枪伤伤道中烧伤所致凝固性坏死区及其临床意义

目的：探明四肢软组织遭高速步枪子弹贯穿射击后伤道周围组织损伤情况，为确定清创范围提供实验依据。方法：10只市售健康成年猪，麻醉后于7m外用国产“九五”式步枪射击后肢软组织，造成不伤及大血管和骨骼的贯通伤。分别于伤后4h，12h，1d，3d和9d行磁共振成像（MRI）扫描，随即处死相应动物做常规病理学检查。结果：发现原发弹道表面有一厚约2mm的“双低信号层”，在T2WI和增强T1WI上均表现为低信号，病理学观察表明系凝固性坏死组织。该层组织外侧依次为肌纤维碎裂区和波浪状变形区，均有血液供应，可自行修复，在T2WI和增强T1WI上表现为高信号。在未经引流的伤道中，内容物可沿肌间隙蔓延形成支道，并在远隔伤道处形成间隙脓肿。结论：枪伤伤道可分为弹道区、凝固性坏死区、组织碎裂区和组织变形区四区。其中凝固性坏死区是独立的枪伤伤道结构，推测由高温子弹造成的重度烧伤引起。

Burn-induced coagulative necrosis around the gunshot wound tract and its clinical significance

Objective:To investigate the degree and range of injury of soft tissues caused by penetrating high-velocity rifle bullets in extremities,and provide experimental support to determine the range of debridement.Methods: Ten adult domestic pigs were shot through the proximal part of one hind limb by 95-type rifle under general anesthesia.No large vessel or bone was wounded.Two pigs were used to be scanned each time by MRI after 4 h,8 h,1 d,3 d and 9 d respectively.The pathological observations were followed after the scanned pigs had been killed.Results: There existed a thin layer of tissue which covered the inner surface of primary tract and showed low signal in both T2WI and enhanced T1WI.This layer was identified to be composed of coagulative necrosis tissue by pathological observation.The outer layers of injured tissue were characterized by interrupted and wave-shaped muscle fibers separately,and showed high signals in T2WI and enhanced T1WI.In un-drained wound, the dirty material and pus may spread along the fascial space as a branch tract to form an interfascial abscess.Conclusion: The gunshot-wounded soft tissue can be divided into four zones,which are wound tract,zone of coagulative necrosis,zone of tissue disruption and zone of tissue distortion.The zone of coagulative necrosis is an intact layer covering wound tract,which is supposed to be caused by burn of bullets with high temperature.