| Objective:The purpose of this study is to compare the renal pelvis pressure and the removal efficiency of different sizes of percutaneous renal access.,in the high Perfusion pressure and high velocity flow environment,discussed best tunnel can give consideration to stone clearance efficiency and operation safety.Methods:Using medical silicone to imitate the kidney to construct an elastic model with a renal pelvis volume of approximately 10 ml.The de-top Fr7 ureter catheter is inserted retrograde retrograde into the renal pelvis by retrograde retrograde in the model.Sealing the model with glass is to keep the watertight and airtight.Marked as the puncture point at the center of the simulation of the renal pelvis.Experiment with a 14-30 f sequence.The experiment begins with a puncture into the center of the puncture,expanding,inserting the PCNL work sheath.To use F8/9.8Wolf ureteroscopy and percutaneous nephrolithotomy surgery tools required for the experiment.The model connect with a Infusion pump with different perfusion pressure(10-80Kpa)and water flow used to measure the changes of the renal pelvisand hydrodynamic effects.Pressure transducer connected retrogradely into the renal pelvis 7Fr ureteral catheter and Mindray Bene View T5 monitor with wound pressure measurement channel.Intraoperative pyeloneal pressure measurements.The pressure system collects 1 data per second.And the data is imported into the computer data in real time;the application of artificial stones(diameter 2.9-3mm)test,different tunnel’s stones removal efficiency,by nephrolithotomy retraction and continuous water flow perfusion,measuring the stone volume to obtain different diameter tunnel and different flow perfusion stones clearance efficiency.Each group of experiments were carried out 3 times,data input into the computer in real time,using SPSS 19 software for statistics analysis,P<0.05 was statistically significant.The observation indexes include perfusion pressure,perfusion flow rate,tunnel diameter,stone removal rate,intrapelvic pressure.Results:The linear regression analysis showed that there was a positive correlation between the perfusion pressure and the internal pressure,the greater the perfusion pressure,the higher the renal pelvic pressure.There is a linear negative correlation between the channel and the internal pressure of the renal pelvis.The larger the channel,the lower the internal pressure of the renal pelvis.When the perfusion pressure was 80 Kpa,the mean intrapelvic pressure of the 14-30 F was 81.33±1.50,33.33±1.15 23.33±1.15,20.33±0.57,15.67±0.57,15.00±0.00,14.00±0.00,12.00±1.00,11.00±0.00 mm Hg.16 F and below internal pressure close to or more than the safety range of 30 mmhg,more than 18 F are in a safe range;14F group of average intrapelvic pressure is higher than above 14 F group(P <0.05).18 F group of average intrapelvic pressure is higher than above 18 F group(P <0.05),20 F group average intrapelvic pressure is higher than 22,.24,26,28,30 F group(P <0.05),22 F group average intrapelvic pressure is higher than 28,30 F group(P <0.05),24 F group average intrapelvic pressure is higher than 28,30 F group(P <0.05).there was no significant difference between the 22 and 24 F group(P > 0.05),there was no significant difference between the 22,24 26,F group(P >0.05).there was no significant difference between the 28 and 30 F group(P >0.05).There was a positive correlation between the perfusion flow and the stones removal efficiency,the greater the perfusion flow,the higher the stones removal efficiency 。When the perfusion pressure 80 Kpa,the stone clearance rate of 18~30F channel was 5±0.36,9.2±0.15,9.6±0.52,8.1±0.15,7.2±0.25,,6.6±0.35,6.7±0.15ml/min.20 and 22F group passive stone cleaning efficiency were fatest than other channels(P <0.05),There were the was no statistically significant difference among them(P >0.05).Conclusion: When the perfusion pressure reaches 80 Kpa,the intrapelvic pressure of 20 ~ 22 F channel is safe,and it can be used as the first choice for MPCNL which can deal with middle-large size of kidney stone.on the basis of the high velocity flow has the advantages of safety and high efficiency. |
