EXTRACORPOREAL SHOCK-WAVE LITHOTRIPSY (ESWL) MONOTHERAPY FOR STONES IN LOWER URETER EZEKIEL H. LANDAU, M.D. DOV PODE, M.D. ZVI LENCOVSKY, M.D.
GIORA KATZ, M.D. SIMON MERETYK, M.D. AMOS SHAPIRO, M.D.
From the Department of Urology, Hebrew University Hadassah Medical Center, Jerusalem, Israel ABSTRACT-Extracorporeal shock-wave lithotripsy (ESWL) has been accepted as the method of choice for most upper urinary tract calculi. However, in cases of stones in the lower ureteq ureteroscopic procedures have generally been preferred. Using the Dormer HM3 lithotriptor with modifications in the patient’s position, we were able to successfully treat 155 unselected cases of lower ureteral calculi. The average stone size was 9.6 mm (range 5-23 mm). One hundred forty-three patients had stones located below the lower margin of the sacroiliac joint. These patients were placed in a supine position. The stones were visualized radiologically without use of a ureteral catheter in 78 percent of the patients; in 22 percent a ureteral catheter was inserted prior to ESWL to aid in stone localization. In 145 patients (94 %) treatment was completed in one session; 10 patients (6%) required two sessions. Of the patients, 38 percent were free of stones one day afteT ESWL; 97 percent became stone free within three months, and only 3 patients required endoscopic manipulation, after ESWL, Twelve patients had stones in the midureter overlying the sacroileum. They were placed in the prone position, and the calculi were visualized with the aid of a ureteral catheter. All these patients became free of stones one month after treatment. There were no significant treatment-related complications except for bacteremia in 1 case. In view of the remarkable efficacy, negligible complication rate, and shorter hospital stay as compared to ureteroscopic stone manipulations, we recommend high energy ESWL as the primary monotherapy of mid and lower ureteral stones. Extracorporeal shock-wave lithotripsy (ESWL) has been accepted worldwide as the standard method of treatment for stones in the upper part of the ureter, i.e., above the iliac crest. However, the treatment of choice for stones in the lower ureter is still controversial. The rigid ureteroscope is widely used for ureteral stone extraction in conjunction with various baskets and ultrasonic or electrohydraulic disintegrators .l In a few centers patients have been treated with pulsed-dye lasers which can be transmitted through a thin flexible ureteroscope. 2,3The success rate with the various endoscopic procedures has been over 90 percent in
most series. Ureteroscopy, however, is an invasive procedure with the potential risk of perforation, stricture formation, or even avulsion of the ureter in about 5 percent of cases3-5 Such complications make less invasive procedures preferable. Recently ESWL has been used successfully in the treatment of lower ureteral stones. Miller, Bubeck, and Hautman# first suggested a new positioning technique in the Dornier HM3 lithotriptor, using the perineum as the point of entry for shock waves, while the patient is in a “sitting position.” Since then several centers have presented their results with ESWL as the
(A) Supine position for ESWL of stone below lower margin of sacroiliac joint. (B) Prone position o&dying s&oiliac joi&.
