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Urethral Recanalization Using a Radiofrequency Guide Wire and a Rendezvous Approach for Traversal of a Pelvic Fracture Urethral Distraction Defect
1768
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Special Letters Section
Nirmalarajan et al
’
JVIR
Figure. (a) T2-weighted MR imaging shows hyperintense abscess formation (arrows) posterior to the uterus. (b) After positioning in the left lateral decubitus position, a nonferromagnetic needle (arrows) was placed in the lesion using balanced steady-state free precession sequences. (c) After catheter placement, diluted gadobutrol was instilled in the abscess (arrows) via the drainage catheter (arrowheads) to evaluate if the lesion was completely drained.
Pseudomonas aeruginosa, Enterococcus, and E. coli. The patient was given antibiotics (ceftazidime 500 mg intravenously q12h and metronidazole 2,000 mg intravenously q12h). MR imaging performed 12 days after the procedure demonstrated a decrease in abscess size from 60 55 35 mm3 to 18 5 5 mm3. The abscess was connected to the residual appendicular stump. The drainage catheter was removed on day 14, as it had drained o 20 mL over the last 4 days, symptoms had improved, and the laboratory values showed almost normalized leukocytosis and a Creactive protein of 21 mg/L (normal 0–5 mg/L). The patient was discharged from the hospital 7 days later. The pregnancy progressed without complications, and the patient gave birth to a healthy boy at 40 weeks of gestation. MR imaging using a wide-bore open system offers the benefit of cross-sectional imaging without ionizing radiation or evidence of harmful effects to the fetus and is therefore useful in evaluation of abdominal pain during pregnancy. Because CT is relatively contraindicated during pregnancy owing to radiation exposure to the fetus, MR imaging–guided diagnostic needle aspiration and percutaneous catheter drainage should be considered as an alternative for draining intraabdominal abscesses in patients ineligible for US-guided interventions (1,3). To achieve sufficiently stable access to the abscess, a stiff ferromagnetic standard guide wire can be used, which causes marked susceptibility artifacts. These artifacts are not considered a problem despite limiting the visibility, as they indicate the position of the wire within the abscess. For assessing whether the entire lesion is reached by the drain, diluted (1:20) gadobutrol can be instilled via the catheter. The use of contrast material instead of water provides excellent contrast; even in T1-weighted MR imaging, it can unequivocally be differentiated from neighboring fluid-filled cavities. As this is a nonvascular application, there is no relevant resorption and no relevant exposure of the fetus to the contrast material (4).
MR imaging–guided freehand percutaneous abscess drainage performed by combining nonferromagnetic and standard instruments with steady-state free precession imaging is safe and effective even in complex lesions and should be considered as a viable therapeutic option for the management of intraabdominal abscess during pregnancy. Instillation of diluted gadobutrol via the drainage catheter is helpful to assess abscess size and to determine whether the entire lesion is reached by the drainage catheter.
REFERENCES 1. Sherer DM, Schwartz BM, Abulafia O. Management of pelvic abscess during pregnancy: a case and review of the literature. Obstet Gynecol Surv 1999; 54:655–662. 2. Silverman SG, Lu DSK. Interventional magnetic resonance imaging in the abdomen. In: Grönemeyer DHW, Lufkin RB, eds. Open Field Magnetic Resonance Imaging. Berlin: Springer; 2000. p. 261–273. 3. Wybranski C, Strach K, Krenzien F, et al. Percutaneous abscess drainage using near real-time MR guidance in an open 1.0-T MR scanner: proof of concept. Invest Radiol 2013; 48:477–484. 4. Tremblay E, Thérasse E, Thomassin-Naggara I, Trop I. Quality initiatives: guidelines for use of medical imaging during pregnancy and lactation. Radiographics 2012; 32:897–911.
