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Saudi Journal of Kidney Diseases and Transplantation
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ORIGINAL ARTICLE  
Year : 2011  |  Volume : 22  |  Issue : 3  |  Page : 492-496
Retrograde intrarenal lithotripsy for small renal stones in prepubertal children


Department of Urology, Prince Hussein Urology Center, Amman, Jordan

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Date of Web Publication7-May-2011
 

   Abstract 

Advancements in ureteroscopy have now given the urologist virtually unrestricted access to calculi at all locations in the upper urinary tract. Retrograde intrarenal lithotripsy is a new modality to treat upper urinary tract stones in children. In this retrospective study, we present our experience in retrograde intra-renal lithotripsy in children over a period of 30 months. Fifty-six children with renal stones less than 1.5 cm in size, who underwent retrograde intrarenal lithotripsy during the period from January 2007 to June 2009 at Prince Hussein Urology Center, Royal Medical Center, Amman, Jordan, were included in the study. The average age was 8.2 years and male to female ratio was 2.1:1. The average size of the stone was 1.2 cm, ranging from 0.9 to 1.5 cm. Twelve patients (15.5%) had bilateral stones. All patients had a Double J stent inserted 2-4 weeks prior to the procedure. Ureteroscopy up to the renal pelvis was performed and fragmentation of the pelvic stones was performed by electrohydraulic lithotriptor and the patients were on follow-up during this period. Overall, a total of 78 procedures were performed in these patients. Twelve patients underwent bilateral procedures for bilateral disease, but in separate settings. Nine patients (16%) needed a second session for residual stones. Only four patients (7.1%) needed a third session. The clearance rate was 94.8%. Three patients (3.9%) developed upper urinary tract infection after ureteroscopy; one patient (1.7%) developed frank hematuria postoperatively that was treated conservatively. No residual stones or other complications were detected during an average of 34 months of follow-up. Thus, in the expanding field of pediatric urolithiasis, retrograde intrarenal lithotripsy seems promising and is less invasive and has fewer complications.

How to cite this article:
Abu Ghazaleh LA, Shunaigat AN, Budair Z. Retrograde intrarenal lithotripsy for small renal stones in prepubertal children. Saudi J Kidney Dis Transpl 2011;22:492-6

How to cite this URL:
Abu Ghazaleh LA, Shunaigat AN, Budair Z. Retrograde intrarenal lithotripsy for small renal stones in prepubertal children. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2019 Jul 16];22:492-6. Available from: http://www.sjkdt.org/text.asp?2011/22/3/492/80486

   Introduction Top


Stone disease is a major source of pain and suffering worldwide. Many epidemiologic studies have shown that urolithiasis in children is increasing in the recent years. [1],[2],[3],[4] The cause of stone disease in children is a multifactorial and polygenic condition. Pediatric nephrolithiasis is known to be associated with urinary tract infection, and anatomic as well as metabolic abnormalities, This accounts for the recurrent nature of the disease in children. [1],[3]

The clinical presentation in children is usually subtle with a less male predominance than in adults. [3]

Management options for the renal calculi in children are the same as for the adults, namely, extracorporeal shockwave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), open and laparoscopic surgery, and more recently, the new modality of retrograde intrarenal lithotripsy. [3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14] At present, there is an increasing interest in retrograde intrarenal lithotripsy for the treatment of renal stones; it has been used for even lower calyceal stones of size less than 2 cm. [3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14] Thus, advancements in ureteroscopy have now given the urologist virtually unrestricted access to calculi at all locations in the upper urinary tract. [3],[4],[5],[6],[7],[8],[9],[12],[13] With the advent of smaller ureteroscopes, the ureteroscopic management of renal calculi is becoming increasingly common in pre-pubertal children.

This study was conducted to analyze our expe-rience in treatment of renal stones of less than 1.5 cm in pediatric patients.


   Methods and Materials Top


This retrospective study was conducted by reviewing the records of all children who underwent retrograde intrarenal lithotripsy at Prince Hussein Urology Center, Royal Medical Center, Jordan, during the period from January 2007 to June 2009 (inclusive). A total of 56 children were included in the study. The inclusion criteria were: age range 6-14 years, stone size less than or equal to 1.5 cm and failed ESWL. Exclusion criteria included pa-tients with stone in lower calyx, which were difficult to access by rigid ureteroscope. Other exclusion criteria were anatomical anomalies making the retrograde access difficult, previous endoscopic failure and staghorn matrix stones.

