Maurice Anidjar

The Use of a Novel Reverse Thermosensitive Polymer to Prevent Ureteral Stone Retropulsion During Intracorporeal Lithotripsy: A Randomized, Controlled Trial

PURPOSE We present the first randomized clinical study using BackStop, a novel reverse thermosensitive water-soluble polymer that is dispensed above the stone(s) and temporarily occludes the ureter to prevent retropulsion of stone fragments during ureteroscopic lithotripsy. After fragmentation is completed and concretions are extracted, conventional irrigation with saline dissolves the polymer, which is then flushed out. MATERIALS AND METHODS A total of 68 subjects with a single stone in the proximal ureter and an indication for ureteroscopic lithotripsy were enrolled in this prospective, randomized, single-blind, controlled, multisite clinical study. Each subject was randomly assigned to the BackStop group (34) or the control group (34 with no antiretropulsion device). For subjects in the experimental group BackStop was dispensed into the ureter above the stone using a 3Fr or 5Fr catheter. Ureteroscopic lithotripsy was performed in all subjects using pneumatic or laser energy. Measured end points included the retropulsion rate, the need for subsequent procedures, the stone-free rate at followup, the occurrence of adverse events and ureteral occlusion, if any, and post-stone fragmentation and extraction. RESULTS Subjects randomized to the BackStop group experienced a statistically significant (p = 0.0002) lower rate of retropulsion (8.8%, 3 of 34) vs the control group (52.9%, 18/34). There were no adverse events in the BackStop group and BackStop was successfully dissolved in every subject, resulting in a patent ureter. CONCLUSIONS BackStop appears to be a novel, safe and effective means of preventing stone fragment retropulsion during ureteroscopic lithotripsy for the management of ureteral stones.

In vivo model mimicking natural history of dog prostate cancer using DPC-1, a new canine prostate carcinoma cell line

Dog prostate cancer is usually considered to be highly relevant to human prostate cancer. We report the isolation of a new canine prostate cancer epithelial cell line designated DPC‐1.

An experimental model of bulbar urethral stricture in rabbits using endoscopic radiofrequency coagulation.

OBJECTIVES To develop an experimental model of endoscopic urethral stricture mimicking the human clinical situation. METHODS Twenty-four New Zealand male rabbits were included. Eighteen animals (study group) underwent videourethroscopy with a pediatric resectoscope, and a 3 to 5-mm-long circumferential electrocoagulation of the bulbar urethra was performed, without postoperative urinary diversion. Six animals underwent the same procedure without application of electrocautery (control group). Each animal was assessed for urethral stricture on day 15 and day 30 by videourethroscopy and voiding cystogram. Among the study group, 8 animals were killed on day 15 and 10 on day 30 for histologic evaluation. All the control animals were killed on day 30 for histologic examination. RESULTS Nine animals (50%) in the study group developed a significant bulbar stricture (reducing the lumen by more than 50%) at day 15. Histologic examination confirmed the presence of hyalin fibrosis mutilating the urethral wall. No spontaneous improvement of the stricture was observed on day 30. None of the controls developed urethral stricture, and histologic examination showed a normal urethra in each case. CONCLUSIONS Endoscopic electrocoagulation of the urethral wall provides a reproducible model of stricture in the rabbit.

Randomized controlled trial of virtual reality and hybrid simulation for robotic surgical training

Study Type – Therapy (outcomes research)

Optimization of cardiac preload during laparoscopic donor nephrectomy: A preliminary study of central venous pressure versus esophageal doppler monitoring

Background: While the popularity of laparoscopic donor nephrectomy (LDN) has increased, concern persists about the potential deleterious effects of pneumoperitoneum on renal function. Thus, preload optimization with vigorous intravenous hydration has been recommended. The purpose of this study was to compare central venous pressure (CVP) monitoring with a noninvasive measure of cardiac preload (esophageal Doppler) during LDN. Methods: Thirteen patients were studied. Following induction of general anesthesia, a Doppler probe was inserted in the lower third of the esophagus to measure flow time corrected for heart rate (FTc), which is an index of preload. In 10 patients, a catheter was placed in the right internal jugular vein and CVP measured. CVP and FTc were measured at baseline in the supine and right lateral decubitus positions, then 15 and 60 min after the establishment of CO2 pneumoperitoneum (12–15 mmHg). IV fluids were increased if the FTc fell below 300 msec. Results are expressed as means (±SD). Data were analyzed using repeated measures ANOVA. Results: Lateral positioning and pneumoperitoneum significantly increased CVP from baseline (p < 0.01), while the FTc did not change (p = 0.57). After 60 min of pneumoperitoneum, the FTc was <300 msec in only one patient. Conclusion: CVP is not an accurate guide for administration of IV fluids during LDN. Esophageal Doppler monitoring can be used to noninvasively follow changes in preload during LDN and is worthy of further study.

