Treatment of Renal Stones in Children: A Comparison Between Percutaneous Nephrolithotomy and Shock Wave Lithotripsy Ahmed A. Shokeir,* Khaled Z. Sheir, Ahmed R. El-Nahas, Ahmed M. El-Assmy, Waleed Eassa and Hamdy A. El-Kappany From the Urology and Nephrology Center, Mansoura University, Mansoura, Egypt
Purpose: We compared the results of percutaneous nephrolithotomy and shock wave lithotripsy for the treatment of 1 to 2 cm renal stones in children. Materials and Methods: The study included 166 children with renal stones 1 to 2 cm. A total of 75 patients (82 kidneys) were treated with percutaneous nephrolithotomy and 91 (93 kidneys) were treated with shock wave lithotripsy. Mean followup was 31 ⫾ 10 months (range 6 to 84). Both groups were compared regarding stone-free rate, re-treatment rate, complications and incidence of stone recurrence. Results: Both groups were comparable regarding preoperative characteristics. Of the units treated with percutaneous nephrolithotomy 4 (4.9%) were associated with minor complications. Stone-free rate after a single session of percutaneous nephrolithotomy was 86.6% (71 units), and the remaining 11 kidneys with residual stones were successfully treated with repeat percutaneous nephrolithotomy in 7 and shock wave lithotripsy in 4. Therefore, a total of 78 units (95%) were stone-free after percutaneous nephrolithotomy monotherapy, and the overall stone-free rate at 3 months was 100%. Of the patients undergoing shock wave lithotripsy 1 (1.1%) had development of steinstrasse and was successfully treated with ureteroscopy. The overall re-treatment rate after shock wave lithotripsy was 55%. A total of 79 units (84.9%) were stone-free after shock wave lithotripsy monotherapy, whereas 7 (7.5%) with no gross response to treatment were treated with percutaneous nephrolithotomy and 7 with insignificant stones less than 4 mm were followed. Therefore, the overall stone-free rate at 3 months was 92.5%. The differences in stone-free rates and re-treatment rates significantly favored percutaneous nephrolithotomy, while the incidence of complications and stone recurrence at last followup were not significantly different between the groups. Conclusions: For treatment of 1 to 2 cm renal stones in children percutaneous nephrolithotomy is better than shock wave lithotripsy, yielding higher stone-free and lower re-treatment rates. Key Words: child; kidney; urinary calculi; nephrostomy, percutaneous; lithotripsy, laser
tients were treated with SWL and others with PCNL. The decision was based on the opinion of the treating doctor without objective inclusion or exclusion criteria for each arm of treatment. The objective of our retrospective study was to compare the results of SWL and PCNL for treatment of 1 to 2 cm renal stones in our pediatric patients.
anagement of urinary tract stones in children is a challenging problem. The introduction of percutaneous nephrolithotomy and shock wave lithotripsy has dramatically changed the treatment policy for renal stones in children. Our previous studies have demonstrated that the success rate following SWL in children is influenced significantly by stone size, where patients with stones less than 1 cm had better stone-free rates than those with stones greater than 1 cm.1 On the other hand, PCNL is the procedure of choice for renal stones greater than 2 cm, in situations that make stone fragment passage less likely, such as stones associated with ureteropelvic junction obstruction, and after failure of SWL.2 Based on our previous studies and those of others, we observed a trend of using SWL for treatment of children with renal stones smaller than 1 cm and PCNL in those with stones greater than 2 cm.1–3 Nevertheless, we found no consensus regarding treatment of children with renal stones between 1 and 2 cm. Some of these pa-
M
MATERIALS AND METHODS A total of 263 children younger than 15 years with renal stones were treated at our institution between 1995 and 2004. Among the patients 12 with giant staghorn stones were treated with open surgery, 148 with stones smaller than 1 cm were initially treated with SWL and 30 with stones greater than 2 cm were initially treated with PCNL. Children with stones 1 to 2 cm without distal obstruction were treated with PCNL or SWL according to the preference of the treating doctor. The latter group comprised 166 children and was the subject of the present study. Among these patients 75 were treated with PCNL and 91 with SWL. Bilateral renal stones were diagnosed and treated in 7 patients in the PCNL group and in 2 patients in the SWL group. Therefore, the numbers of treated kidneys were 82 and 93, respectively, in the 2 groups.
Submitted for publication December 4, 2005. Study received ethical committee approval. * Correspondence: Urology and Nephrology Center, Mansoura University,Mansoura,Egypt(FAX:20-50-2263717;e-mail:ahmedshokeir@ hotmail.com, or
[email protected]).
