LAUSR

OBJECTIVE The objective of the present communication is to report the safety and efficacy of applying miniaturized percutaneous nephrolithotomy (mini-PCNL) in Vietnamese patients with recurrent kidney stones using a miniature nephroscope through a 18F metal access sheath. PATIENTS AND METHODS We performed a retrospective cohort study of patients who were diagnosed with recurrent nephrolithiasis and underwent mini-PCNL after previous treatments between 2017 and 2020. Clinical profile, preoperative characteristics, intraoperative events, and postoperative outcomes were obtained from the hospital database. Descriptive statistics were used for the whole analysis. RESULTS Of 89 eligible patients, 54 were male. The mean age was 53.4 years. Mean stone size was 24.9 mm. 37 patients had right side stone, 39 had left side stone, and 13 had stone on both sides. Pain in the flanks and back was the most symptom in our patients (n = 87, 97.8%), followed by hematuria (n = 13, 14.6%), dysuria (n = 8, 8.9%), fever (n = 7, 7.9%), acute renal colic (n = 5, 5.6%), and pyuria in 2 patients. 27 had complex stones, and the remaining stone position included renal pelvis (21, 23.6%), upper calyx (15, 16.9%), lower calyx (14, 15.7%), and middle calyx (12, 13.5%). 35 of them had grade I, 27 grade II, 8 grade III and 2 grade IV of hydronephrosis. Renal failure was documented in 12 patients (13.5%). 18 patients were performed with 2-times punctures (20.2%) and 13 with 3-times punctures (14.6%). We used one percutaneous tract in 79 patients and the remaining 10 were performed with two tracts. The upper, middle, and lower calyx was the site of puncture access in 6 (6.7%), 73 (82.0%), and 10 (11.3%) cases, respectively. 3 patients had bleeding requiring intraoperative blood transfusion and 2 were converted to open surgery. Intraoperative parameters recorded percutaneous puncture duration of 20.9 minutes (5-50), and total operative duration of 112.9 minutes (40-240). 7 patients developed secondary bleeding after surgery, besides 5 cases of fever, 2 cases of septic shock and one case of drainage failure. Early stone-free rate was 89.9% and this rate was 94.4% for patients after one month of mini-PCNL. Mean duration of ureteral catheter circulation was 2.7 days (2-20), mean length of postoperative hospitalization was 6.6 days (4-25) and mean total hospital stay was 12.9 days (7-28). CONCLUSIONS Present results show the safety of mini-PCNL with respect to recurrent nephrolithiasis. Our updated evidence may provide appropriate modified approaches that aim at reducing the risk of recurrent kidney stone development.