INTRODUCTION: Ureteral Stents are constructed of thermoplastic elastomers with durometers ranging from 40 (soft) to 90 (firm) (ASTM, Shore A). Placement of a stent over a guidewire is associated with friction a) between the stent and the wire and b) between the stent and the obstruction. Soft stents produce a lesser degree of irritative "stent pain" but may "buckle" over the guidewire when meeting obstruction, and have low renal coil retention strength. Herein we report a comparison between a firm ureteral stent (durometer 87), a soft ureteral stent (durometer 55) and a new stent formed by a process of interrupted layer co-extrusion which results in a gradual durometer change from a soft (55 A) bladder coil to a firm (87 A) renal coil (Polaris TM).

METHODS: End-application testing was done and the stents were hydrated at 37 degrees C. Renal coil retention strength (ASTM, D-412) was excellent in the firm and Polaris TM stents, but marginal in the soft stents. The dynamic coefficient of friction between all three stents and a 0.038 PTFE guidewire was equivalent. A placement model using silicone tubing to represent a ureter and a short compression bladder around the tubing to create a "stricture" was used to evaluate ease of stent passage, using a load cell.

RESULTS: The firm and the Polaris TM stents passed thru the placement model at an average force of 0.5 pounds, as did the soft stents. When a "stricture" was created the soft stents uniformly failed, yet the firm and Polaris TM stents passed at equivalent forces, averaging 2 pounds.

CONCLUSION: A ureteral stent formed with a soft bladder coil, gradually changing to a firm renal coil appears to enjoy the benefits of both without showing any functional deficiencies.

SUPPORT: Microvasive Urology

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:

1. Biocompatibility in transitory devices
2. Laboratory testing to determine its exact variation in water and urine.
3. Laboratory testing to determine the materials which can successfully be combined with PU in the different devices.
   

This hydro-expanding system is in the preliminatory stages of development and is to be improved with further laboratory testing and clinical experience.

THE CHOICE OF THE BEST METHOD OF INTERIOR
DRAINAGE OF THE UPPER URINARY TRACT

S.Pavlov, I. Aboyan
Diagnostic Center "Zdorovey", Rostov-on-Don, Russia

In urolithiasis treatment the problem of method choosing of upper urinary tract interior drainage takes the principal place after the endoscopic extraction of the calculi.
The long-termed presence of the calculi in urinary tract can not cause the pathological changes in ureter wall.
One of the ways-out in reconstruction of the adequate urine passage from kidneys is the ureter stent placement.
Alike positive stent influence upon ureteral peristalsis the extraction of the local focus of the ureter wall contractility violation, such drainage causes the restriction of adaptation reserves following the long-termed presence of stent in urinary tract.
The problem is difficult because there is still no basis of evidences for stent placement, for definition the duration of drainage.
One of the examination methods allowing to evaluate the functional status of ureter wall is profilometry of ureter measuring the resistance of ureter wall against inserting fluid within ureter catheter.
Ureteromanometry is the registration rhythmical complexes of pressure increasing upon the background line. The basis pressure is 7-9 cm of water pillar; the maximal interureteral pressure is 15-17cm of water pillar. In diuresis increasing the maximal interureteral pressure increases in 6-8 times.
In increasing the local rigidity of ureter wall caused by stricture or changes conditioned by calculi, local raising of interureter pressure can be observed.
Thus, for preserving the urine passage the fluid pressure must exceed resistance pressure in area of obstruction.
There is the special mathematical formula for personal selection of the method for upper urinary tract drainage:
Obstruction coefficient = B x C A - pressure resistance in area of obstruction;
A B - maximal peristaltic pressure above the area of obstruction in state of physiological rest;
C - maximal peristaltic pressure in diuresis stimulation.
When the obstruction coefficient is more than 1 there is no obstruction, and we don't need drainage in area of obstruction.
When it is 0,5 or low it can be supposed the interior drainage - ureter stent. Thus, there is need in long-termed drainage because of the inflammation.
When the obstruction coefficient is within 0,5-1 it is more expedient to use short-termed drainage, for example, ureteral catheter.

URETHRAL STENTS LIQUIDATE INFRAVESICAL
OBSTRUCTION IN PROSTATE CANCER PATIENTS

Yu.G. Alyaev, L.M. Rapoport, A.Z. Vinarov, D.G. Tsaritchenko,
S.V. Stoilov, A.V. Marteushev
Urologic Clinic of Moscow Sechenov Medical Academy, Moscow, Russia

INTRODUCTION. To restore spontaneous urination with suprapubic catheter removed in prostate cancer (T3-4) patients receiving hormonal and radiotherapy, we applied transurethral electroresection and electrovaporization. SpiroFlow urethral stents available provide a possibility to restore spontaneous urination for patients in whom severe intercurrent diseases contraindicate even endoscopic procedures.
OBJECTIVE. To evaluate efficiency of resolvable urethral stents aimed to restore spontaneous voiding.
MATERIALS. According to conventional technique we placed a resolvable urethral stent SpiroFlow into 7 patients having prostate cancer (T3-4) metastatic or not, with bladder previously drained (suprapubic tube in 5 and urethral catheter in 2). Preliminary urodynamic studies revealed bladder hyperreflexia with preserved contractility in 3 patients (with suprapubic tubes) and slight bladder hyporeflexia and hypotonia in patients with urethral catheter. Spontaneous voiding occurred shortly in all 7 patients. In first postoperative days uroflowmetry parameters were Qmax > 8,3 ml/s (Qmean preop > 5,2 ml/s) without residual urine. Subsequently, positive changes were seen: Qmax > 13,1 ml/s (Qmean preop > 10,5 ml/s). The complication was gross hematuria that disappeared spontaneously at 2nd postoperative day in one patient.
CONCLUSION. Resolvable urethral stents help to restore spontaneous voiding and to better life quality in prostate cancer (T3-4) patients having severe intercurrent diseases and receiving hormonal and radiotherapy.

SEVEN YEAR OUTCOME ANALYSIS OF THE UROLUME
STENT FOR BENIGN PROSTATIC HYPERPLASIA

Rakesh Kapoor, David M. Gershbaum, Evangelos
N. Liatsikos, Mihai Alexianu, Gopal H. Badlani
New Hyde Park, NY, USA (Presented by Dr. Gershbaum).

