SELECTED ABSTRACTS

Monday, October 4, 2004
MP-2: Stone Disease: ESWL/Endourology/Open Surgery

MP-2.01

Pelvi-calyceal height, a predictor of success when treating lower pole renal stones with extra-corporeal shock wave lithotripsy?

Shaw G., Symes A., Corry D., Choong S.
The Institute of Urology and Nephrology, London, Stone Unit, London, United Kingdom

Introduction & Objectives: Extra corporeal shock wave lithotripsy (ESWL) is the treatment of choice for the majority of renal stones. Stone size, composition and collecting system anatomy are contributing factors in the success of a treatment. ESWL has the lowest success rate in complete clearance of stones located in the lower pole. We assess the usefulness of pelvi-calyceal height in predicting success rates with these stones.

Material & Methods: We evaluated 52 patients with solitary lower pole calculi of less than 20mm treated with ESWL. Pelvi-calyceal height was measured on intravenous urogram and stone location and size were determined by plain radiograph. The number of treatments, number of shocks and the relative intensity of shock waves were recorded. Success was defined as complete stone clearance.

Results: Twenty-eight patients (54%) had successful treatment while the remaining 24 (46%) had incomplete stone clearance (including two patients in whom treatment had no effect). At a pelvicalyceal height less than or equal to 2.0cm there was a 75% success rate. Less than or equal to 1.5cm there was an 85% success rate. At equal to or less than 1.0cm there was a 92% success rate.

Conclusions: Pelvi-calyceal height is a useful predictor of success when treating lower pole renal stones with ESWL. The greater the pelvi-calyceal height the less likely ESWL is to be successful in completely clearing lower pole renal calculi.

MP-2.02

Ex-vivo evaluation of renal injury of a new electromagnetic shockwave generator with user selectable dual focus size

Haecker A.¹, Leistner R.¹, Knoll T.¹, Koehrmann K.U.¹, Alken P.¹, Michel M.S.¹, Marlinghaus E.H.^2
1University Hospital Mannheim/University of Heidelberg, Department of Urology, Mannheim, Germany, ²Storz Medical, Kreuzlingen, Germany

Introduction & Objectives: Renal hemorrhage due to vascular lesion is the most prominent side effect of ESWL. Parameters determining the extent of the lesion have not yet been completely evaluated. Since many years there is a discussion amongst users whether a large focus or a smaller focus is more effective in terms of disintegration and side effects. Therefore, a new electromagnetic generator was developed which allows the user to change the focal size even during the treatment. The aim of this ex-vivo study was to evaluate the influence of shock wave (SW) induced renal vascular damage at different focal diameters.

Material & Methods: Shock wave induced vascular lesions were investigated using the isolated perfused kidney model. Kidneys from slaughtered pigs were perfused with physiological NaCl solution. The operator was blinded with respect of the generator setting used.Shock waves were applied under ultrasound control in the parenchyma of a kidney pole (10-15 for each parameter) using the electromagnetic shock wave source of a modified Modulith SL 10 laboratory prototype at different SW numbers (25, 50, 125, 250 500 and 1000 SW) in 3 groups. Group A was treated with a wider focus, groups B and C were treated with the smaller original focus at different pressure settings. Peak positive pressure (PPP) in group A was 80 MPa, 60 MPa in group B and 120 MPa in group C (laser hydrophone). Disintegration power as measured by the crater volume in cubes of plaster of Paris was the same in groups A and C.Barium sulphate suspension was perfused after shock wave application. The kidneys were cut into slices (7 mm). X-ray documentation of the paravasation was performed using mammography film (Trimax HM Mamo). The x-ray images were investigated by a blinded person experienced in the analysis but not otherwise involved in the experiment. The area of paravasation, representing the extent of vascular lesion was measured.

Results: In all 3 groups (A, B, C) the diameter of the paravasate increased with higher SW numbers. At the same applied SW number, no differences between the groups were seen. Histological findings showed gap like defects and extravasation of barium sulphate that worsened with increase of the applied SW number.

Conclusions: In this ex vivo study, SW induced renal vascular injury was independent of the focal diameter of the SW generator, PPP and disintegration power.

MP-2.03

What is associated efficacy in extracorporeal shock wave lithotripsy? Our experience using the toshiba Echolith lithotriptor

Zouzumi M., Yanagiuchi A., Nakano Y., Matsumoto H., Fujii A.
Nippon Steel Hirohata Hospital, Urology, Himejisi, Japan

Introduction & Objectives: Our objectives were to assess the value of extracorporeal shock wave lithotripsy (ESWL) in treating urolithiasis, and to determine the factors that may affect treatment success.

Material & Methods: Between July 1993 and June 2003, 3325 patients for renal and ureteral calculi were treated using the Toshiba ECHOLITH ESL500 A/GP lithotripter (ultrasonography-based equipment only with piezoelectric shock waves production) with a total of 5000 treatments. The series consisted of 2331 men and 994 women with an age range from 11 years to 94 years (average age: 51.6 years). There were 1882 patients in left side, 1441 patients in right side, and 2 patients in both sides. ESWL procedures took place under only analgesic (93%) or no anesthetizing (3.4%). Patients were treated with 73123706 (meanSD) shocks under ultrasonic at an average of 1000 bar. Treatment success was defined as residual fragments smaller than 4 mm in size on post-treatment radiological evaluation. The patients were assessed 3 months after ESWL treatments and the results were compared using t-tests to detect factors that might be associated with treatment success.

