Engineering & Urology Society

Aims: The goal of this project was to establish the methods necessary to test the hypothesis that with high resolution magnetic resonance imaging (MRI) scans, an accurate virtual reality (VR) model of the normal female pelvic floor can be created. The long-term goal of this research is to implement functionality into the VR model of the pelvic floor. The model could then be used as a tool for both teaching and testing research hypotheses.

Methods: IRB approval was obtained and one subject was recruited for the study: an asymptomatic nulliparous twenty-three year old female with no urinary incontinence symptoms. She underwent a high resolution pelvic floor MRI scan with a field of view restricted to the area of interest (24 X 24cm with an imaging matrix of 256 X 128mm). The scan had 107 T2–weighted slices in 2 series of axial T2-weighted images with a slice thickness of 3.0mm and slice gap of 0.0mm (General Electric 1.5 Tesla magnet). The slices from both series were interleaved to obtain a slice gap of 1.5mm. The ratio of repetition to echo time was 4200/102ms. Sagittal T2-weighted fast spin echo images were also acquired with slice thickness of 4.0mm, slice gap of 1.0mm, field of view of 24 X 19cm, imaging matrix of 512 X 256mm, and ratio of repetition to echo time of 25513/66.5ms. The digitized scans were imported into MIMCS image analysis software (Materialise) and pelvic floor structures (bladder, urethra, vagina, uterus, cervix, levator ani, obturator externus, obturator internus, and pubic bone) were manually segmented. CTM software (Materialise) was used to create 3-dimensional polygonal models which were then imported to Geomagics (Raindrops), for polygon reduction and surface smoothing. The completed models were displayed on an ImmersaDesk Virtual Reality system, which has a 67 X 50-inch rear projected screen at a 45-degree angle and provides a large angle of view, stereovision, and viewer-centered perspective. Wireless liquid crystal shutter glasses were used to support stereovision while a receiver tracked head position, enabling the computer to alter the perspective view for each eye. The VR model was visually verified by a Urologist and a Urogynecologist.

Results: With a high resolution MRI scan, accurate manual segmentation of pelvic floor structures was feasible. The 3-D models of the structures depicted the anatomy of the female pelvic floor accurately (figure 1). The 9 segmented structures were combined to create a virtual pelvic floor (figure 2), the anatomy of which was verified as accurate by 2 clinicians.

Conclusion: A three-dimensional model of the female pelvic floor is feasible from a high resolution MRI scan. It has the potential to be used as both a teaching and research tool to enhance our understanding of both normal and pathological anatomy and physiology.

Acknowledgements: This research was supported in part by support from the RR&D Service of the VA.

The URO Mentor: A New Computer Based Interactive
Training System for Virtual Life-like Simulation of Diagnostic
and Therapeutic Endourological Procedures

Thomas Knoll, Kai Uwe Köhrmann, Peter Alken, Maurice Stephan Michel
Department of Urology, University Hospital Mannheim, Germany

Introduction: Rapid developments in the urological field, as an expanding knowledge base and emerging new techniques require continuing urological education to achieve life long learning and to keep the urologists up to date. Consequently, specific training is necessary to guarantee qualification of the urologists. The goal of the development of the URO Mentor (Simbionix, Israel) is to overcome the current drawbacks of traditional training methods for ureterorenoscopy and PNL procedures.

Methods: A computer-assisted simulator for training and quality control in ureterorenoscopy was developed using virtual reality, multimedia technology and intelligent tutoring systems. The software system is the heart of the simulator system. It features a proprietary visualization engine (SVE). SVE makes real-time simulation possible by offering a high level object oriented Application Program Interface written in C++, available for use with either Microsoft® DirectX 7® or OpenGL as platforms. SVE includes general procedures that allow for: 2D and 3D rendering, collision detection, collision correction, 3D morphing, 2D image manipulation, mapping, video texture, X-ray rendering, special effects (blood, smoke, stone fragments and more) reflections.

Results: The system allows for a full training session on a wide range of procedures by offering different types of cases and different types of virtual patients. The URO Mentor simulator features full representation of the endourological procedures under direct vision and by using interactive fluoroscopy with a contrast agent. The supported tools include: baskets, graspers, intracorporal lithotripters, guide wires, catheters, stents, biopsy devices, dilation devices. The following endourological procedures can be performed: lithotripsy, tumor resections, treatment of strictures and obstructions, stent placement, biopsies.

Conclusions: The URO Mentor introduces a new generation mannequin equipped with a special haptic device, providing trainees with an unparalleled true-to-life sensation while training for diagnostic and therapeutic endourological procedures. By bringing key advances in the area of urological simulation--with the real-time x-ray renderer for instance--and by integrating in a single system both high quality simulation and learning tools, the URO Mentor opens new perspectives for computer based urological training systems and methods.

Comparison of Robotic versus Laparoscopic suturing:
Analysis of the learning curve.

Benjamin R Lee, M.D., Paul Rotariu, M.D., Peter Pinto, M.D.,
Arthur D. Smith, M.D., and Paulos Yohannes*, M.D. Long Island Jewish Medical Center,
New Hyde Park, NY and *Creighton University, Omaha, NE.

Introduction: Urologic laparoscopy has continued to evolve from a diagnostic to a therapeutic modality, and from mainly an extirpative procedure to presently allow reconstructive procedures. Laparoscopic reconstructive procedures have been limited by needle driver instrumentation, fixed angles at the trocar level, and small working spaces to place the suture. Robotic-assisted laparoscopic suture placement may improve the angle of suture placement and facilitate laparoscopic reconstructive procedures. The purpose of this study was to evaluate the learning curve between robotic-assisted versus manual laparoscopic suturing, as well as assess other skills.

Method: There were eight participants in this study. A series of five trials were performed to assess dexterity (task 1) and free-hand suturing (task 2). Each task was performed using robotic-assisted and manual laparoscopy. The participants were categorized as novice and experienced laparoscopists. Task 1 involved passing sutures through the eye of seven needles positioned one cm apart in a P configuration. Task 2 involved tying one surgeon’s knot, followed by two subsequent knots, for a total of 3 knots.

Results: Average time for trials one and five (Task 1, Robotic-assisted laparoscopy) were 242.6± 106 (SD) and 101.8 ± 50 (SD) seconds, respectively (p<0.001). Both groups demonstrated a statistically significant difference (p<0.001) between the first and last trial. The average time for trials one and five (Task 1, Manual Laparoscopy) were 205.3 and 169 seconds, respectively. Learning curves for robotic-assisted and manual laparoscopy were statistically significant in favor of robotic-assistance. Manual laparoscopic suturing did not demonstrate as much of a difference for the experienced surgeon. Overall difference in improvement between robotic-assisted and manual laparoscopy was not statistically significant.

Conclusion: Robotic-assisted laparoscopy allows suturing and dexterity skills to be performed quicker than manual laparoscopy. The degree of improvement for robotic-assisted suture placement is less for the experienced laparoscopist.

Michael J. Manyak, MD,¹ James K. Hahn, PhD,³ Ge Jin,³ Dongho Kim,³ John Rewcasle, PhD,⁴Sunil Kim, PhD³ and Raymond J. Walsh,PhD²

From the Departments of Urology¹ and Anatomy², School of Medicine,
and the School of Applied Science and Engineering³, The George Washington University;
and Endocare, Inc.⁴

Introduction: Cryotherapy uses a technique to selectively freeze tissue to cause controlled tissue destruction. Cryotherapy for localized prostate cancer requires perineal insertion of multiple small diameter probes into the prostate at selected spatial intervals. Transrectal ultrasound (TRUS) is used to both properly position the cylindrical probes before activation of the cooling element and to monitor tissue effect. Greater destruction occurs with 2 freeze-thaw cycles during treatment. Despite the prevalence of surgical simulation systems, very few are used routinely for training due to techical difficulties in engineering a system that specifically addresses a discrete task. This simulator was developed as part of a comprehensive computer-based, hands-on training program designed to familiarize the physician with the technical aspects of prostate cryotherapy.

