Abstract
Introduction: The purpose of this study was to compare the success rate and complication of Mini percutaneous nephrolithotomy (mPCNL) with Extracorporeal Shock Wave Lithotripsy (ESWL) in the treatment of stones smaller than two centimeters in the lower calyx.
Method: In this study, 40 consecutive patients with <2cm lower calyx stone were randomly allocated into two groups of patients with mPCNL and ESWL, Group A underwent mPCNL with a direct access to the lower calyx with 14 F one shot Amplatz dilator and pneumatic lithotripsy were placed on a 9F ureteroscope and group B underwent ESWL with standard protocol in Imam Khomeini Hospital,Ahwaz,Iran. BMI,sex,age,stone density,hospital stay,early stone free rate,time to stone free,ancillary procedure,overall stone free rate,Hb drop,were measured and compared in the two groups.
Results: The mean hospital stay in the mPCNL group was 1.3 ± 0/57 days. while the ESWL group were not admitted. The results showed that the mean stone density in the group treated with mPCNL was 869.0 ± 37.12, which was not significantly different from the ESWL group (868.6 ± 36.94). Mean stone size in the group treated with mPCNL was 14.35 ± 0.98 mm, which was not significantly different from the ESWL group (14.30 ± 0.83 mm). The mean stone residue in the group treated with mPCNL was 0.41 ± 0.28 mm which was significantly lower than that of the ESWL of 6.55 ± 1.52 mm (P value < 0.05). In the group treated with mPCNL only 1 patient (5%) were not become stone free ,while in the ESWL group 2 patients (10%) were not become stone free rate at first session.
Conclusions: This study showed that for the treatment of <2cm lower calyx stones the early stone free rate for success rate of Mini percutaneous nephrolithotomy ( mPCNL) was significantly better than Extracorporeal Shock Wave Lithotripsy ( ESWL),also the need for other therapeutic modalithies in mPCNL were lower than ESWL but in needed hospital stay. However but further studies are required.

Key words: Extracorporeal Shock Wave Lithotripsy (ESWL), Mini percutaneous nephrolithotomy (mPCNL), Kidney stone