Pediatric Case Report Late Ureteral Obstruction After Injection of Dextranomer/Hyaluronic Acid Copolymer Samuel Christen, Mario Mendoza, Rita Gobet, Peter Bode, and Daniel Weber Various biological and artificial materials have been introduced for endoscopic treatment of vesicoureteral reflux. Over the past years, dextranomer combined with hyaluronic acid (Dx/Ha) has been established as the most commonly used tissue-augmenting substance for subureteral injection because of its biocompatibility. Nevertheless, the histopathologic analysis of failed Dx/Ha injections showed changes in consistency and volume of the deposit and granulomatous reactions of the adjacent tissue. We report a case of late-onset obstruction 2 years after the injection of Dx/Ha. In the current literature, this potential long-term complication is hardly mentioned. UROLOGY 83: 920e923, 2014. 2014 Elsevier Inc.
U
reteral obstruction after the injection of dextranomer combined with hyaluronic acid copolymer (Dx/Ha; Deflux; Q-Med) is a rare complication that usually develops within the first few days after the intervention. Although few cases of delayed presentation of ureteral obstruction after Dx/Ha injection have been reported,1-3 generally, there is only limited awareness for this risk. This article presents a patient with a very late obstruction and reviews the literature.
CASE REPORT A 4-year-old girl with a unilateral grade III vesicoureteral reflux (VUR) on the left side was treated for recurrent febrile urinary tract infections at a peripheral hospital. An endoscopic Dx/Ha injection was performed after the second breakthrough infection. Under cystoscopic guidance, 0.8-mL Dx/Ha copolymer was injected using the subureteral transurethral injection technique. The postinterventional course was inconspicuous, and the resolution of the hydronephrosis was confirmed by ultrasound imaging at a routine follow-up 1 month later. One year after the intervention, however, the girl presented with pyelonephritis. A persistent VUR was excluded by a voiding cystourethrogram, and the ultrasound examination did not show any abnormalities of the urinary system. Two more febrile urinary tract infections occurred in the second postoperative year. Apart from high fever and dysuria during the infections, no other symptoms were present. Blood pressure measurements were always within the normal reference range. However, the abdominal Financial Disclosure: The authors declare that they have no relevant financial interests. From the Department of Pediatric Urology, University Children’s Hospital Zurich, Zurich, Switzerland; the Department of Pediatric Surgery, Regional Hospital Bellinzona, Switzerland; and the Department of Pathology, University Hospital Zurich, Zurich, Switzerland Reprint requests: Samuel Christen, M.D., Department of Urology, University Children’s Hospital Zurich, Steinwiesstrasse 75, 8032 Zurich, Switzerland. E-mail: [email protected] Submitted: June 21, 2013, accepted (with revisions): October 8, 2013
920
ª 2014 Elsevier Inc. All Rights Reserved
ultrasound scan at this juncture demonstrated severe leftsided hydroureteronephrosis and a prevesical calcification (Fig. 1A, B). Differential diagnosis included an obstructive prevesical urolithiasis and a calcified Dx/Ha deposit. However, a repeated ultrasound examination strongly suggested that the obstruction was caused by an extraluminal calcification. We therefore decided to perform a Cohen ureterocystoneostomy with an excision of the calcified deposit. During the surgery, we found that the bladder wall was unremarkable. Dissection of the distal ureter for 1.5 cm revealed severe scarring. We finally located the calcified Dx/Ha (Fig. 2) within the cicatricial tissue. About 4 cm of the distal ureter, including the Dx/Ha deposit, was resected to create a safe submucosal tunnel. According to our standard procedure, we inserted only a suprapubic catheter and no transureteral stent. The postoperative course was uneventful. The histopathologic analysis revealed dystrophic calcification of the deposit with surrounding foreign-body giant-cell reaction and intramural fibrosis of the resected distal ureter (Fig. 3). No further complications arose during the follow-up. An ultrasound examination 3 months after the surgery showed a complete resolution of the hydronephrosis (Fig. 1C).
