉锤被装入一个直径2.6毫米、长31毫米的不锈钢圆柱形腔内。通过爆破，产生的气体将直径为1.3 mm的钉锤以120 m/秒的初始速度推出腔体，并控制在距腔体尖端5mm的距离内不超限。输尿管、胆道结石抗压强度均低于65 kg/cm^2，属于低强度组。用该碎石机对直径在13mm以内的结石进行了粉碎。输尿管的抗张强度与胆囊、胆管基本相等。这些材料适用于微爆炸。预期的针锤输尿管损伤在3天内治愈。应用针锤微爆治疗输尿管结石和肾结石48例，成功率65%。今后我们将努力提高手术成功率，并努力破坏胆道结石。

There are two kinds of action in explosion; dynamic action due to the energy of shock wave and static action due to the energy of gas generated in detonation. An exploseve catheter mainly using dynamic action was developed. Up to date microexplosion cystolithotripsy using this catheter was performed in 131 cases with a success rate of 100 %. At present microexplosion lithotripsy is the best method for bladder calculi removal. However, the explosive catheter could not be applied to the destruction of ureteral, renal and biliary calculi, because of harmful gas generation. For the settlement of that reason, we newly developed two types of lithotriptor; a pin-hammer and capsule type. A detonation power of these lithotriptors was exanimed. As the result, a pin-hammer lithotriptor was suitable. Three mg trinitroresorcinate is used for explosive. The explosives, an ignition system and a pin-hammer are loaded inside a stainless steel cylindrical chamber 2.6 mm in diameter and 31 mm length. By blasting, the pin-hammer, with a diameter of 1.3 mm, is pushed out from the chamber at a initial velocity of 120 m/sec by generated gas and is controlled not to overrun at a distance of 5 mm from the tip of the chamber. The compressive strength of ureteral and biliary calculi was below 65 kg/cm^2 and belonged to the low strength group. These calculi within 13 mm in diameter were destructed using this lithotriptor. The tensile strength of ureter was alomost equal to gall bladder and bile duct. These materials were suitable in microexplosion. Expected ureteral injury by the pin-hammer was cured within 3days. The application of pin-hammer microexplosion was in 48 patients with ureteral and renal calculi, with a success rate of 65 %. In future we will make efforts to improve a success rate and to destruct biliary calculi.