Urethral Recanalization Using a Radiofrequency Guide Wire and a Rendezvous Approach for Traversal of a Pelvic Fracture Urethral Distraction Defect From: Sindhura Nirmalarajan, MD Allison Borowski, MD John P. Gearhart, MD
None of the authors have identified a conflict of interest. http://dx.doi.org/10.1016/j.jvir.2016.03.026
Volume 27
’
Number 11
’
November
’
2016
Sally E. Mitchell, MD Clifford R. Weiss, MD Royal Perth Hospital (S.N.) 197 Wellington St. Perth, WA 6000, Australia; Division of Vascular and Interventional Radiology (A.B.) Lenox Hill Hospital New York, New York; and James Buchanan Brady Urological Institute and Division of Pediatric Urology (J.P.G.) and Division of Vascular and Interventional Radiology The Russell H. Morgan Department of Radiology and Radiologic Science (S.E.M., C.R.W.) The Johns Hopkins Hospital Baltimore, Maryland
Editor: Urethral injury associated with pelvic fractures carries the potential for significant long-term morbidity. The aims of urethral injury repair are to achieve luminal continuity and realignment while minimizing the risk of restenosis, incontinence, and impotence (1). The present case illustrates the application of a PowerWire Radiofrequency (RF) Guidewire (Baylis Medical, Montreal, Quebec, Canada) for recanalization of a urethral stricture that could not be traversed with conventional urologic techniques. This case is presented with exemption from our local institutional review board. Following a 25-foot fall, a 5-year-old boy sustained a posterior urethral disruption injury associated with a pelvic fracture. Computed tomography (CT) demonstrated a minimally displaced, closed, superior pubic ramus fracture with an adjacent hematoma. A retrograde cystourethrogram demonstrated posterior urethral rupture (Fig a). A suprapubic cystostomy tube was placed for urinary diversion. Urethroscopy performed 4 weeks after the injury demonstrated a urethral stricture near the bladder neck. A subsequent retrograde urethrogram (Fig b) and suprapubic cystogram revealed a 1-cm distraction defect between the bladder neck and blindending urethra. Urethroplasty was attempted after an additional 2 months of urinary diversion. Multiple attempts at antegrade recanalization via the suprapubic tract and retrograde recanalization through the external urethral orifice with a Glidewire (Terumo, Somerset, New Jersey) and 5-F catheter (KMP; Cook, Bloomington, Indiana) were unsuccessful. Hence, a novel rendezvous procedure was undertaken by using an RF guide wire for retrograde urethral recanalization with simultaneous suprapubic cystoscopy. A 10-F cystoscope was introduced through the suprapubic tract and remained in place adjacent to the stricture at the bladder neck for the duration of the procedure. An angled RF wire was loaded onto a 5-F KMP catheter and gradually advanced toward the cystoscope (Fig c). With each application of RF energy and advancement of the wire by 2–3 mm, the position and trajectory were assessed in multiple projections until the
1769
stricture was successfully traversed. A 50S RF wire was then advanced through the space created by the dislodged urethra and initial hematoma until it was in line with the cystoscope at the bladder neck. A 4-F Cobra 1 catheter (Terumo) and angled Glidewire (Terumo) facilitated a more anterior trajectory toward the cystoscope. The Glidewire was replaced with a 30K RF wire, which was advanced until contact was made with the cystoscope, as confirmed by direct visualization and a “metal-contact” alarm emitted by the RF device. The RF wire was exchanged for an Amplatz wire (Cook, Bloomington, Indiana), which was snared in the bladder and pulled through the suprapubic tract to provide through-andthrough access. After balloon angioplasty of the stricture, a 12-F Foley catheter was advanced over the Amplatz wire, and the suprapubic catheter was replaced (Fig d). Followup cystoscopy at 6 weeks demonstrated urethral continuity; however, there was damage to the external sphincter. The Foley catheter was removed after 10 weeks, followed by removal of the suprapubic tube. At 1-year follow-up, the patient continues to require direct catheterization to void. Most posterior urethral injuries are managed with initial suprapubic cystostomy followed by delayed urethral reconstruction. However, optimal management of urethral injuries is still debated, and primary endoscopic realignment has been increasingly used because of its potentially reduced rate of stricture formation (2). A recent retrospective study (3) evaluated the role of primary interventional urethral realignment for traumatic urethral injuries by using retrograde, antegrade, and rendezvous approaches with standard equipment. The study, which concluded that primary interventional urethral realignment may offer a safe and effective alternative to endoscopic urethral realignment, primarily involved anterior urethral injuries and realignment in the acute setting (3). In the case presented here, the injury involved the posterior urethra, and recanalization of the strictured segment was attempted