Michael del Junco

Evaluation and Comparison of Urolithiasis Scoring Systems Used in Percutaneous Kidney Stone Surgery

PURPOSE Contemporary predictive tools for percutaneous nephrolithotomy outcomes include the Guy stone score, S.T.O.N.E. nephrolithometry and the CROES nephrolithometric nomogram. We compared each scoring system in the same cohort to determine which was most predictive of surgical outcomes. METHODS We retrospectively reviewed the records of patients who underwent percutaneous nephrolithotomy between 2009 and 2012 at a total of 3 academic institutions. We calculated the Guy stone score, the S.T.O.N.E. nephrolithometry score and the CROES nephrolithometric nomogram score based on preoperative computerized tomography images. A single observer at each institution reviewed all images and assigned scores. Univariate and multivariate analysis was done to determine the most predictive scoring system. RESULTS We enrolled 246 patients in study. In stone-free patients vs those with residual stones the mean Guy score was 2.2 vs 2.7, the mean S.T.O.N.E. score was 8.3 vs 9.5 and the mean CROES nomogram score was 222 vs 187 (each p <0.001). Logistic regression revealed that the Guy, S.T.O.N.E. nephrolithometry and CROES nomogram scores were significantly associated with stone-free status (p = 0.02, 0.004 and <0.001, respectively). The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss (p <0.0001 and 0.03) and length of stay (p = 0.03 and 0.009, respectively). The CROES nomogram did not predict estimated blood loss or length of stay. CONCLUSIONS All scoring systems and the stone burden equally predicted stone-free status. The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss and length of stay. A single scoring system should be adopted to unify reporting.

Comparison of Outcomes in Patients Undergoing Percutaneous Renal Cryoablation With Sedation vs General Anesthesia

OBJECTIVE To compare the efficacy and safety of local anesthesia with conscious sedation (LACS) with general anesthesia (GA) in patients undergoing percutaneous renal cryoablation (PRC) for renal cortical neoplasms. METHODS We performed a retrospective review of patients undergoing PRC between 2003 and 2013. Patient demographics, tumor characteristics, and perioperative and postoperative follow-up data were recorded and analyzed. We compared 3 principal outcomes across the GA and LACS groups: anesthesia-related outcomes, treatment failure, and complications. RESULTS A total of 235 patients with available data were included. Of these, 82 underwent PRC under GA and 153 patients under LACS. The 2 groups were similar with regard to age, gender, body mass index, American Society of Anesthesiologists score, tumor features, preoperative serum creatinine level, and hematocrit value. The GA and LACS groups had a similar percentage of patients with biopsy-proven renal cell carcinoma (68.5% and 64.2%, respectively; P = .62). The mean follow-up time for GA and LACS was 37 and 21 months, respectively (P <.0001). The mean procedure time for GA was significantly longer compared with LACS (133 vs 102 minutes; P <.001), and the mean hospital stay was shorter under LACS (1.08 vs 1.95 days; P <.0001). There was no difference in immediate failure (0% and 1.9%; P = .051) or recurrences (11% and 3.9%, respectively; P = .051) between GA and LACS groups. There was no difference in intraoperative and postoperative treatment-related complications between the 2 groups. CONCLUSION PRC for small renal masses under LACS is effective and safe. PRC with LACS has the advantage of decreased procedure time and a shorter hospital stay.

Comparison of Optics and Performance of Single Channel and a Novel Dual-channel Fiberoptic Ureteroscope

OBJECTIVE To evaluate performance characteristics and optics of a novel dual-working channel fiberoptic ureteroscope (Wolf Cobra) with 2 single-channel fiberoptic ureteroscopes and to a single-channel distal sensor standard definition digital ureteroscope URF-V (SD-DS). METHODS Four new ureteroscopes (Cobra, Viper, X(2), and SD-DS) were compared for active deflection, irrigation flow, and optical characteristics. We performed a porcine ureteroscopy and measured the time for cleaning the middle calyx after injection of 10 cc of a standardized bloody solution. RESULTS The SD-DS showed a higher resolution (7.42 lines/mm; P = .0001) compared with the fiberoptic ureteroscopes; among the fiberoptic ureteroscopes, the Cobra had the highest resolution than the Viper and X(2) (P = .0001). Grayscale distribution and color representation were identical for the fiberoptic ureteroscopes, whereas the SD-DS provided a superior color representation and a significant higher depth of field. The Cobra provided superior flow with empty working channel (86 cc/min vs 68 cc/min [Viper] vs 62.5 cc/min [X(2)] vs 62 cc/min [SD-DS]; P = .0001) and with various accessories (P <.0001). With regard to deflection, the Storz X(2) and the Cobra provided superior deflection up and down (P <.0001). When evacuating a standardized bloody field, the Cobra provided significant shorter evacuation times compared with those of the Viper, X(2), and SD-DS (36.6 vs 72 vs 65.6 vs 72.6 seconds, respectively; P = .0001). CONCLUSION The additional working channel of the Wolf Cobra may improve vision and performance during challenging ureteroscopic cases by providing an increased flow. The enhanced irrigation capabilities of the Cobra have to be balanced with a larger diameter of this ureteroscope.