COMMENT Endoscopic treatment of VUR with subureteral Dx/Ha injection is a safe and efficient procedure with low complication rates. Apart from the persistent VUR, obstruction is the most common postinterventional complication, with an incidence ratio of 0%-5.7% in published case series.1,4-6 Most of the obstructions documented occurred during the first few days after intervention or were recorded as persistent or progressive hydronephrosis at routine ultrasound controls within the first 3 postoperative months.2,4,6-8 To date, only 3 cases1-3 of delayed ureteral obstruction have been reported after Dx/Ha injection. Two other cases 0090-4295/14/$36.00 http://dx.doi.org/10.1016/j.urology.2013.10.053
Figure 1. (A) Ultrasound scan 2 years after dextranomer or hyaluronic acid (Dx/Ha) injection, showing severe left-sided hydroureteronephrosis, and (B) an obstructive echogenic formation (marked with crosses) at the ureterovesical junction. (C) Complete resolution of the hydroureteronephrosis on an ultrasound control 3 months after the removal of the Dx/Ha deposit and reimplantation of the left ureter.
Figure 2. Intraoperative findings: because of extensive scarring, it was necessary to open the detrusor muscle for transvesical mobilization of the ureter (stented by a catheter). (A) The Dx/Ha deposit was found approximately 2 cm proximal to the orifice. (B) After further release of the ureter, the narrowing (arrow) caused by the intramural Dx/Ha deposit (*) can be seen. (Color version available online.)
of late-onset ureteral obstruction secondary to endoscopic VUR treatment have been published: 1 patient 3 years after the injection of collagen9 and another patient 18 months after the injection of calcium hydroxyapatite.10 In a retrospective multicenter study of 745 patients, Vandersteen et al1 reported only 5 cases (0.7%) of ureteral obstruction after Dx/Ha injection. Four of these patients presented with immediate symptoms. Only 1 patient was reported with pyelonephritis 6 months after the intervention, despite normal results on an ultrasound scan and a voiding cystourethrogram 3 months postoperatively. Repeated ultrasound examinations of this patient showed progressive hydronephrosis that required ureteral stenting. Arlen et al2 reported a patient with mild hydronephrosis detected on the routine follow-up ultrasound 6 weeks after the injection of Dx/Ha. A severe increase of the hydronephrosis was seen 15 months after injection, and an open right ureteral reimplantation was performed. The excised Dx/Ha bleb was described as calcified and considerably increased in volume. The latest case was reported by Zemple et al3 in January 2012. An ultrasound scan detected progressive mild hydroureteronephrosis 18 months after Dx/Ha injection. Because of an obstructive curve in the renogram 4 years UROLOGY 83 (4), 2014
Figure 3. Histologic examination shows a pseudocyst filled with amorphous pale material consistent with hyaluronic acid and foreign-body reaction in the periphery with multinucleated giant cells (hematoxylin and eosin staining, 100 original magnification). (Color version available online.)
after injection, they decided to perform a cystoscopic puncture of the Dx/Ha pseudocapsule to irrigate the material with saline. A clear improvement of the hydronephrosis was observed in ultrasound imaging 2 months after the intervention. 921
The current literature discusses different causes of late obstructions. Some authors have observed an increase in the volume of the subureteral bleb that could cause a progressive obstruction.2 This might be because of the calcification of the injected Dx/Ha, which has been described by several authors.11,12 Another possible cause might be a severe inflammatory foreign-body reaction resulting in the formation of a pseudocapsule around the implant, which has often been mentioned in the histopathologic reports.13,14 In some cases, a cephalad migration of the graft along the ureter has been found15; a similar dislocation of the injected material has been observed with a relapse of VUR. Furthermore, an intramural fibrosis of the distal ureter can potentially cause a vesicoureteral junction stenosis.
