Prospective outcomes of 11-13Ch. ultra-mini percutaneous nephrolithotomy (UMP): A consecutive cohort study

Ultra mini PCNL (UMP) has been described as a less invasive technique of PCNL for the treatment of small to medium sized stones in attempt to reduce the surgical morbidity.

Evaluate prospectively the outcomes of UMP.

Single surgeon prospective concurrent cohort study of UMP in India. Effectiveness was assessed by stone-free rates, operative time, complications including transfusion, sepsis rates, length of stay and analgesic requirements.

In 2013, data on 98 consecutive patients who underwent UMP was collected prospectively. Mean stone size (±SD)was 15.85 ± 4.53mm. The mean Hounsfield unit (HU) was 1105 ± 165HU. Access to the kidney was from the upper pole (8), interpolar (36) and lower pole(55) with no instances of failed access. Mean operating time was 54 minutes (range 28-120 minutes). The mean change in haemoglobin was -0.81g/dl and mean change in creatinine was 0.05mg/dl. No patients were transfused or suffered acute kidney injury. There were fiveClavien-Dindo complications (Grade I x4, IIIb x 1) with the most serious being a perinephric collection requiring intervention. Post-operative oral analgesia was sufficient in 89 patients (91%) with 9 patients (9%) requiring IM or IV analgesia. Median length of stay was 30 hours (IQR 10 hours). 13 patientshad nephrostomy drainage. 8 patients required a stent for one week. Intraoperatively, 98% of patients were stone free on fluoroscopy, which was 76% on day 1 post op ultrasound and 83% on CT at 1 month. Stone free was the absence of detectable calculi.

UMP for 10-20mm stones appears to be effective and safe with few complications and a short length of stay. Further multicentre studies are required but if confirmed, UMP may be a valuable addition to the armamentarium of the endourologist.