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clinmed/1999120008v1 (December 13, 1999)
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Extracorporeal Shock Wave Lithotripsy In Children.

Vincent C. Onuora FRCS(Ed);  Abdelmoniem H. Koko FRCS(Ed)

Mohammed Al Turki FACHARTZ;  Nasser Al Jawini FACHARTZ.

Department of Urology, Riyadh Medical Complex, Riyadh, Saudi Arabia.

All Correspondence:

Dr V C Onuora,

P O Box 29765,

Riyadh 11467.

Saudi Arabia

Tel/Fax: 966 1 435 6172

email: vconuora@deltasa.com

Abstract.

Between 1993 and 1998, 67 children with stones in the urinary tract were treated by ESWL in our department.  There were 38 boys and 29 girls and their ages ranged from 5-16 years (mean 12.9).  The majority of the children presented with pain (79 %) or haematuria (13.4 %).  Diagnosis was established by the use of sonography and intravenous urography (IVU).  Stone disease was associated with horseshoe kidney, posterior urethral valve, pelvi-ureteric junction obstruction and external meatal stenosis in one child each.  There were 56 renal (37 pelvic, 16 calyceal and 3 staghorn); eleven ureteric and 3 bladder stones. The stone sizes ranged from 4 mm to 40 mm (mean 16) in the largest diameter.  ESWL was done as an outpatient procedure in 20 children (30 %), and the rest required admission to the hospital.  Double J stents were placed in 15 children with stones larger than 20 mm.  General anaesthesia was used in 19 children, usually those below the age of twelve.  The others received intravenous pethidine for sedation and analgesia.  The mean number of shocks delivered was 3000 and the generator voltage ranged from 16 to 19 kV.  Most of the patients required only one ESWL session (mean 1.7).  The overall stone free rate was 82 % and this was achieved during a mean period of twelve weeks.  Four children developed febrile urinary tract infection and 2 steinstrasse.  Follow-up was poor.  Our results suggest that at short term, ESWL was an effective and safe treatment modality for urinary lithiasis in children.

Key words:  Extracorporeal shockwave lithotripsy; children; Saudi Arabia

Introduction.

     The advent of extracorporeal shock wave lithotripsy (ESWL) as a non-invasive technique has revolutionalised the management of urinary tract calculi.  It is considered a safe and effective treatment for urinary lithiasis in adults.  However, the application of this modality of treatment in children followed rather slowly.  Although evidence has accumulated on the efficacy of ESWL in treating calculi in children (1-3), the effects of shock wave on the paediatric urinary tract still need to be clarified.  Indeed, ESWL was considered by some to be contra-indicated in children (4).o:p>

    As a contribution to the growing data in this field, we report our experiences on the use of a second-generation lithotriptor (Siemens Lithostar) in the treatment of renal calculi in children in Saudi Arabia.

Patients and Methods.

    Between January 1993 and December 1998, 67 children with stones in the urinary tract were treated by ESWL using the Siemens Lithostar lithotriptor.  There were 38 boys and 29 girls and their ages ranged from 5-16 years (mean 12.9).  Prior to shock wave treatment, all patients underwent renal and bladder sonography, intravenous urography (IVU), blood tests for renal function, coagulation profile, urine analysis and urine culture.  Patients with allergy had a dimercapto succinic acid (DMSA) renal scan.  Fifty-three children (79%) presented with pain; 8 with micro-haematuria; one with gross haematuria.  Urine culture was positive in eight children (12%) and they received appropriate antibiotic therapy before stone treatment.

    Stone disease was associated with horseshoe kidney in one case; three other children had previously undergone surgery for posterior urethral valve, pelvi-ureteric junction obstruction and meatal stenosis respectively.

    There were 56 renal stones (37 pelvic, 16 calyceal, and 3 staghorn). Eleven children had ureteric and three bladder stones.  Only three children had radiolucent calculi. Renal calculi were bilateral in three others. The stone size ranged from 4 to 40 mm (mean 16) in the largest diameter.  ESWL was done as an out patient procedure in 20 children.  Fifteen patients with bulky stones (> 20 mm) had internal stents before treatment and three had placement of ureteric catheters for visualization of radiolucent stones.  General anaesthesia was used in 19 patients, usually those below the age of twelve years.  The rest received pethidine for sedation and analgesia. The mean number of shocks delivered was 3000, and the generator voltage ranged from 16 to 19 kV.  Most of the patients required only one ESWL session (mean 1.7)

    Plain abdominal x-ray was done on the day after treatment and repeated monthly in the outpatient department.  Patients with radiolucent stones and those with bulky stones were followed with ultrasound scans. A patient was regarded as stone free if no stone fragment was discernible and the time to this status was noted.   A “successful outcome” was defined to include stone free patients and those patients with stone fragments less than 4 mm which were deemed passable.

