Traumatic penile fracture: what radiologists should know Poster No.:

C-0695

Congress:

ECR 2014

Type:

Educational Exhibit

Authors:

G. Pompili, A. Munari, A. Campari, F. Melchiorre, G. Contalbi, G. Cornalba; Milan/IT

Keywords:

Trauma, Embolisation, Diagnostic procedure, MR, Catheter arteriography, Genital / Reproductive system male

DOI:

10.1594/ecr2014/C-0695

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Learning objectives To discuss Magnetic Resonance Imaging (MRI) features of traumatic penile fractures. To review the role of selective endovascular embolization in treatment of post-traumatic non-ischemic priapism.

Background Traumatic penile fracture • • •

•

rare urological emergency defined as the rupture of the tunica albuginea (TA) of the corpus cavernosum (CC) caused by blunt trauma to the erect penis (vigorous sexual intercourse, abnormal bending, forceful manipulation, rolling over on the erect penis in bed, direct injury) possible urethral and spongiosal involvement (20% of penile fractures)

TA is the fibroelastic sheath that surrounds both CC and corpus spongiosum (CS), that thins from 2-3 mm to 0,5-0,25 mm during erection, resulting susceptible to injury. Clinical manifestation: typical symptoms and signs • • • • •

acute pain immediate loss of erection patients report history of a snap or cracking sound purple ecchymosis, penile swelling and penile deviation toward the side opposite to the injury ("Aubergine" sign, see fig. 1) hematuria or dysuria indicates subsequent urethral injury

Diagnosis • • •

patient's history physical examination imaging

Complications • • •

sexual dysfunction (painful erection, erectile dysfunction) penile plaques (deformity and deviation) urethral stenosis or fistula Page 2 of 16

•

cavernosal artery fistula causing high-flow priapism

Treatment •

surgery: hematoma evacuation and suture of the tunical tear

Urgent surgical repair is required in case of TA disruption, because its integrity is essential for erection. Accurate identification of the fracture allows a localised surgical exploration, avoiding long incision and wide dissection or complete degloving of the penis, with higher post-operative morbidity •

conservative management: in absence of CC or CS injury

when imaging confidently suggests an intact TA, the conservative conduct has proven to be a feasible and safe option Role of imaging: pre-operative planning •

•

• •

solves cases with atypical presentation or conditions that limit physical examination (large hematomas may impede palpation of CC rupture or small tunical tear) identifies "false" penile fracture (rupture of the dorsal vein or artery resulting in hematoma without tunical tear), clinically indistinguishable from the "true" fracture precisely localizes tunical albuginea interruption and assess its extent evaluates hematomas and complications such as urethral and spongiosal involvement (20% of penile fractures)

Ultrasound (US) is a feasible and non-invasive first-line diagnostic approach, as it can rapidly identify large disruptions of the TA and detect blood collections. It is operator dependent and lacks tissue contrast; moreover US is difficult to interpret in the presence of subcutaneous blood and oedema. Magnetic Resonance (MR) is the most accurate imaging procedure and determinates the need for surgical intervention. Thanks to the excellent soft tissue contrast resolution, MRI depicts precise location and severity of TA interruption. It also identifies hematomas and urethral injuries, and allows diagnosis of fracture mimics which need conservative management. Moreover MRI is a non-contact examination, better tolerated in such a tender and painful condition. Retrograde urethrography identifies urethral tears but does not allow demonstration of the TA disruptions. It is an invasive examination, needs contrast media and carries the risk of extravasion and introduction of infection. Angiography should only be performed when embolization is needed.

