Effects Of Electro-Mechanical Parameters Of Electrosurgical Unit On The Structure Of Pancreatic Eschar And Its Function Of Pancreatic-Fistula-Prevention

Surgical energy instruments provide a novel method to solve problems of postoperative pancreatic fistula,among which Electrosurgical Units(ESUs)are widely used in clinic due to its simple operation,low operation cost and excellent hemostatic effect.The electromechanical parameters of ESUs directly affect the structure of eschar associated with hemostasis,which would have impact on the effect of pancreatic duct closure.At present,the influences of the types and parameters of surgical energy instruments on postoperative pancreatic fistula have been studied in the way of review and summary based on the comparison of the related studies.There is a lack of in-depth analysis of the electro-mechanical parameters of ESUs,and the existing studies cannot provide guidance for the clinical application of ESUs.Therefore,it is necessary to study the influences of the electromechanical parameters of ESUs on the structure and eschar of pancreas and to evaluate the effect of pancreatic duct closure through an in vitro experiment and analysis method,so as to provide theoretical support for the application of ESUs in the field of pancreatic surgery.In this thesis,the validity of previous in vitro simulation experiment was evaluated by in vivo animal testing.The influences of working parameters of ESUs on the closure effect of porcine pancreatic duct was analyzed.Then,the effect of the diameter of electrode front end on the eschar structure of pancreatic cross-section was investigated by mechanical testing and tissue morphology analysis.Last,the response surface methodology was used to study the effects of the main electro-mechanical parameters of ESUs on the closure of the pancreatic duct in pigs.The main results and conclusions are summarised as follows:(1)In vivo animal testing results were consistent with those of in vitro simulation experiment concerning the effects of ESUs working parameters on the prevention of pancreatic fistula by eschar.The degree of tissue contraction and the depth of tissue damage were affected by the power of ESUs;the compactness of eschar surface structure was mainly determined by the working mode of ESUs;the binding strength of eschar tissue interface was influenced by acting time.Among them,the effect of working mode is the most significant.Then,in the prerequisite condition of sufficient power output,the closure effect of pancreatic duct is better when the peak voltage of working mode is lower.(2)The eschar structure and burst pressure of the pancreatic duct were affected by the diameter of the electrode front end.With the diameter increasing from 0.5 mm to 5 mm,the burst pressure of the pancreatic duct increased first and then decreased.When the diameter was 2 mm,the burst pressure reached a peak value.(3)The closure effect of pancreatic duct was significantly influenced by the diameter of the electrode front end,the power of ESUs and the acting time.The diameter of the electrode front end is an independent factor,which dominates the density of eschar surface and the degree of tissue contraction.The power and the acting time mainly affect the eschar thickness and the degree of eschar carbonization,and there exists an interaction between the two above factors.Response surface methodology helps to select optimalizing electro-mechanical parameters of ESUs to provide a best effect of preventing pancreatic fistula.