Comparison of low power and high power holmium YAG laser settings in flexible ureteroscopy.

PURPOSE: To compare the efficacy of conventional low power and high power holmium: yttrium aluminum-garnet (Ho: YAG) laser lithotripsy settings during retrograde intrarenal surgery (RIRS).  METHODS: The prospective study was conducted in patients undergoing RIRS for renal stones less than 2 cm diameter. Pulsed Ho:YAG laser (Lumenis® Pulse TM P120 H) was used for laser lithotripsy and the patients were randomized into low power (LP) and high power (HP) laser lithotripsy settings groups. The lasing duration, total laser energy used (Joules), laser energy used to ablate 1 mm3 of stone (Joules/mm3), operative duration, stone ablation speed (mm3/s) and stone free rate were compared. RESULTS: A total of 120 underwent RIRS with 63 and 57 patients in LP and HP group, respectively. Median stone volume and stone density were comparable between the groups. The total energy used and laser energy used to ablate 1mm3 of stone (Joules/mm3) were significantly higher in the HP group than in LP group (27.9 (16.4-46.2) J/ mm3 vs 9.7 (5.3-17.7) J/ mm3) (p < 0.01). Median (IQR) ablation speed were 0.8 (0.5-1.3) mm3/s and 0.6 (0.4-1) mm3/s in the LP and HP groups, respectively. The median lasing time, operative time and stone free rate were similar in both the groups. CONCLUSION: The total energy used and J/mm3 were lower in the LP group than in HP group with similar lasing duration, operative duration, ablation speed and stone free rate for renal stones less than 2 cm.

Comparative Study of Percutaneous Nephrolithotomy in Supine and Prone Positions.

BACKGROUND: The aim of the study is the compare efficacy and safety of percutaneous nephrolithotomy in supine and prone positions. Percutaneous nephrolithotomy is conventionally performed in prone position but in recent years numbers of supine percutaneous nephrolithotomies is increasing globally. METHODS: The hospital based cross-sectional observational study was conducted in the Department of Urology, Bir Hospital from July 2018 to January 2020. A total of 81 consecutive patients undergoing percutaneous nephrolithotomy were divided into two groups, with 38 patients in Supine (Group 1) and 43 patients in Prone (Group 2) positions, respectively. Patient's demographics, access time, operative duration, stone free rate, radiation dose and duration, irrigation fluid volume, post-operative hemoglobin drop and complications were compared. RESULTS: Demographic and stone characteristics were comparable in both groups. Supine Group (Group 1) had significantly shorter operative duration than Prone Group (Group 2), 44.63 ± 12.44minsvs 53.02 ±12.67mins (p< 0.04). The mean radiation duration was 99.11 ± 61.17secs in Group 1 and 108.40 ± 51.65 secs in Group 2 (p=0.46), respectively. Although the mean radiation dose was lower in Group 1 (375.1µGym2) than in Group 2 (465.7 µGym2), it was not statistically significant(p=0.24). The stone free rate at 1 month duration were comparable with 92.1% and 93.02% in Group 1 and Group 2 respectively (p=0.16). Overall complication rates were similar in both groups (15.7% in Group 1 vs 16.2% in Group 2), respectively. None of the patients in both groups had complications higher than Clavien IIIa. CONCLUSIONS: PCNL in supine position has significantly shorter operative time with similar complications and stone free rates as compared to prone position.

Stone Clearance by Computed Tomography after Percutaneous Nephrolithotomy: A Descriptive Cross-sectional Study.

INTRODUCTION: Percutaneous nephrolithotomy has the highest stone free rate among other procedures with relatively higher complication rate. Post-operative imaging after stone surgeries has not been uniform. This study was done to study about the stone clearance by computed tomography after percutaneous nephrolithotomy. METHODS: The descriptive cross-sectional study was conducted in the Department of Urology, Bir Hospital for six months duration. The patients undergoing percutaneous nephrolithotomy and those with intra-operative fluoroscopic clearance were evaluated with a low dose computed tomography after 48 hours to assess residual fragments its size and location. Patient's demographics, stone characteristics and complications were compared between the stone free and with residual stone patients. RESULTS: Out of 72 percutaneous nephrolithotomy performed, 40 patients were included in the study. Low dose computed tomography kidney, ureter and bladder after 48 hours of surgery detected residual fragments in 11 (27.5%) patients. The RFs size of <4mm were found in 7 (63.63%) of cases whereas RFs of >4mm were found in 4 (36.36%). The stone size was 352.47 ± 97.47 mm2 and 254.79 ± 172.68mm2 in group with residual fragments and stone free group respectively. CONCLUSIONS: Low dose computed tomography kidney, ureter and bladder done for assessment of stone clearance after 48 hours of percutaneous nephrolithomy detected residual in around one fourth of patients, however majority of them had residual fragments <4mm. Intra-operative fluoroscopic clearance may over estimate stone clearance after percutaneous nephrolithomy as about one third of patients still may have residual fragments of >4mm size.