Saudi Journal of Kidney Diseases and Transplantation

: 2007  |  Volume : 18  |  Issue : 2  |  Page : 200--205

Comparison of the Effect of Body Position, Prone or Supine, on the Result of Extracorpreal Shock Wave Lithotripsy in Patients with Stones in the Proximal Ureter

Afshar Zomorrodi, Amirreza Elahian, Nematollah Ghorbani, Anahita Tavoosi 
 Urology Transplant ward, Imam Hospital, Tabriz, Iran

Correspondence Address:
Afshar Zomorrodi
Associate Professor Urology Transplant ward Imam Hospital, Tabriz


The aim of this study was to determine whether positioning of the patient, prone or supine, plays a significant role on the treatment of stones in the proximal ureter with extracorporeal shock wave lithotripsy (ESWL). 68 patients with proximal ureteric stones underwent ESWL. The procedure was performed in the supine position in 35 (Group 1) and the prone position in 33 patients (Group 2). Stone-free rates, repeat ESWL rates, shocks per patient and shocks per session were compared in both groups. The mean session number per patient was 1.93 ± 0.82 in Group 1 and 1.88 ± 0.79 in Group 2 (P = 0.786). The stone-free rates, three months after ESWL, were 81.8% in Group 1 and 82.9% in Group 2 (P = > 0.05). Thus, these two parameters were similar in both Groups. Also, the number of shocks per session was 3066.1 ± 346.3 in Group 1 and 3148.5 ± 621.0 in Group 2. This difference was nonsignificant (P = 0.49). Our study suggests that the treatment of proximal ureteric stones with ESWL in the prone position is as safe and effective as when the patient is placed in the supine position.

How to cite this article:
Zomorrodi A, Elahian A, Ghorbani N, Tavoosi A. Comparison of the Effect of Body Position, Prone or Supine, on the Result of Extracorpreal Shock Wave Lithotripsy in Patients with Stones in the Proximal Ureter.Saudi J Kidney Dis Transpl 2007;18:200-205

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Zomorrodi A, Elahian A, Ghorbani N, Tavoosi A. Comparison of the Effect of Body Position, Prone or Supine, on the Result of Extracorpreal Shock Wave Lithotripsy in Patients with Stones in the Proximal Ureter. Saudi J Kidney Dis Transpl [serial online] 2007 [cited 2021 Dec 8 ];18:200-205
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Since the initial application in 1980,[1] the indications for the use of extracorporeal shock wave lithotripsy (ESWL) have rapidly extended from stones in the kidney to stones in almost the entire urinary tract. Extra­corporeal shock wave is the least invasive and most widely accepted form of treatment for ureteric stones.[2],[3],[4],[5],[6] In situ ESWL has been shown to be effective for ureteric stones at all levels.[7],[8] The least invasive procedure, urgent in situ ESWL, appears to be the preferred treatment option for ureteric stones associated with obstruction.[9] Chang et al.[10] reached a similar conclusion for upper ureteric stones, causing varying degrees of obstruction. The AUA guidelines state that ESWL and ureteroscopic lithotripsy (ULT) are both acceptable choices for stones of 1 cm in size located in the distal adult ureter.[11] Stone clearance after ESWL can vary and is influenced by stone size, location, chemical composition and type of lithotripter. The success rate of ESWL is reportedly inversely proportional to stone size.[12] It has been reported that ESWL with the patient in prone position is a safe and effective form of treat­ment for calculi in the distal ureter.[13] ESWL has become the favored treatment for most urinary tract stones. Overall stone-free rates after ESWL vary from 50 to 87% [14],[15] depending on many factors affecting the overall success rate. Coz et al.[15] analyzed the outcome of ESWL according to site in 2016 urinary tract stones. Stone-free rates for lower calyceal stones and upper or iliac ureteral stones are lower than the overall stone-free rate. After disintegration, the clearance of fragments depends upon their location. Successful ESWL is usually defined as being stone-free, three months after treatment. Residual frag­ments larger than 5 mm in diameter are generally considered a failure of the ESWL session. If the residual fragments are between 1 and 4 mm in size in an asymptomatic and un-infected patient, they are likely to be cleared spontaneously. Elevated serum calcium was found to influence the outcome of ESWL adversely.[16] Elevated urinary excretion of citrate was found to be positively associated with stone clearance.[17]

The Body mass index (BMI) is a non­urological patient factor that influences the outcome of ESWL.[16],[ 18], [19] Obesity may cause difficulty in imaging and placement of the calculus at the shock wave focal point. The best chance for successful ESWL was found in patients with a BMI of 20 to 28.[16] Consistent with this, Robert et al [19] found patients with a BMI > 25 as having significantly deeper urinary calculi and a worse outcome after ESWL.