INTRODUCTION: The UroLume stent has been used for bladder outlet obstruction secondary to benign prostatic hyperplasia (BPH), urethral strictures and detrusor external sphincter dyssynergia (DSD). The results of long term follow-up are available for urethral stricture and DSD. We report here the seven-year long-term outcome, complications and tissue response, on a cohort of 27 patients enrolled in the study of UroLume for BPH patients.
MATERIALS AND METHODS: Between April 1990 and July 1992, 126 patients were enrolled in a prospective clinical trial of the UroLume stent for symptomatic BPH at 11 participating Medical Centers. Thirty-one patients were in urinary retention (UR) and 95 were not in retention at the time of device insertion. Average age at insertion was 70.2 years with a range of 48 to 90 years. Twenty-seven of these original patients have been continued to be followed for seven years post implant. Follow-up assessment includes pre/postoperative peak flow (ml/sec), pre/postoperative Madsen-Iversen Symptom Score, urinary incontinence and tissue response (none, mild, moderate, marked). For all analyses, the Student's t test for paired data was used.
RESULTS: At seven years, mean pre/post flow rate was 9.5/11.9 ml/sec. Mean pre/postoperative Madsen-Iversen Symptom Score 13.5/6.7 (p<0.01). 58.3% reported pre-implant incontinence. In terms of incontinence, post-implant, 41.7% of the patients were better, 45.8% were the same and 12.5% were worse. With regard to tissue response, 12.5% had none, 79% mild, 4.2% moderate, and 4.2% marked.
CONCLUSIONS: The UroLume stent is an effective treatment for symptomatic BPH. It has a low morbidity and a mild epithelial tissue response.

LAPAROSCOPY-ASSISTED MINILAPAROTOMY
UROLOGIC SURGERY

Seung C Yang, Koon H Rha, Young J Byun, Ji K Ryu
Department of Urology, Yonsei University, College of Medicine, Seoul, Korea

Introduction and Objectives: We have devised a modified surgical technique of laparoscopy-assisted surgery through minilaparotomy. It is a hybridized form of conventional open and laparoscopic surgery and it combines the benefits of both techniques by reducing postoperative pain and scarring as in laparoscopy, but maintaining the safety of conventional open surgery.
Methods: We retrospectively reviewed all urologic operations performed using laparoscopy-assisted surgery though minilaparotomy from January 1992 to September 1999. With the use of specially designed retractors, all urologic procedures were performed with a minilaparotomy less than 8 cm long. Abdominal muscles were not cut but rather stretched to avoid unnecessary nerve damage.
Results: There were 227 patients with mean age of 40.2 years(range 16-70). The procedure performed were 37 simple, 110 live donor, 12 radical nephrectomies; 12 nephrolithotomies, 20 ureterolithomies, 33 pyeloplasties.. The operative time for laparoscopy-assisted surgery through minilaparotomy ranged from 79 to 290 minutes (mean 125). There was no conversion to open surgery, no peri- or postoperative complications, and only 3 patients needed a blood transfusion at any stage. Pain was significant on the first day but resolved quickly. All patients resumed consistent oral intake on the second day. All patients commenced ambulation by the second postoperative day and were able to resume full ambulatory activity by the 4th postoperative day.
Conclusions: The laparoscopy-assisted minilaparotomy surgery is a truly minimally invasive technique maintaining the advantages of conventional surgery. Our method may be used as a first-line approach for simple nephrectomy, living donor nephrectomy and radical nephrectomy, as well as surgery for kidney and ureter stones.

QUANTIFIABLE TESTS OF LAPAROSCOPIC
DEXTERITY: ROBOTIC VERSUS MANUAL LAPAROSCOPY

William W. Roberts, Iulian Iordachita, Alexandru Patriciu,
Dumitru Mazilu, Thomas W. Jarrett, Louis R. Kavoussi, Dan Stoianovici
URobotics Laboratory, Brady Urological Institute,
Johns Hopkins Medical Institutions, Baltimore, Maryland

OBJECTIVE: We have developed a method and specific tests for evaluating laparoscopic surgical dexterity. This algorithm was applied in the laboratory to compare a robotic system with manual use of laparoscopic instruments.
MATERIALS AND METHODS: Six tests requiring needle manipulation and placement were performed on a laparoscopic trainer using the ZEUS™ (Computer Motion Inc., Goleta, CA) robotic system as well as standard laparoscopic instruments. Subjects received numerical dexterity scores for their performance with both the manual and robotic configurations. Evaluation of the haptic force-feedback mechanism of the ZEUS grasper was also undertaken.
RESULTS: The test scores accurately reflected the subject's level of laparoscopic training and experience. Comparison of manual and robotic configurations revealed decreased dexterity using the robotic system. The force feedback experiments demonstrated an imperceptible response at the haptic handles.
CONCLUSIONS: A method of quantifying dexterity was developed and successfully implemented to evaluate the ZEUS robotic system. This algorithm is also applicable to other robotic laparoscopic systems.

JET INJECTION ALLOWS ENDOSCOPIC AND
PERCUTANEOUS NON VIRAL TRANSFER OF NAKED DNA

Haupt Gerald, Haupt Angela, Reimann Sylvia, Senge Theodor, Engelmann Udo
Departments of Urology, Universities of Cologne and Bochum, Germany

