Renal Function
Following By M.T.
Extracorporeal
Lithotripsy
in Children
Corbally, J. Ryan, J. Fitzpatrick, and R.J. Fitzgerald Dublin, Ireland
l Although extracorporeal shockwave lithotripsy (ESWL) has revolutionised the management of urinary calculous disease, the long-term effects of ESWL on renal function are not known. This study of 18 children demonstrated a mild, statistically insignificant decrease of 15% in DTPA measured glomerular filtration rate following ESWL. In view of this, we recommend that pretherapy and post-therapy estimates of renal function be obtained in all patients undergoing ESWL. Long-term follow-up is necessary to further quantify the effects of ESWL on the developing kidney. Copyright o 1991 by W.B. Saunders Company INDEX WORDS: pediatric.
Urinary lithotripsy;
urinary calculus disease,
S
INCE ITS INTRODUCTION, extracorporeal shockwave lithotripsy (ESWL), has revolutionised the therapeutic approach to upper renal tract calculi. Although considerable experience has been gained with ESWL in the non-operative treatment of urolithiasis in adults, as yet there has been no widespread application to the pediatric population. Moreover, there has been increased clinical awareness that ESWL may itself cause morphological damage to the renal parenchyma. The significance of reported parenchymal changes on long-term function, and their effect on the growing kidney, are not known. Because of increasing use of ESWL in children, this retrospective study was performed to establish the effects, if any, of ESWL on renal function, and to establish management algorithms to allow careful monitoring following standard ESWL treatment protocols. MATERIALS
AND METHODS
All pediatric patients aged 14 years or less who had undergone ESWL therapy for renal tract calculi were included in this study. Information was obtained from computerised records and patient’s charts. A standard pro-forma was used to compile information on height, weight, blood pressure, serum urea and creatinine, and. glomerular filtration rate (GFR) measured by DTPA scan. When possible, these studies were repeated after ESWL. Patients were included in the analysis of renal function only if they had a pre- and post-ESWL scan. In some patients a pre-ESWL DMSA scan had been done and, therefore, quantitative comparisons were not possible. In addition, a pre-ESWL excretory urogram was performed on all patients to assess urinary tract morphology. Relative GFR was corrected to body surface area and the results expressed as mWminil.73 m’. ESWL was performed under general anaesthesia using the Siemens Lithostar Lithotripter (Dublin, Ireland). This machine uses fluoroscopy for stone targetting and delivers shock waves generated by an electromagnetic shock head. Coupling to the patient for shock wave delivery is via a water balloon applied to the patient’s skin. A specialised gantry to accomodate children was not Journal of Pediatric Surgery, Vol26, No 5 (May), 1991: pp 539-640
required. A paired which are presented
Student’s t test was used to compare as mean -+ standard deviation.
results,
RESULTS
Eighteen patients aged 2 to 12 years (mean, 5.4 years) were identified. Nine patients presented with infection, 2 with haematuria, and 3 with haematuria and infection. Four patients were asymptomatic. Eight patients had staghorn calculi, 7 had multiple small stones, and 3 had single stones. Calculous disease was more common on the left, with only 3 stones involving the right tract. Two patients had myelomenigocoele, 1 had spinal dysraphism, 2 had an imperforate anus, and 3 had vesicoureteric reflux. One patient had a horseshoe kidney and another had bilateral duplex systems. Nine patients had previously undergone operation for calculous disease, namely nephrolithotomy (3), pyelolithotomy (3) ureterolithotomy (1) cystolithotomy (1) and nephrectomy (1). The mean ESWL shock dose was 3,988 shocks (range, 1,000 to 12,000) delivered over 1 to 4 treatment sessions with a mean shock/session dose of 2,111 shocks. Calculous fragmentation was observed in 17 patients with immediate complete clearance (less than 1 week) in 10, early clearance (less than 1 month) of minor residual debris in 2, and late clearance (at 3 months) in 5. There was overt failure in one patient. Two patients had urinary tract infection after ESWL, one of whom required temporary percutaneous nephrostomy for acute ureteric obstruction. One patient developed meatal stenosis attributed to passage of a stone fragment, although passage of fragments was not routinely looked for. Transient frank haematuria occurred in two patients and the remaining 16 patients had transient microscopic haematuria lasting 1 or 2 days. Pre- and post-GFR (DTPA scan) were available for 10 patients. No changes in blood pressure, serum creatinine, or urea were noted during this study. From Our Lady’s Hospital Crumlin, The Childrens Hospital, and the Urology Department, The Mater Misericordae Hospital, Dublin, Ireland. Presented at the 37th Annual International Congress of the British Association of Paediattic Surgeons, Glasgow, Scotland, July 25-27, 1990. Address reprint requests to M.T. Corbally, MCh, FRCSI, Senior Registrar in Paediatric Surgery, The Hospital for Sick Children, Great Ormond St, London, UK. Copyright o 1991 by W B. Saunders Company 0022-3468/9112605-0008$03.00/0 539
