Should mini percutaneous nephrolithotomy (MiniPNL/Miniperc) be the ideal tract for medium-sized renal calculi (15-30 mm)?

INTRODUCTION: Reducing the percutaneous nephrolithotomy (PCNL) tract size reduces the morbidity associated with the procedure. Prolonged procedure time is a concern. Modification in technique required is to fragment the stone into smaller particles and remove them using the vacuum cleaner effect. This prospective study compares the efficacy and morbidity of reducing the tract size from the standard 24-16.5 Fr for stones sized from 16 to 30 mm.

METHODS: 123 patients were enrolled in this prospective study and distributed into 2 groups based on the tract size used (group A 16.5/17.5 Fr Miniperc, N = 61 and group B: 22/24 Fr standard PCNL, N = 62). Critical factors assessed were procedure time, fluoroscopy time, blood loss, pain score, stone clearance status and complications.

RESULTS: Both the groups were comparable with respect to age, creatinine and stone size. The blood loss (hemoglobin and PCV drop) was significantly less for group A (p < 0.001). Both the groups were comparable with regards to the pain score (p > 0.05). Nephrostomy was placed in 3 patients in group A and 14 patients in group B (p = 0.01). There was no significant difference in the procedure time amongst the 2 groups. A total of 9 patients (4 in group A and 5 in group B) had residual fragments greater than 3 mm.

CONCLUSION: The 16.5 Fr Miniperc tract offers lower morbidity in terms of blood loss and maintains stone clearance comparable to larger 24 Fr tract size. It should be the ideal size used for medium sized renal stones.