Introduction: Gene therapy may play a major roll in future tumor therapy. The ideal vector has yet to be determined. Viral transfection bears a lot of risks. Therefore we investigated a new, non viral method: jet injection. By a newly designed jet injector plasmid vectors are injected directly into cell cultures and tissue. Jet injection allows gene transfection with up to 2 cm of penetration depth. We investigated tissue effects of jet injection earlier in the Beagle prostate. However, the effects of jet injection on cell cultures are unclear. Also the stability of DNA has to be tested.
Material and methods: By a newly designed jet injector plasmid vectors are injected directly. Galactosidase lacZ gene and EGFP serve as markers. A number of various cancer cell lines (LNCAP, Dunning, PC3, CAKI-1, KU-19-19, RT-4) as well as human fresh tissue of surgical specimen (kidney, urinary bladder, prostate, testis) and necropsy tissue specimen of cynomolgus (heart, lung, pancreas, liver, spleen and urinary tract organs) were treated. ß-galacto-sidase acitivity and GFP, respectively, were determined 24 and 48 hours after jet injection. In cell cultures the durability of expression was tested by staining and or fluoroscence microscopy after each passage. In addition, cell lines and DNA vectors were examined regarding damages induced by jet injection.
Results: Jet injection allows gene transfection with up to 2 cm of penetration depth. Transfection rate depends on tissue: epithelial cells are easier to transfect than stromal cells. Transfection rate also depends on the injections pressure and varies with different nozzle types. Maximum transfection rate was 25 % in tissue. In cell cultures transfections rate was 5 to 7 fold higher than
in controls. Stable expressions were observed (> 20 passages). Regarding damages, 10 to 25 % more cells were stained by trypane blue after jet injection. Cell survival was equally distributed for all cell lines tested. Vectors were damaged depending mainly on jet injection pressures.
Conclusions: Jet injection leads to DNA damage depending on the individual injector and its setting. Cell damage occurs in about 20 % of the cells and is less related to the injector parameters. Jet injection allows targeted application of plasmids and can be easily repeated thus partially overcoming its lower transfection rate as compared to viral vectors. Its transfection rate is higher as with needle injection, its penetration depth by far larger as with the "gene gun". Jet injection can be used endoscopically and seems to be an ideal candidate for local gene therapy.

TELEROBOTIC SURGICAL MENTORING FROM HOME

L Su, A Patricu, W W Roberts, T W Jarrett, D Stoianovici, L R Kavoussi
URobotics Laboratory, Brady Urological Institute,
Johns Hopkins Medical Institutions, Baltimore, Maryland

OBJECTIVE: Current methods of disseminating operative skills and techniques of new minimally invasive surgical procedures into general surgical practice have been associated with significant learning curves and increased complication rates. We report on the use of a cost-effective home-based telesurgical station, through which surgical expertise can be transmitted from a mentor to a less experienced surgeon in a remote location.
METHODS: We designed a novel telesurgical station located in the mentoring surgeon's home that required only a personal computer, commercially available software and standard telecommunication lines. A 650 MHz PC fitted with a Zydacron Z360 Codec and Zydacron Z208 Communication Board (Zydacron Corp, Manchester, NH) allowed real time two-way audio and video data to be transmitted between the mentoring surgeon's home and an operating room twenty miles away over four commercially available ISDN phone lines. A client-server application was developed to allow the mentor to activate the electrocautery, alternate between operative cameras and annotate on the local surgeon's video screen. The mentor also controlled 2 robotic devices: AESOP (Computer Motion, Goleta, CA), a robotic arm that holds and positions a laparoscope and TELEPAKY which allows fluoroscopic placement of an 18 gauge needle for percutaneous renal drainage. Finally, a voice activated interface, HERMES (Stryker Endoscopy, Mountain View, CA), provided the mentor with control of the light source, camera controls and the laparoscopic insufflator.
RESULTS: Four cases were successfully mentored from home using the telerobotic surgical consultation system (see Table). There were no intraoperative complications and all patients had an uneventful post-operative course.

CONCLUSION: Telerobotic surgical systems offer a mechanism through which surgical expertise can be transferred. Progress in computer and telecommunication technology has allowed for the development of a cost-effective home-based telesurgical station that can permit an experienced surgeon to disseminate and monitor state-of-the-art surgical techniques globally.

A COMPACT MRI COMPATIBLE POSITIONING ARM FOR INTERVENTIONAL AND CLASSIC SCANNERS

Keenan Wyrobek², Louis L. Whitcomb², Dan Stoianovici^12
1URobotics Laboratory, Brady Urological Institute, Johns Hopkins Medical Institutions
²Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland

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Magnetic Resonance Imaging (MRI) has become the preferred method for high-resolution soft-tissue imaging for pre/post operative diagnosis, but is not widely employed for interventional imaging. MRI imaging has improved in speed and resolution and with the improvements the need has grown for MRI compatible intervention devices. Just as X-Ray fluoroscopy, first developed for diagnostic imaging, has become an ubiquitous tool for intervention guidance, we conjecture that the next decade will see the widespread use of MRI for real-time interventional diagnosis and guidance. As the first step in developing a modular line of MRI compatible clinical devices, we report the development of a MRI compatible passive arm for positioning interventional devices within MRI systems.
The high-intensity variable magnetic field used in high-resolution MRI imaging precludes the use of many traditional engineering materials and actuation schemes. The materials employed in the construction of the new arm, such as polyetherimide, kevlar, and nylon, ensure that it is MRI safe and it does not induce imaging artifacts. These have been selected for their nonmagnetic, dielectric, and reduced nuclear cross-section. The arm presents a serial link architecture constructed of seven round parts of similar geometry. The links are interconnected at their inclined faces implementing six revolute joints, thus rendering a six degree-of-freedom passive arm. The fully extended length of the arm is 300mm. An integrated MRI compatible actuator is used for locking the arm. The actuator uses pneumatic pressure available in all operating rooms. The air pressure is used to tension a kevlar cord that simultaneously locks all six joints.
The first prototype has been designed, manufactured, and experimentally tested. It demonstrated a holding capacity of 100N at its fully extended length. When unlocked, the low friction allows the end of the arm to be easily repositioned. The arm is a sturdy platform for novel MRI compatible surgical devices. A second-generation arm is presently under development.

ROBOTIC CT-GUIDED PERCUTANEOUS RENAL ACCESS

Alexandru Patriciu, Stephen Solomon, Louis Kavoussi, Dan Stoianovici
URobotics Laboratory, Brady Urological Institute,
Johns Hopkins Medical Institutions, Baltimore, Maryland