Methods: The computer-based cryotherapy simulation system mimics the major surgical steps involved in the procedure. The performance objective of the trainer is to simulate 3 principle surgical maneuvers: perineal entry site selection for the cryoprobes, cryoprobe tip positioning within the prostate gland, and tissue freezing based on cryoprobe position. The mock procedure is viewed on a simulated ultrasound display whose image is manipulated in real time by the user, mimicking the TRUS display of the actual surgical procedure. The simulated TRUS display is generated from 3-D ultrasound where both the interaction of the ultrasound with the instruments and the ice balls are simulated using ray-casting methods. The thermal and mechanical simulation of the tissue is done using a modified finite-element method. The prostate is segmented out and rendered in 3-D to give a longitudinal overview of the prostate with probes inserted. Multiple anatomic variations provide the user with a rich variety of simulated case scenarios. A surgery planning software is incorporated into the simulator to give the ideal probe placement for each anatomic variant.

Results: The simulation system has been developed with several refinements. Preliminary evaluation indicates that the system is effective for training the user in both technique and treatment.

Conclusion: This system development demonstrates the practical application of a simulator in a comprehensive prostate cryotherapy training program.

Shane T. Russell, Akira Kawashima, Michael R. Bruesewitz,
Andrew J. LeRoy, Bernard F. King,
Terri J. Vrtiska, Cynthia H. McCollough, George K. Chow, Robert R. Hattery
Departments of Urology and Radiology, Mayo Clinic, Rochester, Minnesota

Introduction: Three-dimensional (3D) computed tomography (CT) virtual cystoscopy is a rapidly evolving non-invasive diagnostic imaging technique for detecting intraluminal bladder pathology. The value of virtual cystoscopy is currently limited by the visual resolution of the bladder wall and hence the ability to accurately identify and characterize small and sessile lesions. We report a novel phantom pelvis/bladder model to define the optimal scanning parameters to improve the diagnostic accuracy of virtual cystoscopy.

Methods/Results: A Plexiglas rectangular phantom pelvis measuring 25cmx18cmx20cm was constructed and filled with a diluted contrast material solution with an attenuation value of 30 Hounsfield Units (HU) to simulate pelvic soft tissue. A 12.5cm diameter circular “bladder” with a watertight removable lid was constructed from 2mm thick Plexiglas, and mounted to a removable Plexiglas plate. A “trigonal ridge” made from liquid rubber was secured to the bladder floor in the correct anatomical position. A 20cm tall Plexiglas stand consisting of 2 vertical 12mm diameter pillars and 4 5mm diameter horizontal “arms” was designed to support a 2.5cm diameter hollow-tube “rectum” posterior to the bladder, two anterolaterally placed porcine hip bones, and a sealed sack of minus 100HU processed animal fat surrounding the bladder to simulate perivesical fat. Simulated “tumors” made from Solidwater plastic polymer (Gammex RMI, Middleton, WI) varied in shape and size (2mm to 10mm in height and diameter), and had a CT density of 30HU. The phantom bladder was scanned filled with either air, mimicking in vivo studies performed with retrograde insufflated bladder air or carbon dioxide, or with a water/contrast medium mixture measuring 1000HU to simulate passive antegrade bladder filling on delayed images of an intravenous urogram. Scanning was performed with a Light Speed multi-detector helical CT scanner (GE Medical Systems, Milwaukee, WI) with varying slice thickness of 1.25 to 5.0mm and with 0%, 50%, and 75% overlap. Virtual 3D-CT cystoscopic images were generated on an Advantage workstation using GE 4.0 Navigator software. Improved visualization of the bladder wall and polyps was noted with decreasing collimation thickness, increasing percent overlap, decreased table speed, and lower pitch, giving optimal screening parameters of 1.25mm slice thickness, 75% or 50% overlap, and 3.75mm/rot HQ mode.

Conclusion: The challenge of this project was to develop a phantom bladder model which most accurately recreated the anatomic and physiologic milieu of the human pelvis, which could then be subjected to an infinite number of repeat CT studies. Using an anatomically accurate bladder phantom could thereby spare human subjects the risks inherent in the numerous scans needed to develop the optimal scanning techniques which find the ideal balance between radiation exposure and image resolution.

Dan Stoianovici*, Dumitru Mazilu, Alexandru Patriciu,
Alexandru Stanimir, Nicolae Craciunoiu, Louis Kavoussi
URobotics Laboratory, Urology Department
Johns Hopkins Medical Institutions, Baltimore, MD

We report the development of a new robotic system for CT-guided operations. Its name, “Tracker”, or “T” for short, was derived from its capability of performing active tracking of respiratory and other soft tissue motion. Tracker performs precise manipulation of a needle or other surgical instrument in the confined space of the imager without interfering with the imager functionality (Figure 1).

Tracker is connected to the mobile table of the CT allowing the patient and the robot to be jointly sent into the CT gantry for imaging and interventional procedures. The robot presents six degrees of freedom configured for decoupled positioning, orientation, and insertion of the instrument. The Tracker robot comprises the PAKY radiolucent needle driver and the RCM robotic module previously developed in our URobotics Laboratory. In addition, two other modules have been purposely designed: a new passive positioning arm and an active three degrees of freedom translational stage mounted on a bridge-like support. A new ball-worm drive version of the RCM robot is also included. The entire system comprises only two components, the robot and the control box, connected with a single cable. A touch-screen display and a joystick are conveniently mounted on the robot.

Acknowledgement: This work was partially supported by grant No. 1R21CA088232-01A1 from the National Cancer Institute (NCI). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NCI.

Ramakrishna Venkatesh, Jaime Landman, Scott Minor*, David Lee, Maged Ragab,
Jamil Rehman, Chandru P. Sundaram, Ralph V. Clayman**
Affiliation: Division of Urology, Washington University School of Medicine, St. Louis, MO
* Division of Physical Therapy, Washington University School of Medicine, St. Louis, M0
** Professor and Chairman, Department of Urology, University of California, Irvine, CA

Introduction: Peristalsis is an important physiological mechanism of various tubular structures such as bowel, ureter, fallopian tube and vas deferens. The process of peristalsis is affected by different patho-physiological conditions. We describe a novel method of studying the peristaltic activity of a small tubular structure, in this case the ureter, using a magnetic sensor that can be deployed laparoscopically in an extraluminal fashion. This technology can be used simultaneously with electromyographic (EMG) needle electrodes that measure electrical potentials.

Materials: The GMR (Giant Magneto Resistive) technology uses a magnet to create a magnetic field and a sensor, which is very sensitive to changes in the magnetic field, to accurately detect small movements of an object within a magnetic field. The technology is based on the giant magneto-resistive phenomenon first described in 1988 in the metallurgy literature. The GMR sensor allows measurement of displacements of an object in the linear, radial and rotational systems making it applicable for studying peristaltic activity. Modified insulated bipolar EMG ‘needle’ electrodes were used for recording ureteric action potentials.

Methods: Porcine ureteral peristaltic function was evaluated for studying the electro-mechanical activity of the ureter. The GMR device and EMG electrodes were deployed to simultaneously record the mechanical contractions and the electrical potentials of the ureter. These devices were deployed laparoscopically: with minimal disturbance to the ureter. The first set of EMG electrodes was placed on the proximal ureter just below the uretero-pelvic junction; the GMR sensor and the magnet were positioned on the surface of the ureter 3 cms. distal to the EMG electrodes. Next, 2 additional sets of EMG electrodes were placed 3 and 6 cms. distal to the GMR sensor. Signals depicting ureteral electro-mechanical activity were amplified and displayed synchronously on the oscilloscope. Recordings were correlated with direct laparoscopic visual observation of the ureter for peristalsis.