0022-5347/06/1762-0706/0 THE JOURNAL OF UROLOGY® Copyright © 2006 by AMERICAN UROLOGICAL ASSOCIATION
706
Vol. 176, 706-710, August 2006 Printed in U.S.A. DOI:10.1016/j.juro.2006.03.080
TREATMENT OF RENAL STONES IN CHILDREN Preoperative Evaluation Excretory urography was the primary imaging modality. In patients who presented with calculous anuria or impaired renal function the imaging modality involved combined abdominal ultrasound, plain abdominal x-ray and antegrade pyelography. Noncontrast spiral computerized tomography has been frequently used for the last 4 years. Urine specimens were obtained for culture. Technique of Percutaneous Nephrolithotomy Using general anesthesia, percutaneous renal access was achieved under fluoroscopic guidance in 68 patients and PCNL was completed in the same session. In the 7 patients with calculous anuria percutaneous renal drainage was guided by ultrasonography. The nephrostomy was left until maximum decrease in serum creatinine, followed by PCNL. Dilation of the tract to the minimal size necessary for instrumentation and stone removal (22Fr) were then performed using coaxial telescopic dilators. Ultrasonic lithotripsy was used for stone fragmentation. In older children the tract was dilated up to 30Fr, which allowed the use of adult instruments to extract the stone intact. At the end of the procedure a nephrostomy tube (16Fr to 22Fr) was left in the kidney for 48 hours. Technique of Shock Wave Lithotripsy All patients were treated with the electromagnetic Lithotripter S® in the supine position. General anesthesia (1 mg/kg ketamine) was used for all children 12 years or less, while 1 mg/kg meperidine hydrochloride and/or 1.5 [micron]g/kg fentanyl was used for older children. The session was started at the lower power, which was gradually increased in steps every 100 shocks to an intensity of 65% of maximum power. A maximum of 2,000 shock waves were delivered per session. Fluoroscopy was used for localization of all radiopaque stones and ultrasound was used for radiolucent stones. Cases were reviewed weekly after the first session, using a plain film and abdominal ultrasound to assess fragmentation, presence of obstruction and the need for re-treatment. This followup continued until complete stone clearance or failure to disintegrate the stone after 3 sessions. X-ray diffraction analysis of stones was available after stone removal for 40 patients in the PCNL group and 60 in the SWL group. The stone-free rates were measured for each treatment modality as monotherapy, and then overall stonefree rate (after secondary procedures) was measured at 3 months. Treatment success was defined as complete stone clearance. Noncontrast spiral computerized tomography was used to diagnose the presence of residual fragments during the last 4 years of the study. Followup Patients were seen every 3 months during the first year and every 6 months thereafter. At each visit urinalysis, urine culture, serum creatinine and abdominal ultrasound were performed. If stone recurrence was diagnosed, excretory urography was carried out. Noncontrast spiral computerized tomography was used during the last 4 years of followup in all patients. Both groups were compared regarding the stone-free rate, re-treatment rate, necessity of auxiliary procedures, complications and incidence of stone recurrence.
707
Chi-square and Student’s t tests were used as appropriate for comparison, and p value ⬍0.05 was considered significant. RESULTS The preoperative characteristics of the patients, urinary tracts and stones were comparable for both treatment groups (table 1). In the PCNL group subcostal puncture was used in 75 renal units and supracostal puncture in 7. For the 52 kidneys with stones in the renal pelvis only percutaneous access was achieved through the middle calix in 25 and lower calix in 27. A lower caliceal puncture was used for the 10 kidneys with stones in the renal pelvis and lower calix. Stones in the pelvis and upper calix were retrieved through a lower caliceal puncture in 3 kidneys and an upper caliceal puncture in 3. Puncture of the corresponding calix was carried out for the 14 kidneys with caliceal stones (6 lower, 4 middle and 4 upper). Mean operation time was 53 ⫾ 25 minutes (range 32 to 122). There was no major complication. Intraoperative complications were encountered in 2 patients (2.4%), of whom 1 had development of significant bleeding that required blood transfusion, and 1 suffered perforation of the renal pelvis, which was treated with prolongation of nephrostomy drainage for 4 days. In both patients the stones were successfully removed. Postoperative course was complicated by fever (greater than 38.5C) in 