PEDIATI~,IC U R O L O G Y .... !
PERCUTANEOUS NEPHROSTOMY IN INFANTS WALTER M. O'BRIEN, M.D . . . . . ALAN H. MATSUMOTO, M.D. EDWARD G. GRANT, M.D. M. DAVID GIBBONS, M.D. From the Department of Surgery (Pediatric Urology), Georgetown University Children's Medical Center, and Department of Radiology, Section of Vascular and Interventional Radiology, Georgetown University Hospital, Washington, D.C.
A B S T R A C T - - W e reviewed our experience with p ercutaneous nephrostomy placemer,,t in children less than one year of age during a five-year period. Placement was successful in 8 of 9 cases. There :were no complications. The procedure favorably altered the outcome for each pat:ient and was useful for reversing azotemia prior to surgical intervention for repair of an v,bstruci~ed system (2 r e n a l units), for providing drainage of pyonephrotie kidneys (3 renal units), for demonstrating ii inadequate recovery of renal function after relief of obstruction (2 renal units), and for replacing a ! S~rgically placed nephrostomy that was dislodged (1 renal unit). Our experience has encouraged us i: :to accept the technique, and we believe that- it is a valuable nonsurgical alternative t,~at should be ~i)~available to urologists managing infants with urinary tract pathology. (:
of p e r c u t a n e o u s n e p h r o s t o m y aeters in adults is a routine and ted procedure. Indications, teehts, and complications have been ~ted. 1 As experienee has increased, intervention in the urinary tract :ended to the pediatric popularesent our experience during the s with placement of percutaneous ',s (PN) in ehildren less than one nd a review of the literature. daterial and Methods ~viewed the medical records of all less than one year of age who underfrom 1983 to the present. Records wed for age, elinieal presentation, inal approaeh, type of anesthesia, cornand ultimate outcome. Results the five-year period from 1983 to the total of 8 PN were plaeed in 6
SEPTEMBER 1990
/
children. Clinical data for eaeh patient are shown in Table I. Patients' ages ranged from four days to seven months. Indications for PN were mainly for therapeutic relilef of urinary tract obstruction, in the presenee or absence of an associated infeetion. PN also allowed evaluation of genitourinary anatomy via antegrade contrast studies and provided access to perform dynamic manometric measurements when indicated. Nephrostomy placement was attempted nine times and was successful in 8. Successful placement of PN favorably altered the outcome for each patient. In 2 eases (Cases 2 and 3), PN allowed for reversal of azotemia prior to definitive surgieal repair of obstructed kidneys. In 2 eases (Cases 2 and 5't PN combined with antimicrobial therapy resolved complicated urinary tract infections associated with sepsis. In 2 eases (Cases 1 and 4), nephrostomy placement in obstructed kidneys demonstrated that there was no recoverable renal function. These patients underwent nephrectomy and avoided the need for an unnecessary attempt at reconstructive surgery. In 1 instance (Case 6), a
VOLUME XXXVI, NUMBER 3
269
TABLEI. Case Age/Weight (kg) 1
7 mos/9.5
Clinical data in 6 inJants with percutaneous nephrostomy
Indication Hydronephrosis
Anesthesia
Pathology
Outcome
Demerol, Phenergan, Thorazine 1% Xyloeaine
Upper pole ectopie No recovery of function after ureterocele; lower pole 4 wks: nephreetomy vesicoureteral reflux 2a 3 wks/3.7 Urinary aseites Congenital UPJ Improvement after 4 wks; obstruction in dismembered pyeloplasty solitary kidney 2b 3 mos/4.8 Pyonephrosis; General UVJ obstruction Improvement: ureteral azotemia reimplant 3 4 days/4.4 Azotemia Demerol Congenitally obstructed 3 mos of nephrostomy drainmegaureter in age; unable to replace after solitary kidney dislodged; ureteral reimplant No improvement after 8 wks 4 9. mos/6.8 Hydronephrosis General UPJ obstruction nephreetomy 5 3 wks/0.8 Anuria; sepsis 1% Xyloeaine; Bilateral obstruction Resolution of renal eandidiasis morphine secondary to renal after 3 wks of nephrostomy eandidiasis drainage and IV antifungal therapy 6 3 mos/6.4 Surgical nephrosChloral S/P pyeloplasty Nephrostomy successfully tomy dislodged hydrate replaced KEY:mos = months; wks = weeks; UPJ = ureteropelvie junction; UVJ = ureterovesical junction; IV = intravenous.
