Pediatric Ureteroscopic Management Of Intrarenal Calculi

Main Category: Urology / Nephrology
Also Included In: Pediatrics / Children's Health
Article Date: 15 Dec 2008 - 1:00 PDT

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UroToday.com - This study by Stacy T. Tanaka, et al., from Children's Hospital at Vanderbilt, retrospectively reviewed ureteroscopic experience for stone treatment in children younger than 14 years of age.

The study included 50 (52 kidneys) who had had intrarenal calculi. The mean age of the group was 7.9 years, and mean stone size was 8 mm. The stone-free rate after a single ureteroscopic procedure was 50% on initial postoperative imaging and 58% with extended follow-up. The group found that the initial stone-free status was dependent on preoperative stone size but not the location. Additional stone procedures were required in 18 upper tracts. Younger patient age and larger preoperative stone size were associated with the need for additional procedures. Additional procedures were required in patients who hade stones greater than 6 mm but not in patients who had stones smaller than 6 mm.

The group concluded that ureteroscopy is a safe method for the treatment of intrarenal calculi in the prepubertal population. The group had shown that their ureteroscopic stone-free rate for upper renal calculi is lower than that reported for ureteral calculi. Parents should be informed that additional procedures will likely be required, especially in younger patients.

Their experience at Vanderbilt is slightly different from our experience at Children's Hospital of Philadelphia. Children at our institution treated for intrarenal calculi have a high stone-free rate after initial ureteroscopy. I do have to admit that we are unable to get the ureteroscope up to the kidney in just about half the patients. We have to pre-stent these patients and bring them back. We used to be very aggressive in placing the ureteroscope without pre-stenting and our overall success rate early on was low. Typically these children needed more than one procedure secondary to difficulty in manipulating the scope into the lower pole because the ureter is not dilated. This is further exascerbated by there being some blood in the urine, making visibility quite low. When the ureteroscope did not pass easily and we had pre-stented the patients, our success rate went up dramatically. Overall we have a stone-free rate of greater than 95%.

Our 5% failure rate was early on when we were not pre-stenting. With the larger stone size, patience is a virtue. You need to take your time and just literally remove as many fragments as possible. If you pre-stent in most of these cases, ureteral access chutes can also be very helpful with the manipulation of the ureteroscope in and out of the ureter. This will also aid in removing all of the small stone fragments after laser lithotripsy. In our experience pre-stenting or not pre-stenting did not change the number of procedures that were performed per patient. For children for whom the ureteroscope went up initially and we performed laser lithotripsy, we needed to leave the stent in for two weeks and then come back under anesthesia to remove it. Those children who needed pre-stenting ended up with ureteroscopy two weeks later and after having had that ureteroscopy very rarely needed stenting afterwards. When stenting was required it was always placed on a string so the patients did not have to undergo a third anesthetic.

In my opinion, pre-stenting might be beneficial for intrarenal calculi and should be further evaluated and not just discounted because it seems to be superficially a secondary, unnecessary procedure. In my experience, those that we pre-stented had two procedures and those that we did not pre-stent ended up having two procedures anyway.

Tanaka ST, Makari JH, Pope JC 4th, Adams MC, Brock JW 3rd, Thomas JC
J Urol. 2008 Nov;180(5):2150-4.
doi:10.1016/j.juro.2008.07.079

Written by UroToday.com Medical Editor Pasquale Casale, MD

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