The following is a summary of “Renal Location Within the Retroperitoneum in Various Body Positions Using Magnetic Resonance Imaging: Implications for Percutaneous Nephrostolithotomy,” published in the MAY 2023 issue of Urology by Smith, et al.
For a study, researchers sought to evaluate the difference in cranio-caudal renal position between the supine and prone positions and the effect of arm position on renal location, using magnetic resonance imaging (MRI) in subjects with a BMI < 30.
A prospective trial approved by the Institutional Review Board (IRB) was conducted involving healthy subjects. MRI scans were performed on the subjects in three positions: supine, prone with arms at the side, and prone with arms raised using vertically placed towel bolsters. Images were acquired during end-expiration breath holds. Distances between the kidneys and anatomical landmarks such as the diaphragm (KDD), top of the L1 vertebra (KVD), and lower edge of the 12th rib (KRD) were measured. Nephrostomy tract length (NTL) and other measures for visceral injury were also assessed. Statistical analysis was performed using the Wilcoxon signed-rank test (P < 0.05).
A total of ten subjects (5 male, 5 female) with a median age of 29 years and a BMI of 24 kg/m were included in the study. The right KDD did not show a significant difference between positions, but KRD and KVD exhibited significant cephalad movement in the prone position compared to the supine position. The left KDD showed caudal movement in the prone position, while no significant differences were observed in KRD or KVD. Arm position did not affect any of the measurements. The right lower NTL was shorter in the prone position.
In subjects with a BMI < 30, the prone position resulted in significant cephalad movement of the right kidney but not the left kidney. The arm position did not impact the anticipated renal position. Preoperative end-expiration supine CT scans can reliably predict the location of the left kidney and may be useful for improving preoperative counseling and surgical planning.
Source: goldjournal.net/article/S0090-4295(23)00163-2/fulltext