PN was performed in a postoperative patient in whom the surgically placed nephrostomy had become dislodged. Nephrostomy placement failed in 1 patient (Case 3). In this patient, a PN had been placed three months earlier for relief of obstruction at the ureterovesieal junction of a solitary kidney. The initial nephrostomy allowed reversal of azotemia and permitted time for increased growth and maturation. The tube became dislodged and attempts to replace it were unsuccessful. A guide wire was placed into the renal pelvis, but the tract could not be dilated. The patient subsequently underwent a right ureteral reimplantation for a congenitally obstructed megaureter and recovered uneventfully. No complications related to placement of the PN were experienced, although in 1 patient transient baeteremia developed at the time of catheter removal. Technique The technique for nephrostomy placement in infants is similar to that used for adults, except that a specially designed neonatal nephrostomy set is used (Cook Urological, Spencer, IN). Under sonographic guidance a posteriorly-oriented calix or infundibulum below the twelfth rib is punctured with a 21 or 22-gauge needle. Fluoroscopic visualization is subsequently used for guide wire placement, tract dilation, and tube insertion. A 6F pigtail-type nephrostomy tube is placed into the renal pelvis and a cathe-
ter retention disk is sutured to the s k i n . Nephrostomy placement is done using either general or local anesthesia with supplemental sedation• General anesthesia offers the advantage of keeping the patients immobile, allowing for accurate tube placement. However, tube placement is also technically feasible using local anesthesia alone or in combination with sedation and avoids the risk of general anesthesia inl septic, azotemie, or premature infants. . . diaper . . teehmque . . A . double is used for nephrostomy drainage The nephrostomy tube) is allowed to drain between the inner and outer: diaper. This technique is used for children discharged from the hospital with their nephros! tomy tube in place. There is no increased risk of urinary tract infection with this technique eom: pared with dosed catheter drainage. 1° Comment PN placement was first described in 1951 the relief of an obstructed kidney, n Since time, PN placement has become a routine p r o eedure. Nephrostomies have been placed to re, lieve obstruction associated with azotemia and infection, to treat ureteral strictures, to place ureteral stents, to provide access for treatment:~ of calculous disease, and to assess the potential!:! for recovery of severely impaired renal func2 tion. Recent attention has focused on PN place::: ment in children. In 1979, Babcock, Shkolnik;~i!i and Cook 2 described PN placement in a nine} !~ ;i
270
UROLOGY / SEPTEMBER1990 / VOLUME XXXVI, NUMBEltSi,i
week-old infant. Since then, there have been multiple reports describing radiologie intervention in the genitourinary tract in children. Stanley, Bear, and Reid 3 presented their initial experience with PN in 28 children ranging in age from one day to eighteen years with no catheter placement failures and only one minor complication. More recently, they updated their experience and reported on their results in 50 children, noting that catheter placement was successful in all patients, and there were only two complications. 4 Winfield and associates 5 summarized their experience with PN in 10 pediatric patients, of whom 8 were less than one year of age. The procedure was successful in all cases, with no significant eomplieations. Ball a n d colleagues 6 p e r f o r m e d i n t e r v e n t i o n a l uroradiologie procedures in 49 children ranging i n age from one day to twenty-two years. N i n e t y - e i g h t percent of the procedures were technically successful and were considered de: finitive procedures or procedures that favorably ; ~ltered the clinical course in 95 percent of :cases. 6 The same group subseqently described a :i!'i new 5F nephrostomy catheter system speeifi'cally designed for neonates that was successfully ~:?.hsed in 8 children less than one month of age. v :: ~iedy and Lebowitz 8 deseribed their experienee i :::with 101 pereutaneous interventions in infants, !~~hildren, and young adults, including 18 pa:han six months of age. The proeehighly successful with complications in only 5 children and tube disoecurring in another 5 patients. 8 Irv:, and Thomas 9 performed PN in 16 ages one day to fourteen years, with essful attempt. ?rt summarizes our experienee with ent in infants less than one year of :aneous nephrostomies were successt in 8 of 9 attempts without eomplie instance of catheter-related sepsis atered when the nephrostomy was . . . . . . . . . ithout adequate antimicrobial cov:~~:i~i~erage.This complication was clearly avoidable. ii~iii~iCeneral anesthesia was used m 2 eases, but the ! iii;~iremainderwere performed using local anesthe:~:,sla and/or sedation. The teehmque used for )my placement is similar to that used s, but a smaller catheter specifically for pediatric patients is used. [ouble diaper" technique, successfully | in all of our patients, avoids an exlinage bag and theoretically lessens the for entanglement and dislodgement of