after 3 months of urinary diversion. This case demonstrates the potential utility of the RF wire as an additional tool for urethral realignment in the delayed setting. RF wire technology has been safely implemented for the recanalization of peripheral vessels, central vein occlusions, and bile duct occlusions (4). The ability of the RF wire to vaporize tissue that directly contacts the electrode tip, combined with its capacity for mechanical advancement, contributed to the successful traversal of the urethral stricture in the present case. Multiple projections to assess the trajectory of the wire with each small advancement is necessary to reduce the risk of false tract formation (4). The rendezvous approach in the present case reinforces the importance of target visualization of the opposite side of the occluded segment (4), as the cystoscope provided a landmark for advancement of the wire, enabled direct visualization of the wire, and confirmed the position of the wire with a metal–contact alarm. This case illustrates the potential of the RF guide wire for urethral recanalization in selected cases of urethral distraction
1770
’
Special Letters Section
Nirmalarajan et al
’
JVIR
Figure. (a) Retrograde cystourethrogram demonstrates posterior urethral rupture with extravasation of contrast agent into the pelvis, particularly along the right lateral border (arrow) of the bladder (asterisk). (b) A subsequent retrograde urethrogram demonstrates a urethral stricture (arrow) at the bladder neck. (c) The RF wire (white arrow) is advanced toward the cystoscope (black arrow). (d) Foley (white arrow) and suprapubic (black arrow) catheters are in place at the end of the procedure.
defects in which conventional techniques have failed to reestablish urethral continuity.
REFERENCES 1. Mundy AR, Andrich DE. Urethral trauma. Part II: types of injury and their management. BJU Int 2011; 108:630–650.
2. Barrett K, Braga LH, Farrokhyar F, Davies TO. Primary realignment vs suprapubic cystostomy for the management of pelvic fracture–associated urethral injuries: a systematic review and meta-analysis. Urology 2014; 83:924–929. 3. Lee MS, Kim SH, Kim BS, Choi GM, Huh JS. The efficacy of primary interventional urethral realignment for the treatment of traumatic urethral injuries. J Vasc Interv Radiol 2016; 27:226–231. 4. Guimaraes M, Uflacker A, Schönholz C, Uflacker R. Successful recanalization of bile duct occlusion with a radiofrequency puncture wire technique. J Vasc Interv Radiol 2010; 21:289–294.
’
Special Letters Section
Nirmalarajan et al
’
JVIR
Figure. (a) T2-weighted MR imaging shows hyperintense abscess formation (arrows) posterior to the uterus. (b) After positioning in the left lateral decubitus position, a nonferromagnetic needle (arrows) was placed in the lesion using balanced steady-state free precession sequences. (c) After catheter placement, diluted gadobutrol was instilled in the abscess (arrows) via the drainage catheter (arrowheads) to evaluate if the lesion was completely drained.
Pseudomonas aeruginosa, Enterococcus, and E. coli. The patient was given antibiotics (ceftazidime 500 mg intravenously q12h and metronidazole 2,000 mg intravenously q12h). MR imaging performed 12 days after the procedure demonstrated a decrease in abscess size from 60 55 35 mm3 to 18 5 5 mm3. The abscess was connected to the residual appendicular stump. The drainage catheter was removed on day 14, as it had drained o 20 mL over the last 4 days, symptoms had improved, and the laboratory values showed almost normalized leukocytosis and a Creactive protein of 21 mg/L (normal 0–5 mg/L). The patient was discharged from the hospital 7 days later. The pregnancy progressed without complications, and the patient gave birth to a healthy boy at 40 weeks of gestation. MR imaging using a wide-bore open system offers the benefit of cross-sectional imaging without ionizing radiation or evidence of harmful effects to the fetus and is therefore useful in evaluation of abdominal pain during pregnancy. Because CT is relatively contraindicated during pregnancy owing to radiation exposure to the fetus, MR imaging–guided diagnostic needle aspiration and percutaneous catheter drainage should be considered as an alternative for draining intraabdominal abscesses in patients ineligible for US-guided interventions (1,3). To achieve sufficiently stable access to the abscess, a stiff ferromagnetic standard guide wire can be used, which causes marked susceptibility artifacts. These artifacts are not considered a problem despite limiting the visibility, as they indicate the position of the wire within the abscess. For assessing whether the entire lesion is reached by the drain, diluted (1:20) gadobutrol can be instilled via the catheter. The use of contrast material instead of water provides excellent contrast; even in T1-weighted MR imaging, it can unequivocally be differentiated from neighboring fluid-filled cavities. As this is a nonvascular application, there is no relevant resorption and no relevant exposure of the fetus to the contrast material (4).