All the patients underwent appropriate preoperative evaluation with abdominal radiography, renal and bladder ultrasound, excretory urography or renal computed tomography (CT) scan. Patients with recurrent stones underwent metabolic studies. Urinary tract infection was ruled out in all patients prior to the procedure. All patients had a double J (DJ) catheter inserted -two to four weeks prior to the procedure. Patients with bilateral disease were managed in two separate sessions.

The procedures were done under general anesthesia in all patients. Prophylactic dose of first-generation cephalosporins was given with the induction of anesthesia. The DJ catheter was removed and a safety guidewire was inserted through a retrograde open-ended catheter into the pelvis. Ureteroscopy using a 7.5-F rigid ureteroscope was performed up to the renal pelvis. The stone was identified, and using an electrohydraulic lithotripter, the stone was fragmented into tiny pieces. The larger pieces were extracted using a forceps or Dormia basket. If the stone was mobile in the pelvis, it was pushed to an easily accessible calyx and was fragmented there in a more fixed position. Irrigation with a hand-held syringe mechanism was used to maximize visualization. At the end of the procedure, a DJ stent was reinserted. The patient was discharged home on short course of antibiotics and pain killers.

The patients were seen in the clinic after 4 weeks when they were evaluated for residual stone fragments by abdominal radiography or by limited renal CT in radiolucent stones. If no residual stones were detected, the DJ stent is then removed. The patients were then followed up every 6 months in the clinic for recurrent stones or complications. In cases where there was a residual stone or recurrent stone, a second session was scheduled for the patient.

The data collected were analyzed for stone-free status and postoperative complications.


   Results Top


During the period from January 2007 to June 2009 (inclusive), a total of 56 children underwent ureteroscopy for renal stones at Prince Hussein Urology Center. The average age was 8.2 years (range 6-14 years). Thirty-eight patients were boys and 18 were females, making the male to female ratio 2.1:1. The average stone size was 1.2 cm, ranging from 0.9 to 1.5 cm. Twelve patients (15.5%) had bilateral stones as shown in [Table 1].
Table 1: Demographic data.

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The distribution of stones was as following: 34 patients (60.7%) had single pelvic stones; five had bilateral stones, six patients (10.7%) had upper group calyx stones, 4 patients (7.2%) had middle group calyx stones, and 12 patients (21.4%) had multiple stones in the pelvis and calyces; and 7 had bilateral disease [Table 2].
Table 2: The distribution of stones.

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A total of 78 procedures were performed. Twelve patients underwent bilateral procedures for bilateral disease in separate settings. Nine patients (16%) needed a second session for residual stones, five of whom had multiple stones. Only four patients (7.1%) needed a third session. Three of the second sessions were done for residual ureteric stones. The average residual stone size was 5 mm (range 4.5-7 mm).

The percentage of complete clearance of stones from the first session was 88.5% and it was 94.8% after the second session in patients with residual stones [Figure 1].
Figure 1: Clearance rate after retrograde intrarenal lithotripsy.

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Regarding the complications, three patients (3.9%) developed upper urinary tract infection after ureteroscopy and one patient (1.7%) de veloped frank hematuria postoperatively that was treated conservatively [Table 3]. No other complications including ureteral stricture were recorded up to a follow-up period of 34 months.
Table 3: Complications.

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   Discussion Top


Renal stones in pediatric age group have been a challenge since ages, but the recent advances in the ureteroscope have made it possible to access renal stones with less invasiveness in comparison to PCNL and open pyelolithotomy. [1],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14]

The size of stones targeted by our study was equal to or less than 1.5 cm which forms a relatively small stone burden and also allows some space for manipulating the stone in the pelvis. This achieves a better stone-free rate with less residual stones. [7],[9],[10] Staghorn matrix stones were excluded from the study since they carry a risk of getting infected and also carry the risk of causing sepsis and stone regrowth in the future. [8] However, in some studies, retrograde intrarenal lithotripsy was found effective in larger staghorn stones. [8]

In our study, 78 procedures were done by rigid ureteroscope. The presence of a DJ catheter prior to the ureteroscopy allowed easy dilatation of the ureteric orifice and the ureter, which allowed easy passage of ureteroscope to the ureter and pelvis. This decreased the incidence of ureteric injury during ureteroscopy by the rigid ureteroscope. [6],[7],[9] It also decreased the incidence of ureteral orifice stricture caused by balloon dilatation. [7]