2 patients (2.4%). Fever was controlled by intravenous antibiotics and antipyretics. Of the 82 renal units 71 (86.6%) were stone-free after a single PCNL procedure, and the remaining 11 (13.4%) with residual stones were successfully treated with repeat PCNL in 7 (8.5%) and SWL in 4 (4.9%). Therefore, a total of 78 renal units (95%) were stone-free after PCNL monotherapy and the overall stone-free rate at 3 months was 100%. Shock Wave Lithotripsy Pre-SWL Double-J® stent was inserted in 2 patients with calculous anuria until normalization of serum creatinine. Of the 93 renal units 42 (45.2%) were stone-free after a single session, 25 (26.9%) after 2 sessions and 12 (12.9%) after 3 sessions. Therefore, a total of 79 renal units (84.9%) were stone-free after SWL monotherapy. Of the remaining 14 renal units (15.1%) 7 (7.5%) failed to respond to SWL and were successfully treated with PCNL, while in the remaining 7 units (7.5%) there were residuals fragments less than 4 mm, which were treated with medical management and followup. Therefore, the overall stone-free rate at 3 months was 92.5%. There were no complications after SWL but one 14-year-old boy had steinstrasse in the pelvic ureter that was successfully treated with ureteroscopy. Percutaneous Nephrolithotomy vs Shock Wave Lithotripsy All PCNL procedures were carried out with the patients under general anesthesia with a mean hospital stay of 3 ⫾ 1.2 days (range 2 to 14). All SWL procedures were performed on an outpatient basis, with 80 patients requiring general anesthesia and 12 receiving sedoanalgesia. Although the incidence of complications was more with PCNL, the difference was not statistically significant (table 2). The number of kidneys requiring re-treatment was significantly higher in
708
TREATMENT OF RENAL STONES IN CHILDREN TABLE 1. Preoperative characteristics of SWL and PCNL groups Characteristics
PCNL
SWL
No. pts Mean age ⫾ SD (range) No. Males/No. females No. clinical presentation (%): Hematuria Abdominal pain Recurrent urinary tract infection Calculous anuria No. Corresponding renal unit (%): No dilatation Hydronephrosis Pyelonephritic changes Stones: Mean mm length ⫾ SD (range) Mean mm width ⫾ SD (range) N No. lt side (%) No. rt side (%) No. bilat (%) N No. opaque (%) No. lucent (%) N No. de novo (%) No. recurrent (%) N No. single (%) No. multiple (%) N No. renal pelvis (%) No. calices (%) No. renal pelvis ⫹ calices (%)
75 6.6 ⫾ 1.2 (0.6–14) 45/30
91 6.4 ⫾ 1.4 (2–14) 50/41
15 (20) 15 (20) 38 (51) 7 (9)
25 (27) 26 (29) 38 (42) 2 (2)
11 (13) 62 (76) 9 (11)
20 (22) 61 (66) 12 (13)
0.16 0.841 0.091
0.306
14.4 ⫾ 3.1 (12–20) 12.4 ⫾ 4.2 (5–14)
13.9 ⫾ 4.2 (11–20) 11.3 ⫾ 3.3 (9–18)
44 (59) 24 (32) 7 (9)
39 (43) 50 (55) 2 (2)
75 (91) 7 (9)
89 (96) 4 (4)
72 (88) 10 (12)
85 (91) 8 (9)
67 (82) 15 (18)
75 (81) 18 (19)
52 (63) 14 (17) 16 (20)
70 (75) 11 (12) 12 (13)
0.23 0.17 0.09
0.401 0.595 0.988 0.21
the SWL group (55% for SWL vs 8.5% for PCNL, p ⬍0.05, table 2). The stone-free rate for PCNL monotherapy (95%) was significantly better than that for SWL (84.9%, table 2). The influence of stone composition as defined by x-ray diffraction analysis and stone location on stone-free rates was comparable between the groups (table 3). After a mean followup of 31 ⫾ 10 months (range 6 to 84) stone recurrence for the stone-free patients at last followup was not different between the treatment groups (table 2). Of the patients receiving SWL who had residual fragments at 3-month followup 1 (14.3%) became free of stones, the size of the fragments was stationary in 4 (57.1%) and regrowth of the fragments was encountered in 2 (28.6%) who underwent re-treatment with SWL. DISCUSSION There is marked variation in the pattern of urolithiasis in children in developed and developing nations. Pediatric urolithiasis remains endemic in developing nations, affecting children younger than 1 year to adolescence.4 The preva-
TABLE 2. Results of PCNL and SWL groups No. PCNL (%) No. SWL (%) p Value Complications: Fever Steinstrasse Significant bleeding Pelvic perforation Totals Re-treatment Secondary procedures Stone-free (monotherapy) Stone clearance at 3 mos Recurrence rate at last followup
p Value
2 0 1 1 4 (4.9) 7 (8.5) 4 (4.9) 78 (95) 82 (100) 7 (8.5)
0 1 0 0 1 (1.1) 51 (55) 8 (8.6) 79 (85) 86 (92.5) 9 (10.5)
0.293 ⬍0.001 0.452 0.049 0.031 0.871
