Use of Volume Rendered, Maximum Intensity Projection Images to Assess Whether the Medial Calyx Synonymous with the...

Area of Science:

• Urology
• Anatomy
• Medical Imaging

Background:

• Percutaneous nephrolithotomy (PCNL) is a common procedure for kidney stone removal.
• A prevailing surgical belief suggests aiming for the medial calyx is necessary to access posterior calyces.

Purpose of the Study:

• To anatomically verify the accuracy of the belief regarding PCNL access to posterior calyces.
• To determine the typical projection of posterior calyces in the pelvicalyceal system.

Main Methods:

• Analysis of volume rendered and maximum intensity projection reconstructions of normal pelvicalyceal systems.
• Assessment of calyx projections in various rotational and anteroposterior planes by an experienced urologist.
• Determination of appropriate PCNL access for upper, interpole, and lower calyces.

Main Results:

• Of 508 studied calyces, 72% of posterior calyces projected laterally, while 28% projected medially.
• In the upper calyx, posterior calyces projected laterally in 94% (right) and 89% (left).
• In the lower calyx, posterior calyces projected laterally in 86% (right) and 64% (left).

Conclusions:

• The study refutes the assumption that the medial calyx is always synonymous with the lateral calyx for posterior access.
• Posterior calyces frequently project laterally, challenging traditional PCNL access strategies.
• Findings suggest a need to re-evaluate surgical planning for PCNL based on individual calyx anatomy.