ABSTRACTS -Fourteenth Annual Meeting

Saturday, May 1, 1999
Dallas, Texas

TECERADIOLOGY IN UROLOGY: EFFECT OF VARYING COMPRESSION ALGORITHMS ON CLINICAL DECISION MAKING.

Benjamin R. Lee, *Michael D. Fabrizio, Jomo Smith,Rich Tempel, Thomas W. Jarrett, David Chan and Louis R. Kavoussi, James Buchanan Brady Urological Institute Bayview Medical Center Baltimore, MD.

Teleradiology is the electronic transmission of radiographic images from one site to another. This technology has the ability to allow expert radiaologic consultation to remote and underserved areas when the attending radiologist is not available at the examination site. A study was performed to assess the effect of different compression algorithms (80:1, 60:1, 40:1, 20:1, uncompressed) and whether teleradiology imported studies convey information to make relevant clinical decisions involving urology.

We evaluated 495 radiographs comprising 50 intravenous pyelograms compressed at five different ratios 80:1 60:1, 40:1, 20:1 and uncompressed. Average size of scout film (KUB) was 10.4 Megabytes of information. Digitized images were transferred to an Ethernet Network. Digitized images were then uncompressed on the remote end, viewed by urologists, and graded according to confidence in making a diagnosis, image quality, diagnostic decisions reassessed. All analog radiographs were reviewed by an attending racliologist

Overall, diagnostic quality of transmitted radiographs were equivalent to analog radiographs. Viewing radio graphs transmitted to a PC-based viewing station is aan appropriate means of reviewing films with sufficient quality to base clinical decision.



A NEW AUTOMATED SYSTEM FOR URINALYSIS: A SIMPLE, COST EFFECTIVE AND RELIABLE METHOD DISTINGUISHING BETWEEN A GLOMERULAR AND NON-GLOMERULAR SOURCE OF HAEMATURIA.


Mr. R. N. Kore, Dr. C. S. Dow Mr. K.M.Desai Department of Urology, WaIsgrave Hospital, Coventry Department of Biological Sciences, University of Warwick

We present a new apparatus of auto-analysis of urine to detect the source of red blood cells in patients with haematuria. A specially designed software overcomes the difficulties faced by the coulter method. The differentiation of cell into glomerular and non-glomerular types by measuring cell-size makes it objective and hence much more accurate than phase contrast microscopy. The analysis is simple, less labour intensive and takes only 30 seconds per sample, automaticity and low consumable cost make it cost effective.

OBJECTIVES: The investigation and management of haematuria forms a major part of urological practice. Detecting the source of red blood cells in urine of the outset would, greatly assist in selecting apropriate further investigations.

We describe a simple and rapid method of differentiating these cells into gIomerulor and non-glomerular types to deduce their site of origin. We also compare its efficacy with phase contrast microscopy.

MATERIALS AND METHODS: One hundred and six urine samples from patients with known diagnoses were analyzed by Microbial Systems' cellfacts; analyzer. A dipstick examination was performed on all the specimens. Phase contrast microscopic examination was done for comparison on 45 urine specimens. The results of cellfacts analysis were correlated with the diagnoses to assess sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of this method. A cost analysis was also carried out.

RESULTS: Sixty-nine urine samples were positive for red blood cells using both cellfacts; and dip stick analysis Out of the 37 patients with negative analysis seven had been referred with previously defected microscopic haematuria but were found to have no detectable pathology in the urinary tract on clinical examination and investigations. The remaining 30 patients were diagnosed to have urological or nephrological conditions without haematuria. In the positive group twenty (29%) patients were from glomerular group with the red blood cell size ranginbg from 4 to 5.1 micron (average 4.25) and forty nine (71 %) from the non-glomerular group with a range of 4.67 to 5.70 micron(average 5.47). The overlap zone was from 4.67 to 5.1 micron. At the decision level (cutoff point) of 4.75 micron the distribution of dysmorphic and eumorphic red blood cells for glomerular and non-glomerular specimens was 18(90%), 2(10%) and 2(4%). 47(96%) respectively. The sensitivity, specificity, positive predictive value (PPV) and negative predictive (NPV) 90.0, 95.9, 90.0 and 95.9 respectively. Cost analysis showed significantly low consumable and labour costs.