Results: The average number of treatment of ESWL per case was 1.71.6 times. In 4305 (86.0%) cases, ESWL treatments were carried out with no taking a measure (ESWL in situ). One or two lithotripsy sessions were sufficient in most cases (93.7%). There were 40 cases of R1 (calyceal diverticulm), 1170 cases of R2 (renal pelvis), 209 cases of R3 (ureteropelvic junction), 811 cases of U1 (upper ureter), 225 cases of U2 (middle ureter), and 1023 cases of U3 (lower ureter). The mean sizes were 8.6 ± 3.9 mm for R1, 10.8 ± 9.6 mm for R2, 11.3 ± 7.1 mm for R3, 8.3 ± 5.1 mm for U1, 6.9 ± 3.1 mm for U2, and 5.9 ± 3.7 mm for U3. Overall success rates were 93.7% (51.6% for R1, 88.8% for R2, 97.2% for R3, 98.3% for U1, 89.8% for U2, and 97.2% for U3). Complications such as sharp pain, nausea and vomiting occurred in 11 %. Subcapsular hematoma and gastrointestinal injury did not occurred in. The significant factors associated with the efficacy were the diameter of the stone (P<0.05) and the place of stone.

Conclusions: ESWL is a safe and efficient first-line therapy for treatment of renal and ureteral calculi with acceptable treatment success rates and few complications. This study confirmed that the efficacy of ESWL is significantly influenced by stone size and place.

MP-2.04

Density of renal stone on computerized tomography: a predictor of stone fragmentation by extracorporeal shock wave lithotripsy but not of chemical composition of stone

Singh S.K., Mandal A., Goswami A., Rajarajan V., Mete U., Sharma S.
Post Graduate Institute of Medical Education and Research, Urology, Chandigarh, India

Introduction & Objectives: To evaluate the density of stone on computerized tomography for predicting the fragmentation of renal stone by extracorporeal shock wave lithotripsy (ESWL) and its chemical composition.

Material & Methods: Thirty patients with a single stone up to 20 mm in their kidney were studied. Density of renal stones on a W450 CTscanner (Hitachi Medical Corporation) was determined as described by Joseph et al., 2002. The patients received ESWL treatment with an electromagnetic Lithostar Multiline lithotriptor (Siemens) upto a maximum of 3 sessions (maximum 3500 shocks in one session) at an internal of 21 days. The stones were analysed by Fourier Transform Infra-red spectroscopy (FT-IR) for their chemical composition.

Results: An overall success rate of ESWL was 73.3%. There was partial fragmentation in 3 cases and no fragmentation in 5 cases. Patients with success and failures were comparable for their age, body mass index and stone size. Patients with mean stone density less than 1000 Hounsefield Units (HU) (group A) had significantly higher success rate in comparison to those with stone density more than 1000 H.U. (group B) (16/18, 88.8% vs 6/12, 50%; p<0.01). For stone fragmentation 77.7% (7/9) patients in group B required more than 7500 shocks, whereas only 56.2% (9/16) patients in group A required more than 7500 shocks (p<0.05). The success rate of the lower pole stone (3/10, 30%) was significantly lower (p<0.05). Out of 7 failures with lower calyceal stone 5 had stone density more than 1000 HU and in the remaining 2, it was approaching 1000. The density of stone was not related to chemical composition of stone. Calcium oxalate monohydrate (COM) was the predominant constituent in 23 cases and the mean density of these stones ranged from 338 - 1579 HU. The CT density of stone with different composition overlapped. In all the 8 cases who had unsuccessful treatment with ESWL, the stones had COM predominance.

Conclusions: The density of stone on CT may be used to predict the stone fragmentation by ESWL but not the chemical composition. The stone density appears to be one of the factors responsible for low success rate of ESWL for lower pole stones.

MP-2.05

Evaluation for acceptability of analgesic-free ESWL with Modulith SLK

Kim D., Woo S., Kim E.
College of Medicine Eulji University, Urology, Daejeon, South Korea

Introduction & Objectives: Electromagnetic lithotriptors, especially in the third generation, have the advantages of less pain and minute adjusting of shock wave intensity. Noticing these advantages of Modulith SLK, we evaluated the acceptability of analgesic-free ESWL, that is to say ESWL without any pre- & intra-procedural pain relieving preparations.

Material & Methods: Prospective analysis was done with renal stone patients who were scheduled for the first session ESWL procedure on an ambulatory basis. Patients with renal colic, uncontrolled UTI and bleeding tendency were excluded. ESWL treatment was performed with the third generation electromagnetic lithotriptor, Modulith SLK (Storz, Switzerland). Before starting the procedure patients were informed that no pain relieving preparation was done and if necessary, they could ask for analgesics injection at any time during ESWL. Monitoring the tolerability of each patient, shock waves were applied with stepwise increase of intensity (gradual increase by 5%) from 2.5 kV to 12.5-13.5 kV. The visual analog scale (VAS) had been used to determine overall pain level by way of a 0 to 100 mm line to indicate the severity of pain between 0 (no pain) and 100 (maximal possible pain). Patient demographics, BMI, stone size, shock wave numbers, intensity, stone fragmetation rate, pain score (VAS) and questionnaire for acceptability were evaluated.

