Year : 2011 | Volume
: 27 | Issue : 1 | Page : 151--153
Extracorporeal shock wave lithotripsy in impacted upper ureteral stones: Comparison between stented and non-stented technique
Vikash Kumar, Jayesh V Dhabalia
Department of Urology, Lokmanya Tilak Municipal Medical College and Lokmanya Tilak Municipal General Hospital, Sion, Mumbai, India
Department of Urology, Lokmanya Tilak Municipal Medical College and Lokmanya Tilak Municipal General Hospital, Sion, Mumbai
|How to cite this article:|
Kumar V, Dhabalia JV. Extracorporeal shock wave lithotripsy in impacted upper ureteral stones: Comparison between stented and non-stented technique.Indian J Urol 2011;27:151-153
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Kumar V, Dhabalia JV. Extracorporeal shock wave lithotripsy in impacted upper ureteral stones: Comparison between stented and non-stented technique. Indian J Urol [serial online] 2011 [cited 2020 Sep 27 ];27:151-153
Available from: http://www.indianjurol.com/text.asp?2011/27/1/151/78406
Authors conducted a prospective randomized trial from June 2007 to June 2008 to compare the result of extracorporeal shock wave lithotripsy in impacted upper ureteric calculus with and without prior stenting. A total 60 patients with solitary, radio-opaque-impacted upper ureteral stones, of size ≤ 2cm were enrolled in this study and divided in two equal groups: a stented group with a double-J stent fixed pre-ESWL and a non-stented group treated by in situ ESWL. Randomization was done according to the day of presentation; patients presenting on even-numbered days were assigned to the stented arm of the study and those presenting on odd-numbered days were included in the non-stented arm. The stone was considered impacted if it caused moderate to severe hydronephrosis above its level, with non-visualized ureter below it on excretory urography. All patients were treated using Dornier Doli S lithotripter. Pre-treatment X-ray KUB and intravenous pyelogram and post-treatment KUB were used to evaluate fragmentation and clearance. Results were compared in terms of clearance rates, number of shock waves and sessions, morbidity and incidence of complications. Patient characteristics like age, sex, stone side, stone length and stone width were comparable in two groups. In results overall stone free rate was 88.3%. No significant statistical difference was observed in stone-free rate between the stented and non-stented groups being 90% and 86.7%, respectively (P = 0.346). One session was required in 28.3% of patients, whereas multiple sessions were required in 71.7% of patients. No significant statistical difference was noted in re-treatment rate in the two groups. Patients in the stented group significantly complained of side effects attributable to the stent predominantly dysuria, urgency, frequency and suprapubic pain.
The authors concluded that ESWL is an effective and reasonable initial therapy in the management of impacted upper ureteral stones measuring ≤2cm. Pre-ESWL ureteral stenting provides no additional benefit over in situ ESWL. Moreover, ureteral stents are associated significant patient discomfort and morbidity.
Urinary obstruction caused by an impacted stone is a serious problem as it may lead to progressive kidney dysfunction or severe complications, including pyonephrosis and sepsis. Stone impaction was thought to influence the success of fragmentation during ESWL. This fear has led many urologists to recommend JJ stenting before ESWL to create an artificial chamber, with an improved stone-fluid interface, for better fragmentation during ESWL and to relieve the obstruction.  However, this view has been challenged by some, who showed that the results of treatment are similar whether the stone is pushed back or treated in situ, with or without a stent. There are studies supporting ESWL even in impacted stone documented in IVU. , The 1997, as well as, 2007 AUA guidelines, report on the management of ureteral calculi, state that "Routine stenting is not recommended as part of SWL."  But the issue of stenting in impacted calculus is not discussed. In patients with impacted ureteral stones undergoing urgent in situ ESWL, urine (water) is present in the ureter above the stone, and there are no associated factors that may diminish the efficacy of shock wave energy. Other studies have shown that ESWL can relieve obstruction and even though disintegration may be partial after the first ESWL session, the obstruction is often relieved. Author has confirmed the belief of postulated benefit of a space-creating effect by a bypass stent may be negated by the stent itself, as it impedes shock wave propagation and energy transmission.  Several studies showed that stent may cause ureteral irritation, spasm and constriction as well as impede stone clearance instead of facilitating it. ,
In results at 3 months, stone-free rate was 90% in the stented group and 86.7% in the non-stented group. This difference was not statistically significant, which shows that insertion of a JJ stent did not add to the results and this additional procedure may not be necessary. There was no statistically significant difference between the average number of sessions per patient, retreatment rates and number of shock waves in both the stented and non-stented groups; all were higher for the stented group. This was found comparable to previous results published by other working groups.  Insertion of a JJ stent is an invasive procedure, usually requiring general or regional anesthesia, thus increasing the risk and morbidity of the procedure, especially in elderly patients with associated multiple co-morbidities. Despite the efficacy of laser lithotripsy, ESWL is the first-line treatment for upper ureteral stones because of its non-invasive nature.  Stent placement can also be technically difficult, particularly in an acute and completely obstructed system with the risk of ureteral perforation approaching 11% and failure rate approaching 20% even in the presence of well-trained urologists.  An additional procedure will be required for stent removal adding to the cost and risk of complications. Moreover, JJ stents are associated with some morbidity in the form of intractable discomfort, urgency and hematuria.  The presence of a stent may thus be detrimental, necessitating a high-power index to achieve the desired effect, which may in turn increase the complication rate.  Three patients had self limiting fever (1 in stented, 2 in non-stented) but different studies reported systemic sepsis after endoscopic manipulation or JJ stent insertion in impacted stones. The stent itself may act as nidus of infection and encrustation leading to irretrievable stents, especially in stone formers, as longer stent indwelling time is often required in patients who undergo lithotripsy.
The fear of higher steinstrasse is also negated in this study as there is no significant difference in incidence in two groups. El-Assamy et al,  found that the incidence of steinstrasse was doubled in the stented vs the non-stented patients (4.3% vs 2.1%). Although in previous studies it has been observed and postulated that stenting is required for stones bigger than 1 cm. This study strongly supports use of ESWL without stenting even in stone more than 1cm. One of the limitations of this study is that it has not used a validated questionnaire for ureteric stent symptom assessment. Another is that the effect of stenting or non-stenting has not been separately analyzed for > 1-cm stone group of patients. Also the average time to clearance and efficacy quotient has not been mentioned in this study.
This study draws an important conclusion that in the treatment of impacted upper ureteric stone ESWL without stent placement, gives comparable success rate along with added benefit of avoiding stent-associated morbidity. But it needs further validation in randomized studies focussed on stone size between 1 and 2 cm.
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