Preclinical Study of the Novel Vascular Occluding Agent, WST11, for Photodynamic Therapy of the Canine Prostate

PURPOSE Vascular targeted photodynamic therapy with WST09 shows promise for recurrent prostate cancer after radiation but hydrophobicity in aqueous solutions limited application. We tested the safety and efficacy of WST11, a novel water soluble vascular occluding agent, for vascular targeted photodynamic therapy of the dog prostate and compared it to WST09 vascular targeted photodynamic therapy. MATERIALS AND METHODS Optical fibers were inserted in the prostate and connected to diode lasers. WST11 (Steba Biotech, Cedex, France) at varying doses, including a drug control with no light in 34 dogs, and WST09 (Steba Biotech) (2 mg/kg) in 3 dogs were infused during 10 minutes. Illumination was initiated at 5 or 10 minutes, and lasted up to 33.2 minutes based on laser fluence and delivered energy. Blood was collected for analysis and pharmacokinetics. The end point was at 1 week. RESULTS No vascular targeted photodynamic therapy associated change was observed in blood pressure or blood test values. Circulating WST11 increased with drug infusion and decreased rapidly during 1 hour to reach undetectable levels by 24 hours. All except 1 dog with bowel intussusception did well after vascular targeted photodynamic therapy with only mild urinary symptoms that resolved within 24 to 48 hours. Lung and liver were normal. Hemorrhage was present in all prostates except controls. This translated into necrosis at a WST11 threshold and within a window of doses at fixed illumination. Necrosis was associated with loss of the vessel endothelial layer. Fluence highly impacted necrosis. WST11 vascular targeted photodynamic therapy was advantageously comparable to WST09 vascular targeted photodynamic therapy, and optimally ablated about 5.0 cm(3) of tissue per lobe and about 10 cm(3) of the whole prostate. CONCLUSIONS The safety and efficacy of WST11 vascular targeted photodynamic therapy in the dog prostate support clinical applications for prostate cancer and benign prostatic hyperplasia.

Successful salvage of kidney allografts threatened by ureteral stricture using pyelovesical bypass.

Ureteral stricture is the most common urologic complication after renal transplantation. When endourologic management fails, open ureteral reconstruction remains the standard treatment. The complexity of some of these procedures makes it necessary to explore other means of repair. This study evaluated the intermediate‐term outcome of subcutaneous pyelovesical bypass graft (SPBG) on renal transplant recipients. We reviewed 8 patients (6 male and 2 female; mean age 52 years) with refractory ureteral strictures postrenal transplantation, who received SPBG as salvage therapy. All patients failed endourologic management and half failed open management of their strictures. After a mean follow‐up of 19.4 months, 7 out of 8 renal grafts have good function with mean GFR of 58.5 mL/min/1.73 m2, without evidence of obstruction or infection. One patient lost his graft due to persistent infection of the SPBG and one patient developed a recurrent urinary tract infection managed with long‐term antibiotics. SPBG offers a last resort in the treatment of ureteral stricture after renal transplantation refractory to conventional therapy.

Validation of the da Vinci Surgical Skill Simulator across three surgical disciplines