Results: We evaluated the GMR device on three ureters in three porcine models. After establishment of pneumoperitoneum and exposure of ureter, the mean times to deploy the GMR device and 3 pairs of EMG electrodes were 75 and 65 minutes respectively. The pigs were hydrated under basal standard intravenous infusion rate of 5mls. /lb./hour and the intraabdominal pressure was maintained between 10-12 mm. Hg. A peristaltic wave of contraction was seen in the pig ureter at an average of once every 26 seconds. A consistent correlation was found between laparoscopically observed ureteral peristalsis and the peristaltic signals picked up by the magnetic sensor. The electrical potentials generated just before the mechanical ureteric contractions were shown as rapid onset and restoration of bipolar deflections by the EMG electrodes. The mechanical contractions detected by the GMR sensor were depicted as unipolar upward deflections from the baseline with varying amplitude corresponding to the force of ureteric contraction. On forced diuresis the ureter was distended with urine with no visible peristaltic activity and there was no recordable electro-mechanical signal.

Conclusions: The GMR sensor provides a novel method for studying peristaltic activity of ureter in-vivo. It is sensitive, small, minimally invasive and can be deployed with little dissection of the structure under study. Magnetic sensor technology has the potential to facilitate the study of peristaltic activity in other tubular structures such as bowel, fallopian tube and perhaps even the vas deferens. It can potentially provide additional information regarding the impact of medications and intraluminal stents on ureteral physiology.

A novel device to prevent recurrent bacterial urinary tract
infection (RBUTI) in females with persistent vaginal voiding

Irving M. Bush, M.D., Linda Zielinski, R.N., Roland Williby, P.A.and Aaron Bush,
West Dundee, Illinois

With the recent increased resistance of E-coli to trimethoprim/sulfa methoxazole (<22%), and the effect of urine on bacterial adhesion and mucosal surface laminar flow we reviewed our 20-year experience with 543 non-cystocele RBUTI patients (ages 20-45) with persistent vaginal voiding.

A 4-month protocol utilizing a temporarily placed vaginal absorptive device before each voiding was completed by 174 RBUTI patients. After ruling out urethra stricture, neurogenic disturbances, bladder neck obstruction and partner’s prostatitis, 148 had 3 negative cultures post-protocol. 26 had persistent RBUTI. 65/148 stopped having vaginal voiding for at lease 4 additional months. This simple method supplemented with short term urinary antiseptic therapy, when indicated, is a better solution to RBUTI then continuous long-term antibiotics which temporizes the problem rather than solves it.

LOCAL RECURRENCE OF PROSTATE CANCER ( rPCa ) TREATED BY HIGH INTENSIVE FOCUSED ULTRASOUND (HIFU)

Objectives Biopsy proven rPCa after surgery (Ø> after 52m), radiation (Ø after 65m) or early hormonal ablation (:Øafter 32m) becomes an increasing problem because of poor (highly invasive and high sideeffect rate) therapeutic alternatives.

Methods In a prospective study of 69 patients with rPCa and increased PSA were treated with HIFU [ABLATHERM; EDAP -TMS] at 2.25/3.0 MHz and 5/4,5 sec/lesion. 24 had a previous history of radical surgery (S), 23 of radiation (R), 22 of hormonal ablation (HA) as primary failed therapy. Initial Gleason score >= 7 showed in 79,2% (S), 87,7% (R), and 63,6% (HA). The typically small volume tumors/prostates (S =Ø 4 cc, R= Æ 11 cc, HA=Ø 14 cc), visible in transrectal ultrasound (TRUS) were treated locally with HIFU through a rectal approach in a single session treatment. After treatment (Ø 35-92 min) discharge followed within 23 hours. All patients had a suprapubic urinary drainage (Ø 29 days). Follow up by PSA, biopsies, complaint score, was in month 1,3,6, 9, 12, 18, etc.

Results Biopsies (min 2 consecutive sextant sets) were cancer free in 66 %(S)/ 72,3% (R) and 70,6 % (HA). In the group which had been pretreated with HA one patient developed a fistula but we found no incontinence. In patients after radiation 5 fistulae (21,7%) and in 43,5% incontinence I°-II° occurred. After previous surgery we observed one fistula and in 33,3% incontinence I°-II°. The pretreatment PSA at 1,9 ng/ml(S), 8(R) and 14(HA) and decreased to PSANadir to 1,5 ng/ml(S), 1 (R) and 0 (HA). Follow up was 216 (S) / 32 (R) / 339 (HA) days.

Conclusions Transrectal HIFU was proven to be a successful method for the treatment of rPCa because of its minimal invasiveness and its single session tissue ablative character. Side effects differ according to number, period of time and type of local pre-treatment and have to be balanced against the classical therapeutic alternatives. Biopsy short term efficacy between 66-72% and last PSA values of 1(S), 2( R) and 1ng/ml (HA) after HIFU showed to be more than competitive.

USE OF THE CAVITRON ULTRASONIC SURGICAL ASPIRATOR
(CUSA) FOR LAPAROSCOPIC PARTIAL NEPHRECTOMY
IN A PORCINE MODEL

Stefan Corvin, Christoph Adam, Alfons Hofstetter
Department of Urology, Ludwig-Maximilians-Universitaet, Munich, Germany

Objectives. Partial nephrectomy is still one of the most challenging operations in urological laparoscopy. Control of hemorrhage is very difficult to achieve with laparoscopic techniques. In open surgery, the Cavitron Ultrasonic Surgical Aspirator (CUSA, Tyco Healthcare) has been shown to cut renal parenchyma selectively, avoiding damage of vascular structures or the collecting system. It was the aim of this study to evaluate whether the CUSA can provide a safe and effective laparoscopic partial nephrectomy.

Methods. Laparoscopic pole resections of the left or right kidney were performed in 6 pigs under general anesthesia. Following exposure of the kidney the renal capsule was incised by means of electrocautery. The CUSA was then used for dissection of the renal parenchyma. After complete circular dissection of the renal parenchyma the collecting system and central vessels were divided using an Endo-GIA. Hemostasis was achieved by electrocoagulation. 8 weeks later the animals were sacrificed and the kidneys were removed for clinical investigation.

Results. The operations were performed successfully in all animals without temporary ischemia. The CUSA allowed precise and effective tissue dissection without significant hemorrhage. Parenchymal vessels were coagulated selectively. The collecting system and central vessels remained intact and could be divided following application of the Endo-GIA. Mean operation time was 80±15 min. Urinary fistula or other complications were not seen postoperatively.

Conclusions. These experimental results demonstrate the suitability of the CUSA for a safe laparoscopic partial nephrectomy without temporary ischemia and with reduction of the operative trauma for the kidney. Based on own experiences with other techniques including electrocautery and laser technology for partial nephrectomy it can be concluded that the CUSA represents an interesting alternative to other techniques.

Financial support was provided by Tyco Healthcare, Toenisvorst, Germany and by the Friedrich-Baur-Foundation, Ludwig-Maximilians-Universitaet, Munich, Germany

Noninvasive Male Sterilization by Focused Ultrasound Ablation of the Epididymis: Thermal Measurements in a Canine Model

Nathaniel M. Fried, PhD1, William W. Roberts, MD¹, E. James Wright, MD1, Stephen B. Solomon, MD
^1,2Depts. of Urology¹ and Radiology², Johns Hopkins School of Medicine, Baltimore, MD

Introduction: Therapeutic focused ultrasound has previously been shown to thermally occlude the vas deferens and may offer a noninvasive, incisionless alternative to conventional surgical vasectomy. However, problems with skin burns and inconsistent vas occlusion have been encountered during preliminary animal studies. In this study we explore focused ultrasound ablation of the epididymis as an alternative anatomical target for noninvasive male sterilization. Experimental thermocouple temperature measurements were conducted to determine the optimal range of ablation parameters for thermal occlusion of the epididymis without skin burns.

Methods: A two-radian ultrasound transducer mounted on a plastic clip delivered 4 MHz ultrasound energy to the canine epididymis. Thermocouples placed in the epididymis, intradermally, and on the skin surface recorded temperatures during ablation. A wide range of ablation parameters were studied (Control, 3W/120s, 5W/90s, 7W/60s) on both the left and right testicles (n=2) in a total of four dogs.