CONCLUSIONS: Cellfacts analysis is a simple rapid, objective and cost effective method for glomerular/ non glomerular differentiation of urinary red Wood cells especially when a low number of such cells are present.



MANAGEMENT OF VOIDING DYSFUNCTION WITH TRANSCUTANEOUS ELECTROSTIMULATION

Ian. K. Walsh, Patrick F. Keane, Robin Johnston and Gordon WG Loughridge,
Department of Urology Level 3, Belfast City Hospital, Belfast, Northern Ireland


Patients with refractory irritative voiding dysfunction are encountered frequently in urological practice. Current neuromodulotory approaches are effective but invasive. To follow up our previous cystometric studies, we now report our clinical experience in treating such patients with third sacral transcutaneous neurostimulation (S3TENS). 45 patients (41 female, 4 male; 37 sensory urgency, 5 detrusor instability, 3 interstitial cystitis; mean age 49 y) participated. Mean symptom duration was 13.6 years. The patients were refractory to an average of three standard treatment modalities (e.g. bladder drill, anticholinergic therapy, hydrostatic dilatation) Transcutaneous current was applied via the bilateral S3 dermatomes of frequency 10Hz pulse width 200ms, at he maximum tolerable level during waking hours for one week. Throughout ambulatory treatment, each patient completed a voiding-diary. Urgency and bladder pain were scored an a visual analogue scale. Data was collected of treatment completion and 36 patients (80%) reported an improvement in their daytime frequency (p= 0.001). 27(60%)noticed a reduction of nocturia (p = 0.001). 34 (76%) reported an improvement in urgency (p = 0.002). Of the 7 patients with bladder pain, 5 (71%) found this to be less severe, pain being abolished in two patients (p = 0.001). Responsive patients continue with long term, intermittent ambulatory treatment. S3TENS appears effective as a noninvasive, ambulatory treatment option. for patients with irritative voiding dysfunction refractory to conventional therapy.


ROBOTIC TELESURGERY: ROLE OF TIME DELAY ON SURGICAL PERFORMANCE

Benjamin R., Stoianovici, Man Kay Li, Peter Goh. Calvin Yang,
Michael D. Fabrizio, Alan W Partin and Louis R. Kavoussi,
Johns Hopkins-Singapore/Nofional University Hospital, Singapore;
James Buchanan Brady Urological lnstitute, Baltimore


Telesurgery ia an advanced form of telemedicine whereby high bandwidth telecommunication lines are used to remote procedures. Inherent in the transfer. of information several thousand miles is the time delay difference. From Italy to Baltimore, Maryland is a time delay difference of 140 msec using a regular telephone line (POTS). Robots can precisely perform accurate manipulations. As surgical robots are integrated into telesurgical systems, the effect of time delay may present a significant challenge. Our objective was to determine the effect of increasing increments of time delay on task performance.

Custom software was developed to program incremental time delays on a video frame grebber board (UltraII,Coreco, Inc., Quebec, Canada) between camera image acquisition and video display. A communications interface was integrated between a robot controller and the end effector robotic arm (PAKY-RCM, Johns Hopkins Hospital. Urobotics lab and AESOP 1000, Computer Motion Inc., Goleta, CA). A series of tasks were performed using variable time delays between real time (0 msed and 1000 msec. Accuracy was measured as a function of errors and posses. Time delays greater than 700 msec may not allow sufficient accuracy to perform remote robotic surgical procedures.