Abstract: We present a simple method for robot registration in computer tomography imaging systems and its application to percutaneous renal access under CT-guidance. The method uses the laser markers readily available on any CT scanner and does not require imaging thus eliminating radiation exposure.
Methods: The system comprises a CT scanner, a personal computer (PC), and the PAKY-RCM robot attached to the CT table. The PC is equipped with a motion control card for robot control and acquires CT images in DICOM format through a network connection. The laser markers commonly available on the CT scanner are used for robot registration through a needle alignment processes. The registration process involves two steps. In the first one the CT-image plane is registered in the robot space. This is achieved by moving the robot in two different positions such that the instrument is contained in the image plane. Using the robot position information a partial registration is achieved. This registration will provide 3DOF (Degrees Of Freedom). The remaining 3DOF are solved by acquiring an image with the instrument in the image plane in a specific position. By matching the position of the instrument in the image and in the robot coordinate space the remaining 3DOF are computed. Once the registration is computed, the radiologist chooses the target in the slice image displayed on the PC monitor, and the robot automatically aligns and delivers the needle.
Results: Preliminary accuracy testing was performed in-vitro using 1 mm diameter metallic balls. The target was placed in the same image plane with the needle tip and also in different planes. The targeting error achieved over fifty experiments was less than 1 mm in plane and 1.5 mm for out of plane targets. With these satisfactory results, the extensive clinical experience with the PAKY-RCM robot in percutaneous renal access under C-Arm guidance we proceeded for the clinical application. Five robotic radiological interventions including a nephrostomy tube, kidney and spine biopsy and radio frequency ablation have been successfully performed.
Conclusions: The paper presents a simple CT-robot registration method using the laser markers of the CT scanner and its application to CT-guided interventional procedures. The registration may be used with traditional (non CTF) scanners and it does not involve additional registration devices, using the procedure instrument (needle) as a registration marker. The method allows for performing needle access in an oblique direction, for which the skin entry point and the target are located in different CT slices. This is a significant improvement over the manual method, in which the needle is restricted to the fluoro image of the CTF scanner.

IN VITRO AND EX_VIVO ANIMAL EXPERIMENTS WITH A NEW CONCEPT FOR THE MANAGEMENT OF URINE INCONTINENCE

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, at least 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 along the urethra and cause a communication between the bladder and the vulva, resulting in very high rates of ascending 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 prototypes of these devices were tried in vitro conditions (using a glass made simulated bladder) and then in ex-vivo animal bladders removed from sheep, swine and cow. Each device was inserted easily into the bladder, they were activated voluntarily using a remote control device and they were retrieved as easily.
RESULTS : All prototypes could occlude the BO completely in all in-vitro experiments. The devices could be manipulated with the remote control device to open and close the simulated BO. Similar results were obtained when they were tried in ex-vivo animal bladders, even under high intravesical pressures (up to 100 cm H20)
CONCLUSIONS : The use of an intravesical device for the management of incontinence is a novel approach. It seems that the devices are safe and effective in the management of UI. The devices are in their final stages of development after being tested in laboratory setting. Chronic animal experiments are underway and clinical experiments will commence in the next future.

EFFECT OF FIBROBLAST PROTEASES ON TENSILE
STRENGTH OF VARIOUS PUBOVAGINAL SLING MATERIALS

Mihai Alexianu, Mahesh Mathrubutham, Evan R. Eisenberg, Paul Yohannes and Gopal H. Badlani
New Hyde Park, NY

PORCINE SMALL INTESTINE SUBMUCOSA IMPLANTATION FOR PUBOVAGINAL SLINGS: RESULTS AND CONCLUSIONS AFTER TWO YEARS IN EIGHTY SEVEN FEMALE PATIENTS

Rutner, A.B., Levine, S.R., Schmaelzle J.F.
El Camino Urology Medical Group, Mt. View, CA

Introduction: Processed porcine small intestine submucosa (SIS)* is a unique material with special properties that make it an ideal implant as a sling for stress urinary incontinence. Its apparent resistance to infection, biocompatibilty and ability to induce host tissue ingrowth into its collagen matrix with subsequent total replacement of the implant results in a dependable sling .
Materials and Methods: 87 female patients with stress urinary incontinence underwent implantation with a 4-layer strip of SIS (Stratasis ESTM) between 1-1-99 and 2-1-01. Bone screws with attached prolene sutures were utilized to fix the the graft material to the inner surface of the pubic bone on either side of the urethra. Many of these patients underwent other vaginal or abdominal pelvic procedures under the same anesthetic.
Results and Conclusions: 83/87 (95.5%) of this group of patients became dry after the surgery and remain so. Four patients (4.5%) have varying degrees of stress incontinence. One failed because one of the bone anchors dislodged spontaneously 2 weeks after surgery. Another sling failed because we were unable to place one of the bone anchors satisfactorily and the result was an asymetrical sling fixation. The other 2 procedures simply failed. During the past 2 years, there have been no infections of the graft or anterior vaginal wall, no erosions and no extrusions of any sling. Most patients voided the day after surgery. Those with additional procedures tended to have their catheters a longer period of time. All patients voided well within a few days Patients with mild or moderate preoperative urgency that were managed satisfactorily with antispasmotics continued to respond well to medications after surgery. Severe urgency, not responsive to medications before surgery, does is not improved by this sling procedure. Such a clinical problem is probably a contraindication to this type of procedure.
* SIS implant material supplied by Cook Urological, Bloomington, Indiana

THE TENSION FREE VAGINAL TAPE (TVT) - A NEW SYNTHETIC SLING FOR WOMEN WITH STRESS URINARY INCONTINENCE (SUI)

Yitzhak Berger M.D., Pratik Patel M.D.
St. Barnabas Medical Center Livingston and UMDNJ- Newark Medial School, Newark NJ.

TECHNOLOGY: This new technology can be performed under local anesthesia and under outpatient settings. A synthetic Prolene Mesh tape (Gynecare, Johnson & Johnson) protected with plastic sheath, is placed around the mid urethra via a small vaginal incision and is delivered bilaterally with trocars into the retropubic space. After each passage of the trocars, cystoscopy is performed and once bladder injury is excluded, the tape is loosely positioned (hence tension free) underneath the mid urethra. The bladder is then filled and insitu "cough test" is obtained and the tape is adjusted as necessary, The vaginal incision is closed, the Foley catheter is removed within 3-5 hours and the patient is discharged home after urination.
INTRODUCTION: We present our experience with the Tension free Vaginal Tape (TVT), a minimally invasive outpatient pubovaginal sling (PVS) operation, A synthetic (Prolene mesh) is placed, via small vaginal -incision and under local anesthesia, around the mid urethra and into the retropubic space where it ,remains adhered without need for it's anchoring (Velcro effect). The international experience with the TVT has showed 85-94% surgical success rate without associated genitourinary erosions. The details of this new technology will be described, along with our 2 years of experience with it.
METHODS: 148 women, ages 33-88 underwent TVT for symptoms of SUI either alone (100 patients) or in conjunction with repairs of uterine and/or vaginal vault prolapse (48 patients).
RESULTS: At 8-30 months follow-up of patients after TVT alone and TVT in conjunction with other pelvic surgery, the cure rate of SUI was 92% and 90 % respectively. The complications of TVT included: vaginal dehiscence (1/148-0.6 %), prolonged urinary retention (2/148 - 1.2 %) and pelvic pain (5/148- 3.3%), without urethral erosions, vascular or bowel injuries.
CONCLUSIONS: Our experience with this new technology reaffirms the TVT to be a safe and effective surgical therapy for women with SUL. Its durability will require further monitoring.