Results: In this study, 53 male and 23 female with average age 50 (20-76 years old) were included. Stone surface area was 80.1 ± 82.3mm²(meanS.D) and stone fragmentation rate after the first session ESWL was 60.6 ± 26.1%. Shock wave volatages and numbers were 14.70.9 kV and 3974139. Pain scores evaluated with 100mm VAS were 22.6 ± 16.1. There was weak negative correlation between pain scores and patient?s age (Pearson correlation factor r= -0.390). Other factors such as sex, stone size and fragmentation rate had no correlation with pain scores. No patient asked analgesics injection for intolerable pain during ESWL. There were no complications reported relating to procedural pain. To the questionnaires for acceptability, 71 patients (93.4%) answered that the procedure was tolerable enough to accept next session ESWL, if needed. In patients answering unacceptability, any factors, including pain scores, had no statistical significance compared to acceptibility group.

Conclusions: We concluded that analgesic-free ESWL with Modulith SLK could be safely applied to most patients in our local community with acceptable tolarability. However, we couldn?t identify factors to discriminate unacceptable group from acceptable group. Individual tolerability rather than degree of subjective pain perception seems to be more important in respect of requesting pain control. Further research including more patient population will be needed to identify factors relating to individual tolerability.

MP-2.06

Comparison of results after lithotripsy of Therasonic LTS and SDS-5000 for urinary stones

Yoon S.M., Kang S.C., Rue J.G., Lee T.
Inha University Hospital, Urology, Incheon, South Korea

Introduction & Objectives: We compared results of Therasonic LTS (piezoelectric type) with SDS-5000 (spark gap type) for management of urinary stones.

Material & Methods: We evaluated 516 patients treated with Therasonic LTS from June 1996 to April 2001 and 314 patients treated with SDS-5000 from September 2001 to January 2003. We compared the success rates and shock wave sessions by the sizes and locations of stones, and cumulative success rates, complications.

Results: Between both groups, stones were located in kidney in 272 cases (52.7%) and 92 cases (29.3%), in ureter in 244 cases (47.3%), and 222 cases (70.7%), respectively. The distribution of stone sizes was 322 cases (62.4%), and 178 cases (56.7%) in less than 1cm2. The success rates of Therasonic LTS and SDS-5000 were 92.6% and 94.6%, respectively (p>0.05). In comparision to the success rates according to stone location and sizes, for Therasonic LTS and SDS-5000, there were no significant differences (p>0.05). But, In relation to the success rates according to stone sizes, for both Therasonic LTS and SDS-5000, the smaller sizes of the stones were the more successful (p<0.05). Average shock wave sessions were 3.06 and 2.54 respectively in Therasonic LTS and SDS-5000. There was statistically significant difference between two groups (p<0.05). In relation to the shock wave sessions according to stone sizes, for both Therasonic LTS and SDS-5000, the smaller sizes of the stones were the shorter therapeutic effect (p<0.05). The 3 cumulative success rates were 69.4% and 81.4%, and 5 cumulative success rates were 82.2% and 88.2%, respectively. With the complications, there were pain, gross hematuria, steinstrasse, APN, but were successfully controlled by conservative treatment.

Conclusions: The success rates were similar between Therasonic LTS and SDS-5000, but average shock wave sessions of SDS-5000 was shorter than that of Therasonic LTS. The complications developing clinical problems were not reported at both lithotripsies. Therefore, we suggest that ESWLs using Therasonic LTS and SDS-5000 are safe and effective methods, which should be considered as acceptable options for the primary management of urinary stones in selected patients.

MP-2.07

Lower calyceal calculi: multimodal management through SWL, URS and PNL

Pattnaik P.K.
S.S.Urological Institute and Bombay Hospital, Mumbai, India

Introduction & Objectives: Success rate for clearance of lower calyceal calculi depends on anatomical length, angulations configuration and size of the calculus. The aim of our study is to evaluate the efficacy of SWL, URS and PNL for clearance of the calculi.

Material & Methods: It is a prospective randomized study, symptomatic lower calyceal calculi ranging from 0.5mm to 2.5cm were divided into 2 groups. Group I consisted of 100 patients with 0.5-1.5cm calculi who were subjected to SWL/URS. Group II had 100 patients with stone size ranging from 1.6-2.5 cm, who were subjected to URS/PNL 3 months stone-free rate, morbidity, hospital stay, retreatment rate and ancilliary procedures were evaluated.

Results: In Group I: 68 patients become stone-free by SWL monotherapy, 32 patients were subsequently treated by flexible URS + Holmium laser fragmentation. In this group, 28 patients become stone-free. Residence fragments were seen in 4 patients in whom mini-perc was done to clear the fragments. In Group II: 29 patients became stone-free by SWL + D. J. Stenting - In 33 patients, flexible URS + Holmium laser fragmentation were required for clearance. 38 patients required PNL to make them stone-free. Avarage hospital stay ranged from 1.5 to 3 days. Complications were minimal and managed conservatively.

Conclusions: SWL is ideal as 1st line treatment up to 1.5cm size stones. Flexible URS + Holmium laser should be used for clearance if SWL fails or if the stone size is more than 2cm as 1st line treatment. More than 2 cm, most ideal treatment is PNL (Mini Perc) as 1st line therapy for quick clearance with least morbidity.