CORBALLY
540
Mean total GFR decreased from 93.8 + 20.4 preESWL to 80 + 18.3 mWmim1.73 m2 post-ESWL, and although this represented a 15% decrease, this was not statistically significant (P > .05). Mean GFR decreased in the treated kidney from 38.7 + 13.4 to 32.2 r 16.6 and in the contralateral kidney from 55 & 22.5 to 48 * 21.2 mLlmim1.72 m’. These changes were not statistically significant (P > .05). DISCUSSION
Urolithiasis in childhood is relatively uncommon and tends to be located in the upper tracts. In early childhood, most calculi are secondary to infection and urinary stasis. Formerly, therapy has involved operative removal with its attendant morbidity and known deleterous effect on renal function.’ ESWL has revoIutionised the treatment of upper renal tract calculi, primarily because of ease of use, lack of morbidity, patient tolerance, and avoidance of open operation. However, several experimental and clinical studies have demonstrated significant renal parenchymal trauma after ESWL, especially when higher shock doses are used.’ The renal injuries range from mild contusions to major haematomas, and were originally reported by Chaussy et al to be less than l%.’ Recently, magnetic resonance imaging following standard ESWL has documented morphological changes in up to 63% of patients, although the changes usually are minor.3 Experimental studies have demonstrated a clear relationship between shock wave dose and parenchymal injury.4 However, most experimental studies have used shock doses in excess of standard therapeutic levels and the clinical significance of this
ET AL
information is unclear. It is known that renal parenchymal changes correlate with interstitial and tubular scarring, tubular dilation, and cast formation centered in the? midportion of the kidney, possibly a result of shockwave damage to thin-walled veins.3Xs This has led to concern about possible late sequelae following ESWL, especially at higher dose levels and in the growing kidney. Lingeman and Kulb have reported the development of significant hypertension in 8% of adult patients who had ESWL.h Although information on safe dose limits is empirical, it is recommended that the shock dose should not exceed 2,000 to 3,000 shocks in one session.‘,’ There are no standardised protocols for ESWL delivery and follow-up that will provide objective assessment of the long-term biological effects. This study has demonstrated a 15% overall decrease in GFR after ESWL, which was not statistically significant. Notwithstanding the inherent limitations of DTPA scanning and the difficulties of a retrospective study, we have demonstrated the need for careful pre- and postESWL evaluation and long-term follow-up to allow proper and safe use of this facility. This should include estimates of renal function before and after ESWL and some measurement of morphological changes, if any. Finally, recent reports of hypertension following ESWL in adults indicate the need for long-term evaluation of blood pressure.
ACKNOWLEDGMENT The authors wish to express their thanks for the help and cooperation given by the Children’s Research Centre, Crumlin.
REFERENCES 1. Lingeman JE, McAteer JA, Kempson SA, et al: Bioeffects of extracorporeal shock wave lithotripsy J Endourol1:89-98,1987 2. Chaussy CH, Brendell W, Schmiedt E: Extracorporeally induced destruction of kidney stones by shock waves. Lancet 2:1265-1268,198O 3. Kaude JV, Williams MC, Millner MR, et al: Renal morphology and function immediately after extracorporeal shock wave lithotripsy. Am J Radio1 145:305-313,1985 4. Drach GW, Dretler S, Fair W, et al: Report of the United
States cooperative study group of extracorporeal lithotripsy. J Urol 135:1127-1133,1986
shock wave
5. Newman R, Hackett R, Senior D, et al: Pathologic effects of ESWL on canine renal tissues. Urology 29:194-200, 1987 6. Lingeman JE, Kulb TB: Hypertension following extracorporeal shock wave lithotripsy. J Ural 137:45A, 1987 (abstr) 7. Kroovand RL: ESWL use in children. Dialog Pediatr Ural 10:2-s, 1987
Following By M.T.
