Percutaneous Nephrolithotomy Puncture and Tract Dilation: Evidence on the Safety of Approaches to the Infundibulum of the Middle Renal Calyx.

Objective: To investigate the anatomical relations of the papillary, infundibular, and pelvic approach to percutaneous nephrolithotomy and evaluate the amount of vascularization at the respective sites.
Materials and Methods: ^99m Tc-dimercaptosuccinic acid single-photon emission computed tomography/computed tomography (SPECT/CT) renal scintigraphies or computed tomography perfusion (CTP) was performed in 40 patients (prone n = 20 or supine position n = 20). The angle of approach (AoA) for access tracts and the respective regions of interest to the mid-calyceal papilla and infundibulum as well as renal pelvis were designed and compared.
Results: The design of access tracts aiming to the renal pelvis, papilla, and infundibulum of the renal calyx was impossible for the nondilated collecting systems as all these tracts were in close vicinity. In both SPECT/CT and CTP, there was no statistical difference between the AoA for infundibular or pelvic access in comparison with the papillary puncture in either prone or supine position regardless of the degree of dilation of the system. The comparison of the measurements in the regions of interest showed that there was no difference in blood supply between the infundibular and pelvic access in comparison with the papillary approach in both positions regardless of the degree of collecting system dilation.
Conclusion: The use of SPECT/CT and CTP showed that the punctures to the mid-calyceal renal papilla-fornix and infundibulum as well as the renal pelvis at the same level have similar AoA. The sites of the parenchyma involved in the tract dilation of the respective approaches are not related to significant differences in terms of vascularization.
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