输尿管双极电凝热损伤的动物实验研究

Electro-thermal Injury to the Ureter by Bipolar Electrocoagulation in Rabbits

目的探讨输尿管双极电凝损伤后机能改变及其并发症发生的原因。方法日本长耳兔36只。一期实验12只,动物处死后于24条输尿管下段共取60条输尿管平滑肌条,分为正常组(20条),电凝损伤1秒组(20条)、3秒组(20条),电凝损伤组以双极电凝40 W在时间继电器控制下分别作用1秒或3秒,行输尿管离体平滑肌收缩频率及收缩力测定,HE染色观察损伤节段病理形态改变。二期实验24只,随机再分为电凝1秒(12只),电凝3秒(12只)2组,选择单侧兔输尿管距肾盂8 cm处分别予以双极电凝1秒或3秒。实验后饲喂2周,观察术后输尿管并发症,取损伤节段输尿管测定机能状况及病理形态改变。结果一期实验中,正常输尿管收缩频率、收缩力分别为(15.85±3.65)次/min、(0.835±0.182)g,电凝1秒组分别为(36.35±9.54)次/min、(0.335±0.096)g,电凝3秒组分别为(43.95±10.03)次/min、(0.320±0.096)g。电凝损伤后输尿管节段收缩频率加快,收缩力变小(P均=0.000)。二期实验中,电凝1秒组有2例(2/12,17%)出现尿漏,自行停止,输尿管收缩频率与收缩力分别为(25.58±3.20)次/min、(0.483±0.093)g,与一期实验电凝1秒组相比呈现低频率(P=0.001)、收缩力增高(P=0.000)趋势;电凝3秒组发生尿漏6例(6/12,50%),8例(8/11,73%)损伤节段输尿管出现狭窄,收缩频率与收缩力分别为(40.45±7.95)次/min、(0.305±0.113)g,与一期实验电凝3秒组相比收缩频率(P=0.329),收缩力(P=0.718)差异均无显著性。电凝损伤后均出现炎症反应,损伤部位细胞空泡化改变,2周后炎症反应程度重。电凝1秒对输尿管损伤严重程度较3秒轻。电凝3秒损伤输尿管平滑肌全层及腔内假复层上皮层,二期实验中有肌层挛缩,假复层上皮层剥离表现。结论输尿管双极电凝热损伤后尿漏、输尿管狭窄的发生与损伤后输尿管机能改变、局部细胞结构损伤有关。

Objective To explore the causes of clinical complications after electro-thermal injury to the ureter by bipolar electrocoagulation.Methods Thirty-six Japanese long-eared rabbits（1.9-2.4 kg,6-8 months old） were randomly divided into two groups for phase Ⅰ and Ⅱ experiments（12 and 24 animals respectively）.In phase Ⅰ experiment,totally 60 pieces of smooth muscles were collected from the 24 ureters of the 12 rabbits.The 60 pieces of ureteral smooth muscles were then divided into control,and 1-and 3-second electrocoagulation（bipolar electrocoagulation at 40 W） groups with 20 in each.The extent and frequency of smooth muscles contraction in the 1-and 3-second electrocoagulation groups,as well as histopathological changes of the injured segments were determined.In phase Ⅱ experiment,the rest 24 rabbits were randomly divided into 1-and 3-second electrocoagulation groups with 12 in each;electrocoagulation was made at the ureter at one side,8 cm away from the renal pelvis.We observed the complications occurred to the ureter during two weeks after the operation,and then killed the rabbits to collect the injured ureter to determine its histopathological changes.Results In phase Ⅰ experiment,the frequency and extent of contraction of the ureteral smooth muscles were（15.85±3.65） times/min and（0.835±0.182） g;（36.35±9.54） times/min and（0.335±0.096） g,and（43.95±10.03） times/min and（0.320±0.096） g,respectively in the control,and 1-and 3-second electrocoagulation groups.After electrocoagulation,the frequency of muscle contraction increased significantly,and extent of contraction decreased significantly（both P=0.000）.In phase Ⅱ experiment,in 1-second electrocoagulation group,2 cases of urine leakage were detected（2/12,17%）,which was cured spontaneously afterwards;the frequency and extent of ureteral contraction were（25.58±3.20） times/min and（0.483±0.093） g,which were significantly lower and higher respectively than those in the 1-second electrocoagulation group in phase Ⅰ（P=0.001 and 0.000,respectively）.In 3-second electrocoagulation group,6 cases（6/12,50%） of urine leakage and 8 cases（8/11,73%） of ureteral stricture were found;the frequency and extent of ureteral contraction were（40.45±7.95） times/min and（0.305±0.113） g,respectively,which were not significant different from those in the 3-second electrocoagulation group in phase Ⅰ（P=0.329 and 0.718）.Inflammation response and cell vacuolization of the injured site occurred after electrocoagulation,and the inflammation response deteriorated in two weeks.1-second electrocoagulation was less damaging than 3-second electrocoagulation,which damaged the whole layer of the local ureteral smooth muscle,as well as the pseudostratified epithelium in the ureteral tubule.In phase Ⅱ experiment,3-second electrocoagulation groups showed local smooth muscle contracture and detachment of pseudostratified epithelium.Conclusion Urine leakage and stricture after bipolar electrocoagulation are related to the ureteral dysfunction and local cellular structure changes.