/
SEPTEMBER 1990
/
the catheter. This technique also has been well accepted by the parents who may be intimidated by the presence of a drainage bag. Our experience with nephrostomy placement is similar to that reported by others. We emphasize that a PN can be safely performed in infants by an experienced interventional radiologist. PN should be included in the therapeutic inventory available to the urologist managing infant urinary tract pathology. PN can be safely performed in patients with azotemia to allow stabilization of renal function and correction of electrolyte and acid-base balance disorders prior to operative intervention. Definitive surgical repair of an obstructed urinary tract then can be performed eleetively. PN is an important eomponent in the s u c c e s s ful management of patients with urinary tract obstruction complicated by bacterial or fungal infection. In some eases, satisfactory urinary drainage can be achieved without surgery, permitting effective antimierobial or antifungal therapy. PN has proved to be useful for assessing the potential for functional recovery of obstructed kidneys. 12 In many eases, contrast urography and isotope renography may not give adequate information about the potential for recoverable renal function after relief of a congenitally obstructed kidney. Temporary nephrostomy decompression of the obstructed kidney for four to eight weeks permits assessment of its function. If renal functional recovery is adequate, an attempt at reconstruction of the obstructed kidney is indicated. However, the demonstration of minimal or no functional recovery after drainage provides further objective evidence that nephreetomy is the surgical procedure of choice. PN is also a valuable adjunct in the management of postoperative patients in whom a surgically placed nephrostomy becomes dislodged. In addition, it may be helpful in managing postoperative obstruction seeondary to edema. In conclusion, our experience with placement of PN in children less than one year of age has encouraged us to accept the technique, both diagnostically and therapeutically. The procedure is safe and effective and has become a valuable nonsurgieal alternative available to urologists who share in the care of infants and young children with urinary tract pathology.
VOLUME XXXVI, NUMBER 3
3800 Reservoir Road NW Washington, D.C. 20007-2197 (DR. GIBBONS) 271
References 1. Stables DP: Percutaneous nephrostomy: techniques, indications and results, Urol Clin North Am 9:15 (1982). 2. Babcock JR, Shkolnik A, and Cook WA: Ultrasound-guided pereutaneous nephrostomy in the pediatric patient, J Urol 121:
327 (1979). 3. Stanley P, Bear JW, and Reid BS: Pereutaneous nephrostomy in infants and children, AJR 141:473 (1983). 4. Stanley P, and Diament MJ: Pediatric percutaneous nephrostomy: experience with 50 patients, J Urol 135:1223 (1986). 5. Winfield AC, e t aI: Pereutaneous nephrostomy in neonates, infants and children, Radiology 151. 617 (1984). 6. Ball WS Jr, lbwbin R, Strife JL, and Spencer R: Interventional genitourinary radiology in children: a review of 61 procedures, AJR 147:791 (1986).
272
7. Towbin RB, and Ball WS: New pediatric 5-F drainage system, Radiology 163:827 (1987). 8. Riedy MJ, and Lebowitz RL: Percutanenus studies of the upper urinary tract in children with special emphasis on infantsi : Radiology 160:231 (1986). 9. Irving HC, Arthur RJ, and Thomas DFM: Percutaneous nephrostomy in paediatries, Clin Radiol 38:245 (1987). 10. Monttagnino B, Gonzales ET, and Roth DR: Open catheter drainage after penile surgery (abstr.), American Academy of Pediatrics Meeting, New Orleans, November 2, 1987. 11. Goodwin WE, Casey WC, and Woolf W: Pereutaneous troear (needle) nephrostomy in hydronephrosis, JAMA 1 5 7 : 8 9 1 (1955). 12. Pode D, Shapiro A, Gordon R, and Lebensart P: Percuta,: neous nephrostomy for assessment of functional recovery of obstructed kidneys, Urology 19:482 (1982).
