The Agreement Between Current Stone Analysis Techniques and SEM-EDAX in Urolithiasis.

PURPOSE: Nowadays, there are many physical and chemical methods available for urinary stone analysis. According to the latest guidelines, infrared spectroscopy (IR) or x-ray diffraction (XRD) are the two preferred methods in this issue. Therefore, we decided to do a practical comparison between the two above-mentioned techniques with a reference method in order to set up a proper analysis method in our clinical laboratories. MATERIALS AND METHODS: A total of 60 kidney stones were obtained at Labbafinejad hospital through open surgery or percutaneous nephrolithotomy. Then stone analysis techniques included both a morphological examination by SEM (Scanning Electron Microscopy) and internal structure analysis by EDAX (Elemental distribution analysis X-ray), XRD, IR and wet chemical analysis. SEM together with EDAX (SEM-EDAX) was considered as reference methods. RESULTS: The results of XRD had the highest agreement with SEM-EDAX analysis (93%), while the total agreement of FTIR and wet chemical analysis was 81% and 71% respectively. The agreement of FTIR for calcium oxalate stones was acceptable (90%), but for uric acid and cystine stones was challenging (65% and 76% respectively). CONCLUSION: Our results revealed that XRD is more reliable than FTIR; but considering cost issues, FTIR is more suitable for routine clinical laboratory. Moreover, wet chemical analysis, which is routinely used in our laboratories is insufficient for stone analysis and it is mandatory to be replaced by techniques that are more accurate.

Totally tubeless percutaneous nephrolithotomy is feasible in morbidly obese patients.

OBJECTIVE: Regarding technical difficulties that obese body habitus might impose to percutaneous nephrolithotomy (PNL) success and higher risk of peri-operative complications in this group of patients, we decided to retrospectively gather data from our patients during past 8 years to determine the stone free and complication rates. MATERIAL AND METHODS: Between January 2007-December 2015, seventy-eight obese patients with body mass index over 35 who had indication for PNL including stones larger than 2 cm in pelvi-calyceal system or smaller extracorporeal shock wave lithotripsy (ESWL) resistant stones or who were not a fit candidate for ESWL due to increased skin to target distance, with no contraindication of PNL (including bleeding diathesis, inability to be positioned in prone) were enrolled. They were randomly assigned to group 1 (standard PNL with nephrostomy and ureteral stent) or group 2 (totally tubeless PNL with no ureteral stent and no nephrostomy). The outcomes were compared. RESULTS: The transfusion rate, operation time, and the hemoglobin drop were same across the groups (p>0.05). Total analgesic use was equivalent of 33.8 vs. 14.7 mgs of morphine sulfate (18-77 mg) and was significantly lower in total tubeless group (p=0.001). Return to normal activity was described as total number of in-patient and outpatient days from time of admission to the point which the patients returns to normal life activity such as going to job or school and was 19.4 vs. 9.3 days (6-30 days, p=0.001). CONCLUSION: Totally tubeless PNL in obese subjects would have lower analgesic use and return to normal activity versus standard PNL. Totally tubeless PNL is recommended for obese patients.