NONLINEAR CLASSIFICATION METHODS AND TISSUE - TYPE IMAGING FOR DIFFERENTIATING CANCEROUS PROSTATE TISSUE FROM NONCANCEROUS PROSTATE TISSUE


Feleppa EJ, Fair WR, Tsai H, Porter C, Balaji KC, Manolakis D, Liu T", Lee P, Kalisz A, Rosado A , Reuter V, Moul J, Sesterhenn I, Riverside Research Institute, New York. Memorial Sloan-Kettering Cancer Center, Now York, Walter Reed Army Medical Center, Washington, DC; Armed Forces Institute of Pathology, Washington, DC

OBJECTIVE: Our objective is to improve ultrasonic imaging methods for guiding prostate biopsies and for evaluating defected cancers. METHODS: We acquire ultrasonic radio-frequency (RF) echo signals in the scan planes used to guide TRUS-guided biopsies, and we correlate average power spectra of signals from the biopsied tissue with histological determinations of tissue type. (Our data base contains records for over 300 patients and 2,000 biopsies.) We also acquire RF data from prostate glands immediately prior to radical prostatectomy, and perform correlations over the entire gland volume. We then apply and test non-linear methods of classification, including nearest-neighbor and neural-net techniques for differentiating cancerous from non-cancerous tissue based on values of spectral parameters and clinical variables. (Leave-one-out and randomly selected training and testing methods provide our means of performance assessment.) These classification tools provide tissue-typing values that we display in 2-D and 3-D images.

RESULTS: Previous, results produced ROC-curve areas of 0.75 for nearest-neighbor methods vs. 0.58 for TRUS. Current results suggest neural-net classifiers can provide excellent classification accuracy, e.g., 93.8% for learning-vector quantization. CONCLUSION: Our results sugget that future real-time 2-D imaging and off-line 3-D imaging based on non-linear tissues classifiers could vastly improve the detection and evaluaition of prostate cancer.



IN VIVO COMPARISON OF TENSTILE STRENGTH OF THREE SYNTHETIC MATERIALS AND CADAVERIC FASCIA LATA.

Marlene Carujo Leslie Kushner, Tawfiquil Bhuiya, and Gopal H. Badlani,
New Hyde Park, NY



INTRODUCTION AND OBJECTIVES: Pubovaginal slings for stress urinary incontinence can be constructed of fascia or synthetic materials. Synthetic materials offer an advantage over fascia because of its consistent strength, availability and resistance to enzymatic degradation. The goal of this study was to demonstrate fibroblast ingrowth and collagen deposition in 3 different synthetic materials (ProteGenTM , Prolene and Gore-tex(R) and cadaveric fascia lata and to implantation into the weight bearing abdominal wall fascia of a pig.

METHODS: Materials (2 x 1cm) were soaked in 5,000 units/cc of bacitracin prior to implantation into the abdominal wall fascia of each of 3 pigs (35 kg) Materials were attached with 6 prolene sutures and irrigated with bacitracin solution. The skin was closed received intravenous penicillin pre-op and for 24 hours post-op. At 6 weeks, the materials were retrieved and divided in half. Tensile strenght was recorded on one half using the Intron Tensiometer with a crosshead speed of second fixed, paraffin embedded, sectioned slide mounted and stained with H/E and Trichrome.

RESULTS: The mean load (to break material) after 6 weeks of implantation for ProteGenTM , Prolene and Gore-tex(R) and cadaveric fascia Iota was 12.07, 7.07, 5.35 and 1.89 kgf with a displacement of 5.00, 5.20 4.64 and 4.13mm, respectively. Histochemical analysis revealed a lymphohistocytic reaction with all materials which was greatest with ProteGenTM. Giant cell reaction was seen in all materials except Gore-tex(R). Eosinophils were markedly increased with ProteGenTM but mild with both Prolene and cadaveric fascia Iata and absent with Gore-tex(R).

CONCLUSION: Fibroblast infiltration and collagen deposition was present in all materials at 6 weeks. tenstle strength followed the rank order of ProteGenTM > Gore-tex(R) .Prolene >cadaveric fascia lata.

SOURCE OF FUNDING: Microinvasive/Boston Scientific Corp.



A LIGHT-GUIDE NEEDLE FOR SUBURETERIC INJECTION OF MATERIALS TO TREAT VESICOURETERAL REFLUX (VUR).


