The ACS system: a new way of prognosis for the effectiveness of percutaneous nephrolithotomy

Aim: to develop a simple and reliable system for predicting the results of percutaneous nephrolithotripsy (PNL). Materials and methods. The analysis of 138 patients, who underwent PNL (standard method) over the period of 2011-2015, was performed. Low-dose non-contrast multispiral computed tomography (MSCT) was performed in all patients during the post-operative stage, 24 hours after PNL. The presence of residual concrements (≤ 4 mm) or their total absence in kidneys was regarded as a criterion for effective concrement elimination. Results. According to the data obtained from MSCT, the patients were divided into two groups. The first group (88 patients) included those who did not have residual concrement fragments after PNL or who had clinically insignificant residual concrement fragments. The second group included 55 patients with residual concrement fragments. Among the parameters used in the study, the most informative were: • The presence of a stone in renal calyx in a ≤ 450 position («acute angle» - A) • The presence of a stone (≥ 10 mm) in renal calyx with a narrow (