CONCLUSION Late ureteral obstruction after subureteral injection of Dx/ Ha is a rare but important complication with the potential for causing permanent renal damage. The latency of 2 years documented in our case report is the longest interval between a Dx/Ha injection and the appearance of an obstruction that has so far been reported. Changes in the Dx/Ha bleb, such as an increase in volume or calcification, must be interpreted as an early sign of a potential obstruction. The lack of symptoms or other clinical findings in the early follow-up underlines the importance of this observation. Therefore, we propose a routine long-term follow-up with serial ultrasound examinations to evaluate the Dx/Ha bleb for at least 2 years. Moreover, we recommend a routine clinical and sonographic follow-up after any treatment of moderate and high-grade VUR through puberty to monitor renal growth, renal function, and blood pressure. A standard treatment for late obstruction after Dx/Ha injection cannot be recommended on the basis of the current literature. Open surgical resection of the Dx/Ha deposit and ureteral reimplantation is an effective option. However, this is a rather invasive approach, and other strategies should be considered, such as ureteral stenting or endoscopic removal. Further studies are necessary to evaluate whether these minimally invasive options can efficiently resolve late Dx/Ha obstructions. References 1. Vandersteen DR, Routh JC, Kirsch AJ, et al. Postoperative ureteral obstruction after subureteral injection of dextranomer/hyaluronic acid copolymer. J Urol. 2006;176:1593-1595. 2. Arlen AM, Pakalniskis BL, Cooper CS. Asymptomatic chronic partial obstruction of a normal ureter following dextranomer/hyaluronic acid copolymer (Deflux) injection for grade I vesicoureteral reflux. J Pediatr Urol. 2012;8:e27-e30. 3. Zemple RP, Potretzke AM, Kryger JV. Delayed onset ureteral obstruction following Deflux injection for vesicoureteral reflux. J Pediatr Urol. 2012;8:e23-e26. 4. Mazzone L, Gobet R, Gonzalez R, et al. Ureteral obstruction following injection of dextranomer/hyaluronic acid copolymer: an infrequent but relevant complication. J Pediatr Urol. 2012;8:514-519.
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5. Puri P, Mohanan N, Menezes M, Colhoun E. Endoscopic treatment of moderate and high grade vesicoureteral reflux in infants using dextranomer/hyaluronic acid. J Urol. 2007;178:1714-1716. 6. Läckgren G, Wahlin N, Sk€oldenberg E, Stenberg A. Long-term followup of children treated with dextranomer/hyaluronic acid copolymer for vesicoureteral reflux. J Urol. 2001;166:1887-1892. 7. Snodgrass WT. Obstruction of a dysmorphic ureter following dextranomer/hyaluronic acid copolymer. J Urol. 2004;171:395-396. 8. Kempf C, Winkelmann B, Roigas J, et al. Severe complications after endoscopic injection of polydimethylsiloxane for the treatment of vesicoureteral reflux in early childhood. Scand J Urol Nephrol. 2010; 44:347-353. 9. Kirlum HJ, Stehr M, Dietz HG. Late obstruction after subureteral collagen injection. Eur J Pediatr Surg. 2006;16:133-134. 10. Zaccara A, Castagnetti M, Beniamin F, Rigamonti W. Late onset ureteric obstruction after endoscopic subureteric injection of calcium hydroxyapatite for primary vesicoureteric reflux. Urology. 2007;70:811.e1-811.e3. 11. Noe HN. Calcification in a Deflux bleb thought to be a ureteral calculus in a child. J Pediatr Urol. 2008;4:88-89. 12. Palagiri AV, Dangle PP. Distal ureteral calcification secondary to Deflux injection: a reality or myth? Urology. 2011;77:1217-1219. 13. Stenberg A, Larsson E, Läckgren G. Endoscopic treatment with dextranomer-hyaluronic acid for vesicoureteral reflux: histological findings. J Urol. 2003;169:1109-1113. 14. Routh JC, Ashley RA, Thomas JS, et al. Histopathological changes associated with dextranomer/hyaluronic acid injection for pediatric vesicoureteral reflux. J Urol. 2007;178:1707-1710. 15. Broderick K, Thompson JH, Khan AR, Greenfield SP. Giant cell reaction with phagocytosis adjacent to dextranomer-hyaluronic acid (Deflux) implant: possible reason for Deflux failure. J Pediatr Urol. 2008;4:319-321.