Results: A large therapeutic window (Power = 3-5 W, SI = 0.8 – 1.4 W/cm2, Time = 60-120 s) exists over which thermal occlusion of the epididymis may be achieved without adverse effects (e.g. skin burns, testicular injury). Epididymis thermal occlusion rates measured 83 % (10/12) compared with 40 % (4/10) for vas ablation, while skin burn complications measured 0 % compared with 40 % for the vas, during preliminary animal studies.

Conclusions: The epididymis represents a larger target than the vas deferens for thermal occlusion, eliminating problems with co-location of the ultrasound focus within the target and skin burns. Future research will focus on conducting long-term, pre-clinical azoospermia studies to definitively confirm sterilization after focused ultrasound ablation of the vas and epididymis.

D. Frimberger(1), L. Kavoussi(2), C., A. Patriciu (2), D. Mazilu (2),
A. Hofstetter(1), R. Oberneder(1), D.Stoianovici(2)
1 Department of Urology, Klinikum Großhadern, Ludwig-Maximilians- Universität München
2 Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, USA

Purpose: The rapid development of laparoscopy in urology necessitates the training of specialists to warrant the high standard of patient care. Additionally continuos training is crucial, which not all resident programs can due to the high cost and the lack of patient numbers. Telementoring allows a specialist to assist an operation team in a variable distance by real time data communication over ISDN lines. For the first time a telerobotic surgery, using two robots was performed between the USA and Germany.

Methods and results: Two surgical robots, AESOP and the at the Johns Hopkins Hospital (JHH) developed PAKY+ RCM were used to perform a laparoscopic renal cyst removal at the University hospital of Großhadern in Munich. The hardware of the computer system utilizes Pentium III PCs and Zydacron boards (Zydacron, Inc., Manchester, N.H., USA) along with Video and Audio software for the communication. The telementor in Baltimore, USA was able to maneuver the robots from a distance of 8000 km via 8 ISDN lines (512kB). Additionally the Telementor was able to draw lines and arrows on the screen to suggest port sites or incision lines to the local team. Communication was managed by webcams and microphones. The telerobotic operation was performed without complications or system- and communication failures, respectively.

Conclusions: Telementoring enables physicians to work together online with specialists from distant centers. Next to the training experience, telemedicine can be used to consult specialists in emergency settings, or in situations where no experienced surgeon is available.

Mohamed A. Ghafar(2), Vlad Bargman(1) and Ihor S. Sawczuk(1,2),
(1)Hackensack University Medical Center, Hackensack, NJ and (2)
Columbia University, New York, NY

Introduction: Cryotherapeutic assisted partial nephrectomy may be a useful technique for the excision of intrarenal masses. The purpose of this study was to evaluate the technique and results of treating patients with localized renal masses by cryotherapeutic assisted partial nephrectomy.

Methods: Nineteen patients had cryotherapeutic assisted partial nephrectomy of 20 renal tumors ranging in size from 1.5 to 10 cm under intraoperative ultrasonographic guidance. Seventeen patients had tumors ranging from 1.5 to 9.3 cm and a normal contralateral kidney, 1 patient had a tumor (10 cm) and renal insufficiency, and 1 patient had hereditary bilateral tumors (Von Hippel?Lindau). Tumors were located at the upper (7), middle (5), lower (8) pole of the kidney and were biopsied before cryosurgery. All tumors were surgically removed during a single freezing technique using the ice ball as a guide for excision. Mean cryoablation time was 11 minutes for the single freezing

Results: There were no intraoperative complications. Cryosurgery was technically successful in all patients, and the ice ball was created up to 1 cm beyond the tumor edge. By resecting the frozen lesion, margins were easily discernable and allowed for intraparenchymal masses to be accessible to partial resection irrespective of location within the kidney. Mean surgical time was 162 minutes and blood loss averaged 312 ml. There was no difference between preoperative and postoperative creatinine (mean 0.93 mg/dl pre and mean 0.99 mg/dl post). No positive margins were encountered. Mean follow up was 11 months (range 2 to 20 months) and no recurrences have been detected. Pathology revealed 13 clear cell renal cancers, 2 chromophobe renal cancers, 3 oncocytomas and 2 angiomyolipomas.

Conclusions: Open cryotherapeutic, assisted partial nephrectomy is an alternative technique for facilitating excision of intracortical renal masses.

HOLMIUM LASER ENUCLEATION OF THE PROSTATE (HoLEP)
COMBINED WITH TRANSURETHRAL MECHANICAL
MORCELLATOIN IS SUPERIOR TO TURP FOR THE RELIEF
OF BLADDER OUTFLOW OBSTRUCTION (BOO).

Peter J Gilling, Katie M Kennett R.N., Andre Westenberg, Mark R Fraundorfer.
Tauranga Hospital, Tauranga, New Zealand.

Introduction: TURP has been considered the endoscopic standard for the relief of BOO due to Benign Prostatic Hyperplasia in the past. A true endoscopic enucleation which mimics Open Prostatectomy has been developed utilizing the Holmium Laser. A transurethral tissue morcellator has been developed to remove this tissue. Endoscopic resection (TURP) and Endoscopic enucleation and morcellation (HoLEP) are compared in a randomized trial.

Patients and Methods. 60 urodynamically obstructed patients with prostate volumes 40 -200 ml.were randomized. AUA scores, Qmax values, Pdet/Qmax, Schaffer grade, TRUS and Post-void residual (PVR) urine volumes were measured preoperatively and at 6 months postop. Intraoperative and perioperative values were also compared. Adverse events were assessed.

Results: The patients were well-matched for all preoperative parameters. More tissue was retrieved/removed by HoLEP and morcellation (40.4+/-5.7 vs. 24.7+/-3.4g, p<0.05) intra-operatively and the TRUS prostate volume at 6 months was significantly smaller at 6 months in the HoLEP group (28.4+/-1.8 vs. 45.4+/-4.4 ml) p<0.001. Catheter times and Hospital stay were significantly shorter in the HoLEP group. There was one transfusion in the TURP arm. At the 6 month mark the Pdet/Qmax values (20.8+/-2.8 vs. 38.5+/-2.7 cmH2O) and the Schaffer grade (0.2+/-0.09 vs. 1.2+/-0.2) were both significantly less (p<0.001) in the HoLEP group

Conclusions: HoLEP combined with mechanical morcellation removes more tissue than TURP and is superior to TURP for the relief of bladder outflow obstruction.

The Electrical Prostate Morcellator: An Alternative to Manual
Morcellation for Laparoscopic Nephrectomy Specimens?

Avrum I Jacobson, Robert Marcovich, Joel Patrick A. Aldana, Daniel Lowe,
Arthur D. Smith, and Benjamin R. Lee
Department of Urology, Long Island Jewish Medical Center, New Hyde Park, NY

Introduction and Objectives: Renal morcellation after laparoscopic nephrectomy has traditionally been performed with either the Cook high speed electrical laparoscopic morcellator (HSEL) or by manual morcellation. Manual morcellation is tedious and time consuming, and unforeseen morbidity has led to the removal of the HSEL from the market. A new safer method of morcellation would therefore be of great benefit to the laparoscopic urologist. This is the second study to investigate the use of the Coherent electrical prostate morcellator (EPM) for renal morcellation. In a previous study (Landman et al. Urology 56:677-681, 2000), morcellation was performed under external laparoscopic visualization. We hypothesized that direct vision from inside the sack may decrease the risk of perforation.

Methods: 30 porcine kidneys, divided into 3 groups of 10, were evaluated. All morcellation was performed inside a LapSacTM (Cook Urological), in a pelvic trainer. Group 1 underwent morcellation using the EPM in a fluid environment under direct vision. Group 2 underwent morcellation using the EPM in a fluid environment, monitored by laparoscopic vision outside the LapSac. Finally, Group 3 underwent manual morcellation with ring forceps. The groups were assessed for time of morcellation, size of fragments, and sac integrity.

Results: The mean morcellation time for the three groups respectively was 86.9, 47.1, and 15.1 minutes (p<0.0001). The mean fragment size was 0.011g, 0.015g, and 1.36g respectively. This was significantly different between the manual morcellation group and the EPM groups (p<0.001), but not between the two EPM groups (p=0.12). In Group 1, 1 pinhole perforation occurred; in Group 2, 9 perforations occurred (5 large and 4 pinhole); in Group 3, there were no perforations (p<0.001).

