Raymond Ko

Percutaneous nephrolithotomy for staghorn calculi: a single center's experience over 15 years.

BACKGROUND AND PURPOSE Percutaneous nephrolithotomy (PCNL) for staghorn calculi is one of the more challenging endourologic procedures. Although excellent stone-free rates are universally reported in the literature, complication rates vary widely, especially related to the need for blood transfusion. The purpose of this study was to evaluate the outcomes of PCNL for patients with staghorn calculi in a large series of patients at a single, tertiary referral, endourologic stone center. PATIENTS AND METHODS Between July 1990 and December 2005, 1338 patients underwent PCNL for renal stone disease at our institution. Among this group, 509 procedures were performed for patients with a partial or complete staghorn calculus. Data analysis included procedure time, length of hospital stay, number of access tracts, transfusion rates, other early and late complications, and stone-free status. RESULTS Mean patient age was 53.8 years (range 4-84 yrs). The average procedure time was 104 minutes. Sixteen percent of the cases needed multiple access tracts (range 2-5), with the lower calix being the most commonly used in 64.1%, followed by the upper calix in 18.5% and the middle calix in 17.4%. Various intracorporeal lithotriptors were used, including ultrasound, pneumatic, electrohydraulic, and holmium:yttrium-aluminium-garnet laser. The transfusion rate among this group was 0.8%. There was no statistically significant difference in transfusion rates (0.7%-1.2% P = 0.24) or other major complications in patients who were treated with either a single tract or among those needing multiple tracts. Stone-free rates at hospital discharge and at 3 months follow-up were 78% and 91%, respectively. CONCLUSION PCNL is a safe and effective procedure in the management of staghorn calculi, with outcomes similar to those reported for percutaneous management of smaller volume nonstaghorn stones. Attention to accurate tract selection and placement as well as possession of the full array of endourologic equipment are essential to achieving an excellent outcome.

Anti-Adhesive Coating and Clearance of Device Associated Uropathogenic Escherichia coli Cystitis

PURPOSE A previous study showed decreased uropathogen adherence using a novel anti-fouling coating consisting of mussel adhesive protein mimics conjugated to poly(ethylene glycol). We assessed the ability of methoxy polyethylene glycol-dihydroxyphenylalanine (Nerites Corp. Ltd., Madison, Wisconsin) coated ureteral stents to resist bacterial adherence, infection development and encrustation in a rabbit model of uropathogenic Escherichia coli cystitis. MATERIALS AND METHODS Sof-Flex stent curls that were uncoated and coated with 3 coatings, including Surphys 002, 008 and 009, respectively, and uncoated Percuflex Plus stents were inserted transurethrally into the bladder of 50 male New Zealand White rabbits (Charles River Laboratories, Montreal, Quebec, Canada), followed by instillation of uropathogenic E. coli strain GR12 (10(7) cfu). Urine was examined for bacteria on days 0, 1, 3 and 7, and for cytokine levels on day 7. On day 7 the animals were sacrificed. Stent curls and bladders were harvested for analysis. In a parallel experiment stents were challenged in vitro for 7 days with GR12 in human urine. RESULTS Surphys 009 coated devices showed decreased urine and stent bacterial counts compared to those in controls. Eight of 10 rabbits in the Surphys 009 group had sterile urine by day 3 vs 1 in each control group (p = 0.013), while stent adherent organisms were decreased by more than 75%. While no statistical differences were found in encrustation and bladder inflammation across the groups, immune scoring was lowest in the uncoated Sof-Flex control and Surphys 009 groups (p = 0.030). CONCLUSIONS Surphys 009 strongly resisted bacterial attachment, resulting in improved infection clearance over that of uncoated devices. However, this did not translate to decreased encrustation, which appeared to be independent of infection in this model.

First Prize: Novel Uropathogen-Resistant Coatings Inspired by Marine Mussels

BACKGROUND AND PURPOSE Success in the prevention of urinary device infections has been elusive, largely due to multiple bacterial attachment strategies and the development of urinary conditioning films. We investigated a novel anti-fouling coating consisting of mussel adhesive protein mimics conjugated to polyethylene glycol (mPEG-DOPA(3)) for its potential to resist conditioning film formation and uropathogen attachment in human urine. METHODS Model TiO(2) -coated silicon disks ( approximately 75 mm(2)) were either coated with mPEG-DOPA(3) or left uncoated and sterilized using ethylene oxide gas. For bacterial attachment experiments, coated and uncoated surfaces were separately challenged with bacterial strains comprising six major uropathogenic species for 24 hours at 37 degrees C in human pooled urine. Starting inoculum for each strain was 10(5) CFU/mL and 0.5 mL was used per disk. Following incubation, the disks were thoroughly rinsed in phosphate buffered saline to remove non-adherent and weakly-adherent organisms and cell scrapers were employed to dislodge those that were firmly attached. Adherent bacteria were quantitated using dilution plating. Representative disks were also examined using scanning electron microscopy, energy dispersive x-ray analysis, and live/dead viability staining. RESULTS The mPEG-DOPA(3) coating significantly resisted the attachment of all uropathogens tested, with a maximum >231-fold reduction in adherence for Escherichia coli GR-12, Enterococcus faecalis 23241, and Proteus mirabilis 296 compared to uncoated TiO(2) disks. Scanning electron microscopy and viability staining analyses also reflected these results and demonstrated the ability of the coating to resist urinary constituent adherence as well. CONCLUSION Model surfaces coated with mPEG-DOPA(3) strongly resisted both urinary film formation and bacterial attachment in vitro. Future in vitro and in vivo studies will be conducted to assess whether similar findings can be demonstrated when these polymer coatings are applied to urologic devices.

Percutaneous nephrolithotripsy in patients with diabetes mellitus.

