BJU International (1999), 84, 339–342

Minimally invasive treatment of urinary tract calculi in childrenM. FRASER, A.D. JOYCE, D.F.M. THOMAS*, I . EARDLEY and P.B. CLARKPyrah Department of Urology and *Department of Paediatric Urology, St. James’s University Hospital, Leeds, UK

Objective To report experience of a broad multimodality stones were treated with the lithoclast. Combinedtherapy including PCNL was required in three patients.approach to the treatment of calculi in children using

extracorporeal shock wave lithotripsy (ESWL), uretero- Results Of the 43 children treated, 38 (88%) wererendered stone-free. Metabolic disorders accounted forscopy/laser lithotripsy, lithoclast and percutaneous

nephrolithotomy (PCNL). three of the five cases of residual calculi. Complicationsrequiring intervention occurred in two children (7%)Patients and methods The treatment and outcome were

reviewed in 43 children managed by a range of and three subsequently underwent open pyelolitho-tomy or ureterolithotomy after unsuccessful minimallyminimally invasive modalities, either singly or in

combination, between 1990 and 1997. These patients invasive treatment.Conclusions Used selectively, the range of minimallyrepresent a selected group deemed suitable for mini-

mally invasive management during a period of invasive procedures available for adults, includingureteroscopy and PCNL, can be safely and eCectivelydeveloping experience with these techniques. Of this

cohort, six children had previously undergone open extended to the treatment of urinary tract calculi inchildren. The role of open surgery will diminish furtherstone surgery and contributory metabolic abnormali-

ties were identified in seven. ESWL was the sole with the availability of specialized instruments forpaediatric PCNL.treatment modality in 24 children (56%). In five

children (12%) ureteroscopy/laser lithotripsy was com- Keywords Urinary tract calculi, lithotripsy, ureteros-copy, methods, outcomebined with ESWL, eight (18%) underwent ureteros-

copy/laser lithotripsy alone, whilst three with bladder

minimally invasive therapies in a broad multimodalIntroduction

approach to calculi in children.The management of urinary tract calculi has developedto such an extent over the last two decades that open

Patients and methodssurgical procedures for stone disease in the adult arenow viewed as uncommon. In contrast, minimally invas- During a 7-year period (1990–97), 43 children (26 boys

and 17 girls, median age 8.3 years, range 0.9–15.3)ive technologies have yet to play a comparable role inthe management of paediatric urolithiasis. In part this were treated with a range of minimally invasive modalit-

ies, either singly or in combination. Over a similar periodmay reflect the relatively low incidence of stones inchildren (two per million compared with two per thou- (1992–97), 30 open stone procedures were performed

on 25 children, of which 23 were nephrolithotomy orsand in adults) resulting in more limited opportunitiesto acquire experience with the necessary techniques. In pyelolithotomy for renal calculi. Five were carried out

in conjunction with pyeloplasties, two with open removaladdition there have been concerns about the suitabilityand safety of the instrumentation required to undertake of bladder calculi, and two with open ureterolithotomy.

Two open bladder stone extractions and two ureterolitho-minimally invasive procedures in children. Since theintroduction of ESWL by Chaussy et al. [1] in 1982, tomies were also carried out as isolated procedures. As

during this reported experience with minimally invasiveseveral reports have attested to its safety in this agegroup [2–10]; more recent reports describe successful technologies our policy of selection of patients for these

procedures was developing, this ‘open’ stone groupendourological procedures such as ureteroscopy andpercutaneous nephrolithotomy (PCNL) [11–18]. Thus, cannot be considered as a control group, but simply

reflects the paediatric stone workload of the unit.we reviewed our experience with an evolving policy ofIn 26 children (60%) calculi were confined to the

kidney; five children (12%) had isolated ureteric calculiand two (5%) had bladder calculi alone. The remainingAccepted for publication 31 March 1999