MR imaging–guided freehand percutaneous abscess drainage performed by combining nonferromagnetic and standard instruments with steady-state free precession imaging is safe and effective even in complex lesions and should be considered as a viable therapeutic option for the management of intraabdominal abscess during pregnancy. Instillation of diluted gadobutrol via the drainage catheter is helpful to assess abscess size and to determine whether the entire lesion is reached by the drainage catheter.
REFERENCES 1. Sherer DM, Schwartz BM, Abulafia O. Management of pelvic abscess during pregnancy: a case and review of the literature. Obstet Gynecol Surv 1999; 54:655–662. 2. Silverman SG, Lu DSK. Interventional magnetic resonance imaging in the abdomen. In: Grönemeyer DHW, Lufkin RB, eds. Open Field Magnetic Resonance Imaging. Berlin: Springer; 2000. p. 261–273. 3. Wybranski C, Strach K, Krenzien F, et al. Percutaneous abscess drainage using near real-time MR guidance in an open 1.0-T MR scanner: proof of concept. Invest Radiol 2013; 48:477–484. 4. Tremblay E, Thérasse E, Thomassin-Naggara I, Trop I. Quality initiatives: guidelines for use of medical imaging during pregnancy and lactation. Radiographics 2012; 32:897–911.
Urethral Recanalization Using a Radiofrequency Guide Wire and a Rendezvous Approach for Traversal of a Pelvic Fracture Urethral Distraction Defect From: Sindhura Nirmalarajan, MD Allison Borowski, MD John P. Gearhart, MD
None of the authors have identified a conflict of interest. http://dx.doi.org/10.1016/j.jvir.2016.03.026
Volume 27
’
Number 11
’
November
’
2016
Sally E. Mitchell, MD Clifford R. Weiss, MD Royal Perth Hospital (S.N.) 197 Wellington St. Perth, WA 6000, Australia; Division of Vascular and Interventional Radiology (A.B.) Lenox Hill Hospital New York, New York; and James Buchanan Brady Urological Institute and Division of Pediatric Urology (J.P.G.) and Division of Vascular and Interventional Radiology The Russell H. Morgan Department of Radiology and Radiologic Science (S.E.M., C.R.W.) The Johns Hopkins Hospital Baltimore, Maryland
Editor: Urethral injury associated with pelvic fractures carries the potential for significant long-term morbidity. The aims of urethral injury repair are to achieve luminal continuity and realignment while minimizing the risk of restenosis, incontinence, and impotence (1). The present case illustrates the application of a PowerWire Radiofrequency (RF) Guidewire (Baylis Medical, Montreal, Quebec, Canada) for recanalization of a urethral stricture that could not be traversed with conventional urologic techniques. This case is presented with exemption from our local institutional review board. Following a 25-foot fall, a 5-year-old boy sustained a posterior urethral disruption injury associated with a pelvic fracture. Computed tomography (CT) demonstrated a minimally displaced, closed, superior pubic ramus fracture with an adjacent hematoma. A retrograde cystourethrogram demonstrated posterior urethral rupture (Fig a). A suprapubic cystostomy tube was placed for urinary diversion. Urethroscopy performed 4 weeks after the injury demonstrated a urethral stricture near the bladder neck. A subsequent retrograde urethrogram (Fig b) and suprapubic cystogram revealed a 1-cm distraction defect between the bladder neck and blindending urethra. Urethroplasty was attempted after an additional 2 months of urinary diversion. Multiple attempts at antegrade recanalization via the suprapubic tract and retrograde recanalization through the external urethral orifice with a Glidewire (Terumo, Somerset, New Jersey) and 5-F catheter (KMP; Cook, Bloomington, Indiana) were unsuccessful. Hence, a novel rendezvous procedure was undertaken by using an RF guide wire for retrograde urethral recanalization with simultaneous suprapubic cystoscopy. A 10-F cystoscope was introduced through the suprapubic tract and remained in place adjacent to the stricture at the bladder neck for the duration of the procedure. An angled RF wire was loaded onto a 5-F KMP catheter and gradually advanced toward the cystoscope (Fig c). With each application of RF energy and advancement of the wire by 2–3 mm, the position and trajectory were assessed in multiple projections until the
1769