Stones located in the bony pelvis were not originally amenable to ESWL. However, Jenkins [13] et al reported that some modifi­cations in patient positioning, such as place­ment in the prone position, allowed for successful fragmentation.

In this study, we decided to evaluate the influence of patient body positioning, prone or supine, on the success of treatment of patients with ureteric stones using ESWL in our center.

 Materials and Methods

The study included 68 patients with solitary upper ureteric stones treated with ESWL. It was conducted between November 2003 and July 2004 at The Imam Hospital, Tabriz, Iran. 33 patients were placed in the supine position during lithotripsy, while the remaining 35 were in the prone position. Excretory urography and/or plain abdominal X-ray were used to confirm the location of the stone. Upper ureteric stones were defined as stones located between the ureteropelvic junction and pelvic brim. Patients with stones in other parts of the urinary system, and those with stones smaller than 10 mm or larger than 20 mm were excluded from the study.

The two groups were established as follows: If stone targeting in the supine position was possible, the patient was assigned to be treated supine (Group one) .If the stone targeting was not possible in the supine position, the patient was assigned to be treated prone (Group two). The ESWL device used was lithostar with X­ray control for targeting. Two weeks after ESWL, a plain X-ray of the abdomen was taken to assess stone fragmentation. If no stone or fragments were detected at this stage, the patient was considered to be stone-free and was asked to return three months later for a repeat X-ray. If the film revealed any stone material, ESWL was repeated and the patient was radiographed two weeks later. This system was repeated three times.

In each patient, the stone size, number of shockwaves applied per treatment and number of sessions required to achieve stone-free status were recorded. Stone size was registered as the maximum diameter measured on a plain abdominal film. The number of shockwaves per treatment was established by dividing the total number of shockwaves received by the patient by the number of sessions required to become stone-free. Treatment failure was defined as radiologically confirmed persis­tence of the stone with no fragmentation after three ESWL sessions.

The results were analyzed statistically using a Student's t-test and chi-square test. P 15 mm in 12 (19.2%). The mean stone size in the prone and supine groups was 13.6 and 12.8 mm, respectively. The number of sessions necessary to achieve stone-free status was similar in the prone (1.8 ± 0.7) and supine (1.9 ± 0.8) groups (P=0.78). The mean number of shock waves applied per treatment in the prone group (3148.5 ± 621.0) was not significantly different from that in the supine group (3066.1 ± 346.3).(P=0.95)

Comparison of the results of the two groups using the Chi-Square test did not show any significant difference between them.


The treatment of urinary lithiasis has been transformed in the last 15 years, with the advent of ESWL.[20],[21],[22] ESWL is widely accepted today, despite the initial skepticism expressed by many urologists when Christian Chaussy, an unknown young urologist from Germany, first presented the innovative technique for fragmenting renal stones extracorporeally in 1980. [21]

It is believed that there are about 5500 lithotriptors throughout the world, with more than one third of them practicing in Europe. In 1998, two million ESWL treatments were performed.[23] ESWL is safe and effective in about 98% of patients.[2],[24] Nevertheless, controversy still exists concerning the long­term complications and whether ESWL actually reduces relapses.[25],[26]

Lumbar ureteric stones are stones that exist in the upper ureter, which lies between the iliac crest and the ureteropelvic junction. Ureteric stones located above the iliac crest are primarily amenable to treatment with ESWL. Ureteric stones treated in situ give a success rate no higher than 75%; however this rises to 90% after manipulation of the stone.[27],[28],[29],[30]

Since the introduction of ESWL by Chaussy in 1980, the therapeutic strategy for urolithiasis has completely changed. In 1986, Newman et al.[31] presented the first reports on ESWL in children. Since then, numerous reports have been published on the safety and efficacy of ESWL in children.[31],[ 32]