VOIDING SPIRAL TOMOGRAPHY OF A URINARY BLADDER AND URETHRA

Yu.G. Aljaev, S.K.Ternovoj, E.V.Sinitsin, V.A.Grigorian, I.M.Koroleva, G.P.Filimonov, M.A.Gazimiev
Moscow Medical Academy, Russia

Purpose: Improve diagnostics of urinary bladder and urethral diseases by means of:

1. Development and improvement of the procedure of voiding spiral tomography of urinary bladder and urethra
   
2. Comparison of data obtained during the investigation with the one of ultrasound, contrast X-ray and endoscopy
   
3. Evaluation of voiding spiral tomography's diagnostic value and economic effectiveness in urinary bladder and urethral diseases.

1. It improves the surgeon's spatial perception of a lesion thus allowing a better planning of an operation
   
2. Voiding spiral tomography allows assessing changes in tissues surrounding the lesion and it's extension
   
3. The risk of lower urinary tract infection is much lower (vs endoscopic techniques)
   
4. Patient's work up is less labour and time-consuming

ELASTIC PROPERTIES OF THE PROSTATE USING ULTRASOUND IMAGING

Margot Damaser, Ph.D., Anthony Yin, Inder Perkash, M.D., Christos E. Constantinou, Ph.D.
Research Service, Hines VA Hospital, Hines, IL
SCI Service, Palo Alto VA Medical Center, Palo Alto, CA
Department of Urology, Loyola University Medical Center, Maywood, IL
Department of Urology, Stanford Medical School, Stanford, CA

The treatment of micturition problems in patients with spinal cord injury (SCI) could be facilitated by the development of methods which characterize the elastic properties of the prostate. To this end we have developed a method to evaluate changes in prostate biomechanics during voiding using ultrasound images obtained during routine diagnostic urodynamic evaluations. Ultrasound video sequences of the prostate and urethra ware digitized simultaneously with bladder pressures on 18 patients with spinal cord injury, aged 47±18 years with a mean of 19 years duration of injury. Computer enhancement of the bladder/prostate/urethral interface from sequences of two-dimensional ultrasound images facilitated measurement of mid-prostatic urethral displacement during micturition. Measurements were made at the time of maximum bladder pressure, Pdetmax, and at half maximum pressure, Pdet50. These 2 time points were selected because the diameter of the prostate can be accurately resolved then. Prostatic strain was defined as Ddetmax- Ddet50/ Ddetmax, where D is prostate diameter at the indicated time. Prostatic stiffness b was calculated using the following relationship:
   b= ln{(Ddetmax/Ddet50)/(Ddetmax- Ddet50)/Ddetmax}
Strain is 0.158 ± 0.074, indicating the prostate is in compression at maximum detrusor pressure. Prostatic stiffness is 1.83 ± 1.0. In addition, observations suggest that there are regional differences in compliance within the prostate, such that the distension of the prostate and urethra during micturition is not uniform. Clinical application of this method could provide a quantitative indication of the biomechanics of micturition and can be used in evaluating the impact of pharmacological interventions such as adrenergic blocking agents in relaxing the prostate/urethra.

INITIAL EXPERIENCE OF QUANTITATIVE MEASUREMENT OF URINARY SENSORY FUNCTION ASSESSED BY CURRENT PERCEPTION THRESHOLD IN THE BLADDER USING NEUROMETER

Osamu Ukimura, Tsuyoshi Iwata, Mitsuhiko Inaba, Hisashi Honjo,
Akihiro Kawauchi, and Tsuneharu Miki
Department of Urology, Kyoto Prefectural University of Medicine

Diagnostic technology for lower urinary tract dysfunction have been mainly concentrated on the motor function of detrusor and sphincter, however, the measure of bladder sensory function is important, but difficult so far. Differences in distribution of sensory nerve fibers could determine the therapeutic strategy for neurogenic bladder. The Neurometer (Neurotron Inc, Baltimore, USA) is a computerized automated neurodiagnostic device that can measure peripheral sensory function quantitatively with micro-electronic stimulation of three different types of sensory peripheral nerve fibers, including Aß, Ad, and C fibers, selectively using frequencies of 2000, 250, and 5Hz, respectively. This is the first report to apply this new device to measure of the current perception threshold (CPT) in the bladder using a special intravesical electrode. In the 31 patients, the conventional urodynamic study as well as the measure of CPT values in the bladder was performed. CPT values at frequencies of 2000, 250, and 5Hz were determined on the left index finger skin as well as on the bladder wall using the intravesical electrode. As the determination of CPT values on the skin, the CPT values in the bladder were able to be determined using the device in the all patients but three who had no sensory caused by complete spinal injury. In the 6 patients with cervical or thoracic spinal diseases, the bladder CPT value (4.67±3.1) at the 5Hz was significantly lower (p<0.01) than that in normoactive bladder (43.7±31.5) diagnosed by conventional studies, which could suggest hypersensitivity by abundant C fiber. In the neurogenic bladder determined to be underactive, the relatively higher CPT values at three kinds of stimuli might suggest hyposensitivity compared to those in normoactive bladder. In addition, we experienced two patients with overactive bladder whose CPT values have been changed from hypersensitivity to hyposensitivity with accompanied by improvement of the urgency symptoms by the acupuncture therapy that we reported previously (J Urol 157:A732, 1997, Urol Int 65:190, 2000). In conclusion, quantitative measurement of CPT values was able to be assessed in the human bladder using this device. The quantitative estimation of three different types of sensory peripheral nerve fibers (Aß, Ad, and C fibers) in the bladder could contribute to appropriate selection of therapeutic strategy in individual patients with neurogenic bladders, such as in the patients with overactive bladder caused by abundunt C-fiber, that could be indication for acupuncture, electrostimulation, or intravesical instillation therapy of capsaicin or resiniferatoxin. The measurement of CPT values might be used as a monitoring of these therapeutic responses or the severity of diseases.

