Comparative study of the influense of stone size and volume on the duration of thulium laser percutaneous nephrolithotripsy


DOI: https://dx.doi.org/10.18565/urology.2022.4.27-31

S.V. Popov, I.N. Orlov, M.M. Suleymanov, M.L. Gorelik, M.A. Perfil’ev

1) Luke Clinical Hospital, Saint-Petersburg, Russia; 2) Military medical academy of S.M. Kirov, Saint-Petersburg, Russia; 3) North-Western State Medical University named after I.I Mechnikov, Saint-Petersburg, Russia
Objective. The aim of the investigation was to determine the influence of such parametric characteristics of the stone such as size and volume on the duration of tulium laser disintegration of the urinary stone and to determine which of these parameters is more effective to use like prognostic criterion for the duration of the planned surgical intervention in the percutaneous nephrolithotripsy.
Materials and methods. Overall 52 patients (27 females and 25 males) with an average age of 56,9 (25-79) years participated in the present study. All patients underwent percutaneous nephrolithotripsy with disintegration of the kidney stone by thulium energy. Inclusion criteria were: stone size ≥2 cm, stone density >1100 HU. Exclusion criteria were: patients with a single kidney, urinary tract divertions, coagulopathy. The average operation time was 30 (15–100) minutes, with an average puncture time of 3.15 (1–10) minutes and lithotripsy time of 28 (14–98) minutes. To determine the volume we used the method of automatic lithometry according to CT data using the software: Vitrea ver. 4.1.52. The size of the stone was determined by the longest length in one of the plane. During the study it was found that the average size of the stone was 28.25 (20–58) mm and the average volume was 2579.4 (250–9990) mm3. To confirm our assumption, we decided to determine the dependence of the time of disintegration of the stone on the size and volume of the stone. For this purpose, we graphically presented the correlation of these parameters.
Results. We have drawn 2 graphs reflecting the dependence of lithotripsy time parameters on the size and volume characteristics of the stone. As a result of comparing these parameters we found that size is a prognostically less reliable predictor of lithotripsy time, and is not characterized by a linear distribution, in contrast to the stone volume.
Conclusions. Thereby, the main stereoscopic characteristic of a stone is a volume, which should be the primary guide in selecting the preferred method of treatment as well as in predicting the operative time and associated risks.

About the Autors


Corresponding author: M.M. Suleymanov – PhD, urologist, Saint Luke clinical hospital, state budgetary health institution of Saint-Petersburg, Russia, Saint-Petersburg, e-mail: doc.suleimanov@gmail.com


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