UROLOGY
/
SEPTEMBER 1990 /
VOLUME XXXVI, NUMBI~B;
PERCUTANEOUS NEPHROSTOMY IN INFANTS WALTER M. O'BRIEN, M.D . . . . . ALAN H. MATSUMOTO, M.D. EDWARD G. GRANT, M.D. M. DAVID GIBBONS, M.D. From the Department of Surgery (Pediatric Urology), Georgetown University Children's Medical Center, and Department of Radiology, Section of Vascular and Interventional Radiology, Georgetown University Hospital, Washington, D.C.
A B S T R A C T - - W e reviewed our experience with p ercutaneous nephrostomy placemer,,t in children less than one year of age during a five-year period. Placement was successful in 8 of 9 cases. There :were no complications. The procedure favorably altered the outcome for each pat:ient and was useful for reversing azotemia prior to surgical intervention for repair of an v,bstruci~ed system (2 r e n a l units), for providing drainage of pyonephrotie kidneys (3 renal units), for demonstrating ii inadequate recovery of renal function after relief of obstruction (2 renal units), and for replacing a ! S~rgically placed nephrostomy that was dislodged (1 renal unit). Our experience has encouraged us i: :to accept the technique, and we believe that- it is a valuable nonsurgical alternative t,~at should be ~i)~available to urologists managing infants with urinary tract pathology. (:
of p e r c u t a n e o u s n e p h r o s t o m y aeters in adults is a routine and ted procedure. Indications, teehts, and complications have been ~ted. 1 As experienee has increased, intervention in the urinary tract :ended to the pediatric popularesent our experience during the s with placement of percutaneous ',s (PN) in ehildren less than one nd a review of the literature. daterial and Methods ~viewed the medical records of all less than one year of age who underfrom 1983 to the present. Records wed for age, elinieal presentation, inal approaeh, type of anesthesia, cornand ultimate outcome. Results the five-year period from 1983 to the total of 8 PN were plaeed in 6
SEPTEMBER 1990
/
children. Clinical data for eaeh patient are shown in Table I. Patients' ages ranged from four days to seven months. Indications for PN were mainly for therapeutic relilef of urinary tract obstruction, in the presenee or absence of an associated infeetion. PN also allowed evaluation of genitourinary anatomy via antegrade contrast studies and provided access to perform dynamic manometric measurements when indicated. Nephrostomy placement was attempted nine times and was successful in 8. Successful placement of PN favorably altered the outcome for each patient. In 2 eases (Cases 2 and 3), PN allowed for reversal of azotemia prior to definitive surgieal repair of obstructed kidneys. In 2 eases (Cases 2 and 5't PN combined with antimicrobial therapy resolved complicated urinary tract infections associated with sepsis. In 2 eases (Cases 1 and 4), nephrostomy placement in obstructed kidneys demonstrated that there was no recoverable renal function. These patients underwent nephrectomy and avoided the need for an unnecessary attempt at reconstructive surgery. In 1 instance (Case 6), a
VOLUME XXXVI, NUMBER 3
269
TABLEI. Case Age/Weight (kg) 1
7 mos/9.5
Clinical data in 6 inJants with percutaneous nephrostomy
Indication Hydronephrosis
Anesthesia
Pathology
Outcome
Demerol, Phenergan, Thorazine 1% Xyloeaine
Upper pole ectopie No recovery of function after ureterocele; lower pole 4 wks: nephreetomy vesicoureteral reflux 2a 3 wks/3.7 Urinary aseites Congenital UPJ Improvement after 4 wks; obstruction in dismembered pyeloplasty solitary kidney 2b 3 mos/4.8 Pyonephrosis; General UVJ obstruction Improvement: ureteral azotemia reimplant 3 4 days/4.4 Azotemia Demerol Congenitally obstructed 3 mos of nephrostomy drainmegaureter in age; unable to replace after solitary kidney dislodged; ureteral reimplant No improvement after 8 wks 4 9. mos/6.8 Hydronephrosis General UPJ obstruction nephreetomy 5 3 wks/0.8 Anuria; sepsis 1% Xyloeaine; Bilateral obstruction Resolution of renal eandidiasis morphine secondary to renal after 3 wks of nephrostomy eandidiasis drainage and IV antifungal therapy 6 3 mos/6.4 Surgical nephrosChloral S/P pyeloplasty Nephrostomy successfully tomy dislodged hydrate replaced KEY:mos = months; wks = weeks; UPJ = ureteropelvie junction; UVJ = ureterovesical junction; IV = intravenous.