Development of a Novel iPad-Based Laparoscopic Trainer and Comparison With a Standard Laparoscopic Trainer for Basic Laparoscopic Skills Testing

INTRODUCTION We developed the iTrainer (iT) as a portable laparoscopic trainer, which incorporates the iPad tablet. We then compared the iT with a standard pelvic trainer (SPT) to assess surgical skills as well as its image quality, resolution, brightness, comfort, and overall performance. MATERIALS AND METHODS We designed and constructed the iT to be compatible with the Apple iPad 3 and standard laparoscopic instruments. Participants were assigned to perform the thread-the-loops task on both trainers and were prospectively randomized to start on either the iT or the SPT. Each participant was allowed a 2-minute warm-up before the 2-minute testing period. We scored participants using the product of skill quality (0-4 scale) and quantity of loops threaded (0-10 scale). Participants then rated each trainer on image quality, resolution, brightness, comfort, and overall performance on a 5-point Likert scale. RESULTS A total of 45 subjects including 10 undergraduates, 10 medical students, 10 general surgery and urology residents, and 15 experts (fellows and attending surgeons) participated in this study. There was no significant difference between thread-the-loops task scores completed on the iT when compared with the SPT for all groups tested (p > 0.05) with the exception of the medical student group, who performed better on the SPT (p < 0.05). On evaluation of each trainer, participants rated the iT as having superior image quality and resolution when compared with the SPT (p < 0.05) but rated the SPT higher in overall performance (p < 0.05). Brightness and comfort were rated similarly for both trainers. CONCLUSIONS We have demonstrated face validity and criterion validity for the thread-the-loops task on the iT. The iT rated superior in image quality and resolution but inferior in overall performance compared with the SPT. The iT provides trainees a unique advantage over SPT as an additional resource to laparoscopic training as it is inexpensive, portable, and can be readily available for training.

Development and evaluation of a retroperitoneal dialysis porcine model.

OBJECTIVES We attempted to create a surgical model to evaluate the retroperitoneal space for the ability to transfer solutes through the retroperitoneal membrane. Our dual objectives were to develop a technique to assess the feasibility of retroperitoneal dialysis (RPD) in a porcine model. METHODS We incorporated two 35-kg Yorkshire pigs for this pilot study. In the first animal, we clamped renal vessels laparoscopically. In the second animal, we embolized renal arteries. In both animals, we dilated the retroperitoneal space bilaterally and deployed dialysis catheters. We measured serum creatinine (Cr), urea, and electrolytes at baseline 6 hours before the dialysis and every 4 hours after. RESULTS We successfully created retroperitoneal spaces bilaterally and deployed dialysis catheters in both animals. In the first animal, dialysate and plasma Cr ratio (D/P) on the left and right side were 0.43 and 0.3, respectively. Cr clearance by 40 minutes of dialysis treatment was 6.3 mL/min. The ratio of dialysate glucose at 4 hours dwell time to dialysate glucose at 0 dwell time (D/D0) for left/rights sides were 0.02 and 0.02, respectively. kt/Vurea was 0.43. In the second animal, D/P Cr for left/right sides were 0.34 and 0.33, respectively. kt/Vurea was 0.17. We euthanized the pigs due to fluid collection in the peritoneal space and rapid increase of serum Cr, urea, and electrolytes. CONCLUSIONS We demonstrated the feasibility of creation of a functionally anephric porcine model with successful development of retroperitoneal spaces using balloon inflation. Notwithstanding minimal clearance and limited diffusion capacity in this experiment, additional studies are needed to examine potential use of retroperitoneal space for peritoneal dialysis.