 

Results.

    Sixty-seven reno-ureteral units and three bladders were treated. ESWL resulted in complete stone fragmentation in 53 units (79 %) and one bladder stone, usually after one session (mean 1.7).  However, 21 units required multiple shock wave sessions.  One child with staghorn stone needed eight sessions and received a total of 14,000 shocks spread over three months.  He had DJ internal stenting but still developed ureteric obstruction from steinstrasse. He underwent two sessions of ureteroscopic stone extraction before achieving a stone free state after 52 weeks.

    Fifty-five reno-ureteral units (82 %) were stone free after 12 weeks.  Residual fragments (< 4 mm), which required no further treatment, were present in five units.  Hence the success rate for ESWL was 89.6 %.  The procedure failed in two units (1 pelvic and 1 upper ureteric). In both cases, the stone was removed by open surgery because of lack of necessary paediatric endoscopic instruments.  Five children (5 units) failed to come for any follow-up. 

    ESWL was successful in treating one bladder stone but it failed in two cases.  In both failures the stone was more than 30 mm in size and had to be removed by open surgery.

    Auxiliary procedures were required in 20 children and included placement of DJ stents in 15, ureteric catheters in 2 and ureteroscopic stone removal in 3.  Four children developed febrile urinary tract infection; two steinstrasse and one child had impacted urethral stone. 

    There was one stone recurrence and it occurred at 18 months.  However, most of the patients abandoned follow-up once a stone free status was achieved.  One child was lost for two years with a DJ stent in place.  Amazingly, this was successfully removed in one piece.

Discussion.

    In this study, the 12-week stone clearance rate was 82 % and most of the patients required only one session of ESWL.  If the five children with small stone fragments were regarded as successful outcome, the overall success rate would rise to 89.6 %.  Five children failed to attend follow-up clinic altogether.  It is conceivable that some or all of them achieved stone free status.  Thus ESWL was highly effective in the treatment of ureterorenal stone disease in this group of children.  Our results compare favourably with those of others (5,6).  The ease with which stone fragments pass through the small ureters of children has been ascribed to several factors.  Children are more mobile than adults and mobility is known to favour stone passage.  Another factor is that stones in the urinary tract of children have not had time to impact firmly.  Although this was not our experience, congenital anomaly has been cited as the most common cause of urolithiasis in children (7).  Children with anomalies in the urinary tract and concomitant urinary stones would be best managed by open operation.

    We encountered minor and infrequent complications using the Siemens Lithostar machine. Four children developed febrile urinary tract infection and responded readily to antibiotic treatment. We usually administered antibiotics to cover the ESWL session and continued treatment with oral drugs for a few days post lithotripsy.  An untreated urinary infection is a contraindication for lithotripsy in our unit.  The occurrence of urinary infection despite these precautions emphasizes the need for antibiotic therapy to cover lithotripsy.  Fragmentation of infectious stones can lead to the development of septicaemia (8).  The other complications we encountered related to the passage of stone fragments.  Steinstrasse occurred in two ureters and needed stent insertion.  A stone fragment impacted in the urethra in one child necessitating extraction under general anaesthesia.  Nevertheless, this low complication rate is significant since endo-urological procedures on children have their limitations owing to the small sizes of the patients.

    The Siemens Lithostar proved to be an effective second-generation lithotriptor for ESWL of renal and ureteric stones in children.  Because the focal zone is small, there was no need for lung shielding from the shock waves.  However, the long-term effects of ESWL on the developing renal parenchyma in children are not clear.  Although many investigators (9,10,11) have reported shock wave lithotripsy to be safe, doubt still persists (12).  It might be prudent to use open surgery or percutaneous nephrolithotomy for large staghorn calculi (13) that would require many sessions of shock wave treatment.  One of our patients with a large stone burden required eight sessions of ESWL.  Repeated hospital attendances place a lot of strain on both patient and parents and could be a factor for abandonment of treatment.  Long-term follow-up was poor among our population.  This is a common finding in our community.  Need to travel long distances and little health consciousness mitigate against prolonged outpatient treatment.  Thus it was difficult to convince stone free patients to make further attendances to the hospital.  One child in this study was lost for two years with a double-J stent.  These shortcomings prevented us from doing a proper evaluation of stone recurrence.  Other studies reported a recurrence rate of 10 to 20 % following ESWL (14,15).  Before embarking on shock wave treatment, it is wise to advise the parents on the need for follow-up.  This is especially so in developing communities.