Kazuhiro Ishizaka, Hideki Nagamatsu, Masao Ando, and Hiroyuki 0shima,
Department of Urology, Tokio Medical and
Dental University School of Medicine, Tokyo, Japan



INTRODUCTION: Subureteric injection therapy is an alternative to treat VUR The popular procedure is performed with cystoscopic injection needle which is introduced through bladder mucosa, although extrusion of injected materials from the puncture hole is a problem. Transperineal or transvaginal approach could be an alternative to avoid mucosal perforation, but the technique is more difficult. We have developed a light-guide needle to make the needle tip placement easier. We have used autologous fattissue as an injected material because it is safe and inexpensive. Fat tissue is for more susceptible to escape from the mucosal hole. Collagens have been authorized to use for only the treatment of incontinence in Japan. Further, we sometimes observe positive skin test.

A LIGHT-GUIDE NEEDLE: The needle is 14G in diameter and 10cm in lenght. Optical fibers were attached to the needle around the inner lumen to light up the tip. The inner diameter can be as larger 18G because a large diameter of internal lumen is supposed to be better to minimize the damage of adipose cells. The end of lumen is connected to be to infuse fat tissue from the syringe.

INJECTION TECHNIQUE: Patients were placed in lithotomy position under spinal anesthesia. The autologous fat tissue was harvested with 20ml syringe and a 15 gauge needle from the subcutaneous tissue in the lower abdomen. Cystoscopy was performed and the ureteral orifices were observed. The light guided needle was inserted from the perineum (in children) or from the vagina (in adults) and progressed toward the submucosa between the ureteral orifice and the internal urethral meatus under cystoscopic observation. When the tip of the needle reaches the submucosa, you can see the light through the mucosa. Tjhe needle was advanced under observation of the light of the tip until it got to subureteric position. The injection was terminated when a submetal bulge and an inverted crescentic appearance of the ureteral orifice were observed. Usually about 10ml of fat tissue was injected. The reflux status was determined by voiding cystourethrography several days after the procedure.

RESULTS We have treated 7 ureters including 4 grade III secondary VUR by lipoinjection with the light-guide needle. VUR was disappeared in 5 ureters at least temporarily.

COMMENTS: The light of the tip was visible throughout the mucosa and was effective guide for placement. This procedure has resolved the problem of extrusion through the puncture hole. The light-quided needle, is applicable to injection of other materials such as collagen which can be delivered with thinner needle.



THE ABLATION OF PROSTATE TISSUE USING THERMAL RODS.

Robert D. Tucker, University of Iowa ,Iowa City, IA; Christian Huidobro,
University of Chile, Santiago, Chile; Thayne Larson, Mayo Clinic, Scottsdale, AZ Eugene V. Kramolowsky, Virginia Urology Center, Richmond, VA


We are developing a system for the thermal treatment of prostate cancer in which tissue temperatures are elevated to levels greater than 460C. The system utilizes thermal rods, percutaneously implanted by a procedure analogous to brachytherapy seeds. The rods, a magnetic alloy of cobalt and palladium, are 1 mm diameter and 14 mm long. When placed within +/- 300C of parallel to an alternating radio frequency magnetic field of approximately 75 gauss, the rods heat by induced eddy current. As they heat, they reach a temperature at which they undergo a transition from being magnetic to non-magnetic and stop heating. This transition point, the Curie temperature, makes the rods temperature self-regulating. The Curie point is preprogrammed at manufacture and can be controlled to within 10C. Each rod is capable of ablating approximately I to 2 cc of tissue at temperatures greater than 480C. The rods are permanent, biocompatible implants, which makes the procedure attractive for retreatment in an outpatient setting.

In an ongoing clinical protocol in Santiago, patients with localized prostate cancer scheduled for radical prostatectomy (RP) have thermal rods with regulation temperatures of 55, 60, and 700C implanted parallel to the urethra. The magnetic field is created by a 50 kHz power supply that drives a coil placed under a chair. Following implantation, the patient is positioned in the chair with the rods parallel to the magnetic field for one-hour thermal treatments. Approximately two weeks after thermal treatments, a RP is performed. The prostate is then sectioned with the rods in place to document thermal destruction. This data is used to determine rod placement, treatment time and the number of treatments to ensure adequate tissue destruction without damage to the urethra.