preferred treatment of distal ureteral stones using the HM3 lithotriptor,‘-l4 or a second-generation lithotriptor. l5 This approach had no significant morbidity, and the results were comparable to the best results of ureteroscopic procedures. Stones overlying the sacroiliac joint are not readily accessible for ESWL in the supine position because of interference of the shock-wave transmission by the pelvic bones. However, noninvasive fragmentation of stones in this region has been described, using ESWL in the prone position.15*16 We report on our experience with ESWL as the primary treatment in patients who presented with stones in the lower half of the ureter and review the increasing experience worldwide. Material and Methods During the last two years all patients presenting with distal ureteral stones which required intervention were treated by ESWL in situ. Patients with significant hydronephrosis, recurrent colic, infection, or stones larger than 5 mm were included. A total of 155 consecutive patients were treated with the Dornier HM3 lithotriptor and were followed prospectively thereafter. There were 100 men (65 % ) and 55 women (35 % ). The age of the patients ranged between three and eighty years (mean 45 years). All patients were evaluated by plain abdominal radiographs and an intravenous pyelogram. One hundred forty-two patients had a solitary stone and 13 patients had two to four stones located in the distal ureter; 16 patients also had small calculi in the ipsilateral kidney. The diameter of the treated ureteral calculi was between 5-23 mm with an average of 9.6 mm. Of the patients 83 percent had various grades of hydronephrosis on the pretreatment intrave-
nous pyelogram (IVP), Epidural anesthesia was used in 92.3 percent of the cases; 7.7 percent of the patients received general anesthesia. One hundred forty-two patients had stones below the inferior margin of the sacroiliac joint. These patients were placed in a flat supine position with a slight rotation of the treated side downward, using horizontal adjustment of the leg and shoulder supports. The nearly horizontal position of the pelvis enables x-rays and shock waves to enter through the obturator foramen or greater sciatic notch. The patients were secured with the usual straps on the thorax, abdomen, and legs. No modifications of the conventional Dornier HM3 chair were necessary (Fig. 1A). Whenever pretreatment stone localization without anesthesia was difficult (e.g., semiopaque stones, obesity), a ureteral catheter was inserted endoscopically. Twelve patients with stones overlying the sacroiliac joint were treated in the prone position. The patients were placed with their arms embracing the standard subassembly of the back, and their knees resting on the straightened lower subassembly (Fig. 1B). The water level in the bath was lowered so that only the abdomen and thighs were submerged. In all of these cases a ureteral catheter was placed distal to the stone to aid in stone localization. Patients with urinary tract infection were treated with parenteral antibiotics starting twelve to twenty-four hours prior to ESWL. Six patients underwent percutaneous nephrostomy drainage prior to ESWL because of obstruction and fever at the time of admission to the hospital. Sixteen patients who had stones in the distal ureter and in the ipsilateral kidney underwent ESWL for both stones at the same session. We do not routinely use urethral catheterization for drainage of the bladder during treatment. The results were evaluated radiologically by plain abdominal x-ray films, one day, ten days,
TABLE I. Stone-free rate post ESWL Stone Size (mm) 5-10 lo-25 TOTALS
stones in distal ureter
Stone-Free Rate (%) 10 Days 30 Days
89/91 (97.8) 38198 (38.8) 68192 (73.9) 87192 (94.6) 38140 (95) 16/45 (35.5) 25143 (58.1) 31/42 (73.8) 541143(37.8) 931135(68.8) 118/134(88.1) 127/131(97)
TABLE II. Stone-free rate post ESWL with or without a ureter catheter Ureter al Catheter
13132 (41) 41/111 (37)
Stone-Free Rate (% ) 10 Days 30 Days 22132 (69) 71/103 (69)
one month, and three months after treatment. Excretory urography was obtained at one month and six months post-treatment. If unsatisfactory disintegration was found after treatment, ESWL was repeated once within four to six weeks. Results
30132 (94) 88/102 (86)
3 Months 32/32 (100) 95199 (96)
teral catheter during ESWL is shown in Tables I and II. A significant difference in the stone-free rate within ten days or one month was found with stones larger than 10 mm. However, three months after treatment there was no difference. This indicates that the time interval which is required for complete elimination of the stone fragments increases with the stone size but the end result is similar. Placement of a ureteral catheter had only minimal and nonsignificant effect on the stone-free rate following ESWL. Excretory urography post treatment showed marked improvement of the hydronephrosis and contrast excretion in 89 percent of the cases within one month. There were no significant treatment-related complications. The incidence of ureteral colic following treatment was low, only 19 patients (12%) required parenteral analgesics. Two patients had a temperature elevation above 38 “C, one of them had transient bacteremia. No intestinal complications occurred following ESWL using the prone position.