PURPOSE To compare the surgical outcomes in a cohort of patients with diabetes who were undergoing percutaneous nephrolithotripsy (PCNL) for renal stone disease to a nondiabetic group of patients at a single center. PATIENTS AND METHODS Between July 1990 and December 2005, all patients scheduled for PCNL were prospectively included in a single-center database. Preoperative, intraoperative, and postoperative data were prospectively collected and analyzed. Primary outcomes evaluated were stone-free rates and complications, including the need for blood transfusion, while the secondary outcome was length of hospital stay. This report specifically reviews these outcomes in patients known to have diabetes at the time of surgery. Both outcomes were compared with those obtained in our nondiabetic patient population. RESULTS Analysis of the data from 183 (13.7%) patients with diabetes of the 1338 patients undergoing PCNL revealed that patient age (63.1 years), surgical time (90.8 minutes), and complications (major 2.2%), including need for transfusion (0.5%) and stone-free rate (94.5%), were not significantly different from those observed in our nondiabetic patients. The average length of hospital stay was significantly longer in the diabetic group (4.4 days vs 3.9 days, P = 0.022). Uric acid stone composition was found to be the most common stone composition among the patients with diabetes in this study (41%). CONCLUSIONS PCNL can be performed with excellent stone-free rates and with an acceptable complication risk in the diabetic population. The incidence of uric acid stone disease appears to be significantly higher than previously reported and warrants heightened efforts directed toward stone prevention in this population.

Occupational Noise Exposure during Endourologic Procedures

INTRODUCTION Long-term noise exposure in the workplace is a known cause of hearing loss. There has been limited study on the potential harm related to shock wave lithotripsy (SWL) or intracorporeal devices on patients and operating room personnel. PATIENTS AND METHODS We used a digital sound meter to measure decibel levels in the operating room during several endourologic procedures. The decibel levels were recorded during SWL (Storz SLX-F2), percutaneous nephrolithotomy using single- and dual-probe ultrasonic lithotripters (Olympus LUS-2, CyberWand), and during ureteroscopy using the Versa Pulse Holmium:YAG laser. Findings were compared with the U.S. Department of Labor Occupational Health and Safety Administration and Canadian Centre for Occupational Health recommendations on permissible noise levels in the workplace. RESULTS The background sound level in the operating room prior to endourologic procedures ranged between 58 and 60 dB. In the SWL control room, 5 m from the source, the mean sound level was 68 dB (range 64-75) during treatment. The mean corresponding decibel level recorded at the patients head during SWL was 77 dB (range 73-83). Noises produced by intracorporeal lithotripters were recorded at the surgeons head, 2 m from the source. Measurements of the CyberWand (dual-probe) device revealed a higher mean decibel reading of 93 dB (range 85-102). Noise levels recorded for the Olympus LUS-2 (single-probe) ultrasound and the holmium laser were 65 dB (62 -68) and 60 dB (58-62), respectively. CONCLUSION Although we noted that patients and urologists maybe exposed to significant noise levels during endourologic procedures, the duration of exposure is short. This risk appears to be minimal, based on current occupational guidelines, for most operating personnel.

68 Ga-PSMA PET/CT vs. mpMRI for locoregional prostate cancer staging: correlation with final histopathology

BackgroundProstate-specific membrane antigen (PSMA) positron emission tomography (PET) can be used to locate lesions based on PSMA avidity, however guidelines on its use are limited by its infancy. We aimed to compare multiparametric magnetic resonance imaging (mpMRI) and PSMA PET/CT to prostatectomy histopathology.MethodsWe conducted a chart review from February 2015 to January 2017 of 50 male patients staged for prostate cancer using PSMA PET/CT and mpMRI who then underwent radical prostatectomy. Pre-operative PSMA PET/CT and mpMRI were paired with corresponding histopathology. Correlations, sensitivity, and specificity were used for comparisons.ResultsA total of 81 lesions were confirmed by histopathology. Fifty index lesions were detected by histopathology, all of which were detected by PSMA PET/CT (100% detection), and 47 by mpMRI (94% detection). Thirty-one histologically confirmed secondary lesions were detected, 29 of which were detected by PSMA PET/CT (93.5% detection), and 16 by mpMRI (51.6% detection). PSMA had better sensitivity for index lesion localization than mpMRI (81.1 vs. 64.8%). Specificity was similar for PSMA PET/CT and mpMRI (84.6 vs. 82.7%).SUVmax of index lesions ranged from 2.9 to 39.6 (M = 9.27 ± 6.41). Index lesion SUVmax was positively correlated with PSA (rho = 0.48, p < 0.001) and ISUP grade (rho = 0.51, p < 0.001).ConclusionsPSMA-PET/CT provided superior detection of prostate cancer lesions with better sensitivity than mpMRI. PSMA-PET/CT can be used to enhance locoregional mpMRI to provide improved detection and characterization of lesions.

Knotted proximal loop of ureteric stents: Review of the literature and five case reports

The use of ureteric stents has become routine urological practice. Indications for insertion of ureteric stents include relieving ureteric obstruction,1 to promote ureteral healing following injury,2 prophylactically prior to extracorporeal shock wave lithotripsy (ESWL) or following complicated ureteroscopy3 to prevent ureteral obstruction, and to assist with ureteral identification during pelvic surgery.4 Placement of ureteric stents is associated with welldocumented complications including stent migration, encrustation, fragmentation and patients being lost to follow-up.3,5–7 Knot formation of ureteric stents is a rare complication with only 15 cases reported in the literature at the proximal end,8–22 two cases reported at the mid-portion of the ureteric stent23,24 and one case reported at the distal end.25 We present five cases of proximal stent knotting in one institution over a one-year period.