Currently, the primary method for treatment of symptomatic urolithiasis is ESWL. How­ever, clinicians argue about the position of patients (supine or prone) during ESWL. Some authors believe that supine positioning is cost effective, [32] has low morbidity [33] and prone positioning carries the risk of small intestinal perforation.[34] On the other hand, some authors are in favor of prone posi­tioning.[13],[35],[36],[37],[38],[39]

In their study of 96 patients, Goktas et al[33] observed that patients tolerated supine positioning better, in general. In their report, the mean number of sessions per patient was 1.64 +/- 0.75 in the supine group and 1.33 +/­0.59 in the prone group (p = 0.224). In this study, the stone-free rates three months after ESWL were 88.3% in the supine group and 90.6% in the prone group. The difference between the results was statistically non­significant (p <0.05). Similarly, in our study, we could not find any significant difference in outcomes of ESWL in prone and supine positions. Also, treatment of proximal ureteral stones with lithostar devices in the prone position was not associated with any signi­ficant complications.

A limitation of the study was that stone composition was not considered. Also, 17.6% of the present patients who had ESWL underwent some ancillary procedures to become stone-free; an impacted stone was the most frequent reason for failure in these cases.


Treatment of proximal ureteral stones by ESWL in the prone position is safe and as effective as that in the supine position.