EDITORIAL COMMENT The authors report a case of a 4-year-old girl developing ureteral obstruction within 2 years after subureteric injection of dextranomer combined with hyaluronic acid (Dx/HA) for grade III vesicoureteral reflux. This patient had recurrent febrile urinary tract infections after Dx/HA injection but no apparent flank pain. Ureteral reimplantation was performed, and histopathology revealed dystrophic calcification and foreign-body reaction. Dx/HA was approved by the Food and Drug Administration for use in the United States in 2001. Ureteral obstruction has been described in the early postoperative period in less than 1% of children undergoing the injection.1 Many, but not all, cases of post-Dx/HA ureteral obstruction are associated with abnormalities in the urinary system structure or function.1,2 Although reports of late ureteral obstruction after Dx/HA injection remain infrequent, several have been published in the recent years.2,3 Identification of possible factors predisposing patients to post-Dx/HA ureteral obstruction is made challenging by the fact that these events remain rare, and presentation can be widely variable. Clinicians should be encouraged to share their experiences, even when adverse events are uncommon. These reports underscore the need for continued symptomatic and perhaps sonographic surveillance of patients for at least several years after Dx/HA injection. Kathleen Kieran, M.D., Department of Urology, University of Iowa Hospitals and Clinics, Iowa City, IA
References 1. Vandersteen DR, Routh JC, Kirsch AJ, et al. Postoperative ureteral obstruction after subureteral injection of dextranomer/hyaluronic acid copolymer. J Urol. 2006;176:1593-1595.
UROLOGY 83 (4), 2014
2. Arlen AM, Pakalniskis BL, Cooper CS. Asymptomatic chronic partial obstruction of a normal ureter following dextranomer/hyaluronic acid copolymer (Deflux) injection for grade I vesicoureteral reflux. J Pediatr Urol. 2012;8:e27-e30. 3. Nseyo U, Mancini JG, Wiener JS. Symptomatic bilateral delayed partial ureteral obstruction after bilateral endoscopic correction of
UROLOGY 83 (4), 2014
vesicoureteral reflux with dextranomer/hyaluronic acid polymer. Urology. 2013;81:184-187.
http://dx.doi.org/10.1016/j.urology.2013.10.059 UROLOGY 83: 922e923, 2014. 2014 Elsevier Inc.
923
U
reteral obstruction after the injection of dextranomer combined with hyaluronic acid copolymer (Dx/Ha; Deflux; Q-Med) is a rare complication that usually develops within the first few days after the intervention. Although few cases of delayed presentation of ureteral obstruction after Dx/Ha injection have been reported,1-3 generally, there is only limited awareness for this risk. This article presents a patient with a very late obstruction and reviews the literature.
CASE REPORT A 4-year-old girl with a unilateral grade III vesicoureteral reflux (VUR) on the left side was treated for recurrent febrile urinary tract infections at a peripheral hospital. An endoscopic Dx/Ha injection was performed after the second breakthrough infection. Under cystoscopic guidance, 0.8-mL Dx/Ha copolymer was injected using the subureteral transurethral injection technique. The postinterventional course was inconspicuous, and the resolution of the hydronephrosis was confirmed by ultrasound imaging at a routine follow-up 1 month later. One year after the intervention, however, the girl presented with pyelonephritis. A persistent VUR was excluded by a voiding cystourethrogram, and the ultrasound examination did not show any abnormalities of the urinary system. Two more febrile urinary tract infections occurred in the second postoperative year. Apart from high fever and dysuria during the infections, no other symptoms were present. Blood pressure measurements were always within the normal reference range. However, the abdominal Financial Disclosure: The authors declare that they have no relevant financial interests. From the Department of Pediatric Urology, University Children’s Hospital Zurich, Zurich, Switzerland; the Department of Pediatric Surgery, Regional Hospital Bellinzona, Switzerland; and the Department of Pathology, University Hospital Zurich, Zurich, Switzerland Reprint requests: Samuel Christen, M.D., Department of Urology, University Children’s Hospital Zurich, Steinwiesstrasse 75, 8032 Zurich, Switzerland. E-mail: [email protected] Submitted: June 21, 2013, accepted (with revisions): October 8, 2013
920
ª 2014 Elsevier Inc. All Rights Reserved
ultrasound scan at this juncture demonstrated severe leftsided hydroureteronephrosis and a prevesical calcification (Fig. 1A, B). Differential diagnosis included an obstructive prevesical urolithiasis and a calcified Dx/Ha deposit. However, a repeated ultrasound examination strongly suggested that the obstruction was caused by an extraluminal calcification. We therefore decided to perform a Cohen ureterocystoneostomy with an excision of the calcified deposit. During the surgery, we found that the bladder wall was unremarkable. Dissection of the distal ureter for 1.5 cm revealed severe scarring. We finally located the calcified Dx/Ha (Fig. 2) within the cicatricial tissue. About 4 cm of the distal ureter, including the Dx/Ha deposit, was resected to create a safe submucosal tunnel. According to our standard procedure, we inserted only a suprapubic catheter and no transureteral stent. The postoperative course was uneventful. The histopathologic analysis revealed dystrophic calcification of the deposit with surrounding foreign-body giant-cell reaction and intramural fibrosis of the resected distal ureter (Fig. 3). No further complications arose during the follow-up. An ultrasound examination 3 months after the surgery showed a complete resolution of the hydronephrosis (Fig. 1C).
COMMENT Endoscopic treatment of VUR with subureteral Dx/Ha injection is a safe and efficient procedure with low complication rates. Apart from the persistent VUR, obstruction is the most common postinterventional complication, with an incidence ratio of 0%-5.7% in published case series.1,4-6 Most of the obstructions documented occurred during the first few days after intervention or were recorded as persistent or progressive hydronephrosis at routine ultrasound controls within the first 3 postoperative months.2,4,6-8 To date, only 3 cases1-3 of delayed ureteral obstruction have been reported after Dx/Ha injection. Two other cases 0090-4295/14/$36.00 http://dx.doi.org/10.1016/j.urology.2013.10.053
Figure 1. (A) Ultrasound scan 2 years after dextranomer or hyaluronic acid (Dx/Ha) injection, showing severe left-sided hydroureteronephrosis, and (B) an obstructive echogenic formation (marked with crosses) at the ureterovesical junction. (C) Complete resolution of the hydroureteronephrosis on an ultrasound control 3 months after the removal of the Dx/Ha deposit and reimplantation of the left ureter.
Figure 2. Intraoperative findings: because of extensive scarring, it was necessary to open the detrusor muscle for transvesical mobilization of the ureter (stented by a catheter). (A) The Dx/Ha deposit was found approximately 2 cm proximal to the orifice. (B) After further release of the ureter, the narrowing (arrow) caused by the intramural Dx/Ha deposit (*) can be seen. (Color version available online.)
of late-onset ureteral obstruction secondary to endoscopic VUR treatment have been published: 1 patient 3 years after the injection of collagen9 and another patient 18 months after the injection of calcium hydroxyapatite.10 In a retrospective multicenter study of 745 patients, Vandersteen et al1 reported only 5 cases (0.7%) of ureteral obstruction after Dx/Ha injection. Four of these patients presented with immediate symptoms. Only 1 patient was reported with pyelonephritis 6 months after the intervention, despite normal results on an ultrasound scan and a voiding cystourethrogram 3 months postoperatively. Repeated ultrasound examinations of this patient showed progressive hydronephrosis that required ureteral stenting. Arlen et al2 reported a patient with mild hydronephrosis detected on the routine follow-up ultrasound 6 weeks after the injection of Dx/Ha. A severe increase of the hydronephrosis was seen 15 months after injection, and an open right ureteral reimplantation was performed. The excised Dx/Ha bleb was described as calcified and considerably increased in volume. The latest case was reported by Zemple et al3 in January 2012. An ultrasound scan detected progressive mild hydroureteronephrosis 18 months after Dx/Ha injection. Because of an obstructive curve in the renogram 4 years UROLOGY 83 (4), 2014
Figure 3. Histologic examination shows a pseudocyst filled with amorphous pale material consistent with hyaluronic acid and foreign-body reaction in the periphery with multinucleated giant cells (hematoxylin and eosin staining, 100 original magnification). (Color version available online.)
after injection, they decided to perform a cystoscopic puncture of the Dx/Ha pseudocapsule to irrigate the material with saline. A clear improvement of the hydronephrosis was observed in ultrasound imaging 2 months after the intervention. 921
The current literature discusses different causes of late obstructions. Some authors have observed an increase in the volume of the subureteral bleb that could cause a progressive obstruction.2 This might be because of the calcification of the injected Dx/Ha, which has been described by several authors.11,12 Another possible cause might be a severe inflammatory foreign-body reaction resulting in the formation of a pseudocapsule around the implant, which has often been mentioned in the histopathologic reports.13,14 In some cases, a cephalad migration of the graft along the ureter has been found15; a similar dislocation of the injected material has been observed with a relapse of VUR. Furthermore, an intramural fibrosis of the distal ureter can potentially cause a vesicoureteral junction stenosis.
CONCLUSION Late ureteral obstruction after subureteral injection of Dx/ Ha is a rare but important complication with the potential for causing permanent renal damage. The latency of 2 years documented in our case report is the longest interval between a Dx/Ha injection and the appearance of an obstruction that has so far been reported. Changes in the Dx/Ha bleb, such as an increase in volume or calcification, must be interpreted as an early sign of a potential obstruction. The lack of symptoms or other clinical findings in the early follow-up underlines the importance of this observation. Therefore, we propose a routine long-term follow-up with serial ultrasound examinations to evaluate the Dx/Ha bleb for at least 2 years. Moreover, we recommend a routine clinical and sonographic follow-up after any treatment of moderate and high-grade VUR through puberty to monitor renal growth, renal function, and blood pressure. A standard treatment for late obstruction after Dx/Ha injection cannot be recommended on the basis of the current literature. Open surgical resection of the Dx/Ha deposit and ureteral reimplantation is an effective option. However, this is a rather invasive approach, and other strategies should be considered, such as ureteral stenting or endoscopic removal. Further studies are necessary to evaluate whether these minimally invasive options can efficiently resolve late Dx/Ha obstructions. References 1. Vandersteen DR, Routh JC, Kirsch AJ, et al. Postoperative ureteral obstruction after subureteral injection of dextranomer/hyaluronic acid copolymer. J Urol. 2006;176:1593-1595. 2. Arlen AM, Pakalniskis BL, Cooper CS. Asymptomatic chronic partial obstruction of a normal ureter following dextranomer/hyaluronic acid copolymer (Deflux) injection for grade I vesicoureteral reflux. J Pediatr Urol. 2012;8:e27-e30. 3. Zemple RP, Potretzke AM, Kryger JV. Delayed onset ureteral obstruction following Deflux injection for vesicoureteral reflux. J Pediatr Urol. 2012;8:e23-e26. 4. Mazzone L, Gobet R, Gonzalez R, et al. Ureteral obstruction following injection of dextranomer/hyaluronic acid copolymer: an infrequent but relevant complication. J Pediatr Urol. 2012;8:514-519.
922
5. Puri P, Mohanan N, Menezes M, Colhoun E. Endoscopic treatment of moderate and high grade vesicoureteral reflux in infants using dextranomer/hyaluronic acid. J Urol. 2007;178:1714-1716. 6. Läckgren G, Wahlin N, Sk€oldenberg E, Stenberg A. Long-term followup of children treated with dextranomer/hyaluronic acid copolymer for vesicoureteral reflux. J Urol. 2001;166:1887-1892. 7. Snodgrass WT. Obstruction of a dysmorphic ureter following dextranomer/hyaluronic acid copolymer. J Urol. 2004;171:395-396. 8. Kempf C, Winkelmann B, Roigas J, et al. Severe complications after endoscopic injection of polydimethylsiloxane for the treatment of vesicoureteral reflux in early childhood. Scand J Urol Nephrol. 2010; 44:347-353. 9. Kirlum HJ, Stehr M, Dietz HG. Late obstruction after subureteral collagen injection. Eur J Pediatr Surg. 2006;16:133-134. 10. Zaccara A, Castagnetti M, Beniamin F, Rigamonti W. Late onset ureteric obstruction after endoscopic subureteric injection of calcium hydroxyapatite for primary vesicoureteric reflux. Urology. 2007;70:811.e1-811.e3. 11. Noe HN. Calcification in a Deflux bleb thought to be a ureteral calculus in a child. J Pediatr Urol. 2008;4:88-89. 12. Palagiri AV, Dangle PP. Distal ureteral calcification secondary to Deflux injection: a reality or myth? Urology. 2011;77:1217-1219. 13. Stenberg A, Larsson E, Läckgren G. Endoscopic treatment with dextranomer-hyaluronic acid for vesicoureteral reflux: histological findings. J Urol. 2003;169:1109-1113. 14. Routh JC, Ashley RA, Thomas JS, et al. Histopathological changes associated with dextranomer/hyaluronic acid injection for pediatric vesicoureteral reflux. J Urol. 2007;178:1707-1710. 15. Broderick K, Thompson JH, Khan AR, Greenfield SP. Giant cell reaction with phagocytosis adjacent to dextranomer-hyaluronic acid (Deflux) implant: possible reason for Deflux failure. J Pediatr Urol. 2008;4:319-321.
EDITORIAL COMMENT The authors report a case of a 4-year-old girl developing ureteral obstruction within 2 years after subureteric injection of dextranomer combined with hyaluronic acid (Dx/HA) for grade III vesicoureteral reflux. This patient had recurrent febrile urinary tract infections after Dx/HA injection but no apparent flank pain. Ureteral reimplantation was performed, and histopathology revealed dystrophic calcification and foreign-body reaction. Dx/HA was approved by the Food and Drug Administration for use in the United States in 2001. Ureteral obstruction has been described in the early postoperative period in less than 1% of children undergoing the injection.1 Many, but not all, cases of post-Dx/HA ureteral obstruction are associated with abnormalities in the urinary system structure or function.1,2 Although reports of late ureteral obstruction after Dx/HA injection remain infrequent, several have been published in the recent years.2,3 Identification of possible factors predisposing patients to post-Dx/HA ureteral obstruction is made challenging by the fact that these events remain rare, and presentation can be widely variable. Clinicians should be encouraged to share their experiences, even when adverse events are uncommon. These reports underscore the need for continued symptomatic and perhaps sonographic surveillance of patients for at least several years after Dx/HA injection. Kathleen Kieran, M.D., Department of Urology, University of Iowa Hospitals and Clinics, Iowa City, IA
References 1. Vandersteen DR, Routh JC, Kirsch AJ, et al. Postoperative ureteral obstruction after subureteral injection of dextranomer/hyaluronic acid copolymer. J Urol. 2006;176:1593-1595.
UROLOGY 83 (4), 2014
2. Arlen AM, Pakalniskis BL, Cooper CS. Asymptomatic chronic partial obstruction of a normal ureter following dextranomer/hyaluronic acid copolymer (Deflux) injection for grade I vesicoureteral reflux. J Pediatr Urol. 2012;8:e27-e30. 3. Nseyo U, Mancini JG, Wiener JS. Symptomatic bilateral delayed partial ureteral obstruction after bilateral endoscopic correction of
UROLOGY 83 (4), 2014
vesicoureteral reflux with dextranomer/hyaluronic acid polymer. Urology. 2013;81:184-187.
http://dx.doi.org/10.1016/j.urology.2013.10.059 UROLOGY 83: 922e923, 2014. 2014 Elsevier Inc.
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