Predictors of clinical outcome after minimally invasive percutaneous nephrolithotomy for renal calculus

Effects of hydronephrosis on the surgical outcomes of fluoroscopically guided supine percutaneous nephrolithotomy

PURPOSE

To evaluate the effect of hydronephrosis on operation success and the development of complications in supine percutaneous nephrolithotomy (PCNL).

METHODS

A total 259 patients were included in the study who underwent supine PCNL in our clinic between September 2019 and November 2023. The patients were divided into four groups: normal, mild, moderate and severe, according to their preoperative hydronephrosis degrees. Demographic data, kidney stone characteristics, clinical aspects, surgical findings, and postoperative complications were compared across groups.

RESULTS

In terms of American Society of Anesthesiologists score, stone-free rate, operation time, fluoroscopy time, and Clavien-Dindo classification grades, a statistically significant difference was found between the hydronephrosis groups. The stone-free rate in the normal, mild, moderate, and severe groups was 86.6, 82.5, 76.0, and 61.5, respectively. The severe hydronephrosis group varied statistically substantially from the other hydronephrosis groups in terms of stone-free rate, according to the post-hoc analysis. In terms of Clavien-Dindo classification grades, the severe hydronephrosis group varied statistically significantly from the normal and mild hydronephrosis groups (p values 0.04, 0.02, respectively). In terms of Clavien-Dindo classification grades, no statistically significant difference was seen between the severe and moderate hydronephrosis groups (p = 0.085).

CONCLUSION

The findings of this study demonstrated that the existence of hydronephrosis was a predictive factor for the occurrence of complications and decreased the success rate of supine PCNL. Furthermore, univariate and multivariate analyses showed that the presence of hydronephrosis was a predictive factor for PCNL success and the development of complications.

Factors Affecting Residual Stone Rate, Operative Duration, and Complications in Patients Undergoing Minimally Invasive Percutaneous Nephrolithotomy

Background and objectives: Although minimally invasive percutaneous nephrolithotomy (MPCNL) has demonstrated its efficacy, complete stone clearance was not always achieved, necessitating a second procedure. The purpose of this study was to evaluate factors associated with residual stone rate, operative duration, complications, and hospital stay, in order to develop algorithms for pre-operative prognosis and planning. Materials and Methods: This retrospective study involved 163 Bulgarian patients who underwent MPCNL with Holmium: YAG lithotripsy for the treatment of kidney stones. Patients were considered stone-free if no visible fragments (<3 mm) were found on nephroscopy at the end of the procedure, as well as on postoperative X-ray and abdominal ultrasound on the first postoperative day. Results: Immediate postoperative stone-free outcome was attained for 83.43% of the patients (136/163). Residuals were associated with staghorn stones (OR = 72.48, 95% CI: 5.76 to 91.81); stones in two locations (OR = 21.91, 95% CI: 4.15 to 137.56); larger stone size (OR = 1.12, 95% CI: 1.006 to 1.25); and higher density (OR = 1.03, 95% CI:1.005 to 1.06). The overall categorization accuracy for these factors was 93.80%, AUC = 0.971 (95% CI: 0.932 to 0.991), 89.71% sensitivity, and 96.30% specificity. Predictors of prolonged operative duration were staghorn stones and volume, R-square (adj.) = 39.00%, p < 0.001. Longer hospitalization was predicted for patients with hydronephrosis and staghorn stones, R-square (adj.) = 6.82%, p = 0.003. Post-operative complications were rare, predominantly of Clavien-Dindo Grade 1, and were more frequent in patients with hydronephrosis. We did not find a link between their occurrence and the outcome of MPCNL. Conclusions: Staghorn stones and stones in more than one location showed the strongest association with residual stone rate. Staghorn stones and larger volume were linked with a longer operative duration. Hydronephrosis increased the risk of complications and longer hospitalization.