Kristene Myklak

Renal Vascular Clamp Placement: A Potential Cause of Incomplete Hilar Control during Partial Nephrectomy

PURPOSE Previous benchtop studies have shown that robotic bulldog clamps provide incomplete vascular control of a Penrose drain. We determined the efficacy of robotic and laparoscopic bulldog clamps to ensure hemostasis on the human renal artery. The effect of clamp position on vascular control was also examined. MATERIALS AND METHODS Fresh human cadaveric renal arteries were used to determine the leak point pressure of 7 bulldog clamps from a total of 3 manufacturers. Five trials were performed per clamp at 4 locations, including the fulcrum, proximal, middle and distal positions. Comparison was done using the Kruskal-Wallis test with p <0.05 considered significant. RESULTS None of the bulldog clamps leaked at a pressure less than 215 mm Hg when applied at the proximal, middle or distal position. In general leak point pressure decreased as the artery was positioned more distal along the clamp. The exception was when the vessel was placed at the fulcrum position. At that position 80% to 100% of trials with the Klein laparoscopic, 100% with the Klein robotic (Klein Robotic, San Antonio, Texas) and 60% to 80% with the Scanlan robotic (Scanlan International, Saint Paul, Minnesota) clamp leaked at pressure below 215 mm Hg. CONCLUSIONS Each vascular clamp adequately occluded flow at physiological pressure when placed at the proximal, middle or distal position. Furthermore, these results demonstrate that there is leakage at physiological pressure when the artery is placed at the fulcrum of certain clamp types. These results suggest that applying a bulldog clamp at the fulcrum could potentially lead to inadequate vessel occlusion and intraoperative bleeding.

PD19-05 THE OPTIMAL GUIDEWIRE TYPE AND EFFECT OF PRIOR USE ON THE EASE OF URETERAL STENT INSERTION

INTRODUCTION AND OBJECTIVES: Ureteral stent insertion is a frequent procedure in endourology, with no clear consensus on the best wire type to facilitate stent insertion. Use of wires may result in deterioration of their protective coating, requiring greater force for stent insertion. The purpose of this study was to identify the effect of wire type, and prior use, upon average insertion force needed for a 6Fr ureteral stent. METHODS: Stent insertion was tested using an ex vivo porcine urinary tract model with continuous water infusion (1cc/min) to simulate urine production. For each trial, a new, soft, 6Fr Cook JJ ureteral stent was advanced over new and used 0.03800 diameter guide wires including the Glidewire (Terumo), Standard Teflon-coated wire (Cook), Superstiff wire (Cook), Sensor wire (Boston Scientific), Zip-wire (Boston Scientific), and Zebra wire (Boston Scientific). A Mark-10 digital force gauge was attached to the stent, and at a constant advancing rate of 2 rotations per second, the forces to advance the stent over the wire were calculated. 10 trials of stent insertion were randomly performed on 12 new and 12 used guide wires (total of 240 placements). RESULTS: The new Glidewire had the lowest average force required for stent advancement (0.18N). The forces for insertion of all other new wires were significantly higher; Standard (1.25N; p<0.01), Superstiff (2.03N; p<0.01), Sensor (1.87; p<0.01), Zip (0.22N; p<0.01), and Zebra (0.61; p<0.01). When comparing the average insertion force between new and used wires, the used wires required greater mean force in the Standard (2.42N vs. 1.25N; p <0.01), Superstiff (2.68N vs. 2.03N; p <0.01), and Zipwire (0.36N vs. 0.22N; p <.01), but there was no statistical difference between used and new fibers in the Glidewire (0.28N vs. 0.18N; p1⁄40.14), Sensor ( 1.66N vs. 1.87N; p1⁄40.18) and Zebra wire (0.59N vs.0.61N; p1⁄40.67). CONCLUSIONS: The Glidewire resulted in the lowest force for ureteral stent insertion. It may be used several times with no significant effect on ureteral stent insertion force due its resilient lubricious hydrophilic coating. Employing a used Standard, Superstiff and Zip-wire may result in additional stent insertion force. Knowledge of the forces required for stent insertion over various guide wires may allow surgeons to improve the ease and safety of stent placement.

Physiology of Spermatogenesis: Opportunities for Disruption

Spermatozoa are highly differentiated male reproductive cells that are specialized for motility and fertilization. The complex production of these cells from primordial germ cells requires coordination between the endocrine system, testicular parenchyma, and the male reproductive tract. The purpose of this chapter is to review the physiology of spermatogenesis and provide an overview of the various ways in which this process can be impaired by cancer and cancer treatments in males of reproductive age. The impact of the local and systemic effects of cancer, surgical excision of reproductive tissue, and gonadotoxic exposure to chemotherapy and radiation therapy on male fertility will be discussed.

MP81-08 HOW WELL CAN UROLOGY TRAINEES DETECT SUBURETHRAL MESH USING TRANSLABIAL ULTRASOUND IN COMPARISON TO A RADIOLOGIST?

INTRODUCTION AND OBJECTIVES: Suburethral mesh implantation for stress urinary incontinence can result in erosion, extrusion, infection, pain, and irritative voiding symptoms. Surgical mesh removal can be challenging when operative records are not available, portions of mesh have been removed, mesh position has changed, or it’s not palpated on physical exam. Translabial ultrasonography is a diagnostic tool that can detect synthetic mesh. The purpose of this study was to compare a group of Urology trainees’ and a radiologist’s ability to identify pelvic landmarks, localize and assess completeness of suburethral mesh. METHODS: Eight urology trainees received a 15-minute lecture on anatomical landmarks and techniques of translabial ultrasound as well as instruction on detection of suburethral mesh. The trainees then reviewed 18 different US studies. Trainees were asked a total of 126 questions including identification of anatomical planes, pelvic structures in different planes, mesh presence, disruption of mesh, and its location along the urethra. The overall correct response rate of all questions was compared to a Board-certified radiologist specialized in translabial ultrasound, which served as our control. The radiologist and trainees were blinded to patient history, clinical, and operative findings. RESULTS: Overall, trainees answered correct on average 83.9% (105/126) of all questions compared to the radiologist 94.4% (119/126; p1⁄40.023). Per category the average trainee was able to correctly identify the anatomical plane in 94.4% (17/18) of questions, detect presence or absence of mesh in 95.8% (17/18), determine mesh disruption in 83.3% (15/18), correctly identify pelvic anatomical structures in 83.3% (15/18), and determine location of mesh in correspondence to the urethra in 72.2 % (13/18). CONCLUSIONS: Urology trainees can learn in a reasonable time how to identify anatomical landmarks on translabial ultrasound and consistently detect the presence of suburethral mesh. Translabial ultrasound can be utilized by urologists to aid in preoperative planning for mesh removal or clinical diagnostics for symptomatic mesh.