PN was performed in a postoperative patient in whom the surgically placed nephrostomy had become dislodged. Nephrostomy placement failed in 1 patient (Case 3). In this patient, a PN had been placed three months earlier for relief of obstruction at the ureterovesieal junction of a solitary kidney. The initial nephrostomy allowed reversal of azotemia and permitted time for increased growth and maturation. The tube became dislodged and attempts to replace it were unsuccessful. A guide wire was placed into the renal pelvis, but the tract could not be dilated. The patient subsequently underwent a right ureteral reimplantation for a congenitally obstructed megaureter and recovered uneventfully. No complications related to placement of the PN were experienced, although in 1 patient transient baeteremia developed at the time of catheter removal. Technique The technique for nephrostomy placement in infants is similar to that used for adults, except that a specially designed neonatal nephrostomy set is used (Cook Urological, Spencer, IN). Under sonographic guidance a posteriorly-oriented calix or infundibulum below the twelfth rib is punctured with a 21 or 22-gauge needle. Fluoroscopic visualization is subsequently used for guide wire placement, tract dilation, and tube insertion. A 6F pigtail-type nephrostomy tube is placed into the renal pelvis and a cathe-
ter retention disk is sutured to the s k i n . Nephrostomy placement is done using either general or local anesthesia with supplemental sedation• General anesthesia offers the advantage of keeping the patients immobile, allowing for accurate tube placement. However, tube placement is also technically feasible using local anesthesia alone or in combination with sedation and avoids the risk of general anesthesia inl septic, azotemie, or premature infants. . . diaper . . teehmque . . A . double is used for nephrostomy drainage The nephrostomy tube) is allowed to drain between the inner and outer: diaper. This technique is used for children discharged from the hospital with their nephros! tomy tube in place. There is no increased risk of urinary tract infection with this technique eom: pared with dosed catheter drainage. 1° Comment PN placement was first described in 1951 the relief of an obstructed kidney, n Since time, PN placement has become a routine p r o eedure. Nephrostomies have been placed to re, lieve obstruction associated with azotemia and infection, to treat ureteral strictures, to place ureteral stents, to provide access for treatment:~ of calculous disease, and to assess the potential!:! for recovery of severely impaired renal func2 tion. Recent attention has focused on PN place::: ment in children. In 1979, Babcock, Shkolnik;~i!i and Cook 2 described PN placement in a nine} !~ ;i
270
UROLOGY / SEPTEMBER1990 / VOLUME XXXVI, NUMBEltSi,i
week-old infant. Since then, there have been multiple reports describing radiologie intervention in the genitourinary tract in children. Stanley, Bear, and Reid 3 presented their initial experience with PN in 28 children ranging in age from one day to eighteen years with no catheter placement failures and only one minor complication. More recently, they updated their experience and reported on their results in 50 children, noting that catheter placement was successful in all patients, and there were only two complications. 4 Winfield and associates 5 summarized their experience with PN in 10 pediatric patients, of whom 8 were less than one year of age. The procedure was successful in all cases, with no significant eomplieations. Ball a n d colleagues 6 p e r f o r m e d i n t e r v e n t i o n a l uroradiologie procedures in 49 children ranging i n age from one day to twenty-two years. N i n e t y - e i g h t percent of the procedures were technically successful and were considered de: finitive procedures or procedures that favorably ; ~ltered the clinical course in 95 percent of :cases. 6 The same group subseqently described a :i!'i new 5F nephrostomy catheter system speeifi'cally designed for neonates that was successfully ~:?.hsed in 8 children less than one month of age. v :: ~iedy and Lebowitz 8 deseribed their experienee i :::with 101 pereutaneous interventions in infants, !~~hildren, and young adults, including 18 pa:han six months of age. The proeehighly successful with complications in only 5 children and tube disoecurring in another 5 patients. 8 Irv:, and Thomas 9 performed PN in 16 ages one day to fourteen years, with essful attempt. ?rt summarizes our experienee with ent in infants less than one year of :aneous nephrostomies were successt in 8 of 9 attempts without eomplie instance of catheter-related sepsis atered when the nephrostomy was . . . . . . . . . ithout adequate antimicrobial cov:~~:i~i~erage.This complication was clearly avoidable. ii~iii~iCeneral anesthesia was used m 2 eases, but the ! iii;~iremainderwere performed using local anesthe:~:,sla and/or sedation. The teehmque used for )my placement is similar to that used s, but a smaller catheter specifically for pediatric patients is used. [ouble diaper" technique, successfully | in all of our patients, avoids an exlinage bag and theoretically lessens the for entanglement and dislodgement of