339© 1999 BJU International

340 M. FRASER et al.

10 children (23%) had stones involving more than one stone fragmentation in 15 patients and electrohydrauliclithotripsy in one (because the laser malfunctioned);site in the urinary tract. Renal stones were bilateral in

four patients. distal ureteric stone fragments were removed by bas-keting in only one of these.Using 24-h urine collections and IVU, respectively, all

patients were evaluated metabolically and radio- Of the four children who had bladder calculi treated,three were boys aged 2, 9 and 10 years, and the othergraphically. From these results and from hospital records,

metabolic risk factors and associated structural abnor- was a girl of 12 years. In addition to the bladder stone,three of these had another minimally invasive proceduremalities were identified (Table 1); stones were not rou-

tinely analysed. performed at the same theatre visit (one PCNL and twoendoscopic incision of ureteroceles) and therefore it wasSix children had previously undergone open stone

surgery, two in conjunction with pyeloplasty for PUJ felt that open removal of the bladder stone would not bein keeping with the overall treatment strategy. Only oneobstruction, and a further five had undergone pyeloplasty

alone. One child had undergone unilateral ureteric child with an isolated bladder stone was treated byminimally invasive means; this provides a satisfactoryreimplantation for high-grade VUR.

ESWL was performed using the Wolf Piezolith 2300 approach, particularly in those with recurrent largeinfective stones for whom repeated cystotomy would belithotripter (Richard Wolf GmBh, Germany), with no

significant adaptations required for treatment other than the alternative.a simple harness for the smaller children. The youngestchild treated in this way was 18 months old (the mean

Resultsage for ESWL was 8 years). ESWL was the sole treatmentmodality in 24 children; in five children (12%) ureteros- The median (range) number of ESWL sessions was 2

(1–9) and as expected, correlated with stone burden. Sixcopy/laser lithotripsy was combined with ESWL andeight children underwent ureteroscopy/laser lithotripsy staghorn/partial staghorn calculi were treated with

ESWL monotherapy in four patients, all being renderedonly. Bladder stones in three were treated with thelithoclast and combined therapy including PCNL was stone-free. If taken in isolation, the stone-free rate after

treatment and at 3 months was 94%, which equates torequired in three.In all, 16 children underwent ureteroscopy, the values in similar published series [4,6,7,19–21]. There

were two ESWL failures; one in a patient with cystinuriayoungest being 18 months old; a semirigid 6.9 F mini-scope was used in all cases. In no patient was dilatation who subsequently underwent successful PCNL, and one

in a patient found later at open pyelolithotomy to haveof the ureteric orifice required. The stone was in thelower third in 14 patients and in the middle third in an infundibular stenosis. The single complication requir-

ing intervention after ESWL was in a boy presentingtwo; left-sided ureteric stones predominated in a ratio ofalmost 251. with an impacted urethral stone fragment after success-

ful fragmentation of his renal stone.A pulsed-dye laser was the preferred energy source forUreteroscopic lithotripsy was successful in clearing 14

of 16 ureters. There was one failure of antegrade accessTable 1 Metabolic risk factors and identified structural anomaliesto a ureteric stone via a nephrostomy track, and one

Characteristic No. patients child with a large distal ureteric stone burden and aheavily encrusted JJ stent proceeded to open ureterolitho-

Metabolic abnormality tomy. There was one significant complication afterCystinuria 2 ureteroscopy/laser lithotripsy: an 18-month-old girlHypercalciuria 2 developed pain and fever following apparently successfulHyperoxaluria 1

fragmentation of a distal ureteric stone. UltrasonographyXanthine oxidase deficiency 1revealed a large perirenal urinoma and the child sub-Hyperuricaemia (relapsed acute lymphatic 1sequently underwent open exploration and drainage ofleukaemia)

Total 7 (16%) this collection. The patient had no further problemsStructural anomaly subsequent to this and remained stone-free with anPUJ obstruction 7 ultrasonographically normal urinary tract at 3 years ofDuplex system 1 follow-up.Ureterocele 2

PCNL was performed on four renal units in threeVUR 1patients (mean age 13 years, range 11–14); a singleNeurogenic bladder 1puncture and track formation was used in each. StonesHorseshoe kidney 1

Total 13 (30%) were retrieved or fragmented with ultrasonic lithotripsyvia a 22 F Amplatz sheath. Stones were completely