stricture was successfully traversed. A 50S RF wire was then advanced through the space created by the dislodged urethra and initial hematoma until it was in line with the cystoscope at the bladder neck. A 4-F Cobra 1 catheter (Terumo) and angled Glidewire (Terumo) facilitated a more anterior trajectory toward the cystoscope. The Glidewire was replaced with a 30K RF wire, which was advanced until contact was made with the cystoscope, as confirmed by direct visualization and a “metal-contact” alarm emitted by the RF device. The RF wire was exchanged for an Amplatz wire (Cook, Bloomington, Indiana), which was snared in the bladder and pulled through the suprapubic tract to provide through-andthrough access. After balloon angioplasty of the stricture, a 12-F Foley catheter was advanced over the Amplatz wire, and the suprapubic catheter was replaced (Fig d). Followup cystoscopy at 6 weeks demonstrated urethral continuity; however, there was damage to the external sphincter. The Foley catheter was removed after 10 weeks, followed by removal of the suprapubic tube. At 1-year follow-up, the patient continues to require direct catheterization to void. Most posterior urethral injuries are managed with initial suprapubic cystostomy followed by delayed urethral reconstruction. However, optimal management of urethral injuries is still debated, and primary endoscopic realignment has been increasingly used because of its potentially reduced rate of stricture formation (2). A recent retrospective study (3) evaluated the role of primary interventional urethral realignment for traumatic urethral injuries by using retrograde, antegrade, and rendezvous approaches with standard equipment. The study, which concluded that primary interventional urethral realignment may offer a safe and effective alternative to endoscopic urethral realignment, primarily involved anterior urethral injuries and realignment in the acute setting (3). In the case presented here, the injury involved the posterior urethra, and recanalization of the strictured segment was attempted after 3 months of urinary diversion. This case demonstrates the potential utility of the RF wire as an additional tool for urethral realignment in the delayed setting. RF wire technology has been safely implemented for the recanalization of peripheral vessels, central vein occlusions, and bile duct occlusions (4). The ability of the RF wire to vaporize tissue that directly contacts the electrode tip, combined with its capacity for mechanical advancement, contributed to the successful traversal of the urethral stricture in the present case. Multiple projections to assess the trajectory of the wire with each small advancement is necessary to reduce the risk of false tract formation (4). The rendezvous approach in the present case reinforces the importance of target visualization of the opposite side of the occluded segment (4), as the cystoscope provided a landmark for advancement of the wire, enabled direct visualization of the wire, and confirmed the position of the wire with a metal–contact alarm. This case illustrates the potential of the RF guide wire for urethral recanalization in selected cases of urethral distraction
1770
’
Special Letters Section
Nirmalarajan et al
’
JVIR
Figure. (a) Retrograde cystourethrogram demonstrates posterior urethral rupture with extravasation of contrast agent into the pelvis, particularly along the right lateral border (arrow) of the bladder (asterisk). (b) A subsequent retrograde urethrogram demonstrates a urethral stricture (arrow) at the bladder neck. (c) The RF wire (white arrow) is advanced toward the cystoscope (black arrow). (d) Foley (white arrow) and suprapubic (black arrow) catheters are in place at the end of the procedure.
defects in which conventional techniques have failed to reestablish urethral continuity.
REFERENCES 1. Mundy AR, Andrich DE. Urethral trauma. Part II: types of injury and their management. BJU Int 2011; 108:630–650.
2. Barrett K, Braga LH, Farrokhyar F, Davies TO. Primary realignment vs suprapubic cystostomy for the management of pelvic fracture–associated urethral injuries: a systematic review and meta-analysis. Urology 2014; 83:924–929. 3. Lee MS, Kim SH, Kim BS, Choi GM, Huh JS. The efficacy of primary interventional urethral realignment for the treatment of traumatic urethral injuries. J Vasc Interv Radiol 2016; 27:226–231. 4. Guimaraes M, Uflacker A, Schönholz C, Uflacker R. Successful recanalization of bile duct occlusion with a radiofrequency puncture wire technique. J Vasc Interv Radiol 2010; 21:289–294.