TEL-LOC: ALTERNATIVE NOVEL DEVICE FOR REPLACEMENT OF INTRACORPOREAL SUTURE KNOTYING.


Charles A. Steiger, Yegoppon Lokshmanon, Leo C. T. Fung,
University of Massachusetts Memorial Health Care Worcester, MA


INTRODUCTION: Intracorporeal suture knot-tying can significantly compromise the success of laparoscopic surgery. Suture holding strength of available devices remains a significant problem. An alternative device has been developed that can be conveniently loaded intracorporeally. It offers superior suture holding strength. This device was compared to the Lapa-Ty (Ethicon, Somerville,NJ) and to the 2+1+1 hand tied knots hand tied knots.

MATERIALS AND METHODS: A Tel-Loc prototype composed of Deliron polymer, measures 0.122"O.D. by 0.150" length. It consists of a C-shaped inner core. The device outer core is deployed through a trigger mechanism locking the sutures in place. Sutures united by Tel-Loc, Lapra-Ty, and 2+1+1 hand tied knot were progressively stressed and the maximal load tolerated wes recorded.

RESULTS: mean peak failure load for the Lapra-Ty was 1.91 +/- 0.34 lb., failure occurred by knot slippage. The 2+1+1 hand tied knot failure load was 10.62 +/- 0.78 lb., failure occurred at the knot. The Tel-loc tolerated a load of 12.47 +/- 0.91 lb., failure occurred at the suture-device interface. There was one instance of the slipping out of the device.

CONCLUSION: The data suggests that the Tel-Loc prototype is superior in holding strength compared to the Lapra-Ty and the 2+1+1 hand-tied suture knot. The Tel-Loc holds the potential to successfully incorporate excelent , suture holding strength and the ability to be loaded intracorporeally. This provides an attractive alternative to currently available laparoscopic suture tying methods



BIODEGRADABLE POLYLACTIDES: IN-VITRO TESTING SPECIFIC FOR THE URINARY TRACT AND COMPARATIVE ANALYSIS OF VARIOUS SURFACE MODIFICATIONS.


Andreas Brauers, Peter K. Jung, A. Mersdorf Doris Rohrmann, and Gerhard Jakse, Aachen, Germany

INTRODUCTION AND OBJECTIVES: We present concerning grafting of lactid copolymers with Hydroxyethylmethacrylate (HEMA) and Oligoethylenoxid-methacrylate (OEOMA) in the development of urological devices such (is ureteric stents and scaffolds.

METHODS: The polymers used were poly (D,L-lactide) PDLLA and poly(D,L-lactide-co-TMC) PDLLA-co-TMC Boehringer, Germany. Polymers were treated by argon plasma, grafted by plasma induced graft-copolymerization with HEMA and OEOMA monomer and investigated by contact-angle measurements (CA) and X-ray photoelectron spectroscopy (XPS). Human urothelial primary cultures were characterized by immunostaining with monoclonal anti-vimentin and anti-cytokeratin 18 antibody and used to evaluate biocompatibility of the polymers following contact to the tested biornaterials. Brc1U- and XTT-test were performed to measure proliferation of RT112 and human urolhelial cells following biornaterial contact. Cell adhesion experiments were performed using quantitative morphometric analysis.

RESULTS: CA and XPS measurement verified successful grafting of HEMA and OEOMA on the polymer. Monomer grafting lead to reduced contact angles and cell adhesion while biocompatibility was not affected. Degradation of the grafted polymers did not affect contact angle measurement. CONCLUSIONS: Surface modification is an effective approach to improve properties of biodegradable materials, which are going to be used as ureteric stents or scaffolds.



A STEADY POSITIONING SYSTEM FOR SURGICAL INSTRUMENTATION.


