A comparison on safety and efficacy between 24 Fr versus 18 Fr pneumatic balloon dilators for percutaneous treatment of renal stones between 10 and 20 mm: results from a contemporary cohort.

Purpose: To assess differences in safety and efficacy between 24 and 18 Fr pneumatic balloon dilators for percutaneous nephrolithotripsy (PCNL) of renal stones between 10 and 20 mm.

Methods: Patients were randomized to dilatation with a 24 Fr (Group A) versus 18 Fr (Group B) Ultraxx pneumatic dilator (Cook Medical^®). In all procedures percutaneous puncture was performed under ultrasound guidance. In both groups the Holmium: YAG Cyber Ho laser generator was used (Quanta System^®). Stone-free rate (SFR) and postoperative complications were assessed.

Results: 42 and 44 patients were assigned to Groups A and B, respectively. Preoperative features were comparable. Mean stone size was 17.8 vs. 16.6 mm in Group A vs. B (p = 0.21). SFR was 95.2% in Group A and 95.4% in Group B (p = 0.19). Postoperative gross haematuria was observed in 5 vs. 2 cases in Group A vs. B (p = 0.04). Mean haemoglobin drop at first postoperative day (POD) was higher in Group A (2.4 vs. 1.1 mg/dl, p = 0.04), while comparable at third POD. Blood transfusion was required in 2 cases in Group A and 1 case in Group B. No patients required embolization. No significant difference was observed in terms of postoperative pain and urinary infection.

Conclusions: 24 and 18 Fr pneumatic dilators are both effective to access renal cavity during PCNL for the treatment of renal stones between 10 and 20 mm. Gross haematuria rate and mean haemoglobin decrease at first POD were significantly higher with 24 Fr dilator, but with no differences in the need for blood transfusions and renal embolization.