All stones were treated in situ. Thirty-two patients with a stone below the sacroiliac joint and all 12 patients with stones overlying the sacroiliac joint underwent ureteral catheterization to facilitate stone localization. The ureteral catheters were removed immediately after treatment. The number of shock waves ranged from 450-3,300 (mean 2,265 f 47) using 22-24 kV. Ten patients (6%) needed a second ESWL session due to incomplete fragmentation. Complete stone-fragmentation was achieved in 98 percent of the cases. This could not always be demonstrated on the fluoroscopy monitor during treatment but was evident on follow-up plain x-ray films one to ten days later. The average hospital stay after treatment was 1.32 f 0.1 days. Of the 155 patients, 143 were followed for at least three months after treatment. The success in terms of stone-free rate from one day to three months is summarized in Table I. Of the 143 patients with stones below the sacroiliac joint 54 (38 % ) became free of stones by the time they were discharged; 69 percent became free of stones within ten days after treatment, 88 percent within one month, and 97 percent by three months. Of the 4 patients who had retained stone fragments at three months, 3 (1.9%) required endoscopic retrieval of the stone particles. All 12 patients with a stone over the sacroiliac joint became stone free within one month. Further breakdown of the results according to the size of the stone or the presence of a ure-
The great majority of ureteral calculi are expected to pass spontaneously. However, stones larger than 5 mm in diameter are more likely to cause hydronephrosis, intractable colic, or infection.” Until now, distal ureteral calcui were an indication for transurethral endoscopic manipulations or open surgery. Endoscopic ureterolithotripsy has improved greatly during recent years, and the success rate with distal ureteral stones has been greater than 90 percent in most series. 1,3~18 However, rigid ureteroscopy may result in complications such as colic or fever in up to 23 percent of the cases, and perforation, avulsion, or stenosis in up to 5 percent.3-5,12 In some cases ureteroscopy may fail due to migration of the stones into the renal
/ AUGUST1992 I VOLUME40,NUMBER2
Results of ESWL
No. of Pts.
Author Selli and Carini7 Petterson and Tiselius* Zehntner et al9 Miller and Hautmann”’ Cole and Shuttleworth” Chakrabarty and Talic12 Becht et aLI3 Reeker et al. I4 Voges et aLI5 Landau et al.
70 28 264 131 40 53 39
for stones in the lower ureter. Review of the world literature
Type of Lithotriptor
Sitting Supine Supine Sitting Sitting Sitting Supine Supine Supine Supine
HM3 HM3 HM3 HM3 HM3 HM3 HM3 HM3 Lithostar HM3
Stone-Free Rate Post ESWL (%) 1 Day 3 Months 49 39 47.2 .
. . is 73 38
collecting system. Laser fragmentation was successful in 87 percent of 151 lower ureteral stones,2 however, large or hard stones are frequently refractory to laser. With increasing experience in the application of ESWL, attempts have been made to use this method as the primary treatment of distal ureteral stones. Miller et al.* reported the first series of ESWL of distal ureteral calculi in 43 patients, by modifying the patient’s position in the HM3 Dornier lithotriptor. The patients were placed in a “sitting position” and the shock waves were directed through the perineum. Treatment was successful in 86 percent of the cases, the retreatment rate was 14 percent, and additional procedures were necessary in 10 percent of the patients. Since then several authors have reported better results using the standard HM3 unit3*7m11.13J4 a second-generation lithotriptor15 (Table III), Stone fragmentation was achieved in 95-100 percent of the cases, and the stone-free rate was about 95 percent (range 87.5-100%) three months after treatment. ESWL was possible if the patient’s position was modified, but there was no need for any modifications in the HM3 lithotriptor chair. In some series the patients were treated in a sitting position.7.10-12 This could be done under epidural anesthesia only, since it requires an awake and cooperative patient. We preferred the supine position as was done in other series8,gJ1.14in which shock waves were directed through the greater sciatic notch. There was no difference in the success rate between these approaches. Several authors have indicated that the most likely explanation for failure of ESWL of impacted ureteral stones is the lack of fluid interface between the stone and the wall of the ureter and the lack of space for expansion. For these reasons retrograde manipulation of the stone back to the kidney was advocated for
VOLUME 40. NUMBER 2
94.2 100 96 94 87.5 90 95 95 87.5 97
Use of Ureter -Catheter (% of Cases)