Extracorporeal
Lithotripsy
in Children
Corbally, J. Ryan, J. Fitzpatrick, and R.J. Fitzgerald Dublin, Ireland
l Although extracorporeal shockwave lithotripsy (ESWL) has revolutionised the management of urinary calculous disease, the long-term effects of ESWL on renal function are not known. This study of 18 children demonstrated a mild, statistically insignificant decrease of 15% in DTPA measured glomerular filtration rate following ESWL. In view of this, we recommend that pretherapy and post-therapy estimates of renal function be obtained in all patients undergoing ESWL. Long-term follow-up is necessary to further quantify the effects of ESWL on the developing kidney. Copyright o 1991 by W.B. Saunders Company INDEX WORDS: pediatric.
Urinary lithotripsy;
urinary calculus disease,
S
INCE ITS INTRODUCTION, extracorporeal shockwave lithotripsy (ESWL), has revolutionised the therapeutic approach to upper renal tract calculi. Although considerable experience has been gained with ESWL in the non-operative treatment of urolithiasis in adults, as yet there has been no widespread application to the pediatric population. Moreover, there has been increased clinical awareness that ESWL may itself cause morphological damage to the renal parenchyma. The significance of reported parenchymal changes on long-term function, and their effect on the growing kidney, are not known. Because of increasing use of ESWL in children, this retrospective study was performed to establish the effects, if any, of ESWL on renal function, and to establish management algorithms to allow careful monitoring following standard ESWL treatment protocols. MATERIALS
AND METHODS
All pediatric patients aged 14 years or less who had undergone ESWL therapy for renal tract calculi were included in this study. Information was obtained from computerised records and patient’s charts. A standard pro-forma was used to compile information on height, weight, blood pressure, serum urea and creatinine, and. glomerular filtration rate (GFR) measured by DTPA scan. When possible, these studies were repeated after ESWL. Patients were included in the analysis of renal function only if they had a pre- and post-ESWL scan. In some patients a pre-ESWL DMSA scan had been done and, therefore, quantitative comparisons were not possible. In addition, a pre-ESWL excretory urogram was performed on all patients to assess urinary tract morphology. Relative GFR was corrected to body surface area and the results expressed as mWminil.73 m’. ESWL was performed under general anaesthesia using the Siemens Lithostar Lithotripter (Dublin, Ireland). This machine uses fluoroscopy for stone targetting and delivers shock waves generated by an electromagnetic shock head. Coupling to the patient for shock wave delivery is via a water balloon applied to the patient’s skin. A specialised gantry to accomodate children was not Journal of Pediatric Surgery, Vol26, No 5 (May), 1991: pp 539-640
required. A paired which are presented
Student’s t test was used to compare as mean -+ standard deviation.
results,
RESULTS
Eighteen patients aged 2 to 12 years (mean, 5.4 years) were identified. Nine patients presented with infection, 2 with haematuria, and 3 with haematuria and infection. Four patients were asymptomatic. Eight patients had staghorn calculi, 7 had multiple small stones, and 3 had single stones. Calculous disease was more common on the left, with only 3 stones involving the right tract. Two patients had myelomenigocoele, 1 had spinal dysraphism, 2 had an imperforate anus, and 3 had vesicoureteric reflux. One patient had a horseshoe kidney and another had bilateral duplex systems. Nine patients had previously undergone operation for calculous disease, namely nephrolithotomy (3), pyelolithotomy (3) ureterolithotomy (1) cystolithotomy (1) and nephrectomy (1). The mean ESWL shock dose was 3,988 shocks (range, 1,000 to 12,000) delivered over 1 to 4 treatment sessions with a mean shock/session dose of 2,111 shocks. Calculous fragmentation was observed in 17 patients with immediate complete clearance (less than 1 week) in 10, early clearance (less than 1 month) of minor residual debris in 2, and late clearance (at 3 months) in 5. There was overt failure in one patient. Two patients had urinary tract infection after ESWL, one of whom required temporary percutaneous nephrostomy for acute ureteric obstruction. One patient developed meatal stenosis attributed to passage of a stone fragment, although passage of fragments was not routinely looked for. Transient frank haematuria occurred in two patients and the remaining 16 patients had transient microscopic haematuria lasting 1 or 2 days. Pre- and post-GFR (DTPA scan) were available for 10 patients. No changes in blood pressure, serum creatinine, or urea were noted during this study. From Our Lady’s Hospital Crumlin, The Childrens Hospital, and the Urology Department, The Mater Misericordae Hospital, Dublin, Ireland. Presented at the 37th Annual International Congress of the British Association of Paediattic Surgeons, Glasgow, Scotland, July 25-27, 1990. Address reprint requests to M.T. Corbally, MCh, FRCSI, Senior Registrar in Paediatric Surgery, The Hospital for Sick Children, Great Ormond St, London, UK. Copyright o 1991 by W B. Saunders Company 0022-3468/9112605-0008$03.00/0 539
