Surgical Success and Predictive Factors for Residual Stones Following Supine Percutaneous Nephrolithotomy in the...

Supine percutaneous nephrolithotomy (sPCNL) is widely accepted as a safe and effective treatment for kidney stones. This study aims to assess surgical outcomes and identify predictive factors for residual fragments following sPCNL in the Galdakao-modified Valdivia position (GMV-sPCNL).

We retrospectively evaluated the clinical data of patients undergoing GMV-sPCNL. The primary outcomes were the stone-free rate (SFR) and the complication rate. Demographic, radiologic, and perioperative parameters were also compared between patients with and without residual stones.

195 patients [Male:127 (65.1%); Female: 68 (34.9%)] were included. The mean age was 48.6±15.6 years; the mean body mass index (BMI) was 27.4±5 kg/m2. The overall SFR was 83.1%. Residual stones were associated with greater stone burden (number, size, surface area, and volume), longer operative time, and longer hospitalization (p<0.05). Gender, age, BMI, stone laterality, and density were not significantly associated with SFR. The receiver operating characteristic analysis showed that having more than two stones, a stone size ≥26 mm, or a stone volume ≥2639.8 mm3 significantly predicted residual fragments. Stone volume demonstrated the best predictive performance, with sensitivity and specificity of 81.8% and 61.0%, respectively. GMV-sPCNL was associated with a low overall complication rate: 86.2% of patients experienced no or only minor complications, and major complications (Clavien-Dindo ≥3) occurred in just 4.6% of cases.

GMV-sPCNL demonstrates high success rates and an acceptable complication profile. Stone burden parameters such as stone number, stone size, and stone volume are important determinants of surgical success.