Grey Lernerer,Dan Stoianovici, Ph.D., Louis L. Whitcomb, Ph.D., Louis R. Kavoussi, M.D.

New surgical procedures use instruments that need to be steadily positioned over the patient. Such devices are often heavy and cumbersome, can not be hand-held thus requiring a supporting arm. We present a mechanical linkage for positioning and supporting such devices in the operating field. Several positioning devices are commercially available for supporting surgical instruments. Shortcomings of all currently available devices are low carrying capacity, low stiffness, and sometimes the inability to fully lock from a single control. A new positioning arm that eliminates these deficiencies is presently under development at our Institution. This arm comprises two links connected by three joints. A connecting mechanism attaches the arm to custom designed sturdy rails on the operating room table. The joints from the proximal to distal ends are spherical-cylindrical-spherical. The spherical joint at the base has been constrained eliminating one rotational degree of freedom such that the overall mechanism presents six degrees of freedom. This eases maneuverability by uniquely defining the configuration of the device for a given end-effector position. The joints are normally locked and may be simultaneously released. All joints are equipped with mechanical brakes. A novel transmis sion mechanism that distributes the braking force to all joints from a single electrical actuator has been designed and implemented. A single button controls the lock/unlock mechanism. The distal end of the arm presents a connector that can be easily customized for accommodating various end-effector instruments. The working envelope is hemispherical with the radius of 400mm. This relatively short geometry increases the rigidity of the arm.

Initial experiments with the new arm demonstrate promising characteristics. The arm exhibits a holding capacity of up to 10 Kg in its most extended position. The arm is highly rigid presenting minimal deflection under maximum-,- payload. In the unlocked mode the arm presents minimal static friction. The arm provides a safe and comfortable platform for novel surgical devices requiring steady surgical positioning.



QUANTIFICATION OF COMPLIANCE AND PHASIC ACTIVITY IN URODYNAMIC TESTING


E.F. Wahl, Ph. D., T T. Lohdes- Vasama, M. D., and B. M. Churchill, M. D.

Improving the sensitivity of and quantifying the determination of compliance, phasic activity, and involuntary detrussor contractions for cystometrograms will enable researchers to further our understanding of the urinary tract. Automated computational techniques, pattern recognition, and optimization strategies were used to remove artifacts, determine baseline abdominal and vesical pressures, pressure-time curves for phasic activity and voluntary detrussor contractions, and baseline 'at rest' detrussor pressure. This automated analysis of a systometrogram (cmg) gives objective quantification and graphical presentation of compliance, phasic activity and cletrusor contractions. Phasic activity is quantified by the total number of pulses, the average amplitude, and the area under the phasic curve which is indicative of the power or energy which causes this activity. Making use of prior cmg test data from apparatus of improved accuracy and the described automated expert system, twelve patients were analyzed. The results ranged from normal phasic activity of 0 to highly unstable systems with phasic activity of 250 min-cm of water/cm 2 and compliance of >100 to abnormal compliance of 1. In cases with phasic activity, this activity increased dramatically as the bladder capacity was approached, being quiet high in the last 5 to 10 minutes of the test. In 5 cases, patients with good compliance showed significant phasic activity. Assuming an impulse neural signal, the urinary system associated with this activity has a principle time constant of about 2-5 seconds. This analysis for two patients with the common problem of incontinence, one with poor compliance and no phasic activity and the other with good compliance but significant phasic activity, demonstrates that this tool makes an ambiguous case more obvious and discernible even to the inexperienced. Furthermore it quantitates the results which is useful for outcome studies and stratification of patient populations.



ONE YEAR FOLLOW-UP OF PROSTATIC INTERSTITIAL LASER TREATMENT FOR SYMPTOMATIC BPH


Michael Seiba, M.D., Jack Vitenson, M.D., Louis Romazzato, Ph.D., Department of Urology, Hackensack University Medical Center, Hackensack, NJ

PURPOSE: We studied the efficacy and the twelve months outcome of transurethral interstitial laser ablation of the prostate as a treatment modality in men with symptomatic benign prostatic hyperplasia, who have failed pharmacologic management.