Conclusions: Despite use of the LapSac, which has been shown to be the most resistant retrieval systems (Rassweiler et al. J Endourol 12(4):325-333, 1998), a 90% perforation rate occurred in the external vision group. Although direct vision inside the LapSac does allow for safer use of the EPM for renal morcellation, the prohibitively long morcellation time would preclude its clinical use. As well, manual morcellation was superior to either EPM group in all categories.

Multiple Urethral Tubation (MUT) : A Continuing Dilatation
and Drainage for Benign Urethral Diseases

E. Macalalag, M. Macalalag, M. Cruz, E. Perez, A. Macalalag, L. Velarde

INTRODUCTION
The Multiple Urethral Tubation (MUT) or catheterization is an innovation by bundling together two or more catheters. It is effective in stenting the urethra, draining the urinary bladder and the peri-urethral gland secretion. The movement of individual catheters on each other and its bundle provides repeated and progressive dilatation. The spaces between catheters also provides adequate drainage of periurethral gland secretions.
MM
One large and one small French foley catheters are chosen for multiple urethral Tubation. These respective catheters are tied together in a parallel fashion using non-absorbable sutures. The summation of the two French sizes of catheter would equal a French size that would allow passage both catheters inserted together into the urethral lumen as the MUT (Multiple Urethral Tubation). Insertion of the bundled catheters of MUT (Multiple Urethral Tubation) is assisted by a mandarine urethral catheter guide which affords rigidity and control of insertion. Insertion is may be done under local,r spinal anesthesia and /or sedation. Multiple urethral Tubation are left indwellin for a range of three to fifteen days. After MUT removal, patients are followed up bimonthly then quarterly for monitoring of any obstructive symptoms. At 1 year post-operatively, Urethrogram is done.

RESULTS:
Out of 601 cases only 491 were complete for collation from treatment to a minimum follow up of 3 years. The diseases of the urethra were 278 strictures sub classified into: simple, complex and complicated; 28 Urethral injuries 102 Congenital anomalies 39 Fistula/sinus; 28 urethral stricture surgeries and 12 complicated strictures of irradiation, tuberculosis and post-infectious.
The over all success rate of MUT is 78% with the least of effective (50%) in irradiated and Tuberculous strictures. The 86% success for recurrent strictures and 80% for complex urethral strictures put this into the highly effective therapy. The 78% success on congenital anomalies even with pereneal hypospadia lessens the headache of management.
1.8% complication rate showing cases of epidydimo-orchitis, false passage, urethral injury, extravasation of urine.

Conclusion:
50% to 92% effectivity of MUT is attributed to the utility model to provide more adequate urinary drainage, periurethral glands drainage and washing; alingment of disease and injured urethra, reduction of edema and local instillation of medicine for a fast unimpaired healing and devoid of stricture recurrences. Urethral catheter with or without balloon, silk 2-0 or 3-0 are readily available, easy to assemble and inexpensive.

CULTURE OF PORCINE URINARY TRACT CELLS ON SMALL INTESTINAL SUBMUCOSA FOR TISSUE ENGINEERING APPLICATIONS.

R Marcovich, A Jacobson, J Aldana, BR Lee, L Kushner, and AD Smith.
Department of Urology, Long Island Jewish Medical Center, New Hyde Park, NY, USA

INTRODUCTION AND OBJECTIVES: Despite efforts to develop new materials for urinary tract replacement or augmentation, autologous bowel remains the only clinically available material currently suited to these tasks. Small intestinal submucosa (SIS) has been used experimentally in animals for bladder augmentation and ureteral segmental replacement, but has met with sub-optimal long-term success. Pre-seeding of SIS grafts with autologous urinary tract smooth muscle and epithelial cells grown in culture prior to implantation could potentially lead to a more favorable long-term outcome. In vitro characterization of human urinary tract cell growth has been previously described (Zhang et al., J Urol 164:928). However, in vivo application in humans would first require testing of this technique in a large animal model. The purpose of this study was to generate a muscle- and urothelium-lined SIS graft in a porcine model, for eventual use in experimental segmental urinary tract replacement in pigs.

MATERIALS AND METHODS: Ureteral and bladder tissue were surgically removed from 20-25 kg domestic female pigs. The urothelium was microdissected from the muscle, dissociated with collagenase 200 units/ml, and plated onto tissue culture flasks in keratinocyte serum-free medium (KSFM). The muscle was minced into 1 mm2 pieces and plated onto 100 mm2 tissue culture dishes in medium 199 (M199) with 20% fetal bovine serum (FBS). When cells were near confluence, they were dissociated from the growth vessels using a commercially available non-enzymatic dissociation solution. Muscle cells were seeded onto 3 cm x 10 cm strips of SIS placed in modified single-well tissue culture plates and, 24-48 hours later, the urothelial cells were seeded on top of the muscle cells. The graft cultures were then maintained in equal parts KSFM and M199/FBS for 4 weeks, then fixed in formalin. Grafts were processed for routine histology as well as for immunohistochemical staining for cytokeratin AE1/AE3 and smooth-muscle actin.

RESULTS: Although porcine urothelium proved quite susceptible to harvest-related injury and did not grow in KSFM as efficiently as human urothelium does, we were able to establish growth of porcine urothelial cells in culture. Porcine smooth muscle cells grew well in M199/FBS, but were often contaminated by residual epithelial cells, which also grew well in this media. A technique was therefore developed to select for growth of the muscle cells. Histological and immunohistochemical analysis of the cell-seeded grafts revealed the presence of a multilaminar myoepithelial structure distributed on the surface of the SIS graft, with muscle cell penetration into the SIS.

CONCLUSION: Although their in vitro characteristics differ to a degree from their human counterparts, porcine urothelial and smooth muscle cells can be grown in culture and on sheets of small intestinal submucosa. These grafts represent a first step towards tissue engineering applications in the porcine urinary tract.

RESIDUAL DNA IN BIOLOGICAL SLING MATERIALS:
A COMPARISON BETWEEN PO-TREATED BOVINE PERICARDIUM,
HUMAN DERMIS, SOLVENT-EXTRACTED AND
FREEZE-DRIED CADAVERIC FASCIA LATA

Daniel L. Mooradian, Amy Lambert, Robert Wonsetler and B. Nicholas Oray
Biovascular, Inc., St. Paul, MN

Purpose: The pubvaginal sling procedure has emerged as an effective surgical treatment for stress urinary incontinence. A variety of biological materials are currently used in this procedure, but the extent to which processing prior to sterilization and use succeeds in removing residual cellular material such as DNA remains unclear. In this report, we compare the levels of extractable DNA found in a novel non-crosslinked, propylene oxide (PO)-treated, acellular collagen matrix derived from bovine pericardium to biological sling materials currently in use.

Materials & Methods: Three (3) samples (10-25 mg) of four (4) biological sling materials: solvent-extracted cadaveric fascia lata (Suspendâ, Mentor, Inc.), freeze-dried cadaveric fascia lata (MTF, Musculoskeletal Transplant Foundation), Processed human dermis (Repliformä, Microvasive, Inc.) and PO-treated bovine pericardium (Veritasä Collagen Matrix, Bio-Vascular, Inc.) were rehydrated in PBS, pH 7.4, minced and then subjected to Proteinase K digestion at 55oC. Extracted DNA was then isolated on a nucleic acid binding column (Sigma #C-9471). Total DNA was quantitated spectrophotometrically at A260 and expressed as mg DNA/mg tissue. The ratio of absorbance at A260 and A280 was calculated to insure the quality of the DNA preparation (i.e. > 1.4).

Results: As seen in Table 1, the amount of DNA extracted from PO-treated pericardium was significantly lower – on a per milligram tissue basis - than that the amount extracted from each of the other materials tested. Indeed, freeze-dried fascia lata contained 5.73 times as much extractable DNA as did PO-treated pericardium. Solvent-extracted cadaveric fascia lata contained less extractable DNA than freeze-dried fascia lata, but 2.94 times as much as PO-treated pericardium. Finally, processed human dermis contained 4.16 times as much extractable DNA as did PO-treated pericardium.