CORBALLY
540
Mean total GFR decreased from 93.8 + 20.4 preESWL to 80 + 18.3 mWmim1.73 m2 post-ESWL, and although this represented a 15% decrease, this was not statistically significant (P > .05). Mean GFR decreased in the treated kidney from 38.7 + 13.4 to 32.2 r 16.6 and in the contralateral kidney from 55 & 22.5 to 48 * 21.2 mLlmim1.72 m’. These changes were not statistically significant (P > .05). DISCUSSION
Urolithiasis in childhood is relatively uncommon and tends to be located in the upper tracts. In early childhood, most calculi are secondary to infection and urinary stasis. Formerly, therapy has involved operative removal with its attendant morbidity and known deleterous effect on renal function.’ ESWL has revoIutionised the treatment of upper renal tract calculi, primarily because of ease of use, lack of morbidity, patient tolerance, and avoidance of open operation. However, several experimental and clinical studies have demonstrated significant renal parenchymal trauma after ESWL, especially when higher shock doses are used.’ The renal injuries range from mild contusions to major haematomas, and were originally reported by Chaussy et al to be less than l%.’ Recently, magnetic resonance imaging following standard ESWL has documented morphological changes in up to 63% of patients, although the changes usually are minor.3 Experimental studies have demonstrated a clear relationship between shock wave dose and parenchymal injury.4 However, most experimental studies have used shock doses in excess of standard therapeutic levels and the clinical significance of this
ET AL
information is unclear. It is known that renal parenchymal changes correlate with interstitial and tubular scarring, tubular dilation, and cast formation centered in the? midportion of the kidney, possibly a result of shockwave damage to thin-walled veins.3Xs This has led to concern about possible late sequelae following ESWL, especially at higher dose levels and in the growing kidney. Lingeman and Kulb have reported the development of significant hypertension in 8% of adult patients who had ESWL.h Although information on safe dose limits is empirical, it is recommended that the shock dose should not exceed 2,000 to 3,000 shocks in one session.‘,’ There are no standardised protocols for ESWL delivery and follow-up that will provide objective assessment of the long-term biological effects. This study has demonstrated a 15% overall decrease in GFR after ESWL, which was not statistically significant. Notwithstanding the inherent limitations of DTPA scanning and the difficulties of a retrospective study, we have demonstrated the need for careful pre- and postESWL evaluation and long-term follow-up to allow proper and safe use of this facility. This should include estimates of renal function before and after ESWL and some measurement of morphological changes, if any. Finally, recent reports of hypertension following ESWL in adults indicate the need for long-term evaluation of blood pressure.
ACKNOWLEDGMENT The authors wish to express their thanks for the help and cooperation given by the Children’s Research Centre, Crumlin.
REFERENCES 1. Lingeman JE, McAteer JA, Kempson SA, et al: Bioeffects of extracorporeal shock wave lithotripsy J Endourol1:89-98,1987 2. Chaussy CH, Brendell W, Schmiedt E: Extracorporeally induced destruction of kidney stones by shock waves. Lancet 2:1265-1268,198O 3. Kaude JV, Williams MC, Millner MR, et al: Renal morphology and function immediately after extracorporeal shock wave lithotripsy. Am J Radio1 145:305-313,1985 4. Drach GW, Dretler S, Fair W, et al: Report of the United
States cooperative study group of extracorporeal lithotripsy. J Urol 135:1127-1133,1986
shock wave
5. Newman R, Hackett R, Senior D, et al: Pathologic effects of ESWL on canine renal tissues. Urology 29:194-200, 1987 6. Lingeman JE, Kulb TB: Hypertension following extracorporeal shock wave lithotripsy. J Ural 137:45A, 1987 (abstr) 7. Kroovand RL: ESWL use in children. Dialog Pediatr Ural 10:2-s, 1987
