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

在爆炸中有两种作用，一种是由冲击波能量产生的动态作用，另一种是由爆轰产生的气体能量产生的静态作用。研制了一种以动力作用为主的爆炸导管。迄今为止，应用该导管行微爆破膀胱碎石术131例，成功率100%。微爆碎石术是目前治疗膀胱结石的最佳方法。但是，爆炸导管不能用于输尿管、肾和胆结石的破坏，因为会产生有害气体。为了解决这个问题，我们新开发了两种类型的碎石机;针锤式和胶囊式。对这些碎石机的爆炸威力进行了测试。因此，针锤碎石机是合适的。三毫克三硝基间苯二酚用于炸药。炸药、点火系统和针锤装在直径2.6毫米、长31毫米的不锈钢圆柱形腔室内。通过爆破，直径为1.3 mm的针锤被所产生的气体以120 m/sec的初始速度从腔室中推出，并且被控制为在距腔室尖端5 mm的距离处不超限。输尿管和胆道结石的抗压强度低于65 kg/cm ^2，属于低强度组。这些结石的直径在13毫米内，使用该碎石机粉碎。输尿管的抗拉强度与胆囊、胆管的抗拉强度相当。这些材料适合于微爆。针锤预期输尿管损伤在3天内治愈。应用针锤式微爆破治疗输尿管肾结石48例，成功率65%。今后我们将努力提高成功率和破坏胆管结石。

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.