MP-2.08

Percutaneous nephrolithotomy (PCNL) in ectopic pelvic kidneys

Hamdy S., Hasouna M., Zahran A., El- Metwaly H., Marzouq E.
Faculty of Medicine, Alexandria University, Urology, Alexandria, Egypt

Introduction & Objectives: PCNL is a challenging technique in pelvic kidneys. The abnormal renal orientation, the unusual and unpredictable blood supply and the overlying loops of intestine are significant difficulties. We will present our technique and will evaluate its safety and efficacy.

Material & Methods: We applied the technique in 5 patients (up to February 2004). One patient had an open surgery few years earlier for multiple stones in the same kidney. Preoperative evaluation included IVU with lateral views and triphasic CT scans. The access was planned according to the stone location, collecting system topography, site of the renal vessels and the iliac vessels relationship. All patients underwent trans-peritoneal PCNL. Laparoscopy-assisted fluoroscopy-guided puncture was done. Alken's dilator set was used to create the working tract under laparoscopic control. An antegrade placement of a DJ was a routine and an intra-peritoneal drain was left at the site of the laparoscope.

Results: The procedure was done in 4 males and 1 female. Patients' age ranged from 23 to 42 years. All patients had ectopic kidneys in the true pelvis. The right side was operated in 2 and the left in 3. We treated single stones in 1 and multiple stones in 4; 2 of them had huge stone burden. In 2 patients we needed to mobilize loops of intestine away from the pelvic kidney. This needed an extra port in 1 and 2 extra ports in the second patient. Two PCNL tracts were done in two patients. Operative time ranged from 1 to 3 hours. All patients underwent a single PCNL session. All patients had complete stone clearance except 1. She had preoperative huge stone burden and in the postoperative evaluation, there was a 6x3 mm residual stone that was successfully treated with ESWL. One patient needed intra-operative blood transfusion and another 1 had delayed bleeding from the site of laparoscope port on the 1st postoperative day. This was controlled conservatively. All patients were discharge on the 4th or the 5th postoperative day.

Conclusions: PCNL is a safe and efficient minimally invasive treatment of stone disease in ectopic pelvic kidneys. Considering the low clearance rate following ESWL in ectopic kidneys, PCNL should be the standard treatment for large and small stones in ectopic pelvic kidneys.

MP-2.09

PNL for calculi in horseshoe kidneys

Pattnaik P.K.
S.S. Urological Institute and Bombay Hospital, Urology, Mumbai, India

Introduction & Objectives: Because of abnormal anatomical position, management of calculi in horseshoe kidneys often poses problems. We have studied the safety and efficacy of PNL in horseshoe kidney calculi.

Material & Methods: Fifty-six patients with calculi in horseshoe kidneys were treated by PNL from 1990 to 2002. Forty-four (79 %) were male and 12 (21%) were female; mean age was 36.8 years; 12 patients had Staghorn Calculi. Mean follow-up was 7 months. Stone-free rate, complications and need for ancillary procedures were evaluated.

Results: In 70% renal access was made through upper calyx, in 10% middle calyx and in 20% lower calyx. 86% become stone free in 1st sitting with PNL as immotherapy without ancillary procedures. In 8% where access was difficult into minor calices, puncture made through the same tract and calculi were removed after fragmentation. In 4% flexible scope + Holmium Laser was used to clear the fragments. In 2% ESWL was given because part of the calculi was near isthemus (mid-line); but no clearance after 3 sitting of ESWL (failure). Complications were minimal, in form of prolonged leak from nephrostomy, bleeding (2%) requiring blood transfusion and post-op pain in 2 cases, No deaths. Stone analysis done in all cases (96% Ca-oxalate, 2% Uric Acid, 2% Struvite).

Conclusions: PNL in horseshoe kidney, although difficult, is done by using flexible scopes with laser and making Y puncture for access to minor calices, maximum success ratio can be achieved with minimal morbidity.

MP-2.10

Flexible percutaneous approach in multiple pyelocalyceal stones

Geavlete P., Cauni V., Georgescu D., Nita G.
Saint John Clinical Emergency Hospital, Urology, Bucharest, Romania

Introduction & Objectives: Multiple pyelocalyceal stones (MPS), especially SWL resistant, could be well operated by percutaneous approach. Our goal was to describe the efficiency of flexible nephroscope by using a single access tract.

Material & Methods: Between September 2002 and November 2003 a total of 23 patients with MPS (between 2 and 11) underwent percutaneous approach after SWL failed. The stone surface area ranged from 334 to 796 mm2. As first step, we only used a single puncture, 17 by inferior calyx and 6 by medium calyx. In all cases, flexible nephroscope (Storz, 24 F.) was used as adjunct to rigid instruments (Wolf and Storz, 28 F.) during primary nephrolitotomy or as a second-look procedure to remove residual renal calculi. Simultaneous fluoroscopic control or intraoperative echography (for radiolucent stones) were necessary. Ballistic shock and ultrasonic probes were used for rigid nephroscopes and electro hydraulic probes (1.6/1.9F) for flexible one. For calculi removal we used flexible grasping forceps and Nitinol tipless basket. In 2 cases additional access tracts were necessary (secondary superior/medium calyceal stones).

Results: As the first step of percutaneous approach, in 19 cases we used the rigid nephroscope for fragmentation and removal of inferior/medium calyceal and pyelic stones, associated in 5 cases with concomitant superior calyceal stone removal. In 2 cases we only used the flexible nephroscope for concomitant superior and medium caliceal stones. In 1 case concomitant ureteropelvic stenosis imposed Nd:YAG laser-assisted incision through the flexible nephroscope. The stone-free rate with a single access tract was 86.9% (20/23 patients). Despite the flexible nephroscope performances, in 2 cases additional access tracts were necessary. So, our global stone-free rate was 95.6% (22/23 patients). No major complications were described.