USE OF CONDUCTIVE GEL TO ENHANCE RADIOFREQUENCY ABLATION

Jamil Rehman, Jaime Landman, Ashvin Desai, Chandru Sundaram,
David G. Bostwick and Ralph V. Clayman
St Louis, MO

Objective: The major drawback to the widespread application of soft tissue ablation using radiofrequency (RF) energy has been the inability to create large, tissue lesions with uniform cell death. Despite changes in the size or number of the electrodes or use of fluid perfusion to enhance the spread of the current, unpredictable lesion size and skip areas of cell necrosis have persisted. Accordingly, we combined a conductive gel with RF.
Methods: An 18 gauge, hollow-needle electrode permitted simultaneous infusion of 4 cc of conductive gel and RF activation at 50 watts of 510k Hz for 5 minutes under laparoscopic guidance. The conductive gel contained 23.4% saline and an inactive polymer-thickening agent. Thirty-seven renal lesions were created in 10 pigs: hypertonic saline gel alone (n=7), monopolar RF with hypertonic saline gel (n=6), bipolar RF with hypertonic saline gel (n=6), monopolar RF alone (n=12), and bipolar RF alone (n=6). Tissues were harvested after one week and light microscopy performed.
Results: The largest lesions were achieved using hypertonic saline gel with monopolar RF (27±4.3mm) followed by hypertonic saline gel with bipolar RF (21±2mm). Lesions were irregular in shape; in general they were larger on the surface of the kidney and smaller toward the pelvis of the kidney. Occasionally there was leakage of gel along the needle tract, especially after the needle was withdrawn. The lesions created by hypertonic saline gel alone were small (2.33±.0.33mm) as were the RF alone lesions: monopolar RF (8.14±1.33mm) and bipolar RF (7.44±1.02mm). There was complete necrosis with all modalities except: one case of monopolar and one case of bipolar RF alone as well as three hypertonic saline gel lesions.
Conclusions: Using an RF needle with instillation of hypertonic saline gel, reproducible ablative renal lesions of 27mm size were obtained. The conductive gel provides for efficient RF energy transfer while, cooling the electrode tip and surrounding tissues; however the lesions are nonspherical with irregular borders.

INCISIONLESS VASECTOMY USING AN ACTIVELY COOLED HIGH-INTENSITY FOCUSED ULTRASOUND CLIP: THERMAL MEASUREMENTS AND BIO-HEAT TRANSFER SIMULATIONS

Nathaniel M. Fried, Yegor Sinelnikov, Bharat Pant, Will W. Roberts, Stephen B. Solomon
Urology and Radiology Departments, Johns Hopkins School of Medicine, Baltimore, MD and Transurgical, Inc., Setauket, NY

Introduction: Surgical vasectomy may lead to complications including scrotal pain, bleeding, and infection. Previous studies have shown that noninvasive transcutaneous delivery of high-intensity focused ultrasound (HIFU) thermally occludes the vas deferens. However, skin burns and inconsistent vas occlusion have presented complications. This study uses thermocouple temperature measurements and bio-heat transfer simulations to determine the optimal ablation dosimetry for vas occlusion without skin burns.
Methods: A two-radian ultrasound transducer mounted on a clip delivered ultrasound energy at a frequency of 4 MHz to the canine vas deferens co-located at the focus between the clip jaws. Chilled (~10 oC), degassed water was circulated through an inflated latex balloon attached to the front side of the clip, providing efficient ultrasound coupling into the tissue and active skin cooling to prevent burns. Thermocouples were placed at the vas, skin, and skin-balloon interface and recorded temperatures during pre-cooling, sonication, and post-cooling phases. Procedures were performed with acoustic output powers of 3-7 Watts, transducer surface intensities of 0.8 - 1.9 W/cm2, and sonication times of 60-120 seconds. Measurements were compared with bio-heat transfer simulations modeling the effects of variations in surface intensity and sonication times on tissue temperatures and coagulation zones.
Results: Active skin cooling produces a thermal gradient in the tissue during ablation, allowing sufficient thermal doses to be delivered to the vas without skin burns, despite greater ultrasound absorption in the skin (~ 3 dB/cm) than the vas (~ 1 dB/cm). However, vas ablation using low power and long sonication times produced excessive tissue necrosis due to thermal diffusion, while high power and short heating times reduced the therapeutic window and produced skin burns due to direct ultrasound absorption.
Conclusions: Both experiments and simulations suggest that a therapeutic window exists in which thermal occlusion of the vas may be achieved without the formation of skin burns. A range of ablation parameters has been identified (Power = 5-7 W, SI = 1.4-1.9 W/cm2, Time = 20-40 sec.) which should provide enough thermal dose to the vas to produce occlusion without skin burns. These ablation parameters will help guide future experiments to refine HIFU vasectomy.

A NEW CW LASER SUITABLE FOR BOTH ENDOUROLOGIC AND SURGICAL PROCEDURES

Andreas J. Gross, Rolf Eichenauer, Ralf Brinkmann, Heinrich-O. Teichmann
Marien-Krankenhaus, Bergisch-Gladbach;
Medizinische Universität zu Lübeck; Medizinsches Laserzentrum Lübeck;
Lisa laser products OHG, Katlenburg-Lindau, Germany

State of the art surgical fibre guided lasers for minimal invasive or endoscopic procedures either operate in continuous wave (cw) mode at around 1 µm or in pulsed mode around 2 µm wavelength. Whereas the 1 µm cw type like diode or Nd:YAG lasers feature good coagulation of circulated tissue, the cutting effect of these lasers is poor. In contrary pulsed 2 µm lasers like Ho:YAG combine sufficient coagulation of well circulated tissue like prostate with excellent tissue ablation. However the evenness of incisions is limited by the pulsed characteristic of the laser emission. As well the endoscopic as unaided sight is impaired by ablated tissue both in liquid and in air.
We report about a new cw DPSS laser (diode pumped solid state laser)(Lisa laser products OHG, Katlenburg-Lindau, Germany) with a wavelength of 2 mm. The laser power to tissue is adjustable from 2 to 80 watts. The laser beam is delivered to the situs through a flexible fibre with 365 mm core diameter, matching with low gauge working channels. The laser can be operated either in cw or in chopped mode. When chopped, the "pulse" duration is adjustable from 10 to 1000 ms at selectable repetition rate.
First experiments with this new laser were performed as well in vivo as in vitro. In in vitro experiments different laser settings were evaluated in comparison to Ho:YAG laser experience. Results are demonstrated from in vitro (liver, heart, chicken breast) and in vivo applications on human prostates and kidneys with respect to cutting efficiency, penetration, evenness of the incision, forward and lateral coagulation of adjacent tissue.
The new 2 µm cw laser shows encouraging results as it fulfils all criteria requested for a surgical laser: precise incision, sufficient coagulation, minimal side effects, fibre delivery, and no sputtering neither in liquid nor in air.