1Chaussy C, Brendel W, Schmied E. Extracorporeally induced destruction of kidney stones by shock waves. Lancet 1980;2 (8207): 1265-8.
2Lingeman JE, Woods J, Toth PD, Evan AP, McAteer JA. The role of lithotripsy and its side effects. J Urol 1989;141:793-7.
3Holden D, Rao PN. Ureteral stones. The results of primary in situ ESWL. J Urol 1989;142:37-9.
4Miller K, Fuchs G, Rassweiller J, Eisenberger F. Treatment of ureteral stone disease. The role of ESWL and endourology. World J Urol 1985;3: 53-7.
5Graf J, Pastor J, Funke PJ, Match P, Senge T. ESWL for ureteral stones: a retrospective analysis of 417 cases. J Urol 1988;139:513-7.
6Hendrix AJ, Bierkens AF, Debruyne FM. ESWL treatment for mid and proximal ureteral calculi: in situ treatment or push bang technique: A randomised trial; Proceedings of the 1st European Symposium on Urolithiasis, Excerpta Medica, Medical Communications BV, Amsterdam, 1990; 172-4.
7Robert M, Delbos O, Guifer J, Grasset D. In situ piezoelectric extracorporeal shockwave lithotrispy of ureteric stones: Br J Urol 1995;76 435-9.
8Cole RS, Shuttleworth KE. Is extracorporeal shock wave lithotripsy suitable for lower ureteric stones? Br J Urol 1988;62:525-30.
9S-Joshi, Obadeyi. Rao, BJU International Volume 84 Issue 3 Page 264 - August 1999.
10Chang SC, Hann C, Tsi-Hsu K. Extracorporeal shock wave lithotripsy for obstructed proximal ureteral stones. Eur Urol 1993;24:177-84.
11Segura JW, Preminger GM, Assimos DG, et al. Ureteral Stones Clinical Guidelines Panel summary report on the management of ureteral calculi. The American Urological Association. J Urol 1997; 158: 1915-21.
12Shiroyanagi Y. Factors associated with failure of ESWL for ureteral stone using Dornier lithotripter U/50. Int J Urol 2002; 9: 304-6.
13Jenkins AD, Gillenwater JY. Extracor­poreal shock wave lithotripsy in the prone position. Treatment of stones in the distal ureter or anomalous kidney. J Urol 1988; 139: 911-5.
14Logarakis NF, Jewett MA, Luymes J, Honey JD. Variation in clinical outcome following shock wave lithotripsy. J Urol 2000;163: 721-5.
15Coz F, Orvieto M, Bustos M, et al. Extracorporeal shockwave lithotripsy of 2000 urinary calculi with the Modulith sl­20: success and failure according to size and location of stones. J Endourol 2000, 14: 239-46.
16Ackermann DK, Fuhrimann R, Pfluger D, Studer UE, Zingg EJ. Prognosis after extracorporeal shock wave lithotripsy of radiopaque renal calculi: a multivariate analysis. Eur Urol 1994;25: 105-9.
17Cicerello E, Merlo F, Gambaro G, et al. Effect of alkaline citrate therapy on clearance of residual renal stone fragments after extracorporeal shock wave lithotripsy in sterile calcium and infection nephrolithiasis patients. J Urol 151: 5-9.
18Ozgur S, Erol A, Gunes Zeki, Dalva I, Cetin S. Predictive value of a new scoring system for the outcome of primary in situ experimental extracorporeal shock wave lithotripsy of upper ureteral calculi. Eur Urol 1995; 28: 36-9.
19Robert M, A'Ch S, Lanfrey P, Guiter J, Navratil H. Piezoelectric shockwave lithotripsy for urinary calculi: comparative study of stone depth in kidney and ureter treatments. J Endourol 1999;13: 699-703.
20Jenkins AD, Gillenwater JY. Extracor­poreal shock wave lithotripsy in the prone position. Treatment of stones in the distal ureter or anomalous kidney. J Urol 1988; 138: 911-4.
21Chaussy C, Schmiedt E, Jocham D, Brendel W, Forssmann B, Walther V. First clinical experience with extracorporeally induced destruction of kidney stones by shockwaves. J Urol 1982; 127: 417-21.
22Drach GW, Dretler S, Fair W. Report of the United States cooperative study of extracorporeal shock wave lithotripsy. J Urol 1986; 135: 1127-9.
23Eisenberger F, Schmidt AS. Extracorporeal shock- wave lithotripsy. Curr Opin Urol 1993; 3: 30-14.
24Wilson WT, Preminger GM. Extracorporeal shock wave lithotripsy. An update. Urol Clin North Am, 1990; 17: 231-4..
25Chaussy CG, Fuchs GJ. Side effects and complications of extracorporeal shock­wave lithotripsy. Curr Opin Urol 1993; 3: 323-6.
26Tolley AD, Downey P. Current advances in shock wave lithotripsy. Curr Opin Urol 1999; 9: 319-22.
27Renner C, Rassweiler J. Treatment of renal stones by extracorporeal shock wave lithotripsy. Nephron 1999; 81 (1): 71-5.
28Planz B, Borchers H. Second in situ ESWL in not disintegrated ureteral stones is preferred to retrograde manipulation. Urol Int 1995; 55: 16-8.
29Mobley TB, Myers DA. Effects of stents on lithotripsy of ureteral calculi: treatment results with 18825 calculi using the lithostar lithotriptor. J Urol 1994; 152: 53-7.
30Watson RB, James AN. Extracorporeal shock wave lithotripsy for ureteric calculi with the Dornier MFL 5000 lithotriptor at multi-user centre. Br J Urol 1993; 72: 683-7.
31Newman DM, Coury T, Lingeman JE, et al. Extracorporeal shock wave lithotripsy experience in children. J Urol. 1986; 136: 238-40.
32Braun PM, Weber A, Michel MS, et al. Are auxiliary measures necessary in therapy of urolithiasis in children? J Endourol 1998; 12 (suppl 1): 1-8.
33Goktas S, Peskircioglu L, Tahmaz L, Kibar Y, Erduran D, Harmankaya C. Is there significance of the choice of prone versus supine position in the treatment of proximal ureter stones with extracorporeal shock wave lithotripsy? Eur Urol 2000 ;38(5):618-20.
34Kayacan Z, Kukul GE, Morbidity associated with patient positioning in extracorporeal shock wave lithotripsy of distal ureteral calculi. Int Urol Nephrol 1994;26( l):13-6.
35Kurtz V, Muller-Sorg M, Federmann G. Perforation of the small intestine after nephro-uretero-lithotripsy by ESWL-a rare complication. chirurrg 1999; 70(3):306-7.
36Shapiro A, Meretyk S, Katz G, Landau EH, Lencovsky Z. Extracorporeal shock-wave lithotripsy (ESWL) monotherapy for stones in lower ureter. Urology 1992;40(2):132-6.
37Ahlawat RK, Bhandari M, Kumar A, Kapoor R . Treatment of ureteral calculi with extracorporeal shock wave lithotripsy using the Lithostar device. J Urol 1991;146(3) : 737-41.
38Amiel J, Touabi K, Peyrottes A, Toubol J. Extracorporeal piezoelectric lithotripsy in the treatment of calculi of the ureter. Apropos of a series of 143 cases. Ann Urol (Paris) 1990; 24(2):135-9.
39Jenkins AD. Dornier extracorporeal shock­wave lithotripsy for ureteral stones. Urol Clin North Am 1988; 15(3):377-84.