Ureteroscopy or Ureterolithotomy
98 79 33 0 12.5 19 0 100 22 22
13 3.5 7.2 11.8 2.5 8 18 0 12 6.5
2 3:7 5.9 3.8 5 5 12.5 1.9
stones in the upper ureter. However, it could not be done safely in most lower ureteral stones. Petterson and Tiseliuss achieved fragmentation rate of 100 percent by regular use of a ureteral catheter; and whenever it was not possible to pass the catheter above the stone, they used fluid infusion through the ureteral catheter to create a fluid interface between the stone and the urothelium. Selli and Carini7 were able to increase the success rate to 97.5 percent using a Zeiss sling during ESWL. In their opinion this combination allowed exact radiologic visualization and at the same time created a wider fluidstone interface. In our experience, in situ fragmentation was achieved whenever the stone could be localized during treatment regardless of stone size, obstruction, or duration of the calculus in situ. Exact localization of a stone in the lower ureter may often be difficult due to the presence of other calcifications in the pelvis. However, it can be done successfully with the aid of a ureteral catheter or use of contrast material. It is not clear whether placement of a Zeiss (lasso) catheter or a stent proximal to the stone is an improvement over the placement of a ureteral catheter below the stone. Miller and Hautmannlo achieved good results without any preliminary manipulations except for instillation of contrast material via a previously inserted nephrostomy in 28 percent of the cases. We did not find a significant difference in the efficacy of ESWL in situ without a ureteral catheter as compared with treatments in the presence of a catheter. The stone-free rate three months after ESWL without a ureteral catheter was comparable to the best outcomes in other series. In our opinion the main role of a ureteral catheter is in the radiologic localization of the stone. A ureteral catheter should be inserted in selected cases whenever stone localization may be difficult.
The remarkable efficacy of ESWL for lower ureteral stones using the HM3 lithotriptor is the result of precise fluoroscopic focusing and the use of high-energy shock waves. Painless extracorporeal lithotripsy without anesthesia, using lower energy and ultrasonic imaging may have inferior results. 16,17 Often, stone disintegration cannot be seen during the treatment. It is recommended, therefore, to apply further shock waves of higher kilovoltage until some effect is noted on the fluoroscopy monitors. Almost half of the patients are free of stone fragments by the time they are discharged. If complete stone fragmentation did not occur, the patient would benefit from re-evaluation followed by a second session of ESWL, four weeks after the first treatment. Ureteroscopy should be reserved for the small number of cases that prove refractory to two sessions of ESWL. In our experience ESWL monotherapy is also effective in cases with complete ureteral obstruction. Although a longer time was required for the stone particles to evacuate, the obstruction was relieved immediately in most cases. There is no need for percutaneous drainage of the kidney prior to ESWL unless obstruction is associated with infection. Stones overlying the sacroiliac joint cannot be treated in the supine position since the bones block the transmission of shock waves. We elected to treat such cases by ESWL in the prone position. Using high energy and a ureteral catheter in each case, we were able to eradicate 100 percent of the stones within one month. Our results were similar to those reported by Jenkins and Gillenwater.le However, we did not find it necessary to modify the original HM3 chair. Puppo et al. I’ applied lower energy using the “pain free” modified Dornier’s generator and therefore had a much lower stone-free rate. No gastrointestinal or other complications occurred as a result of shockwave transmission through peritoneal cavity. The treatment of women of child-bearing age is controversial since there is a theoretical possibility of damage to the internal genitalia . @,I3Most authors who have treated women in this age groupe,7~10*11,15 cited the results of an experimental model which had shown no mutagenic effect of the shock waves in vitro.lg Another experimental study, in vivo, found no adverse effects in terms of rate of pregnancies, fetal number, fetal weight, abortions, or teratogenie anomalies. I1
In our opinion, as opposed to othersso the remarkable efficacy of ESWL, the negligible complication rate, and the shorter hospital stay as compared with rigid ureteroscopy justify the choice of ESWL as the first line of treatment for lower ureteral stones, whenever intervention is indicated.
