Comparison of the effect of miniaturized and standard percutaneous nephrolithotomy on renal function assessed with DMSA scintigraphy.

INTRODUCTION AND OBJECTIVES: We aimed to present a clinical study that compares standard and miniaturized percutaneous nephrolithotomy (PNL) effects on kidney function with scintigraphic imaging in primary kidney stone patients. MATERIALS AND METHODS: One hundred four patients were included in this prospective study between May 2014 and February 2017. Eligible patients were divided into two groups miniaturized PNL (mPNL) and standard PNL (sPNL) with matched-pair analysis (1:1 scenario). Technetium-99m Dimercaptosuccinic Acid cortical scintigraphy imaging was performed before and after the operation. RESULTS: There were no differences between the two groups in terms of success rate (mPNL (63.5%) vs. sPNL (71.2%), p=0.403), serum creatinine, glomerular filtration rate, split renal functions pre- and postoperatively (p≥0.05). There was no relationship between the type of operation and new scar formation (p=0.780). The rates of serious complication (grades 3 and 4 according to modified Clavien-Dindo Classification) were higher in sPNL (p=0.034). Stone burden, duration of operation, hemoglobin drop, multiple access, blood transfusion, and angioembolization were higher in patients with scarred kidneys (p<0.001, p=0.008, p=0.004, p<0.001, p=0.003, p=0.001, respectively). In multivariate analysis, only multiple access was found statistically significant for predicting new scar formation (p<0.001, OR: 24.28). CONCLUSIONS: Miniaturized and standard PNL are reliable and successful operations for treating large kidney stones. No significant difference was found between the operation types regarding a decrease in renal function.

Retrograde intrarenal surgery in the management of pediatric cystine stones.

OBJECTIVE: To investigate the efficacy and safety of retrograde intrarenal surgery (RIRS) in the treatment of pediatric cystine stones. STUDY DESIGN: Data of the pediatric patients who underwent RIRS for kidney stones were retrospectively evaluated. A total of 14 children with cystine stones managed with RIRS were identified. In addition to the patient demographics and stone characteristics, all retrospectively obtained operative data were evaluated and discussed in detail, with an emphasis on the success and complication rates. RESULTS: Mean age of the 14 cases was 10.9 ± 2.2 years (range: 7-15). Mean stone size was 13.6 ± 2.4 mm (range: 10-18) (Summary table). Of these stones, four were located in the renal pelvis, three were in the lower, three were in the middle and the remaining four were located in upper calyx. Ureteral access sheath was used in 12 (85.7%) patients. The double-J ureteral stent was placed pre-operatively in one case and was inserted postoperatively in 12 cases. Mean operation time was 38.2 ± 7.2 min (range: 30-50). Complications were observed in two cases: mild ureteral laceration in the first and fever on the second postoperative day in the second patient. All of the patients were stone free on sonographic evaluation at the 4-week follow-up evaluation. Although potassium citrate treatment was initiated in 11 patients, tiopronin treatment was initiated in four patients for recurrence prophylaxis during long-term follow-up. During a mean follow-up period of 25.7 ± 5.2 months, stone recurrence was noted in one patient. DISCUSSION: Treatment of patients with cystine stones is challenging, due to high risk of rapid recurrence in the presence of residual fragments. Besides allowing complete stone clearance in all cases in the current series, RIRS is a highly reproducible method that can be safely performed, even in recurrences. The major limitations of the current study were low number of patients and short follow-up period. CONCLUSION: The results clearly indicated that RIRS is a safe treatment modality in the management of pediatric cystine stones.