Conclusions: According to our experience applied to MPS selected cases, especially failed ESW, flexible nephroscope may increase the stone-free rate and decrease the need for additional access tracts and procedures, even in multiple calyceal concomitant stone locations.

MP-2.13

Is ultrasonic and pneumatic lithoclast combination (Lithoclast Master) superior to pneumatic lithoclast alone for percutaneous nephrolithotripsy?

Desai M.
Muljibhai Patel Urological Hospital, Urology, Nadiad, India

Introduction & Objectives: To assess and compare the outcome of combination of the pneumatic and ultrasonic lithotripsy device (Lithoclast Master) with the pneumatic lithoclast alone for percutaneous nephrolithotomy (PCNL).

Material & Methods: The pneumatic lithoclast consists of upto12 Hz repetition rate can be fitted with different probes (0.8-3.2mm). The 1 mm lithoclast probe is advanced off-canter through the hollow 3.3mm & 4 mm ultrasonic probe and protrudes about 1mm from the probe. The ultrasonic device with frequency of 24-26 kHz. The whole hand held unit is light (340 g). An irrigation system with a pinch valve helps to control the irrigation fluid by varying the compression on the tube. The foot switch for activating the ultrasound, the pneumatic lithoclast, suction and all together, and a stone bucket at the outlet tube are new features.Between July 2002 and June 2003, 50 consecutive patients of renal stones were treated by standard PCNL using the combination device (Group A). This data was compared with 50 consecutive patients of renal stones treated by standard PCNL using pneumatic lithoclast alone (Group B). Renal insufficiency patients and those who required clearance of stone in more than 1 stage were excluded from the study.

Results: Group A: Average stone size was 566+/-334 square millimeters. Mean stone clearance time was 19.6+/-6.5 minutes. Stone clearance was complete in 48. Group B: Average stone size was 524+/-309 square millimeters. Mean stone clearance time was 31.3+/-14.9minutes. The P value is 0.0001. Time taken to clear100 sq mm of stone in group-A and group B was 3.46 min and 5.97 min respectively. The stone composition, locations were comparable. The residual fragments (RF) in Group A and Group B were 2 and 7 respectively. Blood loss was relatively less in Group A (packed cell volume [PCV] drop in Group A — 5.2+/-3.8%, Group B — 5.6+/-3.7%).

Conclusions: The lithoclast master is easy to use. Rapid coarse fragmentation by proven ballistic lithotripsy, fine fragmentation and pulverization by powerful ultrasonic-lithotripsy & multiplication of fragmentation power by simultaneous use of both technologies reduces the total operative time. Complications and residual fragments were less in the group A. There is no significant difference in blood loss in both the groups.

MP-2.15

Ureteroscopic management of upper ureteral stones by holmium laser

Abu Arafeh W., Zilberman M., Farkas A.
Shaare Zedek Medical Center, Urology, Jerusalem, Israel

Introduction & Objectives: Ureteroscopic management of ureteral calculi is well established as a successful and safe procedure. Although, the results of upper ureteral stones vary, and there is still controversies with ESWL. We present here our experience and results of ureteroscopic treatment of upper ureteral stones, combined with holmium laser lithotripsy.

Material & Methods: Between March 2000 and March 2004, 214 patients with ureteral stone were treated at our department of urology, by ureteroscopy and holmium laser lithotripsy. Out of these 214 patients, 98 were with sones located in the upper third of the ureter, including six cases of uretero-pelvic junction calculi. All patients were diagnosed and evaluated preoperatively by U/S and IVP or DMSA scan in case of iodine contraindication. The stones size varied between 8 mm and 1.2 mm, with different degrees of obstruction. The procedure was performed under regional anesthesia , utilizing the video-endo -vision system, and fluroscopy. The semirigid ureteroscope was introduced in to the ureter under direct vision after insertion of flexible guide wire. Stone fragmentation was performed by holmium laser. Residual fragments were extracted by a specific grasping forceps. JJ stent was placed in all cases at the end of the procedure, to be removed 2-3 weeks later after a plain x-ray control. The operative time was between 45 and 90 min, depending on size and stone location, and the anatomical variation of the ureter.

Results: Out of 98 patients with upper ureteral stone, 94 were free of fragments after the procedure, without any significant complication (93.8%). Access failure was reported in two cases, in which the procedure was abandoned. Ureteral injury occurred in an other two cases due to difficult manipulation, one case was managed conservatively by ureteral stent, whil the other underwent surgical exploration with ureterolithotomy.

Conclusions: Our results confirms that ureteroscopic management of upper ureteral calculi, combined with holmium laser lithotripsy, is a successful and safe procedure, with high stone free rate and minimal complications. We can consider also, that this procedure could be as the procedure of choice in the treatment of upper ureteral sones, in comparison with other non surgical methods like ESWL.

MP-2.16

Unenhanced computed tomography and primary ureteroscopy ? the end of ESWL for ureteric stones

Krah X., Hanschmann U., Lux O., Zak G., Eschholz G., Weber H.
HELIOS-Klinik, Dept. of Urology, Blankenhain, Germany

Introduction & Objectives: Renal colic is one of the most painful experiences of our patients. An urgent therapy, that is quick, safe, effective, pain free and will render the patient without residual stones is therefore highly desirable. In the year 2000 we developed an algorithm that comes as close as possible to those ideals.

