Evaluation of Factors Influenced on the Effectiveness of Percutaneous Nephrolithotomy

Generally, there are many methods for the treatment of urinary stones, of which percutaneous nephrolithotomy (PCNL) is a minimally invasive and highly effective method, and now become the first-line management for urinary stones, especially in the cases of complex stones and staghorne calculi. Accurate assessment of stone location, stone morphology, degree of hydronephrosis as well as urinary system abnormalities is extremely important in the percutaneous nephrolithotomy strategy.

The aim of this study was to evaluate the S.T.O.N.E score as well as other factors that influenced the effectiveness of PCNL.

Descriptive study on 71 patients with kidney stones, who underwent multi-slice CT scan of the urinary system before PCNL and then PCNL at Hanoi Medical University Hospital from July 2022 to July 2023. All patients received the informed consent and agreed to participate in the study. The factors included the stone area, the track length (from the skin surface to the stone central), the degree of urinary tract dilatation, the number of involved calyces, the density of stone, the renal parenchyma thickness, the ureteral wall thickness and fat infiltration measured on MSCT non-contrast phase. These factors were used to predict the effectiveness of PCNL including the stone clearance rate (SCR) and the operation time.

The mean age of the patient group was 53.8±12.3. The male/female ratio was 1.54. There was a significant difference (p<0.05) between the following factors and the operation time: the stone area (<400, 400-799, 800-1599 and >1600 mm2), the degree of urinary tract dilatation (no or might and moderate or severe dilatation), the number of involved calyces (≤ 2, 3 and staghorne calculi), the renal parenchyma thickness (<18 mm and ≥18mm). In contrast, there were no significant differences between the following factors and the surgery time (p>0.05): the track length (<100 and ≥100 mm), and the stone density (<950 and ≥950 HU). Regarding the S.T.O.N.E score (included five factors: Size, Track length, Obstruction, Number of involved calyces, and Evaluation of stone density), there was a strong correlation between S.T.O.N.E score and the surgery time (p<0.001, r=0.94), and the SCR (p=0.001, r=-0.97).

The evaluation of these factors played an important role in the prediction of the effectiveness of PCNL.