© 1999 BJU International 84, 339–342

URINARY TRACT CALCULI IN CHILDREN 341

cleared with no complications in all patients. Two of the appear to be no statistically significant eCects on renalfunction or renal growth. Similarly, there were nopatients selected for PCNL had cystine stones (one bilat-

eral and one an ESWL failure) and the other had the adverse eCects on linear growth.The choice of lithotripter is probably unimportant;additional problem of a neurogenic bladder with signifi-

cant spinal deformity. overall, second-generation devices do not appear toachieve equivalent stone-free rates [25] but other benefitsBladder calculi were treated preferentially with the

lithoclast. Two patients had bladder calculi noted at such as reduced radiation exposure and reduced voltagein the focal zone are important considerations, and makepresentation and in another two, stones within ortho-

topic ureteroceles were treated as bladder calculi after piezoelectric lithotripsy attractive. Also, if the need forgeneral anaesthesia is lessened, re-treatment becomesincising the ureterocele and moving the stones into

the bladder. less of a concern.PCNL has been widely advocated as a suitable treat-Ten of 43 patients had ureteric stents inserted (and

therefore removed). In six patients the decision to insert ment for children with significant stone burden and forthose with spinal or other major physical deformities.a stent was based on significant stone bulk before ESWL

and in four the combination of stone bulk and presence Theoretically, it is more attractive than numerous ESWLsessions or the prospect of repeated open interventions.or history of concomitant ureteric stones was the

determining factor. Ureteric stents were not used rou- Published reports suggest little or no evidence of detri-mental eCects on renal function or of renal scarringtinely after ureteroscopy/laser lithotripsy.

ESWL was performed under general anaesthesia in 15 [18,26]. To date we have been cautious with our use ofthis modality and remain concerned by possible trauma(48%) patients. Overall 38 children (88%) were rendered

stone-free at the completion of treatment and at a mini- to small kidneys created by conventional track sizes. Itis also our experience that a proportion of children withmum of 3 months of follow-up. Patients with metabolic

disorders accounted for three of the five cases of residual stones will also have evidence of structural anomalies,particularly PUJ obstruction. Until data suggest other-calculi. Complications requiring intervention occurred in

two children (5%) and three children (7%) subsequently wise, these children are probably still best treated byopen surgery [27].underwent open pyelolithotomy or ureterolithotomy after

unsuccessful minimally invasive treatment. The children undergoing PCNL in the present serieswere all comparatively older (minimum 11 years) andwere selected for particular aspects of their presentation.

DiscussionTwo of the children had cystine stones (one bilateral,the other an ESWL failure), and the third had a neuro-These findings confirm that technologies developed for

use in the adult can be selectively applied in children, genic bladder with significant spinal deformity and aconcomitant bladder stone. In the presence of large stonewith comparable stone clearance and complication rates.

Where new stone formation is a strong possibility because burdens, particularly in infants and younger children,our approach to date has been open surgery.there are metabolic abnormalities or persistent urinary

infection, the opportunity to reduce the likelihood of The role of PCNL in children remains to be established,particularly in small kidneys and where the stone bulkrepeated major operations is very attractive.

In comparison with many series from the USA which is suBciently extensive to require more than one track.Unpublished data suggest that PCNL may be successfulshow a prevalence of metabolic factors in about half of

the patients [2,24]; the present series identified just over with modified instruments operating through an 11 FAmplatz sheath [28]. If this proves to be eCective it may16% of the children with such factors. In the UK,

infection-related stones remain the major problem. make the procedure more widely appropriate. Similarly,further work to establish a possible role for endopyelo-Ureteroscopy appears to be a safe approach to paediat-

ric stone disease. Concerns about urethral injury in boys tomy in PUJ obstruction in children could herald asignificant advance in paediatric endourology, withand the possible development of VUR appear to be

without foundation. Thomas et al. [13] found only one implications for the management of stone disease. Theselection of a particular treatment modality dependscase of self-limiting reflux on cystography after 18

ureteroscopies in which a third of patients required upon several factors relating to the individual patientand the presentation of the stone. In most patients itdilatation of the ureteric orifice.

The long-term eCects of ESWL remain uncertain, should be possible to plan management using a singlemodality or combination therapy.particularly for hypertension; Frick et al. [5] showed no

demonstrable long-term eCects on renal function or Thus, current technologies available for the minimallyinvasive management of stone disease can be safely andblood pressure, and although Thomas et al. [8] suggested

some reduction in overall functional growth, there eCectively extended to children. Open stone surgery

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342 M. FRASER et al.

eBcacy of paediatric ureteroscopy for management ofremains appropriate in the presence of associated struc-calculus disease. J Urol 1993; 149: 1082–4tural abnormalities (e.g. PUJ obstruction) or large stones

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