The influence of pelvicalyceal system anatomy on minimally invasive treatments of patients with renal calculi.

Introduction And Objectives: Nephrolithiasis has a multifactorial etiology, wherein, besides metabolic factors, the anatomy of the pelvicalyceal system might play a role. Using 3D-reconstructions of CT-urography (CT-U), we studied the morphometric properties of pelvicalyceal anatomy affecting kidney stone formation and compared those with existing literature on their effect on minimally invasive treatment techniques for renal calculi.

Methods: CT-U's were made between 01-01-2017 and 30-09-2018. Patients were chronologically included in two groups: a nephrolithiasis group when ≥ 1 calculus was present on the CT-U and a control group of patients with both the absence of calculi on the CT-U and no medical history of urolithiasis. Patients with a medical history of diseases leading to higher risks on urolithiasis were excluded. In the nephrolithiasis group affected kidneys were measured. In the control group, left and right kidneys were alternately measured.

Results: Twenty kidneys were measured in both groups. Mean calyceopelvic tract width was significantly larger in the lower segments of affected kidneys (3.9 vs. 2.7 mm). No significant differences between the groups were found in number of calyces, infundibular length, infundibular width, calyceopelvic angle, upper-lower angle and diameters of the pelvis. Transversal calyceal orientation in hours was significantly smaller in the upper and lower segments of the nephrolithiasis group (7.69 vs. 8.52 and 8.08 vs. 9.09 h), corresponding with more dorsally located calyces in stone-forming kidneys.

Conclusion: Pelvicalyceal anatomy differs between stone-forming and non-stone-forming kidneys. Understanding the pelvicalyceal system and etiology of stone formation can improve development of endourological techniques.