EFFECT OF FOCUSED MAGNETIC ENERGY ON ABACTERIAL PROSTATITIS SYMPTOMS DUE TO PELVIC MUSCLE DYSFUNCTION

Aaron Bush, Linda Zielinski, R.N., Irving S. Garlovsky, M.D., Jan Bush, R.N., B.S., Holly C. Parramore, R.N., Irving M. Bush, M.D.

Sixty patients with chronic abacterial prostatitis were treated with an inexpensive highly selective device which provides a continuous flow (60 cycle) "null" magnetic field (2000 gauss). This is applied externally to the prostate and pelvic floor muscles through a specially hardened polyvinyl plastic non-conductive chair containing a posterior placed heavy localizing 4 x 5 inch glass plate.
Forty-eight patients finished at least 13 fifteen-minute sessions over 6 to 10 weeks. 17/48 were improved; 5/49 had complete relief; 21/43 had no long term effect; five felt worse. Focused repetitive magnetic therapy which has been effective in female incontinence may provide beneficial results in some patients (46%) with chronic prostatitis.

FLUORESCENCE DIAGNOSIS OF PENILE CARCINOMA - A NEW TECHNIQUE TO ASSIST AND CONTROL ND:YAG LASER THERAPY

P. Schneede, D. Frimberger, D. Zaak, A. Hofstetter
Department of Urology, University of Munich- Grosshadern,
Marchioninistr. 15, 81377 Munich, Germany

Objectives: The macroscopic lesions of penile cancer are often accompanied by invisible dysplasia, premalignant penile intraepithelial neoplasia (PIN), ill-defined tumor edges or carcinoma in situ (CIS). Since squamous cell carcinomas are not very sensitive to radiation or chemotherapy, the gold standard for the disease is partial or total penectomy. In this study, fluorescence diagnosis is used for the first time in assisting the urologist in the detection of neoplastic and preneoplastic lesions in the rare diagnosis of penile cancer.
Methods: 4 patients with biopsy proven penile cancer were examined with 5-aminolevulinic induced fluorescence. A 1% solution of 5-aminolevulinic acid and lidocain jelly (Instillagel®, Farco Pharma, Cologne, Germany) was applied one hour preoperative to the penis and a condom placed over it. The penis was observed under conventional white light and blue excitation light from a xenon arch lamp (wavelength 375-440nm). The fluorescent lesions were biopsied and afterwards treated with Nd:Yag laser coagulation at 20-50 watt energy. The coagulated tissue was sent for histopathological examination and HPV DNA analysis. One biopsy was taken from an unsuspicious area.
Results: The macroscopic tumor, tumor edges and coexisting dysplastic areas presented a strong positive red fluorescence under excitation. The histopathologic examination of the biopsies revealed squamous cell carcinoma of the penis for the visible tumors and PIN II- III for the surrounding fluorescence positive lesions. The one macroscopic and fluorescent negative biopsy showed normal tissue.
Conclusions: Penile cancer is a tragic diagnosis for the patient due to the aggressive nature of the disease and the standard procedure of partial or total penectomy. Organ sparing techniques require good visualization of all existing neoplastic regions in order to guarantee a complete destruction of all tumor material. Fluorescence diagnosis is used in various regions of the human body to detect occult premalignant and malignant lesions and to define tumor margins. In penile cancer, fluorescence diagnosis assists the urologist in detecting HPV-related lesions and neoplastic changes as well as the performance of an online-controlled complete laser coagulation with safe tissue margins.

IN VIVO TRANSUTRICULAR SEMINAL-VESICULOSCOPY

Seung C Yang, Koon Ho Rha, Sang Kwon Byon
Department of Urology, Yonsei University, College of Medicine, Seoul, Korea

Purpose: To evaluate the etiology and treatment of options in patients with hematospermia, we performed endoscopy of the seminal vesicles in 37 patients with hematospermia.
Materials and Methods: The patients were evaluated with either transrectal ultrasound (TRUS) or endorectal MRI. Patients were followed for more 3 months after the endoscopic treatment. Mean age was 47.1 years (range 28-68 years) with duration of infliction being 37 months (range 3 months to 10 years). When the patients who had the definite abnormalities on the imaging studies and did not improve by medications for more than 3 months, transutricular seminal-vesiculoscopy using 6Fr or 9Fr rigid ureteroscope was performed.
Results: Hemorrhage was found in the seminal vesicles and the ejaculatory ducts in 23 (62.2%) and 3 (8.1%), respectively. Calculi were present in the seminal vesicles and the ejaculatory ducts in 6 (16.2%) and 2 (5.4%), respectively. Prostatitis was present in 9 (24.3%) patients. All patients except one reported improvement of hematospermia. Postoperative complications including epididymitis or prostatitis were not observed.
Conclusions: Our series is the first large-scale experience of the seminal vesicle endoscopy in vivo. It can be performed easily with conventional endoscopic equipment. The endoscopic evaluation and management of the hematospermia is a viable clinical option.