Division of Urology Hospital for Sick Children 555 University Avenue Toronto, Ontario N6G M6G 1X8 Canada (DR. LANDAU) References 1. Dretler SP, and Weinstein A: A modified algorithm for the treatment of ureteral calculi: 100 consecutive cases, J Urol46: 732 (1988). 2. Dretler SP: An evaluation of ureteral laser lithotripsy: 225 consecutive patients, J Urol 143: 267 (1990). 3. Higshiharn E, et al: Laser ureterolithotripsy with combined rigid and flexible ureterorenoscopy, J Urol 143: 273 (1990). 4. Blute M, Segura JW, and Patterson DE: Ureteroscopy, J Urol 139: 510 (1988). 5. Flam TA, Malone MS, and Roth RA: Complications of ureteroscopy, Urol Clin North Am 15: 167 (1988). 6. Miller K, Bubeck JR, and Hautmann R: Extracorporeal shock wave lithotripsy of distal ureteral calculi, Eur Urol 12: 305 (1986). 7. Selli C, and Carini M: ‘Reatment of lower ureteral calculi with extracorporeal shock wave lithotripsy, J Urol 140: 280 (1988). 8. Pettersson B, and Tiselius HG: Extracorporeal shock wave lithotripsy of proximal and distal ureteral stones, Eur Urol14: 184 (1988). 9. Zehntner C, Casanova GA, Marth D, and Zingg ES: Treatment of distal ureteral calculi with extracorporeal shock wave lithotripsy-experience with 264 cases, Eur Urol 16: 250 (1989). 10. Miller K, and Hautmann R: Treatment of distal ureteral calculi with ESWL: experience with more than 100 consecutive cases, World J Uro15: 259 (1987). 11. Cole RS, and Shuttleworth KED: Is extracorporeal shock wave lithotripsy suitable treatment for lower ureteric stones? Br J Uro162: 525 (1988). 12. Chakrabarty A, and Talic R: Primary choice of intervention for distal ureteric stone: ureteroscopy or ESWL? Br J Uro162: 13 (1988). 13. Becht E, Moll V, Neisius D, and Ziegler M: Treatment of prevesical ureteral calculi by extracorporeal shock wave lithotripsy, J Urol 139: 916 (1988). 14. Reeker F, et al: Management of ureteral stones by extracorporeal shock wave lithotripsy-3 years of experience, Urol Int 44: 227 (1989). 15. Voges GE, Wilbert DM, Stockle M, and Hohenfellner R: Local shock wave lithotripsy of distal ureteral calculi, Eur Urol 14: 261 (1988). 16. Jenkins AD, and Gillenwater JY: Extracorporeal shock wave lithotripsy in the prone position: treatment of stones in the distal ureter on anomalous kidney, J Urol 139: 911 (1988). 17. Puppo R et al: Extracorporeal shock wave lithotripsy in the Drone wsition for stones situated anteriorlv.,, Eur Urol 15: 115 i1988)18. Sandegard E: Prognosis of stone in the ureter, Acta Chir Stand (Suppl) 219: 17 (1956). 19. Carrol PR, and Shi RY: Genetic toxicity of high energy -shock waves (abstract), J Urol 135: 292A (1986). 20. Kishimoto T, et al: ‘ho years clinical exnerience with extracorporeal shock. wave lithotripsy and transurethral ureterolithotripsy for ureteral stones at Osaka City University Hospital, Eur Urol 16: 343 (1989).
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