    Our experience with bladder stones is too limited to draw any conclusions.  ESWL failed to fragment the stones in two of three children.  These were large calculi measuring more than 30 mm.  Each was removed by supra pubic percutaneous cystolithotomy.  More experience is needed to determine the effectiveness of shock wave lithotripsy for bladder stones in children.

    In conclusion, ESWL was found to be a safe and effective primary treatment modality for renal and ureteric stones in children. It had a high success rate and minimal short-term complications.  However, long-term follow-up is necessary to rule out later complications.  Large staghorn calculi required multiple shock wave sessions and exposed the ‘young’ kidneys to possible hazards.  Lack of follow-up with the associated neglect of internal stents was a complication peculiar to practice in developing communities.  Every effort should be made to educate parents regarding need for adequate follow-up visits before embarking on ESWL.

Acknowledgement:

We are very grateful to Ms Maricar Bomban for her assistance in the collection of data.

Competing interests: none declared

References.

  1. Newman, DM, Coury, T, Lingeman, JE et al.  Extracorporeal shock wave lithotripsy experience in children.  J Urol, 1986, 136, 238-40
  2. Kroovand, RL, Harrison, LH and McCullough, DL. Extracorporeal shock wave lithotripsy in childhood. J Urol, 1987, 138, 1106-8.
  3. Frick, J, Kohle, R, and Kunit, G.  Experience with extracorporeal shock wave lithotripsy in children.  Eur Urol, 1988, 14,181-3
  4. McCullough, DL.  Extracorporeal shock wave lithotripsy:  in Walsh, PC, Retik, AB, Stamey,TA, Vaughan, ED Jr (eds): Campbell’s Urology. Philadelphia, Saunders, 1992, vol 3, pp 2157-82
  5. Vandeursen H, Devos, P and Baert, L.  Electromagetic extracorporeal shock wave lithotripsy in children.  J Urol, 1991: 145: 1229-31
  6. Moazam, F, Nazir, Z, and Jafarey, AM.  Paediatric urolithiasis: To cut or not to cut.  J Paedtr Surg 1994; 29: 761-4
  7. Pelzer, JO, Leuman, E, and Schwobel, MG. The role of surgery and lithotripsy in childhood urolithiasis.  Eur J Paediatr Surg 1994; 4: 196-8
  8. Myers, DA, Mobley, TB, Jenkins, JM. et. al.  Paediatric low energy lithotripsy with the Lithostar. J Urol 1995; 153: 453-7
  9. Thomas, R, Fentz, Harmon, E et al. Effect of extracorporeal shock wave lithotripsy on renal function and body height in paediatric patients.  J Urol 1992; 148: 1064-6
  10. Frick, J, Sarica, K, Kohle, R et al. Long-term follow-up after extracorporeal shock wave lithotripsy in children.  E Urol 1991; 19: 225-9
  11. Mendoza, E, Beer, M, Weber, C et al.  ESWL during pregnancy?  J Endourol. (suppl. 1) 1991; 5: S43 (Abstract)
  12. Eterovic, D, Juretic-Kuscic, L, Capkun, V, and Dujic, Z.  Pyelolithotomy improves while extracorporeal lithotripsy impairs kidney function.  J Urol 1999; 161: 39-44
  13. Wilbert, D, Schofer, O and Reidmiller, H.  Treatment pf paediatric urolithiasis by extracorporeal shockwave lithotripsy.  Eur J Paediatr 1988; 147:579-81
  14. Gerhart JP, Herzberg GZ, Jeffs RD.  Childhood urolithiasis: Experiences and advances. Paediatrics 1991; 87: 445-50
  15. Nijman RJ, Ackaert K, Scholtmeijer RJ et al.  Long-term results of extracorporeal shock wave lithotripsy in children. J Urol 1989; 142: 609-11




This Article
Right arrow Abstract Freely available
Services
Right arrow Similar articles in this netprints
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Onuora, V. C.
Right arrow Articles by Al Jawini, N.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Onuora, V. C.
Right arrow Articles by Al Jawini, N.
Related Collections
Right arrow CLINICAL:
Renal Medicine

Right arrow Paediatrics:
Other Paediatrics

Right arrow Surgery:
Urology

Right arrow Imaging Techniques:
Interventional radiology


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