Significantly different from PO-treated Pericardium, *p = 0.165, **p = 0.0001, ***p = 0.0007

Conclusions: These results confirm that Veritasä collagen matrix, a non-crosslinked, PO-treated bovine pericardium-derived sling material contains an exceptionally low level of extractable DNA when compared to a variety of biological sling materials currently in use.

BIPOLAR RADIOFREQUENCY (RF) ABLATION OF THE KIDNEY:
COMPARISON TO MONOPOLAR RF ABLATION
Stephen Y. Nakada, Travis J. Jerde, Thomas F. Warner, Andrew S. Wright,
Christopher D. Johnson, Dieter Haemmerich, Alan H. Rappe, David M. Mahvi, Fred T. Lee, Jr., Madison, WI.

Introduction: We report initial ex vivo and in vivo studies using bipolar RF ablation of porcine kidneys.

Methods: Ex vivo preparations of 10 porcine kidneys were perfused with continuous Ringer’s solution and treated with either 1) standard external grounded RF (n=3) or 2) bipolar RF ablation with 1 (n=2), 2 (n=3) or 3 (n=2) cm separation between the ground probe and the RF probe using a Model 30 RITA generator (RITA, Mountain View, CA). Gross and histologic assessments were made acutely. Target temperatures were 90°C for 8 minutes. The in vivo study utilized 4 domestic pigs treated with monopolar RF ablation of the lower pole of one kidney and bipolar RF with 12 mm separation between the probes of the contralateral lower pole kidney. Animals were harvested 48 hours later for gross and histologic assessments.

Results: Ex vivo studies revealed grossly monopolar lesions 1.5 cm in maximum diameter and 1.75 cm3 in volume. In comparison, bipolar lesions were 2.7 cm in maximum diameter and 10.3 cm3 in volume using 3 cm electrode separation. In vivo studies showed there were 2 distinct gross lesions using RF: a blanched lesion and a hemorrhagic lesion. Using bipolar RF, larger blanched lesions were achievable than with monopolar RF (2.80 cm3 vs. 1.63 cm3). Overall, the combination of blanched and hemorrhagic lesions were similar between monopolar and bipolar RF (5.01 vs. 5.31 cm3). Histologic assessment verified cell death in the blanched lesions.

Conclusions: Based on ex vivo data, bipolar RF can create larger lesions than with monopolar RF. Based on in vivo data, blanched lesions were associated with complete cell death and predominated when performing bipolar RF.

PHYSICAL AND BIOCHEMICAL CHARACTERIZATION OF A
NOVEL NON-CROSSLINKED, PROPYLENE OXIDE-TREATED
ACELLULAR COLLAGEN MATRIX: COMPARISON WITH
SOLVENT-EXTRACTED AND FREEZE-DRIED CADAVERIC FASCIA LATA

B. Nicholas Oray, Amy Lambert, Robert Wonsetler and D. L. Mooradian
Bio-Vascular, Inc., St. Paul, MN

Purpose: The pubvaginal sling procedure has emerged as an effective surgical treatment for stress urinary incontinence (SUI). The selection of materials for use in this procedure is complicated by uncertainty regarding the mechanical and biochemical demands placed on sling materials in vivo. In this report, we compare key physical and biochemical properties of a novel non-crosslinked, propylene oxide (PO)-treated, acellular collagen matrix derived from bovine pericardium to biological sling materials currently in use.

Materials & Methods: Six (6) samples of three (3) biological sling materials: solvent-extracted cadaveric fascia lata (Suspends®, Mentor, Inc.), freeze-dried cadaveric fascia lata (MTF, Musculoskeletal Transplant Foundation) and PO-treated bovine pericardium (Veritas^TM Collagen Matrix, Bio-Vascular, Inc.) were tested. Mechanical testing was performed on 3mm wide “dogbone” samples on a Chemdyne MC-1000 uniaxial tensile tester. Samples were loaded to failure (cross-head speed 5 mm/min), stress/strain curves were generated, and ultimate tensile strength (UTS) was calculated. Suture retention strength (cross-head speed 100 mm/min) was also measured.

Results: As seen in Table 1, Veritas^TM was thinner than each of the other materials tested. Mechanical testing revealed that the tensile strength of Veritas^TM was equivalent to that of both Suspend^TM and MTF fascia lata, but the suture retention strength of Veritas^TM was higher than either Suspend^TM or MTF fascia Lata.

Table1.

Sling Material	Thickness (mm)	Tensile Strength (MPa)	Suture Retention (g)
PO-treated Pericardium	0.590 ± 0.11	5.02 ± 3.2	900.7 ± 291.6
Solvent-Extracted FL	1.230 ± 0.45	4.27 ± 1.9	340.5 ± 51.7y *
Freeze-dried FL	0.720 ± 0.14	4.12 ± 3.1	584.2 ± 207.4g **

*Suture retention is significantly lower than PO-treated pericardium (p = 0.0009).
**Suture retention is significantly lower than PO-treated pericardium (p = 0.0275).

Conclusions: These results indicate that Veritas^TM, a non-crosslinked, PO-treated bovine pericardium-derived sling material is comparable to and in some instances stronger than products currently used in pubvaginal sling procedures.

SAFYRE: A NEW CONCEPT FOR ADJUSTABLE MINIMALLY INVASIVE
SLING FOR FEMALE URINARY STRESS INCONTINENCE.

Paulo Palma, Cassio Riccetto, Míriam Dambros, Marcelo Thiel, Viviane Herrmann, Nelson Netto Jr.
(University of Campinas – UNICAMP, Campinas, Brazil), Pedro Cortado,
Aparecida Pacetta (Unmiversity of São Paulo – USP, São Paulo, Brazil),
Omar Grossi (Buenos Aires, Argentina) Mario Paladini (Córdoba, Argentina).

INTRODUCTION AND OBJECTIVES: Safyre Sling is a new technique to create a support to mid-urethra, in order to restore the continence in women with stress urinary incontinence (SIU). Safyre consists of a polypropylene mesh that acts as a urethral support, held between two self-anchoring columns which are made of an implant grade polydimethylsiloxane polymer. These columns are the basis of the autofixing system, for minimum surgical damage of pelvic floor natural support structures. A specially designed insertion needle permits both suprapubic or transvaginal approach, according to the surgeon best skills, by changing the needle holder between it’s extremities.

METHODS: Two 0.5 cm transverse incisions are made close to the superior aspect of the pubic bone 5 cm apart. A longitudinal vaginal incision, 1.5 cm in length is made, starting 0.5 cm from the urethral meatus. Notice that this incision is not allowed to encroach on the bladder neck. Dissection is done to create a 1 cm tunnel lateral to the urethra for the introduction of the Safyre insertion needle. First, the needle is advanced through the vaginal tunnel until the perforation of pelvic floor at the level of the mid-urethra. Then, it is redirected against the back of pubic bone and advanced continuously to the benchmarks in the suprapubic area. Cystoscopy is performed to rule out bladder perforation. After the removal of the holder, Safyre Sling is attached to the needle and pulled out to the suprapubic area. The same maneuvers are repeated on the other side. The proper tension of the sling is adjusted maintaining a Metzenbaum pair of scissors between the urethra and the sling, to prevent undue tension. The extremities of the sling are cut and the Metzembaum scissors are removed. No further fixation is needed and the incisions are closed in the usual manner. An indwelling catheter is left in place overnight.

RESULTS: The initial results obtained in 33 patients have showed a cure rate of 97 %. One patient underwent a vaginal mobilization of the sling due to urinary retention. One patient had vaginal exposition of the sling that was removed. Suprapubic pain was notice in 3 patients.

CONCLUSIONS: This sling allows for postoperative adjustment under local anesthesia should it became necessary. It can become an alternative for restoring the urethral support, if the good short-term results prove to be long lasting.