MATERIALS AND METHODS: Fourteen evaluable men with symptomatic BPH underwent transurethral ablation of the prostate using interstitial 810nm diode laser. All men had preoperative baseline international prostate symptom score, quality of life score, ultrasound determined prostate size, post-void residual urine volume, and maximum urine flow. The some parameters were measured post-operatively at 1, 3,6, and twelve months except for prostate ultrasound. RESULTS: The procedure was performed under either local or general anesthesia. There was a 40.3% (p= 0.001) & 38.2% (p= 0.002) decrease in the international prostate symptom score and quality of life scores respectively, 31.8 %, lp= 0.002) decrease in the post-void residual, and 52%, (p= 0.002) increase in the peak flow rate. Postoperative complications included mild dysuria in 10 patients, long-standing urinary retention in I patient, gross hematurio in 2 patients, and clot retention requiring Foley catheter for two days in I patient.

CONCLUSION: The 1 year follow up of transurethral interstitial laser ablation of the prostate in the treatment of symptomatic BPH shows promising short term results with good improvement in the assessment parameters and minimal complication rates. Long-term follow up is warranted to assess the efficacy of this treatment modality



HISTOLOGICAL EVALUATION FOLLOWING ACUTE
LAPAROSCOPIC INTERSTITIAL
HOLIUM:YAG (HO:YAG) LASER IRRADIATION ON RENAL AND ADRENAL TISSUES IN THE CANINE MODEL.

David A.Schulsinger, Aaron Perlmutter, R. Ernest Sosa, Don Marion,
Edmundo Guarnizp, Pedro Ravilizzini, Rolf Muschter,
Ronald Sroka, E. Darracott Vaughan, Jr.,
New York NY


INTRODUCTION AND OBJECTIVES:The gold standard treatment for renal tlumors or renal tumors are radical nephrectomy or adrenalectomy, respectively. Interstitial Holmium:YAG (Ho: YAG) laser is a minimally invasive technique in the treatment of patients with benign prostatic hyperplasia. The purpose of this study was to evaluate the effects of Ho:YAG interstitial laser irradiation on renal and adrenal tissue in the canine models

METHODS: ten female mongrel dogs underwent interstitial laser irradiation (5Hz, 10W) of the adrenal or kidney using the BLM 800 Holmium: YAG laser (Boasel; Starnberg, Germany) at 600, 900 or 1200j. A transabdominal laparoscopic access was utilized for bilateral adrenal irradiation. The animals were sacrificed and the specimens were evaluated by gross and histological analysis.

RESULTS: Histologically, there were well-defined areas of hemorrhage and necrosis in the cortical and medullary protions of the adrenal. Viable tissue was observed beyond the limits of the coagulation zone. Likewise, there was a well defined demarcation between degenerate and viable renal tissue following laser ablation. No observable bleeding from the adrenal gland or kidney was defined in this subgroup.

CONCLUSIONS: Ho:Yag laser ablation of the kidney and adrenal can be delivered in an effective, controllable and reproducible manner. Ho:YAG laser ablation may provide a new treatment modality for zonal tissue destruction where kidney and adrenal gland preservation is necessary. Moreover, laser energy delivered can be performed by the laparoscopic approach.



ACCURACY OF MATHEMATICAL SIMULATIONS OF VOIDING

Margot S. Damaser, Ph.D., Research Service, Hines VIA Hospital, Hines, A and
Deparment of Urology, Loyola University Medical School, Maywood, IL



Using video urodynamics, we measured the urethral diameter of women during voiding and calculated the cross-sectional area in different regions of the urethra at maximum flow. We made simultaneous measurement of bladder pressure, abdominal pressure, and urine flow. We compared these results to the predictions to two mathematical models: a 1 dimensional model based on Bernoulli's equation and a computational fluid dynamics i model of urine flow during voiding. We were able to use the video urodynamics data to determine that the more sophisticated CFD model is more accurate than the 1 dimensional model.






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