RESUMEN
Objective To explore the clinical significance of fused renal pyramid (FRP) structure in the establishment of percutaneous renal access.Methods From May 2017 to April 2018,10 fresh porcine kidneys were selected to cast in blood vessels for grading the kidney artery.Then another 80 isolated porcine kidueys were used to simulate percutaneous renal pu ncture and dilatation to establish F24 operative access by the same surgeon.Under the endoscope and microscope,we compared the effects of four different puncture paths on the occurrence of renal vascular injury when respectively punctured through the normal renal pyramid (group A),the side of the FRP (group B),the centre of the FRP (group C) and the renal column (group D).Results The kidney arteries can be divided into six grades,there is grade Ⅳ branchinterlobar artery walking inside the FRP.The diameter of interlobar artery in the FRP was significantly smaller than that in the renal column (0.442 ±0.012) mm vs.(0.778 ±0.037) mm,(P ＜0.001).Endoscopic observation and pathological tissue section showed the following results.In group A,there was no injured blood vessel distributed along the access.There were six specimens with grade Ⅴ or Ⅵ arteries injury in the cortex.Owing to the small size of the renal pyramid and the inaccurate location of the puncture,there was also injury associated with a normal grade Ⅳ artery in the renal column.In group B,there was a certain distance between the tract and the grade Ⅳ artery that distributed in the FRP,injury was still noticed in four specimens.And six specimens have grade Ⅴ/Ⅵ arterial injury.As the distance between the tract and the renal column decreased,there was a case in which a simultaneously injury occurred to the extremity of a grade Ⅲ artery and a grade Ⅳ artery.In group C,there was a white thin strip of connective tissue exposed along the puncture tract.Ectopic grade Ⅳ artery injury occurred in fourteen specimens,and grade Ⅴ/Ⅵ artery injury occurred in seven specimens.In group D,there were grade Ⅲ to Ⅵ arteries distributed along the operational access,which was cowered with white fat and connective tissue.The number of arteryinjury in grades Ⅲ,Ⅳ,and Ⅴ/Ⅵ were4,19,and 5,respectively.The mean ranks of artery injury degree in groups A (17.0),B (30.1),C (33.5) and D (41.5) gradually increased,and the difference was significant (P =0.006).There was a significant difference between group A and C (P =0.018),while no significant difference between group A and B (P =0.122),groups C and D (P =0.072).The proportion of grade Ⅳ artery injury in group A,B,and C was 5％ (1/20),25％ (5/20),and 70％ (14/20),respectively.There was a significant difference between group A and C (P =0.029),while no significant difference between group A and B (P =0.316).There was no significant difference in the injury of grade Ⅴ and Ⅵ artery in four groups (P =0.827).Conclusions When establishing a percutaneous renal access,vascular injury caused bv puncturing through the FRP cannot be ignored.It is necessary to carefu lly identify and bypass the FRP when selecting the puncture path.If unavoidable,the puncture path shoull be on the centreline of one side pyramid of the FRP.