The limitation of our study is that we used a rigid ureteroscope to access the stones and this caused limited access to the lower group calyx and calyces in acute angles with the pelvis. Flexible and semi-rigid ureteroscopes give better access to all calyces. [3],[4],[6],[9],[10],[11],[12],[13],[14] The other limitation of our study is that we used the electrohydraulic lithotripsy and not the holmium:YAG laser. With electrohydraulic lithotripsy, the stones get fragmented into small pieces, but it does not cause vaporization of the stone completely like the holmium:YAG laser. [9] Therefore, the stone fragments were relatively of larger size and multiple passages were needed for extraction of the stones. Fragments equal to or larger than 4 mm were extracted while stones smaller than 3 mm were left alone to be passed spontaneously because studies have proved that stones up to 3 mm in size will be passed spontaneously. [4],[8],[9]

In patients with bilateral disease, the procedures were done on two separate sessions to decrease the operative time and avoid bilateral discomfort and pain after the procedure. [4]

Postoperative fever was the most common complication in our study. There were three patients (3.9%) with postoperative pyelonephritis that was treated with intravenous anti-biotics. This is similar to the reported international incidence which is around 3% of cases. [12] The patient with postoperative hematuria resolved spontaneously with conservative treatment, with no long-term consequences.

The success of stone clearance in our study was 88.5% after the first attempt and 94.8% after the second attempt [Figure 1] which is comparable with other studies where the success rate is about 95%. [1],[10],[11],[12],[14] Among our patients, even after one session, the stone-free status was very high.

In the expanding field of pediatric urolithiasis in which the best mode of treatment remains a challenge, retrograde intrarenal lithotripsy, a new procedure with excellent results for renal stones in children, seems promising and is less invasive and has fewer complications than other modalities.

 
   References Top

1.Mandeville JA, Nelson CP. Pediatric urolithiasis. Curr Opin Urol 2009;19:419-23.  Back to cited text no. 1
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2.Tarkan LA. Rise in kidney stones is seen U.S. children. New York Times 10-27, 2008.  Back to cited text no. 2
    
3.Desai M. Endoscopic management of stones in children. Curr Opin Urol 2005;15:107-12.  Back to cited text no. 3
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4.Minevich E, DeFoor W, Reddy P, et al. Ureteroscopy is safe and effective in prepubertal children. J Urol 2005;174:276-9.  Back to cited text no. 4
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5.Canes D, Desai M. New technology in the treatment of nephrolithiasis. Curr Opin Urol 2008;18:235-40.  Back to cited text no. 5
    
6.Shah HN. Retrograde intrarenal surgery for lower pole renal calculi smaller than one centimeter. Indian J Urol 2008;24:544-50.  Back to cited text no. 6
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7.Smaldone MC, Cannon GM, Wu HY, et al. Is ureteroscopy first line treatment for pediatric stone disease? J Urol 2007;178:2128-31.  Back to cited text no. 7
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8.Grasso M, Conlin M, Bagley D. Retrograde ureteropyeloscopic treatment of 2 cm or greater upper urinary tract and minor staghorn calculi. J Urol 1998;160:346-51.  Back to cited text no. 8
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9.Smith RD, Patel A. Impact of Flexible ureterorenoscopy in current management of nephrolithotomy. Curr Opin Urol 2007;17:114-9.  Back to cited text no. 9
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10.Stav K, Cooper A, Zisman A, Leibovici D, Lindner A, Siegel YI. Retrograde Intrarenal Lithotripsy outcome after failure of shock wave lithotripsy. J Urol 2003;170:2198-201.  Back to cited text no. 10
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11.Grasso M, Ficazzola M. Retrograde ureteropyeloscopy for lower pole caliceal calculi. JUrol 1999;162:1904-8.  Back to cited text no. 11
    
12.Gross AJ, Bach T. Lower pole calculi larger than one centimeter: Retrograde intrarenal surgery. Indian J Urol 2008;24:551-4.  Back to cited text no. 12
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13.Matlaga BR, Assimos DG. The treatment of lower pole renal calculi in 2003. Rev Urol 2002;4:178-84.  Back to cited text no. 13
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14.Ferraro RF, Abraham VE, Cohen TD, Preminger GM. A New generation of semirigid fiberoptic ureteroscopes. J Endourol 1999;13:35-40.  Back to cited text no. 14
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Correspondence Address:
Lara Alex Abu Ghazaleh
Department of Urology, Prince Hussein Urology Center, P.O. Box 389, Amman, 11941
Jordan
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PMID: 21566306

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