lence rate is high, at 5% to 15%,5 compared to 1% to 5% in developed countries.6 The etiology of stone formation in pediatric populations is largely unknown. The most common causes are developmental anomalies, infection and metabolic risk factors.4 The introduction of PCNL and SWL into clinical practice revolutionized the management of urinary stone disease in adults as well as in the pediatric population. Stone size is one of the most important factors that affect the treatment decision. Shock wave lithotripsy is generally considered to be the first line therapy for stone burden in the kidney less than 2 cm and for proximal ureteral calculi that can be visualized easily for targeting.2 On the other hand, PCNL is the procedure of choice for a renal stone burden greater than 2 cm. Based on our previous experience, our policy was to treat renal stones less than 1 cm with SWL and those more than 2 cm with PCNL. Renal stones between 1 and 2 cm were treated arbitrarily according to the preference of the treating doctor.1,3 The stone-free rate after PCNL in the present series (86.6% after 1 session, 95% after 2 sessions and 100% at 3
TABLE 3. Stone-free rates in relation to stone composition and location
Stone composition (p ⬍0.001): Calcium based Struvite Uric acid Cystine Stone location (p ⬍0.027): Renal pelvis Calices Pelvis ⫹ calices
No. Free/Total No. PCNL (%)
No. Free/Total No. SWL (%)
40 20/21 (95) 10/11 (91) 4/4 (100) 4/4 (100) 82 50/52 (96) 13/14 (93) 15/16 (94)
60 25/39 (64) 13/17 (76) 3/4 (75) 1/2 (50) 93 62/70 (89) 9/11 (87) 8/12 (67)
TREATMENT OF RENAL STONES IN CHILDREN months) is similar to other studies, with stone-free rates approaching 90% with a single session of PCNL7–12 and 100% after combining it with SWL.13 The range of postoperative complications following PCNL in children varies. Fraser et al reported no complications after 4 PCNL procedures.14 At the other extreme Zeren et al reported intraoperative hemorrhage requiring blood transfusion in 16 of 67 PCNL procedures (23.9%) and transient fever greater than 38C during the hospital stay in 29.8%.12 In our study only 2 children had intraoperative complications (2.4%) and 2 had postoperative fever. This wide range of complication rates can partly be explained by the difference in patient and stone characteristics of different series regarding age, stone burden and type, number and location of stones, together with the incidence of urinary tract infection. The lower complication rate in this study may be attributed to small stone burden (1 to 2 cm), the need for only 1 nephrostomy tract and performance of PCNL in children by experienced endourologists only. Further studies of larger numbers of patients are needed to evaluate the various factors affecting the incidence of complications after PCNL in children. The stone-free rate after SWL in this present series is similar to previous studies, with stone-free rates of approximately 85%.8,15,16 The main concern with the use of SWL in pediatric kidneys has been the long-term risk of hypertension, loss of renal function and hyperfiltration. To date, short and long-term followup have failed to show differences in body growth or renal function using first, second and third generation lithotriptors.15-18 No increase in blood pressure has been noted up to 46 months after SWL.2 Another important concern after SWL is the fate of residual fragments less than 4 mm. In the present study only 1 of 7 patients (14.3%) with residual fragments became free of stones, which is in agreement with the results of Shigeta et al,19 while a third of the patients exhibited regrowth of the fragments and needed a second intervention. Therefore, strict regular followup of these patients is advised for early detection and treatment of such events. Analysis of the results of the present study revealed that the complication rate after SWL and PCNL is acceptable with both procedures. It is noteworthy that although 2 significant complications were observed in the group undergoing PCNL (1 pelvic perforation and 1 episode of bleeding), neither of the patients required additional invasive intervention, and both were rendered stone-free. On the other hand, 1 patient in the SWL group required ureteroscopy for treatment of steinstrasse. SWL has the advantages of avoidance of hospital admission and general anesthesia (in older children) but the re-treatment rate is higher and the stone-free rate is lower compared to PCNL. The need to ensure success after 1 intervention favors PCNL for treatment of renal stones greater than 1 cm in the pediatric population. We acknowledge that a disadvantage of this study is its retrospective nature. Other prospective randomized studies are required to draw solid conclusions regarding the treatment of choice for pediatric renal stones of differing sizes.
709
CONCLUSIONS For treatment of 1 to 2 cm renal stones in children SWL and PCNL are safe and effective procedures. However, PCNL gives better results in terms of lower re-treatment and higher stone-free rates.