SABRE SLING (SELF ANCHORING BIO REABSORBABLE):
A NEW MINIMALLY INVASIVE PROCEDURE, USING
BIODEGRADABLE URETHRAL SLING FOR TREATMENT
OF URINARY STRESS INCONTINENCE.

Paulo Palma, Cássio Riccetto, Míriam Dambros, Marcelo Thiel,
Viviane Herrmann, Nelson Rodrigues Netto Jr.
Division of Urology, University of Campinas – UNICAMP, São Paulo, Brazil.

INTRODUCTION AND OBJECTIVES: A new sling material is now available for surgical treatment of stress urinary incontinence (SUI). SABRE sling consists of copolymer of polylactictic acid (PLA) and polycaprolactone (PCL) that acts as a suburethral support. In this study, it is reported on the early outcomes with the SABRE sling for the treatment of SUI.

MATERIAL AND METHODS: Since March 2001 twenty women with proven stress incontinence underwent to a suburethral sling using SABRE sling. The mean patient age was 54 years. Valsalva leak point pressure (VLPP) showed urethral hypermobility in 46% (mean VLPP 68 cm H2O) and sphincteric intrinsic deficiency was diagnosed in 54% (mean VLPP 102 cm H2O). All the procedures were done under spinal anesthesia. The sling was applied through a 1cm longitudinal vaginal incision at midurethra using a specially designed insertion needle.

RESULTS: The mean follow up was 5 months. Of the 20 patients, 14 (70 %) were cured of stress incontinence and 3 (15%) reported significant improvement and 3 (15%) maintained the symptoms. Neither wound infection nor rejection was detected.

CONCLUSION: SABRE sling can become an alternative for restoring the suburethral support, but these early results warrant further evaluation.

Residual Gas Persists in the Collecting System
Following Percutaneous Nephrolithotomy

Joel Patrick A. Aldana MD, Benjamin R Lee MD, Won J Lee MD,
Robert Marcovich MD, Avrum I Jacobson, Arthur D Smith MD
Department of Urology and Radiology, Albert Einstein College of Medicine,
Long Island Jewish Medical Center, New Hyde Park, New York

Introduction and Objectives:
Presence of gas in the kidney following surgical procedures may represent renal abscess, xanthogranulomatous pyelonephritis, other infection or residual gas. The rate of gas absorption following percutaneous nephrolithotomy (PCNL) is unknown. We determined the presence or absence of gas in the renal collecting system 48 hours following percutaneous nephrolithotomy (PCNL) in this study.

Methods:
The study population consists of records of 100 consecutive patients who underwent a percutaneous nephrolithotomy due to stone disease from 1999-2000. Post-PCNL nephrostogram films were reviewed by two urologists, an attending and a fellow, and one attending uroradiologist who determined the presence or absence of air in the urinary tract and location.

Results:
The nephrostograms were routinely performed 48 hours after the percutaneous nephrolithotomy and all films of 100 patients were reviewed. Gas was detected in 98 out of 100 cases which appeared as gas pyelograms outlining the renal calyces. Out of the 98, 33 (34%) demonstrated gas in the upper calyx, 10 (10%) in the middle calyx, 12(13%) in the lower calyx, and 43 (44%) in more than 1 calyx. Gas was not detected in the renal parenchyma nor perirenal areas.

Conclusions:
Gas persists within the renal collecting system 48 hours after a percutaneous procedure. Prospective studies should be done in order to document the amount of time needed for complete resolution of gas within the collecting system.

Figure 1: Gas in the upper pole of the collecting system 48 hours after PCNL.

MODIFICATION OF THE BALISTIC LITHOTRIPTER

Dr. Daniel Porto and Dr. Javier Zeballos
Hospital Maciel, Departamento de Urologia, Montevideo, Uruguay

For the percutaneous lithotripsy procedure, we use a Storz Balistic Lithotripter. One of the problems we encounterd was when we introduced the probe of the lithotripter of about 3mm diameter, into the operating channel we sometimes could not hit the stone because the probe slipped past the stone.
We realized it was because the operating channel was much wider, therefore the probe was modified to enlarge the diameter of its tip to improve its performance during lithotripsy procedures.

HIGH INTENSITY FOCUSED ULTRASOUND ABLATION
OF THE VAS DEFERENS IN A CANINE MODEL

William W. Roberts, David Y. Chan, Nathaniel M. Fried, E. James Wright,
Theresa Nicol, Thomas W. Jarrett, Louis R. Kavoussi, Stephen B. Solomon
Brady Urological Institute and the Johns Hopkins Medical Institutions, Baltimore, Md

PURPOSE: High intensity focused ultrasound (HIFU) is an ablative technology capable of producing thermal coagulative necrosis of sub-surface structures without injuring intervening tissues. We assessed the feasibility of using HIFU to produce occlusion of the canine vas deferens.

MATERIALS AND METHODS: A tunable HIFU transducer was incorporated into a hand-held clip, specially designed to transcutaneously grasp the vas deferens. Slots within the jaws of the clip ensured that the vas deferens and HIFU target zone were properly co-located. Ten vasa were ablated using a range of power and time parameters. Two weeks after ablation, each vas, epididymis, and testis was surgically harvested en-bloc. Retrograde vasography was performed to assess vasal occlusion, followed by pathologic analysis.

RESULTS: HIFU occlusion of the vas deferens was confirmed in four specimens, ablated with parameters at the upper end of the parameter range, 2 of 2 vasa ablated with 7 Watts, 60 sec and 2 of 4 vasa ablated with 7 Watts, 30 sec. Histologic injury was seen in 8 of the 10 ablated specimens. Skin burns developed over four of the targeted vasa and were conservatively managed. Bilateral sham procedures in a control dog resulted in patent vasa and no associated skin burns.

CONCLUSIONS: We have demonstrated the feasibility of noninvasive, transcutaneous HIFU occlusion of the vas deferens with ablation powers at the upper end of the tested range (7 Watts). Modifications of the hand-held clip and optimization of ablation parameters will likely improve the success rate of this procedure. Refinement of this technology may provide a rapid, non-invasive alternative to conventional vasectomy.

PORCINE SMALL INTESTINAL SUBMUCOSA IMPLANTED AS
A PUBOVAGINAL SLING IN 115 FEMALE PATIENTS WITH STRESS
URINARY INCONTINENCE: A 3 YEAR SERIES EVALUATED
FOR DURABILITY OF THE RESULTS

Authors: Alvin B. Rutner, MD, Sari R. Levine, MD, John F. Schmaelzle, MD
Affiliation: El Camino Urology Group, Mt. View, CA

Processed porcine small intestinal submucosa (SIS) has been shown in pre-clinical studies to have innate and unique properties that could make it an ideal material for pubovaginal slings (PVS) for patients with stress urinary incontinence (SUI). Following surgical placement of the SIS graft, local host cells are induced to infiltrate into the graft biomaterial and replace it in approximately 90 days. During that time the acellular collagen graft remains non-allergic and biocompatible. It resists infection and initiates minimal tissue reaction.

In the 3 year period between 1-1-99 and 12-31-01, 115 consecutive women with type II and/or type III SUI underwent implantation of an SIS sling through a small anterior vaginal incision. The ends of the graft were secured to the inner surface of the pubic bone with small bone screws. Concurrent cystocele repairs were frequently reinforced with the same material. Patients were maintained on a Foley catheter until they were voiding satisfactorily (usually 1-7 days ) and were followed thereafter as an outpatient.

