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

Unlabelled: 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.

Objective: Evaluate prospectively the outcomes of UMP.

Methods: 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.

Results: 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.

Conclusions: 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.