Material & Methods: All patients admitted to our institution with acute renal colic, some dilatation on ultrasound and/or a positive urinalysis and without general inflammatory signs are subjected to an unenhanced CAT-scan. In case of a positive study an immediate ureteroscopy is performed aiming at total stone extraction. Double-J stent and transurethral catheter are placed. Perioperatively an oral antibiotic is given, the procedure is preferably done under spinal anesthesia.

Results: Stone detection with unenhanced CAT-scan was about 97%, thus comparable to the literature. In our about 80 patients per year the catheter could be removed the morning after. They could be discharged after an average of 48 hours. About half of them were rendered stone free, an additional 40% had remaining fragments, that did not warrant any additional treatment and about 10% needed ESWL. We saw minor ureteric lesions in less than 5% and did not encounter any serious complications. The ureteric stent was removed after an average of 10 days via flexible cystoscopy.

Conclusions: All our patients were highly contended with our approach and we experience a constant increase in stone cases since the year 2000. Economically and medically it seems the method of choice. ESWL will be confined to kidney stones and the odd ureteric remnant.

MP-2.17

Risk factors of renal colic following ureteroscopy for ureteral stone

Lee N., Jeon Y., Kim J., Kim U., Lee C., Jang S., Kim G.
Soonchunhyang Medical College, Department of Urology, Cheonan, South Korea

Introduction & Objectives: To identify risk factors of renal colic following ureteroscopy for ureteral stone, we analysed several factors related to postoperative renal colic in the patients who underwent ureteroscopic removal of stone.

Material & Methods: From January 2002 to December 2003, 136 patients with ureteral stones underwent ureteroscopy. The ureteroscopy was performed under general or spinal or epidural anesthesia using rigid ureteroscope (8.5Fr.) with 5Fr. working channel were used and ureteral approach were obtained without dilation of the ureter. Electrohydraulic lithotriptor (EHL) was used in fragmentation of the stone. The patients stented were 45 and unstented were 91. The indications of ureteral stenting were ureteral perforation, mucosal injury and obvious mucosal edema. Several factors were analysed to identify the risk factors of postoperative renal colic.

Results: Mean ages were 44.2 ± 13.6 and male to female ratio was 2.03. Laterality of the stones were 76 (55.9%), 59 (43.4%) and 1 (0.7%) respectively in right, left and both. Location of the stones were 8, 30 and 93 respectively in upper, mid and lower ureter. Mean stone size was 0.7 ± 0.34cm. Mean operative time was 37.2 ± 29.6min. Overall success rate of ureteroscopy was 97.1%. Among the unstented group, 12 patients (13%) had postoperative renal colic and 16 patients (17%) had mild to moderate flank or lower abdominal pain. There was no renal colic in stented group but 11 patinets (21.6%) had mild to moderate pain. Among the suspected factors large stone burden and long operative time was associated with the postoperative renal colic in unstented group.

Conclusions: These results suggest that large stone burden and long operative time are main risk factors of postoperative renal colic in the patients with unstented ureteroscopy.

MP-2.18

Ureteroscopic approach in recurrent ureteropelvic junction stenosis

Geavlete P., Mirciulescu V., Nita G., Georgescu D.
Saint John Clinical Emergency Hospital, Urology, Bucharest, Romania

Introduction & Objectives: Although open pyeloplasty remains the gold standard for treating ureteropelvic junction (UPJ) obstruction, endourological procedures, as minimally invasive techniques, could be very effective, especially in recurrences. Our goal was to establish the value of retrograde endopyelotomy (REP) by cold or laser incision in such cases.

Material & Methods: Between November 1997 and November 2003 we performed 30 REP in recurrent UPJ obstruction with III-rd and IV-th grade hydronephrosis (failed ureteropyeloplasty - 17 cases and failed endopyelotomy - 13 cases). Our series was characterized by: absence of renal calculi, absence of crossing renal vessels, stenosis length under 2.5 cm, absence of massive hydronephrosis. We used rigid and flexible endoscopic equipment (Wolf and Storz), cold knife/scissors and Nd:YAG laser (for the last 5 cases). In 17 cases, an indwelling ureteral catheter was placed for 2 weeks (blocked ureteral passage because of the UPJ scar tissue). The incision was made under video assistance and fluoroscopy, until the perinephric fat was largely and clearly exposed. An indwelling pyelostent 8/12 F was placed for 8 weeks. The follow-up schedule included sonography (gray-scale and especially Doppler), intravenous urography (IVP), and, in 11 cases, ureteroscopy.

Results: The success of REP did not correlate with the degree of hydronephrosis. In our cases with postoperative recurrent UPJ stenosis, we didn't describe a significant reduction of hydronephrosis. All cases were evaluated at 6, 12 and 18 months. IVP (especially for the ureteropyelic passage evaluation) and duplex Doppler echography (Resistive Index over 0.70 being considered to be correlated with the obstruction), were the main follow-up investigations. So,we found in 9 cases (30%) normal pyelocaliceal system with large ureteropelvic passage; in 4 cases (13.3%), an important reduction of the hydronephrosis degree with normal ureteropelvic junction; in 17 cases (56.6%) no changes of the hydronephrosis degree.The recurrence rate was 13.3% (4 cases). Minor complications appeared: in 3 cases we coagulated small vessels and 3 cases had urinary tract infections. The mean follow-up period was 38 months (4 to 69 months).