OBJECTIVE In this paper, we evaluate face, content and construct validity of the da Vinci Surgical Skills Simulator (dVSSS) across 3 surgical disciplines. METHODS In total, 48 participants from urology, gynecology and general surgery participated in the study as novices (0 robotic cases performed), intermediates (1-74) or experts (≥75). Each participant completed 9 tasks (Peg board level 2, match board level 2, needle targeting, ring and rail level 2, dots and needles level 1, suture sponge level 2, energy dissection level 1, ring walk level 3 and tubes). The Mimic Technologies software scored each task from 0 (worst) to 100 (best) using several predetermined metrics. Face and content validity were evaluated by a questionnaire administered after task completion. Wilcoxon test was used to perform pair wise comparisons. RESULTS The expert group comprised of 6 attending surgeons. The intermediate group included 4 attending surgeons, 3 fellows and 5 residents. The novices included 1 attending surgeon, 1 fellow, 13 residents, 13 medical students and 2 research assistants. The median number of robotic cases performed by experts and intermediates were 250 and 9, respectively. The median overall realistic score (face validity) was 8/10. Experts rated the usefulness of the simulator as a training tool for residents (content validity) as 8.5/10. For construct validity, experts outperformed novices in all 9 tasks (p < 0.05). Intermediates outperformed novices in 7 of 9 tasks (p < 0.05); there were no significant differences in the energy dissection and ring walk tasks. Finally, experts scored significantly better than intermediates in only 3 of 9 tasks (matchboard, dots and needles and energy dissection) (p < 0.05). CONCLUSIONS This study confirms the face, content and construct validities of the dVSSS across urology, gynecology and general surgery. Larger sample size and more complex tasks are needed to further differentiate intermediates from experts.

Factors Determining Fluoroscopy Time During Ureteroscopy

PURPOSE The aim of this study was to prospectively identify predictors of radiation exposure during ureteroscopy. PATIENTS AND METHODS Eighty-five consecutive patients who presented for ureteroscopies and laser lithotripsy were considered. Fluoroscopy time (FT) was obtained from radiology reports for each patient, and clinical data were obtained from chart review. Nine patients were excluded (three unconfirmed FTs, four staghorn calculi, one ectopic kidney, and one multiple ureteral strictures). Seventy-six patients were included in the study. Univariate and multivariate linear regression were used to identify factors that determined FT. RESULTS The patient cohort was 65.8% male with a mean age of 52.7 years. Mean FT was 183 s, and mean surgical time was 68.4±29 minutes. Mean stone size was 10±5 mm in the greatest dimension. A large proportion of patients (50%) had renal stones, multiple stones were present in 31.6% of cases, and 22.3% of stones were radiolucent. Cases were equally distributed between surgeons A and B, and 46% of patients had preoperative stents. On multivariate analysis, increased FT was independently associated with surgeon A (104 additional seconds per case, P<0.001), longer duration of surgery (14 s per 10 minutes, P<0.001), and male patients (54 s per procedure, P=0.02). Age, stone characteristics, presence of ureteral stent, and stone-free status did not correlate with FT. CONCLUSIONS Surgeon behavior, longer duration of surgery, and male gender were significant predictors of FT and, hence, radiation exposure during ureteroscopy. In the present study, stone characteristics were not found to be predictors of FT.

Hybrid Augmented Reality Simulator: Preliminary Construct Validation of Laparoscopic Smoothness in a Urology Residency Program

PURPOSE We examined the usefulness, reliability and applicability of the smoothness metric of the ProMIS hybrid simulator (Haptica, Dublin, Ireland) for a urology residency program. MATERIALS AND METHODS A total of 15 urology residents divided into junior and senior cohorts were followed prospectively for 6 training sessions. Validated McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) laparoscopic tasks were used. The ProMIS hybrid simulator smoothness parameter, a unit-free metric of movement efficiency, was recorded using 3-dimensional visual tracking technology. Results were compared between cohorts at the midpoint and end of the defined training sessions. End of study junior means were also retrospectively compared to senior mid training means. Statistical significance was determined using the Mann-Whitney U test (alpha = 0.05). RESULTS Statistically significant differences between 8 junior and 7 senior cohorts were measured in all MISTELS tasks. A statistically significant performance variation was also detected at the mid and end testing times. When juniors and seniors were compared between sessions 1 and 3, and 4 and 6, statistically significant performance improvements were noted. Lastly, statistical differences were also maintained when mid session senior means were compared to end of session junior means. A 38% improvement in task completion in the senior cohort as well as a 10-fold decrease in variance was observed compared to a 12% improvement in juniors, indicating greater efficiency of movement in seniors. CONCLUSIONS The laparoscopic smoothness metric in the hybrid simulator demonstrated construct validity by effectively differentiating between experienced and novice urology residents using validated MISTELS tasks. The outcome suggests that the hybrid simulator smoothness metric is a valuable asset in residency programs for preparatory training for live operative experience, allowing improved trainee assessment.