Abbreviations and Acronyms PCNL ⫽ percutaneous nephrolithotomy SWL ⫽ shock wave lithotripsy
REFERENCES 1.
2. 3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
El Sobky, E., Sheir, K. Z., Madbouly, K. and Mokhtar, A. A.: Extracorporeal shock wave lithotripsy in children: experience using two second-generation lithotripters. BJU Int, 86: 851, 2000 Wu, H. and Docimo, S. G.: Surgical management of children with urolithiasis. Urol Clin North Am, 31: 589, 2004 Dawaba, M. S., Shokeir, A. A., Hafez, A. T., Shoma, A. M., El-Sherbiny, M. T., Mokhtar, A. et al: Percutaneous nephrolithotomy in children: early and late anatomical and functional results. J Urol, 172: 1078, 2004 Rizvi, S. A. H., Naqvi, S. A. A., Hussain, Z., Hashmi, A., Zafar, M. N., Sultan, S. et al: Pediatric urolithiasis: developing nation perspectives. J Urol, 168: 1522, 2002 Shah, A. M., Kalmunkar, S., Punekar, S. V., Billimoria, F. R., Bapat, S. D. and Deshmukh, S. S.: Spectrum of pediatric urolithiasis in Western India. Indian J Pediatr, 58: 543, 1991 Yoshida, O. and Okada, Y.: Epidemiology of urolithiasis in Japan: a chronological and geographical study. Urol Int, 45: 104, 1990 Jackman, S. V., Hedican, S. P., Peters, C. A. and Docimo, S. G.: Percutaneous nephrolithotomy in infant and preschool age children: experience with a new technique. Urology, 52: 697, 1998 Rizvi, S. A., Navqi, S. A., Hussain, Z., Hashmi, A., Hussain, M., Zafar, M. M. et al: Management of pediatric urolithiasis in Pakistan: experience with 1,440 children. J Urol, 169: 634, 2003 Jayanthi, V. R., Arnold, P. M. and Koff, S. A.: Strategies for managing upper tract calculi in young children. J Urol, 162: 1234, 1999 Mor, Y., Elmasry, Y. E., Kellett, M. J. and Duffy, P. G.: The role of percutaneous nephrolithotomy in the management of pediatric renal calculi. J Urol, 158: 1319, 1997 Badawy, H., Salama, A., Eissa, M., Kotb, E., Moro, H. and Shoukri, I.: Percutaneous management of renal calculi: experience with percutaneous nephrolithotomy in 60 children. J Urol, 162: 1710, 1999 Zeren, S., Satar, N., Bayazit, Y., Bayazit, A. K., Payasli, K. and Ozkeceli, R.: Percutaneous nephrolithotomy in the management of pediatric renal calculi. J Endourol, 16: 75, 2002 Mahmud, M. and Zaidi, Z.: Percutaneous nephrolithotomy in children before school age: experience of a Pakistani centre. BJU Int, 94: 1352, 2004 Fraser, M., Joyce, A. S., Thomas, D. F., Eardley, I. and Clark, P. B.: Minimally invasive treatment of urinary calculi in children. BJU Int, 84: 339, 1999 Lottmann, H. B., Archambaud, F., Hellal, B., MercierPageyral, B. and Cendron, M.: 99mTechnetium-dimercaptosuccinic acid renal scan in the evaluation of potential longterm renal parenchymal damage associated with extracorporeal shock wave lithotripsy in children. J Urol, 159: 521, 1988
710 16.
17.
TREATMENT OF RENAL STONES IN CHILDREN Vlajkovic, M., Slavkovic, A., Radovanovic, M., Siric, Z., Stefanovic, V. and Perovic, S.: Long-term functional outcome of kidneys in children with urolithiasis after ESWL treatment. Eur J Pediatr Surg, 12: 118, 2002 Thomas, R., Frentz, J. M., Harmon, E. and Frentz, G. D.: Effect of extracorporeal shock wave lithotripsy on renal function and body height in pediatric patients. J Urol, 148: 1064, 1992
18.
19.
Lottmann, H. B., Archambaud, F., Traxer, O., MercierPageyral, B. and Hellal, B.: The efficacy and parenchymal consequences of extracorporeal shock wave lithotripsy in infants. BJU Int, 85: 311, 2000 Shigeta, M., Kasaoka, Y., Yasumoto, H., Inoue, K., Usui, T., Hayashi, M. et al: Fate of residual fragments after successful extracorporeal shock wave lithotripsy. Int J Urol, 6: 169, 1999