Conclusions: REP may represent an efficient minimally invasive technique in recurrent UPJ stenosis, with a reduced rate of complications, short period of hospitalization and good anatomical and functional results.

MP-2.19

Entonox as an analgesic agent during ESWL

Mazdak H.
University of Medical Sciences, Urology, Isfahan, Iran

Introduction & Objectives: Too many studies have evaluated the effect of local and systemic analgesics on relieving the pain associated with ESWL. However, none of them has addressed that of entonox. This study was planned to evaluate the effect of the gas, as an opioid alternative, on pain relief while performing ESWL.

Material & Methods: The study was a clinical trial. The patients were selected from the ones attending Ordibehesht Lithotripsy Center of Isfahan who underwent ESWL. A total number of 150 patients, equally distributed among entonox, petidine and compressed air groups, were selected. Simple method of sampling was applied. The VAS scale was used for measuring the patients pain severity. An individual patient determined his/her own pain severity on the scale before and after the intervention.

Results: The mean age of the 150 pafients was 44.04 11.3 years and 66.7 % were males. There was a significant difference between the mean pain severity scores before and after entonox inhalation (P= 000, F=12.6). That was true for petidin administration too (t=12.94 , p=000). No significant change was observed after the inhalation of the compressed air (p= 0/426,t=0/803). There was no significant difference between entonox and petidin for the aspect of analgesia among patients undergoing ESWL (p= 0/634, F=0.778).

Conclusions: The present study showed that entonox was effective in relieving the pain associated with ESWL. Its efficacy is comparable to that of petidine. Considening the fact that short-term use of this gas is without any major side effect, it can be regarded as an appropriate alternative for petidine in relieving the pain while performing ESWL.

MP-2.20

Renal fractures after laparoscopic renal cryoablation

Colon I.¹, Grunberger I.², Blitstein J.¹, Fuchs G.^3
1SUNY Downstate Medical School, Urology, New York, United States, ²Long Island College Hospital, Urology, New York, United States, ³Cedars-Sinai Endourology Institute, Urology, Los Angeles, United States

Introduction & Objectives: Laparoscopic renal cryoablation (LRC) is an effective nephron-sparing treatment for selected patients, particularly for those with multiple comorbidities and small exophytic peripheral tumors. The purpose of this study is to evaluate the potential operative complication of cryoablation.

Material & Methods: The records of fifteen patients with small renal masses that underwent laparoscopic renal cryosurgery were reviewed. A retroperitoneal laparoscopic approach was used to expose the kidney in most cases. Tumors were biopsied prior to cryoablation and a double freeze-thaw technique was used. Intraoperative laparoscopic ultrasound was utilized to localize and confirm the tumor location, monitor the biopsy and to assess the iceball formation.

Results: A total of 15 patients underwent laparoscopic ablative cryosurgery of renal cortical tumors. All patients had multiple comorbidities, four patients had a solitary kidney and three were on chronic coumadin therapy. Mean patient age was 75.6 years (range 68 to 82 years). The mean tumor size was 2.6 cm with a range of 1.4 cm to 4.4 cm. Eleven patients had satisfactory intraoperative biopsies performed. Three patients had a fast "Initial Freeze", while the rest had a gradual "Initial Freeze". Out of those three patients with a fast initial freeze, two patients developed an LRC induced "renal fracture". Both injuries were recognized intraoperatively after completely thawing the tumor. Intraoperative suturing of Gerota?s fascia over the laceration was required to tamponade the injury in both cases. One of the two patients required 2 units PRBC postoperatively for a drop in hemoglobin. The mean blood loss was 108.2 ml (range 30 to 500 ml). The mean operative time was 120 minutes (range 100 to 212 min). No patient required open conversion or re exploration. No other major intraoperative or postoperative complications were noted. Mean hospital stay was 2.9 days (range 1 to 5 days). Postoperative imaging demonstrated defects consistent with ablation of the affected area; however, a residual non-enhancing mass defect is usually demonstrated.

Conclusions: Laparoscopic renal cryoablation appears to be a safe technique for the treatment of small renal masses in patients with medical comorbidities and/or solitary kidneys. Post Cryo "renal fractures" may increase the morbidity of the procedure and appears to be related to a fast "initial freeze". Long term studies are still necessary to determine the long-term efficacy of this treatment modality.

MP-2.21

Retrograde endoscopic management of ureteral stones greater than 2 cm

Mugiya S., Ozono S., Nagata M., Takayama T., Nagae H.
Hamamatsu University School of Medicine, Department of Urology, Hamamatsu, Japan

Introduction & Objectives: Although the most common treatment for ureteral calculi is extracorporeal shockwave lithotripsy (SWL), SWL has had limited success in treating large ureteral stones. We used retrograde endoscopic lithotripsy, and define the safety and efficacy of this modality in treating large stone greater than 2 cm.