AUTOFLUORESCENCE IMAGING TO OPTIMIZE THE 5-ALA INDUCED FLUORESCENCE ENDOSCOPY OF BLADDER CARCINOMA

D. Frimberger⁽¹⁾, D. Zaak ⁽¹⁾, H. Stepp(1), R. Knüchel⁽²⁾, R. Baumgartner⁽¹⁾,
P. Schneede⁽¹⁾, N. Schmeller⁽¹⁾, A. Hofstetter(1)
¹ Department of Urology: Universitaetskrankenhaus Grosshadern der Ludwig-Maximilians Universitaet, Muenchen, Germany
²Institute of Pathology, University of Regensburg (Germany)

Objectives: 5-aminolevulinic acid induced fluorescence endoscopy (AFE) provides a significantly higher sensitivity in the detection and localization of bladder carcinoma compared to white light endoscopy (WLE). The specificity of AFE is equivalent to WLE, mostly due to false-positive fluorescence of chronic cystitis lesions. Laser induced, spectral autofluorescence detection (Koenig F; J. Urol. 1996) is also an efficient method in the diagnosis of bladder carcinoma. An optical system for detecting autofluorescence (AF) of bladder tumors was designed and the success of reducing the false-positive rate of AFE determined.
Methods: Bladder tissue was excited to AF using the D-light (Fa. STORZ, Tuttlingen, Germany) (375-440 nm) following regular AFE with detection of fluorescence positive areas. The optical image was produced using a special RGB-camera. Biopsies were taken from AFE positive areas, peritumorale edges and normal bladder mucosa. The AF images of the suspicious areas were compared with the AFE images and the histological results.
Results: A total of 43 biopsies were histologically examined (24 benign, 19 neoplastic). AF imaging showed contrast differences between papillary tumors, flat lesions and normal mucosa. The combination of AFE with AF raised the specificity of AFE alone from 67% to 88%.
Conclusions: Autofluorescence imaging is possible. The value of the method in reducing the false-positive rate of the highly sensitive AFE needs to be validated on higher numbers. The combination of AF with AFE has a 20% higher specificity than AFE alone.

URINARY STONES: COMPOSITION, STRUCTURE, PROPERTIES

Yu.Alyaev*, L.Rapoport*, V.Roudenko*, N.Chaban**, G.Kuz'micheva**
*I.M.Sechenov State Medical Academy, Moscow , Russia
**M.V.Lomonosov State Academy of Fine Chemical Technology, Moscow, Russia

In this paper, we describe the results of urinary stone study of over 100 patients. The phase composition and crystal structure of kidney stones were examined by powder X-ray diffraction method (diffractometer HZG-4, CuK* radiation). The element composition was determined by the standard chemical analysis. The hardness of some stones was estimated by scanning tomography ("General Electric").
There are ocsalates the most widespread on territory of Moscow region (~75% of all specimens). Four types of other stones were distinguished based on whewellite content: (i) (~9%) stone rich in whewellite, (ii) (~3%) stones with low whewellite content, (iii) (~3%) stones without whewellite consisting of phosphates, (iv) stones without whewellite consisting of uric acid (~7%) and other phases (~3%). There are a geometrical accordance (epitaxy) between the cell parameters of these phases. The hardness (H) obtained by scanning tomography and X-ray density (dcalc, g/sm3) of urinary stones obeys d(*0.07)=1.539+0.000485H. The difference between the calculated and experimental results can be ascribed to the presence of an organic matter or (and) porcsity of an urinary stone.
The effect of the in vitro and in vivo medicin treatment (blemaren-N, canifron, alcoholic potertilla erecta solution) on the decrease of dimensions and modification of properties of urinary stones is found. A dissolution as shown by the results of analysis can be associated with the stone composition.

WIDER POSSIBILITIES OF SPIRAL COMPUTED TOMOGRAPHY IN PATIENTS WITH NEPHROLITHIASIS

Yu.G. Alyaev, G.P. Filimonov, L.M. Rapoport, V.I. Rudenko,
A.Z. Vinarov, P.V. Vasilyev, A.V. Marteushev
Urologic Clinic, Moscow Sechenov Medical Academy, Moscow, Russia

PATIENTS AND METHODS. In 2000 we used spiral CT (General Electric device) with densitometry in 29 patients having nephrolithiasis. Objective of the study was to determine structural density of renal and ureteral stones and to correlate the density with ESWL results (Lithostar-Plus device produced by Siemens).
RESULTS. The study included series of axial sections, and then stone area was scanned repeatedly in more detailed spiral mode. Further examination used "Tissue Volume" software option that takes primary data obtained during the stone area survey for description of the stone features (dimensions, volume, contours, structure, and density). Moreover, using "Tissue Volume", we get a histogram demonstrating percentage of specific density items in the stone bulk. According to the histogram, we can calculate percentage of the items with certain density interval (from minimal to maximal values). Considering computed densitometry and number of ESWL procedures, we revealed three density areas: 500-600 H (low), 700-1,000 H (medium), over 1,000 (high). Maximal density of 1,900 H was seen in 1 patient.
CONCLUSION. 12 patients with stones of 800-H density required 2-3 ESWL procedures. Evaluating influence of computed densitometry results on efficiency and number of ESWL procedures, one should consider stone location (kidney, ureter), density variation (percentage), stone volume.

OUR EXPERIENCE WITH MAGNETIC RESONANCE
UROGRAPHY (MRU)

Yu.G. Alyaev, L.M. Rapoport, A.Z. Vinarov, N.A. Grigoriev, A.V. Marteushev
Urologic Clinic, Moscow Sechenov Medical Academy, Moscow, Russia

INTRODUCTION. MRU is a new non-invasive method diagnosing upper urinary tract obstruction. Objective of the study was to evaluate informativeness of MRU (when compared to IVU) in disclosure of level and cause of the obstruction.
MATERIALS AND METHODS. In 2000 we conducted MRU in 31 patients aged from 17 to 63. The devices were Signa Horizon and Signa Profile produced by General Electric, with magnetic field intensity of 1,5 and 0,2 T respectively. 17 patients had ureteral stones, 10 ones - hydronephrosis, in 3 patients ureteral stenosis was revealed, one patient suffered from bladder cancer. No contrast materials were used.
RESULTS. Information obtained by MRU on obstruction level and on degree of urinary tract dilatation was analogous to that of IVU. In one case MRU appeared more informative as helped to accurately locate ureteral stone that appeared very mild opaque on IVU. In the cases when IVU was avoided or the involved kidney did not show up, MRU provided sufficient diagnostic information without invasive procedures. In 6 hydronephrosis cases, MRU was preceded by diuretic (Lazix 10 mg) injection - distinct dilatation of collecting system was seen and in 5 cases dilated ureter was visualized, thus retrograde studies were avoided.
CONCLUSION. MRU appears comparable with IVU for diagnosis of upper urinary tract obstruction. MRU plays special role in workup for nonfunctioning kidney, with renal failure and allergies to contrast material.