高速三角破片致猪坐骨神经损伤的特点

Characteristics of the sciatic nerve injuries inflicted by high-velocity triangle fragments in swine

目的探讨高速三角破片敏猪坐骨神经损伤的伤情特点。方法长白猪14只，体重（34．3±5．2）kg。采用随机数字表法分为A、B两组各7只，用初速为（773．1±12．4）m／s的0．37g三角破片致伤，分别瞄准猪右后肢外侧坐骨神经体表投影线中点和旁开2cm射击。观察伤道入口和出口大小、长度，神经与伤道位置关系，伤后48h观察神经大体及光电镜改变。结果破片在伤道内存在不同程度的偏离原射入方向：A、B组分别有5只和1只坐骨神经位于原发伤道内，其中4例出现不同程度断裂；光镜下见神经严重出血水肿、炎细胞浸润，大量神经纤维、轴索断裂，髓鞘着色浅；电镜下见髓鞘严重溃变、轴索变形。A、B组分别有1只和5只位于震荡区内，距原发伤道（2．07±0．45）cm，光镜见神经轻度出血、充血，部分神经纤维、轴索断裂；电镜下可见髓鞘部分分层。A、B组各有1只位于挫伤区内，神经受损程度介于二者之间。结论高速三角破片在组织内走行不稳定；其原发伤道内的猪坐骨神经断裂发生率高，损伤严重，范围广，华勒变性早；位于原发伤道旁的神经亦发生形态学改变，其损害程度与神经和原发伤道距离有关。

Objective To study the characteristics of the sciatic nerve injuries inflicted by high- velocity triangle fragments in swine. Methods According to the injury position, 14 swines weighing （34.29 ± 5.2 ） kg were divided into two groups. All swines were shot by 0.37 g triangle fragments at （773.1 ± 12.4） m/s aimed at the midpoint of the lateral body surface projection of the fight sciatic nerve in Group A （n = 7） and at 2 cm aside from sciatic nerve in Group B （n = 7 ）. The entrance, exit and length of wound tract, distance between nerve and wound tract were detected, and the pathology of sciatic nerve and wound tract at 48 hours after injury were observed under light microscope and electron micro-scope. Results The course of the fragments was deviated to different extent. Six sciatic nerves were in primary wound tract, four of which were lacerated and ruptured at different degrees. The light microscope showed pathological changes including severe hemorrhage and edema, leukocytic infiltration, neurotmesis, axonotmesis and light myelin coloration ; while electron microscope showed severe degeneration of naye/in sheath and neuraxon distortion. Six nerves （one in Group A and five in Group B） were in the concussion zone, with the distance between sciatic nerve and primary wound tract for （ 2.07 ± 0.45 ） cm. Hyporrhea and hyperemia under perilemma and perineurium, partial nerve fiber disrupt and axonotmesis were observed by light microscope and partly myelin sheath delamination by electron microscope. Two nerves （one in Group A and another in Group B） were in the contusion zone, with moderate pathological changes. Conclusions The track of high velocity triangle fragments is unstable in the tissues. High disrupt rate, severe and wide extent lesion, early Wallerian degeneration are the main characteristics of direct injuries of swine＇ s sciatic nerves. Indirect injuries can induce pathologic changes too, for which the lesion severity is related to the distance between nerves and primary wound tract.