Material & Methods: From July 1996 to February 2004, we performed retrograde endoscopic treatment on 56 patients with large ureteral stones greater than 2 cm. The average age of the patients was 54.2 years, and there were 47 men and 9 women. The average maximum stone diameter was 2.6 cm (range: 2 to 11 cm). Nine of the patients had stones larger than 3 cm in diameter. Ten of the 56 patients had stones which had not been properly fragmented by SWL, including four patients with Steinstrasses. The other patients had stones that were considered difficult to treat by SWL because of impaction. Fifty stones were located in the upper ureter, 5 in the middle ureter, and 1 in the lower ureter. The mean duration of impaction was 17.5 months and the longest was 10 years. We used a 6.9 Fr. flexible ureterorenoscope for upper and middle ureteral stones and a 6.9 Fr. rigid ureteroscope for lower ureteral stones. For stone fragmentation, we used a holmium: YAG laser lithotriptor. Treatment was considered successful when the stone was no longer detected and postoperative IVP showed improvement of hydronephrosis.

Results: Of 56 patients 48 were treated solely in a retograde uretroscopic manner. In 47 out of 56 (83.9%) patients, the ureteral stones were fragmented completely by a single endoscopic procedure. Only 1 patient required 3 sessions of endoscopic lithotripsy. Additional SWL was performed after endoscopic debulking to treat small residual stones in 3 patients (5.4%) early in this series. All of them initially had stones larger than 3 cm in diameter. Pyelonephritis was observed in 5 cases, 3 of them required nephrostomy and 2 required insertion of stent before endoscopic procedure. These five cases necessitated a secondary endoscopic lithotripsy. There were no intraoperative complications in all 56 patients. The only postoperative complication was ureteral stricture 1 case. One month after treatment, no patient had evidence of residual stones. Using adjuvant SWL, a 100% stone-free rate was attained with minimal morbidity. IVP showed marked improvement of hydronephrosis,except in one patient who presented with an obstructing ureteral stricture, as described above.

Conclusions: Using a small caliber ureteroscope and a Ho:YAG laser lithotriptor, retograde endoscopic lithotripsy seems to be effective first-line therapy for large ureteral stones greater than 2 cm, which are resistant to SWL, to avoid the futile repetition of SWL and problems related to the prolonged passage of stone fragments.

MP-2.23

Laparoscopic retroperitoneal surgery for ureteropelvic junction obstruction

Kawa G., Satou M., Nishida T., Oguchi N., Muguruma K., Matsuda T.
Kansai Medical University, Moriguchi City, Osaka, Japan

Objectives: Reconstructive laparoscopic procedures have been recognized as less invasive treatment than conventional open procedures. However, though the laparoscopic pyeloplasty has also been accepted as useful, few findings have been reported relevant to the retroperitoneal approach. To elucidate its effectiveness and safety, laparoscopic surgery via the retroperitoneal approach was examined in our institution.

Materials & Methods: Between July 1998 and December 2003, 12 men and 8 women underwent laparoscopic retroperitoneal surgery for ureteropelvic junction obstruction. Mean patient age was 34.2 years (range 13 to 70). Methods of repair were determined by intraoperative findings for the relationship between the ureteropelvic junction and surrounding vessels.

Results: An aberrant renal vessel was found in 9 patients (45%). Only one procedure undergoing as the first experience was converted to open surgery due to difficulty with laparoscopic management. With the laparoscopic retroperitoneal approach, dismembered pyeloplasty was performed in 13 patients, Y-V plasty in 4, and Hellstrom technique in 2. The mean operative time was 272 min (range 155 to 490). The mean estimated blood loss was 36 ml (range 5 to 200). No major complications were observed during the intraoperative period, but urinary tract infection occurred in 3 patients in the postoperative period. In all patients, obstruction was improved or resolved.

Conclusion: We believe that laparoscopic retroperitoneal surgery is not only able to repair ureteropelvic junction obstruction, but can also be done safety and less invasively.

MP-2.24

Percutaneous nephrolithotripsy of multiple calyceal calculi

Pardalidis N., Kosmaoglou E., Papatsoris A., Andriopoulos N., Michalakis A.
H.AF Hospital, Athens, Greece

Objectives: Extracorporeal shock wave lithotripsy (ESWL) has limited success in the management of multiple calyceal stones. In an attempt to improve the success rate we present our experience with percutaneous nephrolithotripsy as a monotherapy.

Materials & Methods: 42 patients (22 males and 20 females) aged 34-72 years (mean 57,25) with multiple calyceal lithiasis, secondary to ESWL of staghorn calculi were treated percutaneously with the Y-tract technique under fluoroscopic control. After general anesthesia was induced, all patients in prone position underwent percutaneous nephrolithotripsy through one subcostal incision. A rigid nephroscope with an ultrasound lithotriptor for stone fragmentation was used and a reentry nephrostomy tube was positioned at the end of the procedure. Nephrostomography was performed and the tube was removed 48 hours postoperatively. The patients were followed up for 6 months with renal ultrasound.

Results: The mean operative time was 83,15min (53-112). No serious intraoperative complications were recorded and no blood transfusion was necessary. Postoperative nephrostomography revealed residual calyceal lithiasis in one patient, who was thereafter managed successfully with ESWL, while the remaining 41 patients were stone free (91,66%). Biochemical analysis of the fragments revealed struvite stones in 83,33% of the cases, calcium oxalate monohydrate in 3% and calcium phosphate in 13,3%. Follow-up ultrasound was normal in all patients.

Conclusion: Percutaneous ultrasound nephrolithotripsy with the Y-tract technique is a safe and efficient method for the treatment of residual multiple calyceal stones and can be established as a monotherapy.