Avaliação tomográfica dos parâmetros anatômicos relevantes na punção renal percutânea nos decúbitos ventral e dorsal

Abstract

Introduction: The search for less invasive and safer techniques of percutaneous access in endourology had, as landmark, the studies undergone by Valdivia Uria, who first proposed and described access through the inclined supine position, with shortened procedure time and better cardiorespiratory parameters, compared with the traditional access in the prone position, and also showing similar success and morbidity rates. Although more than 20 years have elapsed since the first publication of the technique, and despite publications by other authors, the technique has not been so widely embraced as expected. Patients and methods: 71 patients underwent simulated percutaneous nephrostomy through computed tomography (CT), in both the supine and prone positions. The results were correlated with anthropometric variables and quantification of abdominal fat distribution in the visceral and subcutaneous compartments. Results: There was no statistical difference between the number of abdominal organ injuries in the two different positions in the axial plane (p=0.5621). In oblique simulations, the difference in the risk of injury to abdominal organs was statistically significant between the two positions, with more injuries happening in the prone position (p=0.0295). The colon was the most frequently injured organ, followed by the small intestine in a distant second. Indirect injury risk assessment by measurement of the colon-kidney distance showed statistically significant greater proximity of these organs in the the prone position, on both sides. Concerning the analysis methodology, there were a greater number of injuries in the axial plane than in the oblique simulations, both in the prone position (p=0.0274) and in the supine position (p=0.0002). In the axial plane simulations, patients who suffered organ injuries had statistically significant lower weight, Body Mass Index (BMI) and visceral fat amount, regardless of the position. In the oblique plane, no such statistical association was found. Conclusion: There was greater risk of injury to abdominal organs (mainly the colon) in the prone position, both in puncture simulations and in indirect risk assessment of risk through the measurement of the colon-kidney distance. Simulation in the oblique plane was the most adequate method, as it provided results that were closer to the ones from large case series in which the procedure was performed. Concerning the anthropometric factors and the pattern of CT-assessed abdominal fat distribution, patients who suffered organ injuries had statistically significant lower weight, BMI and visceral fat amount, in the axial plane, for analysis of the two methods in both positions and for analysis of the injuries regardless of method and position. In the oblique plane analysis methodology the low p values for weight (0.07) and BMI (0.06) may represent a tendency towards the injury risk, maybe with a limited statistical significance owing to the sample size.