/
SEPTEMBER 1990
/
the catheter. This technique also has been well accepted by the parents who may be intimidated by the presence of a drainage bag. Our experience with nephrostomy placement is similar to that reported by others. We emphasize that a PN can be safely performed in infants by an experienced interventional radiologist. PN should be included in the therapeutic inventory available to the urologist managing infant urinary tract pathology. PN can be safely performed in patients with azotemia to allow stabilization of renal function and correction of electrolyte and acid-base balance disorders prior to operative intervention. Definitive surgical repair of an obstructed urinary tract then can be performed eleetively. PN is an important eomponent in the s u c c e s s ful management of patients with urinary tract obstruction complicated by bacterial or fungal infection. In some eases, satisfactory urinary drainage can be achieved without surgery, permitting effective antimierobial or antifungal therapy. PN has proved to be useful for assessing the potential for functional recovery of obstructed kidneys. 12 In many eases, contrast urography and isotope renography may not give adequate information about the potential for recoverable renal function after relief of a congenitally obstructed kidney. Temporary nephrostomy decompression of the obstructed kidney for four to eight weeks permits assessment of its function. If renal functional recovery is adequate, an attempt at reconstruction of the obstructed kidney is indicated. However, the demonstration of minimal or no functional recovery after drainage provides further objective evidence that nephreetomy is the surgical procedure of choice. PN is also a valuable adjunct in the management of postoperative patients in whom a surgically placed nephrostomy becomes dislodged. In addition, it may be helpful in managing postoperative obstruction seeondary to edema. In conclusion, our experience with placement of PN in children less than one year of age has encouraged us to accept the technique, both diagnostically and therapeutically. The procedure is safe and effective and has become a valuable nonsurgieal alternative available to urologists who share in the care of infants and young children with urinary tract pathology.
VOLUME XXXVI, NUMBER 3
3800 Reservoir Road NW Washington, D.C. 20007-2197 (DR. GIBBONS) 271
References 1. Stables DP: Percutaneous nephrostomy: techniques, indications and results, Urol Clin North Am 9:15 (1982). 2. Babcock JR, Shkolnik A, and Cook WA: Ultrasound-guided pereutaneous nephrostomy in the pediatric patient, J Urol 121:
327 (1979). 3. Stanley P, Bear JW, and Reid BS: Pereutaneous nephrostomy in infants and children, AJR 141:473 (1983). 4. Stanley P, and Diament MJ: Pediatric percutaneous nephrostomy: experience with 50 patients, J Urol 135:1223 (1986). 5. Winfield AC, e t aI: Pereutaneous nephrostomy in neonates, infants and children, Radiology 151. 617 (1984). 6. Ball WS Jr, lbwbin R, Strife JL, and Spencer R: Interventional genitourinary radiology in children: a review of 61 procedures, AJR 147:791 (1986).
272
7. Towbin RB, and Ball WS: New pediatric 5-F drainage system, Radiology 163:827 (1987). 8. Riedy MJ, and Lebowitz RL: Percutanenus studies of the upper urinary tract in children with special emphasis on infantsi : Radiology 160:231 (1986). 9. Irving HC, Arthur RJ, and Thomas DFM: Percutaneous nephrostomy in paediatries, Clin Radiol 38:245 (1987). 10. Monttagnino B, Gonzales ET, and Roth DR: Open catheter drainage after penile surgery (abstr.), American Academy of Pediatrics Meeting, New Orleans, November 2, 1987. 11. Goodwin WE, Casey WC, and Woolf W: Pereutaneous troear (needle) nephrostomy in hydronephrosis, JAMA 1 5 7 : 8 9 1 (1955). 12. Pode D, Shapiro A, Gordon R, and Lebensart P: Percuta,: neous nephrostomy for assessment of functional recovery of obstructed kidneys, Urology 19:482 (1982).
UROLOGY
/
SEPTEMBER 1990 /
VOLUME XXXVI, NUMBI~B;