108/115 (94%) of the patients in this series have had an excellent result and remain relieved of their SUI. Only 7 patients are classified as failed as follows:

Advances in lithotripsy with a frequency-doubled dual-pulse Nd:
YAG laser (FREDDY)

Authors: Christian Tischer, MD
Affiliation: World of Medicine USA, Inc., 4531 36th Street,
Orlando, FL 32811, phone (407) 246-7084, email christian.tischer@womcorp.com

The use of laser technology in urology has increased tremendously over the past ten years. Today laser equipment has become a routinely used tool in many endourology suites. Indications include intracorporal lithotripsy, which accounts for the majority of laser uses in the urology practice, as well as tumor resection, stricture treatment and BPH.
Since the mid 1980s a variety of different lasers were investigated for the treatment of urinary calculi, a condition affecting approximately one out of ten people throughout their lifetime.
An innovative technology that is utilized in a new shockwave lithotripsy laser is presented. It is based on a Nd:YAG solid state laser that emits at 1064 nm which is partially frequency doubled to 532 nm by a KTP and simultaneously applied to the stone. The introduction of a 50 meter intracavity fiber into the resonator allows for a pulse duration of 1.2 microseconds resulting in high peak power and low mean power outputs. Unlike thermal lasers the FREDDY laser (Frequency-doubled dual-pulse Nd:YAG) fragments calculi with shockwaves that are created at the distal tip of the laser fiber in contact mode (also referred to as the photoacoustic effect by plasma formation). This results in very rapid fragmentation, especially noticeable for large calculi such as bladder stones.
Due to low absorption of green light by soft tissue the FREDDY laser demonstrates a high level of ‘intrinsic safety’, virtually eliminating the risk of perforation.
Clinical data and cases performed from Winterpark Urology at Florida Hospital Kidney Stone Center will be presented.

INITIAL HUMAN STUDIES WITH A NEW DEVICE FOR THE
MANAGEMENT OF URINE INCONTINENCE
(Followup of a concept presented during the 16th SUE)

Daniel Yachia, MD
Department of Urology. Hillel Yaffe Medical Centre. Hadera - Israel
Bruce Rappaport Medical School. Technion - Israel Institute of Technology. Haifa - Israel

INTRODUCTION : Urinary incontinence (Ul) is one of the major social and medical problems affecting about 40 million adults of both sexes in the Western world. From diapers to vaginal pessaries, from surgery to bulking injectables, to intraurethral plug-like devices are currently being used for the management of (UI). Although some of the surgical techniques are successful in the treatment of stress incontinence, about 50% of the patients need re-treatment after 5 to 7 years. Intraurethral plug-like devices which were introduced during the last years can mechanically block the involuntary leaking in female patients. However, these devices by being positioned in the urethra caused a communication between the bladder and the vulva, resulting in very high rates of ascending urinary infections.

METHODS : In order to block the bladder outlet (BO) in both sexes and open it voluntarily for voiding a family of intra-vesical devices were designed. The in-vitro and animal study results were presented a year ago. From the 3 device designs presented a year ago 1 was found to be most comfortable to the patient and successful in preventing urine leakage. The device was inserted very easily and was retrieved as easily. It was activated voluntarily using a small magnet placed in the underwear.

RESULTS : The device was left in the bladder up to 29 days in 20 patients. In 70% of the patients the device could occlude the BO completely (0 to 3 gr. in pad weight test). 10% reported significant improvement (1 pad per day instead of 4-7 a day). 20% of the patients could not tolerate the feeling of a foreign body in their bladder. The BO could be opened by removing the magnet situated in the underwear. Voiding measured by uroflow was unobstructed. Device related UTI developed in 15% of the patients.

CONCLUSIONS : The use of an entirely intravesical device for the management of incontinence is a novel approach. The initial clinical studies showed that this device is safe and effective in the management of UI. The device is in its final stages of development and large scale clinical studies will commence in the near future.

SOLO SURGERY : VIDEO-ASSISTED MINILAPAROTOMY RADICAL NEPHRECTOMY - THE INITIAL CASE REPORT

Authors: Seung Choul Yang, Koon Ho Rha, Jin Won Jung, Duck Hyung Kwon, Jae Wook Kim
Affiliation: Department of Urology, Yonsei University, Seoul, Korea

Introduction and Objectives:
Recently more interest in minimally invasive procedures with intent of reducing manpower has occurred. Based on the experience with minilaparotomy nephrectomies(J Urol 165(4): 1099-1102, 2001), we have successfully performed a first solo radical nephrectomy using a newly developed retractor system.

Methods:
A 3.5 cm sized heterogenous enhancing mass on lateral aspect of left kidney midportion was noted on CT in a 40 year old man. He weighed 63 kg and was 157 cm tall. On lateral decubitus position, a 8 cm sized incision was made on the pararectal area at the tip of 10th rib and using specially developed retractor system (Thompson Surgical Instruments Inc, USA), the abdominal wall was elevated and peritoneal contents were pushed medially to secure operative space. Telescopic monitoring was done by laparoscopic holding device, avoiding the use of an assistant. Procedure was performed via minilaparotomy under both direct vision and video monitoring. The kidney and enveloping Gerota's fascia was dissected intact and specimen was delivered using entrapment bag via minilarotomy incision.

Results:
The oepative time was 2 hours and 20 minutes, and blood loss was 300 cc. Oral intake resumed 18 hours after surgery. One dose of morphine sulfate (4 mg) was given intravenously 5 hours after the procedure. The patient was discharged on the porstoperative day 5.

Conclusions:
Solo surgery (radical nephrectomy) utilizing minilaparotomy using video-assistance and retractor system has been successfully performed. We believe this minimally invasive technique with the elimination of surgical assistant has broad implications that go well beyond the urological realm.

PROPERTIES OF UROMAX™ BALLOON DILATORS

*Yohannes P., Lee B.R., Smith A.D.
New Hyde Park, New York; *Omaha, Nebraska, USA.

Objectives: To evaluate the properties of Uromax™ balloon dilators.

Materials and Methods: The surface friction and repeatability of radial force generated were tested in an in vitro model using Uromax (7 mm and 9 mm) balloon dilators. The force of insertion was defined as the force required to push the balloon through a percuflex conduit that represented an in vitro model of the ureter. Surface friction was measured through the percuflex tubing with and without an external restrictive force using a Digital Force Gauge™ (Ametek®, Largo, FL). The balloon was dilated at 20 atm P (7 mm balloon dilator) to 17 atm P (9 mm balloon dilator) for 60 seconds between each pass. The radial force generated by the two sizes was measured using the Instron™ (Instron Ltd., Canton, MA). The radial force was measured after three to eight cycles. In addition, changes in the outer diameter of the balloon dilator after multiple inflation/deflation cycles was assessed using the Laser Mike 183™ (Dayton, OH).

Results: The force of insertion (lbs.) of the non-conformed balloon dilator after deflation was significantly greater (0 lbs. vs. 0.55 lbs.) than the conformed balloon (0 lbs vs. 0.02 lbs.). Similarly, the force of insertion through a percuflex tubing with external compression (¯ 20% OD) showed significant difference between first time insertion after removal of the wing tool and non-conformed balloon (0.24 lbs. vs. 0.40 lbs.). After three cycles of balloon dilatation, the radial force did not significantly change (0.51 vs. 0.48 lbs./force for 21 F, and 2.08 vs. 2.48 lbs./force for 27 F). In addition, the outer diameter of the balloon increased after repeat cycles (p<0.001).

Conclusion: Reconforming the uromax balloon using the wing tool can help maintain a constant level of low surface friction. The balloon diameter and radial force generated by the balloon do not change with repeat dilatations at constant pressure.

HYDRO-EXPANDING DEVICES FOR ENDOUROLOGY

Dr. Javier Zeballos and Dr. Daniel Porto
Maciel Hospital, Department of Urology, Montevideo, Uruguay

The use of the new plyuretanic materials (PU) could make possible the production and design of new multiple hydro-expanding devices to be used with the present endourological techniques. This could open new trends of research and the creation of devices for a progressive slower dilatation of the urinary tract and stent that would facilitate the endourological access
with lower morbility.
Kidney acces percutaneous devices, catheters, guides, made of PU which slowly expand absorbing water (within 24 - 48 hs.) up to twenty times its size, could be suitable for urethral acces, uretheric access, for the treatment of stenosis or stones, and for kidney percutaneous techniques.
This is important since small diameter devices can be introduced in the urinary tract , causing a slower dilatation in 24-48 hs which increases the size in the tract so as to introduce endoscopic instruments in a less traumatic way with better results.
The material we are proposing was tested at LATU (Technological Laboratory of Uruguay) with FTIR, ITR.PLA.217 and is now being evaluated in different aspects: