Original Research
JOURNAL OF ENDOUROLOGY Volume XX, Number XX, 2014 ª Mary Ann Liebert, Inc. Pp. ---–--DOI: 10.1089/end.2014.0394
Complications After Polymeric and Metallic Ureteral Stent Placements Including Three Types of Fistula Geehyun Song, MD, PhD,1 Bumjin Lim, MD,2 Kyung-Sik Han, MD,2 Sang Hoon Song, MD, PhD,2 Hyung Keun Park, MD, PhD,2 and Bumsik Hong, MD, PhD 2
Abstract
Purpose: To report complications, including three types of fistula, intractable hematuria, and pain, which can develop after polymeric ureteral stent (PUS) or metallic ureteral stent placements and to evaluate the risk factors for these adverse events. Patients and Methods: We reviewed seven patients referred to our trauma and reconstructive subdivision for complications that presented after placement of a PUS (two patients), double-layered, coated, self-expandable, mesh metallic stent (three patients), Memokath stent (one patient), or Resonance stent (one patient). We retrospectively reviewed their medical records and accessed the predisposing factors, mechanism of injury, diagnosis, and interventional and surgical management. Results: The two patients with PUS presented with ureteroarterial fistula (UAF). Among patients with a selfexpandable metallic mesh stents, UAF developed UAF in one patient, ureteroenteral fistula (UEF) developed in one patient, and ureterovaginal fistula (UVF) developed in one patient. There were five patients with fistula who had a history of pelvic surgery, radiation therapy, long-term ureteral stent, or high-pressure balloon dilation. Surgical procedures were needed to manage these problems, including nephrectomy in two patients and bypass surgery with ureter ligation in two patients. UAF was seen with massive gross hematuria that necessitated angiography. UEF required small bowel resection. The patient with UVF underwent multiple surgeries for recurrent fistula. Patients with a Memokath or Resonance stent presented with intractable flank pain and hematuria. These persons required a surgical or other procedure to remove the stents. Conclusions: UAF should be highly suspected in patients with long-term ureteral stents, especially if gross hematuria develops. The placement of a metallic ureteral stent using a high-pressure balloon should be performed cautiously, especially in patients with a history of pelvic surgery or radiation. such as lower abdominal pain, dysuria, urinary frequency, flank pain, migration, calcification, and malfunction.5 For an MUS, no reports in the literature have yet studied serious complications such as fistula.3,6 We report our findings for patients referred with serious ureteral stent-related complications that necessitated surgical correction.
Introduction
U
reteral obstruction can develop because of benign or malignant causes. The usual initial management is the placement of an indwelling polymeric ureteral stent (PUS). A subgroup of patients will also need a chronic indwelling stent that must be changed regularly. The long-term failure rate of ureteral stents is high in patients with malignancy-related obstruction,1 which subsequently necessitates the development and introduction of metallic ureteral stents (MUS). There are three types of MUS: Self-expandable metallic mesh wall stents,2 novel thermoexpandable nickel-titanium alloy metallic stents (Memokath),3 and metallic ureteral stents (Resonance).4 Ureteroarterial fistula (UAF), a serious complication associated with ureteral stents, has been well documented in the literature. In addition, less-serious complications are typical, 1 2
Patients and Methods
We retrospectively reviewed the medical records of patients who presented with upper urinary tract obstruction and received ureteral stent insertion. At our center, *7000 PUS were used from 2007, and 26 MUS have been used since 2012. In patients with a MUS, cases of indwelling Memokath and Resonance were referred from other hospitals because of gross hematuria.
Department of Urology, Kangwon National University Hospital, Chuncheon, Kangwon, Korea. Department of Urology, Asian Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
1
End outcome
Intervention Treatment
PUS = polymeric ureteral stent; MUS = metallic ureteral stent UAF = ureteroarterial fistula; UEF = ureteroenteric fistula; UVF = ureterovaginal fistula; UPJO = ureteropelvic junction obstruction; RPF = retroperitoneal fibrosis; RT = radical therapy; CT = computed tomography; AGU = antegrade urography; CIA = common iliac artery; Angio = angiography; RGU = retrograde urography; PCN = percutaneous nephrostomy; DJ = double J ureter stent; BD = ureteral balloon dilation.
BD with stent removal Free PCN Robot-assisted pyeloplasty Free PCN Ileal ureter with bladder augmentation, Free PCN Bowel resection Nephrectomy Free Free
Pseudoaneurysm in right CIA (CT)
Pseudoaneurysm in Right CIA (Angio) PCN stent graft Bypass with ureter ligation PCN change Pseudoaneurysm in right CIA (Angio) PCN stent graft Bypass with ureter ligation PCN change Diagnosis
Massive hematuria Massive hematuria
Sex Age, years Complication Medical history Previous surgery Previous RT Lesion side Stenting duration, months (stent) Symptoms
Bypass Nephrectomy
CT Cystography
Flank pain Hematuria AGU RGU
Male 44 Gross hematuria UPJO No No Left 24
Female 56 UVF Cervical cancer Yes Yes Left 96 (PUS) 10 (MUS) Total incontinence Female 64 UAF Cervical cancer Yes Yes Right 72 Female 58 UAF Rectal cancer Yes Yes Right 31
Female 72 UAF Cervical cancer Yes Yes Right 48 (PUS) 6 (MUS) Massive hematuria
Expandable metallic mesh stent PUS
Table 1. Clinical Features According to Stent Type
Table 1 summarizes the clinical features of our patient cohorts according to stent type. Two patients with long-term indwelling PUS presented with UAF. Among the patients with a self-expandable mesh metallic stent, UAF developed in one patient, ureterovaginal fistula (UVF) developed in one patient, and ureteroenteral fistula (UEF) developed in one patient. These three patients underwent balloon dilation at the time of MUS insertion. All five patients with fistulas had a history of pelvic surgery, including cervical cancer in three patients, ovarian cancer in one patient, and rectal cancer in one patient. Four patients had also received radiation therapy. Among the fistula cases, stent duration was 15 to 96 months with PUS and 6 to 10 months with MUS. In our study cohort, three instances of UAF occurred on the right side. Angiography confirmed pseudoaneurysm in all cases, and two patients underwent stent engraftment, but hematuria developed and relapse occurred several times. After considering the general condition of the patients, they ultimately underwent bypass graft surgery and ureter ligation instead of simultaneous reconstruction (such as ileal ureter). The remaining patient underwent emergency bypass surgery with nephrectomy because the affected kidney was nonfunctional. This patient also showed a pseudoaneurysm on preoperative CT. The patient with UEF had a history of multiple bowel operations, in addition to pelvic surgical procedure and radiation therapy. This patient underwent nephrectomy and small bowel resection. The patient with UVF had a history of radiation cystitis before undergoing MUS. She also had a single kidney. Her bladder was necrotic around the ureteral orifice at the time of surgery, and she needed partial cystectomy and ileocystoplasty. This patient had to receive three additional operations to correct the recurrent fistula. The patient with the Memokath stent initially underwent stent insertion at another hospital because of ureteropelvic junction obstruction. He presented with intermittent hematuria and chronic intolerable flank pain. Antegrade urography revealed ureteropelvic junction obstruction after conversion to percutaneous nephrostomy, and he finally underwent robot-assisted pyeloplasty. The patient with a Resonance stent had a history of retroperitoneal fibrosis, and he complained of dysuria, intermittent hematuria, and flank pain. We performed simple
MUS
Results
Female 51 UEF Ovary cancer Yes No Left 15 (PUS) 7 (MUS) Abdominal pain and fever CT RGU
Memokath
Resonance
We identified seven patients for analysis in this study who were referred to our trauma and reconstructive subdivision for various complications after the placement of ureteral stents. The adverse events in two patients were related to a long-term indwelling PUS and to MUS in the other five patients. Of the five patients, ureteral fistula developed in three after the placement of an indwelling self-expandable metallic mesh stent. The remaining two patients underwent insertion of Memokath or Resonance stents and were referred for reconstructive surgery to correct the underlying ureteral obstructions. We retrospectively reviewed the medical records of these patients and analyzed the predisposing factors underlying their complications, mechanism of injury, diagnosis, and interventional and surgical management according to the type of complication.
Flank pain Hematuria CT
SONG ET AL. Male 51 Gross hematuria RPF No No Left 20
2
COMPLICATIONS OF URETERAL STENT PLACEMENT
balloon dilation and inserted an 8F PUS after ballooning, which was removed 4 weeks after insertion. Discussion
The ureteral stent is used by all urologists, but it can cause serious complications. UAF is a rare but life-threatening condition that is occurring at an increasing rate ( > 100 cases reported worldwide). One of the most common scenarios is that in a patient with a history of minor intermittent hematuria, massive hematuria suddenly develops during the exchange of ureteral stents.7 This occurred in two patients in our hospital who regularly had their PUS exchanged. There are several predisposing factors to UAF, including primary vascular disease, previous pelvic surgery, and radiation therapy.8 If pelvic surgery and/or radiation therapy is followed by regular stent changes, it most likely adds insult to injury and predisposes the patient to fistula formation. These are the three typical risk factors for UAF. Five of our current patients had a history of pelvic surgery, and four patients had received radiation therapy. Pelvic surgery-induced pelvic fibrosis and radiation therapy can fix the ureter to the artery, and then the vascular and ureteral wall can degenerate at the crossing site. Continuous arterial pulsation against the stent wall may worsen any degeneration. In this vulnerable situation, stent change or balloon dilation to insert a MUS can cause pressure necrosis that finally develops into UAF.9 In addition, this condition can also be caused by primary vascular malformation or adjacent arterial aneurysms that erode into the ureter.10 A longer indwelling period can also aggravate degeneration and pressure necrosis at the crossing site. Except for the Resonance 051 stent, however, there are no definitive recommendations for the indwelling period to prevent complications, including UVF. In Table 2, we summarize the MUS characteristics. Although there is no recommendation for the indwelling duration for the Uventa or Memokath stents, clinical trials have recorded time frames for the primary patency rates of these stents of 12 and 36 months, respectively (ClinicalTrials.gov Identifiers: NCT01788865 (UVENTA) and NCT00790686 (Memokath 051 stent)). Hematuria severity varies considerably in patients with UAF, and massive hematuria and flank pain caused by clots are the typical presentations, although these can be subtle enough to make diagnosis difficult. When patients with predisposing factors demonstrate mild to moderate hematuria,
3
a high level of suspicion is needed for early diagnosis and preemptive management because UAF can potentially result in fatal bleeding. The diagnosis of UAF mainly depends on renal angiography and CT to detect contrast extravasation or pseudoaneurysm. Retrograde urography plays a limited role because of blood clots but can occasionally reveal vascular opacification when patients under high suspicion present with mild to moderate hemorrhage at the time of stent change. Routine contrast-enhanced CT demonstrates low sensitivity for detecting UAF. Therefore, if UAF is strongly suspected but there are no positive findings, three-dimensional CT or multiplanar reconstruction CT should be used to detect evasive pseudoaneurysm or subtle extravasation.8 During angiography, several examinations using oblique digital subtraction angiography might be needed to identify small evasive pseudoaneurysms. For effective treatment, communication between specialists including urologists, vascular surgeons, and radiologists is essential. Possible therapeutic options include artery embolization, combination artery embolization and surgical bypass grafting, endovascular repair using stent grafts, and embolization of the ureter during nephrostomy.9 Surgical exploration into the fibrotic pelvis may be followed by severe morbidity and mortality, but femoral-tofemoral bypass grafting is a definite surgical treatment for this condition. The usual first-line treatment is interventional embolization of the pseudoaneurysm using coils or stent engraftment in the artery. The most commonly involved area is the common iliac artery (as was the case in all our present study patients) or the point at which the internal iliac artery branches. Hence, embolization can result in leg ischemia. Instead, endovascular stent engraftment is a safe and effective method for managing acute events; however, the rate of hematuria recurrence remains high with this technique, and additional procedures or reconstructive surgery may be needed.11 The two patients in our cohort who had received a stent graft finally underwent bypass surgery 6 to 8 months after receiving this engraftment. The pathogenesis of UEF shares three typical predisposing factors with UAF. The risk of UEF also rises when balloon dilation is used.12 As shown by our patient in whom UEF developed after MUS, a history of multiple abdominal surgeries is an additional risk factor for UEF because this can induce severe adhesion between the ureter and bowel wall.
Table 2. Comparison of Metal Stents MUS Expandable metallic mesh stent
Memokath
Resonance
Manufacturer’s recommendation Products
N/A
N/A
Up to 12 months
UventaTM
MemokathTM 051 stent
French size Length, cm Company
7F 6–12 cm Taewoong Medical
9.5F–10.5F 3–20 cm Endotherapeutics
Resonance metallic ureteral stent 6.0F 20–30 cm Cook Medical
MUS = metallic ureteral stent.
4
Severe bowel adhesion and previous radiation therapy significantly impair the chance for reconstruction in the bowel, such as the ileum. Our patient with UEF underwent nephrectomy with small bowel resection in the long segment. Vesicovaginal fistula (VVF) significantly reduces quality of life in women. VVF is one of the most challenging problems in female urology, especially when associated with previous radiation therapy. Pelvic radiation for the management of cervical carcinoma is the primary cause of radiation-induced VVF. Fibrosis begins to develop in the bladder lamina propria when radiation therapy ends. Most instances of radiation-related VVF develop within 2 years post-treatment. Some signs may not be apparent until many years after radiation therapy. Usually, radiation cystitis, hematuria, and recurrent urinary tract infection precede the development of VVF. The bladder and vaginal tissue can develop ulceration and necrosis.13 In these situations, performing any traumatic procedure on the damaged tissue can trigger the development of VVF. In our patient, the use of balloon dilation to insert the MUS must have caused the VVF. The early use of metallic mesh wall stents is limited because of frequent reocclusion that results from endothelial hyperplasia, and tumor growth through the meshwork makes removal virtually impossible.14 In our cases, the selfexpandable mesh MUS was a segmented ureteral stent that was composed of double-layered, thermoexpandable, shapememory strands of nitinol with a 7-mm outer diameter. These stents contain polytetrafluoroethylene membrane between the double-layered strands of nitinol to prevent tissue ingrowth. The stent used in our patients was similar to those described in two previous studies.4,15 When inserted into the ureter, the stent generates thermoexpansive radial forces against the ureteral wall that subsequently establish patency. Balloon dilation can be performed if expansion is limited. The 7-mm outer diameter is similar to that of the Memokath stent, but larger than the resonance stent. In a previous report on a similar mesh metallic stent, Liatsikos and associates2 described how these stents are typically inserted. Initial dilation was performed using 7-mm balloons, and pressure was increased until balloon waisting was abolished. If the inserted metallic mesh stent expands insufficiently, repeated high-pressure balloon dilation was needed. They applied overlapping stents to bridge long, obstructed, ureteral segments. As described earlier in our present report, this kind of procedure should be very cautiously performed in patients with any predisposing factors for ureteral fistula. Modi and colleagues16 previously reported that 43% of patients with Resonance stents had to have them removed before 12 months and that all patients who had to have their stents surgically removed presented with painful stent-related symptoms. MUS-related pain was reported in another series also. Agrawal and coworkers17 presented their results on 74 Memokath stents that were evaluated for a mean follow-up period of 16 months. In their report, stent migration and obstruction resulting from encrustation occurred after a mean period of 7.1 months. Although MUS may benefit patients with a long dwell time, the long-term failure rate is also considerably high. Therefore, MUS is an option for patients in which surgical reconstruction of the obstructed ureter is impossible.18
SONG ET AL.
Our two patients in the current study with Memokath or Resonance stents presented because of a benign underlying cause. Their stents did not further develop into obstruction, and their renal units were still functioning after approximately 20 months of indwelling. Stent-related pain and hematuria, however, were significant enough to warrant stent removal and definitive treatment. The MUS is generally not recommended for patients with benign ureteral lesions that can be surgically corrected. Conclusion
UAF should be suspected when intermittent gross hematuria develops because of the long-term use of ureteral stents. The placement of a MUS using a high-pressure balloon should be decided cautiously, especially for patients with a history of pelvic surgery or radiation. MUS should be exclusively used as a palliative measure in patients with a malignancy. Disclosure Statement
No competing financial interests exist. References
1. Rosenberg BH, Bianco FJ Jr, Wood DP Jr, Triest JA. Stentchange therapy in advanced malignancies with ureteral obstruction. J Endourol 2005;19:63–67. 2. Liatsikos EN, Karnabatidis D, Katsanos K, et al. Ureteral metal stents: 10-year experience with malignant ureteral obstruction treatment. J Urol 2009;182:2613–2617. 3. Zaman F, Poullis C, Bach C, et al. Use of a segmental thermoexpandable metal alloy stent in the management of malignant ureteric obstruction: A single centre experience in the UK. Urol Int 2011;87:405–410. 4. Wang HJ, Lee TY, Luo HL, et al. Application of resonance metallic stents for ureteral obstruction. BJU Int 2011;108: 428–432. 5. Pollard SG, Macfarlane R. Symptoms arising from DoubleJ ureteral stents. J Urol 1988;139:37–38. 6. Chung HH, Kim MD, Won JY, et al. Multicenter experience of the newly designed covered metallic ureteral stent for malignant ureteral occlusion: Comparison with double J stent insertion. Cardiovasc Intervent Radiol 2014;37:463– 470. 7. Darcy M. Uretro-arterial fistulas. Tech Vasc Interv Radiol 2009;12:216–221. 8. Krambeck AE, DiMarco DS, Gettman MT, Segura JW. Ureteroiliac artery fisutula: Diagnosis and treatment algorithm. Urology 2005;66:990–994. 9. Araki T, Nagata M, Araki T, et al. Endovascular treatment of ureteroarterial fistulas with stent-grafts. Radiat Med 2008;26:372–375. 10. Sharma SK, Goswami AK, Sharma GP, et al. Congenital iliac arteriovenous malformation: A cause of massive hematuria and ureteral obstruction. J Urol 1988;139:355– 356. 11. Okada T, Yamaguchi M, Muradi A, et al. Long-term results of endovascular stent graft placement of ureteroarterial fistula. Cardiovasc Intervent Radiol 2013;36:950–956. 12. Oh SJ, Jeong BC, Kim HH. Ureteroenteric fistula after retrograde balloon dilatation of ureteral stricture. Int J Urol 2002;9:707–709.
COMPLICATIONS OF URETERAL STENT PLACEMENT
13. Pushkar DY, Dyakov VV, Kasyan GR. Management of radiation-induced vesicovaginal fistula. Eur Urol 2009;55: 131–137. 14. Pandian SS, Hussey JK, McClinton S. Metallic ureteric stents: Early experience. Br J Urol 1998;82:791–797. 15. Chung KJ, Park BH, Park B, et al. Efficacy and safety of a novel, double-layered, coated, self-expandable metallic mesh stent (Uventa) in malignant ureteral obstructions. J Endourol 2013;27:930–935. 16. Modi AP, Ritch CR, Arend D, et al. Multicenter experience with metallic ureteral stents for malignant and chronic benign ureteral obstruction. J Endourol 2010;24:1189– 1193. 17. Agrawal S, Brown CT, Bellamy EA, Kulkarni R. The thermo-expandable metallic ureteric stent: An 11-year follow-up. BJU Int 2009;103:372–376. 18. Nagele U, Kuczyk MA, Horstmann M, et al. Initial clinical experience with full-length metal ureteral stents for obstructive ureteral stenosis. World J Urol 2008;26:257– 262.
5
Address correspondence to: Bumsik Hong, MD, PhD Department of Urology Asan Medical Center University of Ulsan College of Medicine 88 Olympic-ro 43-gil Songpa-gu Seoul 138-736 Korea E-mail: [email protected] Abbreviations Used CT ¼ computed tomography MUS ¼ metallic ureteral stent PUS ¼ polymeric ureteral stent UAF ¼ ureteroarterial fistula UEF ¼ ureteroenteral fistula UVF ¼ ureterovaginal fistula VVF ¼ vesicovaginal fistula
JOURNAL OF ENDOUROLOGY Volume XX, Number XX, 2014 ª Mary Ann Liebert, Inc. Pp. ---–--DOI: 10.1089/end.2014.0394
Complications After Polymeric and Metallic Ureteral Stent Placements Including Three Types of Fistula Geehyun Song, MD, PhD,1 Bumjin Lim, MD,2 Kyung-Sik Han, MD,2 Sang Hoon Song, MD, PhD,2 Hyung Keun Park, MD, PhD,2 and Bumsik Hong, MD, PhD 2
Abstract
Purpose: To report complications, including three types of fistula, intractable hematuria, and pain, which can develop after polymeric ureteral stent (PUS) or metallic ureteral stent placements and to evaluate the risk factors for these adverse events. Patients and Methods: We reviewed seven patients referred to our trauma and reconstructive subdivision for complications that presented after placement of a PUS (two patients), double-layered, coated, self-expandable, mesh metallic stent (three patients), Memokath stent (one patient), or Resonance stent (one patient). We retrospectively reviewed their medical records and accessed the predisposing factors, mechanism of injury, diagnosis, and interventional and surgical management. Results: The two patients with PUS presented with ureteroarterial fistula (UAF). Among patients with a selfexpandable metallic mesh stents, UAF developed UAF in one patient, ureteroenteral fistula (UEF) developed in one patient, and ureterovaginal fistula (UVF) developed in one patient. There were five patients with fistula who had a history of pelvic surgery, radiation therapy, long-term ureteral stent, or high-pressure balloon dilation. Surgical procedures were needed to manage these problems, including nephrectomy in two patients and bypass surgery with ureter ligation in two patients. UAF was seen with massive gross hematuria that necessitated angiography. UEF required small bowel resection. The patient with UVF underwent multiple surgeries for recurrent fistula. Patients with a Memokath or Resonance stent presented with intractable flank pain and hematuria. These persons required a surgical or other procedure to remove the stents. Conclusions: UAF should be highly suspected in patients with long-term ureteral stents, especially if gross hematuria develops. The placement of a metallic ureteral stent using a high-pressure balloon should be performed cautiously, especially in patients with a history of pelvic surgery or radiation. such as lower abdominal pain, dysuria, urinary frequency, flank pain, migration, calcification, and malfunction.5 For an MUS, no reports in the literature have yet studied serious complications such as fistula.3,6 We report our findings for patients referred with serious ureteral stent-related complications that necessitated surgical correction.
Introduction
U
reteral obstruction can develop because of benign or malignant causes. The usual initial management is the placement of an indwelling polymeric ureteral stent (PUS). A subgroup of patients will also need a chronic indwelling stent that must be changed regularly. The long-term failure rate of ureteral stents is high in patients with malignancy-related obstruction,1 which subsequently necessitates the development and introduction of metallic ureteral stents (MUS). There are three types of MUS: Self-expandable metallic mesh wall stents,2 novel thermoexpandable nickel-titanium alloy metallic stents (Memokath),3 and metallic ureteral stents (Resonance).4 Ureteroarterial fistula (UAF), a serious complication associated with ureteral stents, has been well documented in the literature. In addition, less-serious complications are typical, 1 2
Patients and Methods
We retrospectively reviewed the medical records of patients who presented with upper urinary tract obstruction and received ureteral stent insertion. At our center, *7000 PUS were used from 2007, and 26 MUS have been used since 2012. In patients with a MUS, cases of indwelling Memokath and Resonance were referred from other hospitals because of gross hematuria.
Department of Urology, Kangwon National University Hospital, Chuncheon, Kangwon, Korea. Department of Urology, Asian Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
1
End outcome
Intervention Treatment
PUS = polymeric ureteral stent; MUS = metallic ureteral stent UAF = ureteroarterial fistula; UEF = ureteroenteric fistula; UVF = ureterovaginal fistula; UPJO = ureteropelvic junction obstruction; RPF = retroperitoneal fibrosis; RT = radical therapy; CT = computed tomography; AGU = antegrade urography; CIA = common iliac artery; Angio = angiography; RGU = retrograde urography; PCN = percutaneous nephrostomy; DJ = double J ureter stent; BD = ureteral balloon dilation.
BD with stent removal Free PCN Robot-assisted pyeloplasty Free PCN Ileal ureter with bladder augmentation, Free PCN Bowel resection Nephrectomy Free Free
Pseudoaneurysm in right CIA (CT)
Pseudoaneurysm in Right CIA (Angio) PCN stent graft Bypass with ureter ligation PCN change Pseudoaneurysm in right CIA (Angio) PCN stent graft Bypass with ureter ligation PCN change Diagnosis
Massive hematuria Massive hematuria
Sex Age, years Complication Medical history Previous surgery Previous RT Lesion side Stenting duration, months (stent) Symptoms
Bypass Nephrectomy
CT Cystography
Flank pain Hematuria AGU RGU
Male 44 Gross hematuria UPJO No No Left 24
Female 56 UVF Cervical cancer Yes Yes Left 96 (PUS) 10 (MUS) Total incontinence Female 64 UAF Cervical cancer Yes Yes Right 72 Female 58 UAF Rectal cancer Yes Yes Right 31
Female 72 UAF Cervical cancer Yes Yes Right 48 (PUS) 6 (MUS) Massive hematuria
Expandable metallic mesh stent PUS
Table 1. Clinical Features According to Stent Type
Table 1 summarizes the clinical features of our patient cohorts according to stent type. Two patients with long-term indwelling PUS presented with UAF. Among the patients with a self-expandable mesh metallic stent, UAF developed in one patient, ureterovaginal fistula (UVF) developed in one patient, and ureteroenteral fistula (UEF) developed in one patient. These three patients underwent balloon dilation at the time of MUS insertion. All five patients with fistulas had a history of pelvic surgery, including cervical cancer in three patients, ovarian cancer in one patient, and rectal cancer in one patient. Four patients had also received radiation therapy. Among the fistula cases, stent duration was 15 to 96 months with PUS and 6 to 10 months with MUS. In our study cohort, three instances of UAF occurred on the right side. Angiography confirmed pseudoaneurysm in all cases, and two patients underwent stent engraftment, but hematuria developed and relapse occurred several times. After considering the general condition of the patients, they ultimately underwent bypass graft surgery and ureter ligation instead of simultaneous reconstruction (such as ileal ureter). The remaining patient underwent emergency bypass surgery with nephrectomy because the affected kidney was nonfunctional. This patient also showed a pseudoaneurysm on preoperative CT. The patient with UEF had a history of multiple bowel operations, in addition to pelvic surgical procedure and radiation therapy. This patient underwent nephrectomy and small bowel resection. The patient with UVF had a history of radiation cystitis before undergoing MUS. She also had a single kidney. Her bladder was necrotic around the ureteral orifice at the time of surgery, and she needed partial cystectomy and ileocystoplasty. This patient had to receive three additional operations to correct the recurrent fistula. The patient with the Memokath stent initially underwent stent insertion at another hospital because of ureteropelvic junction obstruction. He presented with intermittent hematuria and chronic intolerable flank pain. Antegrade urography revealed ureteropelvic junction obstruction after conversion to percutaneous nephrostomy, and he finally underwent robot-assisted pyeloplasty. The patient with a Resonance stent had a history of retroperitoneal fibrosis, and he complained of dysuria, intermittent hematuria, and flank pain. We performed simple
MUS
Results
Female 51 UEF Ovary cancer Yes No Left 15 (PUS) 7 (MUS) Abdominal pain and fever CT RGU
Memokath
Resonance
We identified seven patients for analysis in this study who were referred to our trauma and reconstructive subdivision for various complications after the placement of ureteral stents. The adverse events in two patients were related to a long-term indwelling PUS and to MUS in the other five patients. Of the five patients, ureteral fistula developed in three after the placement of an indwelling self-expandable metallic mesh stent. The remaining two patients underwent insertion of Memokath or Resonance stents and were referred for reconstructive surgery to correct the underlying ureteral obstructions. We retrospectively reviewed the medical records of these patients and analyzed the predisposing factors underlying their complications, mechanism of injury, diagnosis, and interventional and surgical management according to the type of complication.
Flank pain Hematuria CT
SONG ET AL. Male 51 Gross hematuria RPF No No Left 20
2
COMPLICATIONS OF URETERAL STENT PLACEMENT
balloon dilation and inserted an 8F PUS after ballooning, which was removed 4 weeks after insertion. Discussion
The ureteral stent is used by all urologists, but it can cause serious complications. UAF is a rare but life-threatening condition that is occurring at an increasing rate ( > 100 cases reported worldwide). One of the most common scenarios is that in a patient with a history of minor intermittent hematuria, massive hematuria suddenly develops during the exchange of ureteral stents.7 This occurred in two patients in our hospital who regularly had their PUS exchanged. There are several predisposing factors to UAF, including primary vascular disease, previous pelvic surgery, and radiation therapy.8 If pelvic surgery and/or radiation therapy is followed by regular stent changes, it most likely adds insult to injury and predisposes the patient to fistula formation. These are the three typical risk factors for UAF. Five of our current patients had a history of pelvic surgery, and four patients had received radiation therapy. Pelvic surgery-induced pelvic fibrosis and radiation therapy can fix the ureter to the artery, and then the vascular and ureteral wall can degenerate at the crossing site. Continuous arterial pulsation against the stent wall may worsen any degeneration. In this vulnerable situation, stent change or balloon dilation to insert a MUS can cause pressure necrosis that finally develops into UAF.9 In addition, this condition can also be caused by primary vascular malformation or adjacent arterial aneurysms that erode into the ureter.10 A longer indwelling period can also aggravate degeneration and pressure necrosis at the crossing site. Except for the Resonance 051 stent, however, there are no definitive recommendations for the indwelling period to prevent complications, including UVF. In Table 2, we summarize the MUS characteristics. Although there is no recommendation for the indwelling duration for the Uventa or Memokath stents, clinical trials have recorded time frames for the primary patency rates of these stents of 12 and 36 months, respectively (ClinicalTrials.gov Identifiers: NCT01788865 (UVENTA) and NCT00790686 (Memokath 051 stent)). Hematuria severity varies considerably in patients with UAF, and massive hematuria and flank pain caused by clots are the typical presentations, although these can be subtle enough to make diagnosis difficult. When patients with predisposing factors demonstrate mild to moderate hematuria,
3
a high level of suspicion is needed for early diagnosis and preemptive management because UAF can potentially result in fatal bleeding. The diagnosis of UAF mainly depends on renal angiography and CT to detect contrast extravasation or pseudoaneurysm. Retrograde urography plays a limited role because of blood clots but can occasionally reveal vascular opacification when patients under high suspicion present with mild to moderate hemorrhage at the time of stent change. Routine contrast-enhanced CT demonstrates low sensitivity for detecting UAF. Therefore, if UAF is strongly suspected but there are no positive findings, three-dimensional CT or multiplanar reconstruction CT should be used to detect evasive pseudoaneurysm or subtle extravasation.8 During angiography, several examinations using oblique digital subtraction angiography might be needed to identify small evasive pseudoaneurysms. For effective treatment, communication between specialists including urologists, vascular surgeons, and radiologists is essential. Possible therapeutic options include artery embolization, combination artery embolization and surgical bypass grafting, endovascular repair using stent grafts, and embolization of the ureter during nephrostomy.9 Surgical exploration into the fibrotic pelvis may be followed by severe morbidity and mortality, but femoral-tofemoral bypass grafting is a definite surgical treatment for this condition. The usual first-line treatment is interventional embolization of the pseudoaneurysm using coils or stent engraftment in the artery. The most commonly involved area is the common iliac artery (as was the case in all our present study patients) or the point at which the internal iliac artery branches. Hence, embolization can result in leg ischemia. Instead, endovascular stent engraftment is a safe and effective method for managing acute events; however, the rate of hematuria recurrence remains high with this technique, and additional procedures or reconstructive surgery may be needed.11 The two patients in our cohort who had received a stent graft finally underwent bypass surgery 6 to 8 months after receiving this engraftment. The pathogenesis of UEF shares three typical predisposing factors with UAF. The risk of UEF also rises when balloon dilation is used.12 As shown by our patient in whom UEF developed after MUS, a history of multiple abdominal surgeries is an additional risk factor for UEF because this can induce severe adhesion between the ureter and bowel wall.
Table 2. Comparison of Metal Stents MUS Expandable metallic mesh stent
Memokath
Resonance
Manufacturer’s recommendation Products
N/A
N/A
Up to 12 months
UventaTM
MemokathTM 051 stent
French size Length, cm Company
7F 6–12 cm Taewoong Medical
9.5F–10.5F 3–20 cm Endotherapeutics
Resonance metallic ureteral stent 6.0F 20–30 cm Cook Medical
MUS = metallic ureteral stent.
4
Severe bowel adhesion and previous radiation therapy significantly impair the chance for reconstruction in the bowel, such as the ileum. Our patient with UEF underwent nephrectomy with small bowel resection in the long segment. Vesicovaginal fistula (VVF) significantly reduces quality of life in women. VVF is one of the most challenging problems in female urology, especially when associated with previous radiation therapy. Pelvic radiation for the management of cervical carcinoma is the primary cause of radiation-induced VVF. Fibrosis begins to develop in the bladder lamina propria when radiation therapy ends. Most instances of radiation-related VVF develop within 2 years post-treatment. Some signs may not be apparent until many years after radiation therapy. Usually, radiation cystitis, hematuria, and recurrent urinary tract infection precede the development of VVF. The bladder and vaginal tissue can develop ulceration and necrosis.13 In these situations, performing any traumatic procedure on the damaged tissue can trigger the development of VVF. In our patient, the use of balloon dilation to insert the MUS must have caused the VVF. The early use of metallic mesh wall stents is limited because of frequent reocclusion that results from endothelial hyperplasia, and tumor growth through the meshwork makes removal virtually impossible.14 In our cases, the selfexpandable mesh MUS was a segmented ureteral stent that was composed of double-layered, thermoexpandable, shapememory strands of nitinol with a 7-mm outer diameter. These stents contain polytetrafluoroethylene membrane between the double-layered strands of nitinol to prevent tissue ingrowth. The stent used in our patients was similar to those described in two previous studies.4,15 When inserted into the ureter, the stent generates thermoexpansive radial forces against the ureteral wall that subsequently establish patency. Balloon dilation can be performed if expansion is limited. The 7-mm outer diameter is similar to that of the Memokath stent, but larger than the resonance stent. In a previous report on a similar mesh metallic stent, Liatsikos and associates2 described how these stents are typically inserted. Initial dilation was performed using 7-mm balloons, and pressure was increased until balloon waisting was abolished. If the inserted metallic mesh stent expands insufficiently, repeated high-pressure balloon dilation was needed. They applied overlapping stents to bridge long, obstructed, ureteral segments. As described earlier in our present report, this kind of procedure should be very cautiously performed in patients with any predisposing factors for ureteral fistula. Modi and colleagues16 previously reported that 43% of patients with Resonance stents had to have them removed before 12 months and that all patients who had to have their stents surgically removed presented with painful stent-related symptoms. MUS-related pain was reported in another series also. Agrawal and coworkers17 presented their results on 74 Memokath stents that were evaluated for a mean follow-up period of 16 months. In their report, stent migration and obstruction resulting from encrustation occurred after a mean period of 7.1 months. Although MUS may benefit patients with a long dwell time, the long-term failure rate is also considerably high. Therefore, MUS is an option for patients in which surgical reconstruction of the obstructed ureter is impossible.18
SONG ET AL.
Our two patients in the current study with Memokath or Resonance stents presented because of a benign underlying cause. Their stents did not further develop into obstruction, and their renal units were still functioning after approximately 20 months of indwelling. Stent-related pain and hematuria, however, were significant enough to warrant stent removal and definitive treatment. The MUS is generally not recommended for patients with benign ureteral lesions that can be surgically corrected. Conclusion
UAF should be suspected when intermittent gross hematuria develops because of the long-term use of ureteral stents. The placement of a MUS using a high-pressure balloon should be decided cautiously, especially for patients with a history of pelvic surgery or radiation. MUS should be exclusively used as a palliative measure in patients with a malignancy. Disclosure Statement
No competing financial interests exist. References
1. Rosenberg BH, Bianco FJ Jr, Wood DP Jr, Triest JA. Stentchange therapy in advanced malignancies with ureteral obstruction. J Endourol 2005;19:63–67. 2. Liatsikos EN, Karnabatidis D, Katsanos K, et al. Ureteral metal stents: 10-year experience with malignant ureteral obstruction treatment. J Urol 2009;182:2613–2617. 3. Zaman F, Poullis C, Bach C, et al. Use of a segmental thermoexpandable metal alloy stent in the management of malignant ureteric obstruction: A single centre experience in the UK. Urol Int 2011;87:405–410. 4. Wang HJ, Lee TY, Luo HL, et al. Application of resonance metallic stents for ureteral obstruction. BJU Int 2011;108: 428–432. 5. Pollard SG, Macfarlane R. Symptoms arising from DoubleJ ureteral stents. J Urol 1988;139:37–38. 6. Chung HH, Kim MD, Won JY, et al. Multicenter experience of the newly designed covered metallic ureteral stent for malignant ureteral occlusion: Comparison with double J stent insertion. Cardiovasc Intervent Radiol 2014;37:463– 470. 7. Darcy M. Uretro-arterial fistulas. Tech Vasc Interv Radiol 2009;12:216–221. 8. Krambeck AE, DiMarco DS, Gettman MT, Segura JW. Ureteroiliac artery fisutula: Diagnosis and treatment algorithm. Urology 2005;66:990–994. 9. Araki T, Nagata M, Araki T, et al. Endovascular treatment of ureteroarterial fistulas with stent-grafts. Radiat Med 2008;26:372–375. 10. Sharma SK, Goswami AK, Sharma GP, et al. Congenital iliac arteriovenous malformation: A cause of massive hematuria and ureteral obstruction. J Urol 1988;139:355– 356. 11. Okada T, Yamaguchi M, Muradi A, et al. Long-term results of endovascular stent graft placement of ureteroarterial fistula. Cardiovasc Intervent Radiol 2013;36:950–956. 12. Oh SJ, Jeong BC, Kim HH. Ureteroenteric fistula after retrograde balloon dilatation of ureteral stricture. Int J Urol 2002;9:707–709.
COMPLICATIONS OF URETERAL STENT PLACEMENT
13. Pushkar DY, Dyakov VV, Kasyan GR. Management of radiation-induced vesicovaginal fistula. Eur Urol 2009;55: 131–137. 14. Pandian SS, Hussey JK, McClinton S. Metallic ureteric stents: Early experience. Br J Urol 1998;82:791–797. 15. Chung KJ, Park BH, Park B, et al. Efficacy and safety of a novel, double-layered, coated, self-expandable metallic mesh stent (Uventa) in malignant ureteral obstructions. J Endourol 2013;27:930–935. 16. Modi AP, Ritch CR, Arend D, et al. Multicenter experience with metallic ureteral stents for malignant and chronic benign ureteral obstruction. J Endourol 2010;24:1189– 1193. 17. Agrawal S, Brown CT, Bellamy EA, Kulkarni R. The thermo-expandable metallic ureteric stent: An 11-year follow-up. BJU Int 2009;103:372–376. 18. Nagele U, Kuczyk MA, Horstmann M, et al. Initial clinical experience with full-length metal ureteral stents for obstructive ureteral stenosis. World J Urol 2008;26:257– 262.
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Address correspondence to: Bumsik Hong, MD, PhD Department of Urology Asan Medical Center University of Ulsan College of Medicine 88 Olympic-ro 43-gil Songpa-gu Seoul 138-736 Korea E-mail: [email protected] Abbreviations Used CT ¼ computed tomography MUS ¼ metallic ureteral stent PUS ¼ polymeric ureteral stent UAF ¼ ureteroarterial fistula UEF ¼ ureteroenteral fistula UVF ¼ ureterovaginal fistula VVF ¼ vesicovaginal fistula