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High-flow priapism • • • • •

rare complication of penile and perineal trauma or surgery development of fistulous communication between the cavernosal artery and lacunar spaces of the corpora cavernosa painless partial erection because of rigidity of the corpora cavernosa with flaccid corpus spongiosum may develop up to 72h after penile trauma not a medical emergency because the cavernous tissue is well oxygenated

Diagnosis • • • •

clinical history physical examination cavernosal arterial blood gas (ABG) assessment colour doppler ultrasonography

must be differentiated from low-flow veno-occlusive priapism, which is a medical emergency because of cavernous ischemia Management • • • •

patients can be managed as outpatients observation alone is appropriate for initial management because high-flow priapism resolves without treatment in up to 62% of cases selective arterial embolization is recommended in patients who request treatment (74-78% success rate and 5-39% rate of erectile dysfunction) surgery is the option of last resort (20-60% success rate and 50% rate of erectile dysfunction)

Images for this section:

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Fig. 1: "Aubergine" sign.

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Findings and procedure details Normal penile anatomy The penis is divided into two parts: the body (corpus) and the root (radix). The corpus is the usual site of injury, it is composed of three parallel cylindric masses of erectile tissue: two dorsolateral corpus cavernosum (CC) and the ventromedial corpus spongiosum (CS), with urethra. Tunica albuginea (TA) surrounds both CC and CS. The Buck fascia, a second fibrous sheath, surrounds TA and is divided into dorsal and ventral compartments separating the CC from the CS, while the two CC are separated from each other by a thin membranous septum. The TA is thicker around the CC, where it is fused with the Buck fascia. MR Imaging technique • • • •

MRI is performed in emergency setting with regional surface coil patient in supine position with his penis taped against the abdominal wall (induced erection is prohibited in acute phase!) standard examination protocol includes multiplanar unenhanced T1-w and T2-w sequences differently oriented on the long axis of the penile shaft although gadolinium-enhanced images may more easily show the hematoma and tunical tear, noncontrast MR is sufficient for diagnosis

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Fig. 2: Normal penile MRI anatomy. Axial T2-w image shows the tunica albuginea, the central arteries of the corpora cavernosa (CC), the septum dividing the corpora cavernosum and the urethra (U) within the corpus spongiosum (CS). References: Diagnostic and interventional radiology, S. Paolo - Milan/IT Normal penile MR anatomy MR signal intensity of the three corpora depends on the rate of blood flow within the cavernous spaces that constitute the corpora. Normally, the three corpora are of intermediate T1-weighted and high T2-weighted signal intensity. The CC are isointense relative to one another, as they are connected via fenestrations in their septum and therefore have similar flow. The CS is a separate space and may normally have signal intensity different from those of the CC. TA and Buck fascia have low signal intensity with all sequences and they are not distinguishable from each other appearing as a single thick rim hypointense relative to the surrounded corpora.

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The bulbous and pendulous portion of the urethra are surrounded by the CC. If not dilated or distended, this portions of urethra are difficult to see at MRI; on T2-weighted images, the collapsed muscular urethral walls appears as a band of relative hypointensity compared with the bright cavernous spaces of the CS. MRI findings in penile fracture Tunica albuginea tear (fig. 3, 4) • • •

appears as discontinuity of the low-signal-intensity TA usually unilateral and trasverse generally located ventrally and in the distal third of the penile shaft

Hematoma (fig. 3, 4, 5, 6) False fracture hematoma (fig. 5): absence of tunical tear Urethral injury (fig. 6) • • •

disruption of CS sheath displacement of the urethra urethral tear and extravasation of urine (high signal intensity collection on T2-weighted images)

Endovascular treatment of high-flow priapism • • • •

selective catheterization of internal pudendal artery via contra-lateral femoral access superselective catheterization of common penile artery or cavernosal artery demonstration of active contrast extravasation consistent with cavernosal artery fistula embolization with permanent or temporary material

Complications: erectile dysfunction, residual cavernous turgidity, abscess Choice of embolic agent: permanent material (coils, ethanol, polyvinyl alcohol particles, acrylic glue) • •

resolution rate: 78% erectile dysfunction rate: 39%

temporary material (gelfoam, autologous clot) •

resolution rate: 74%

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•

erectile dysfunction rate: 5%

American Urological Association guidelines recommend the use of absorbable temporary materials Embolization can be repeated in case of recurrence Images for this section:

Fig. 3: Penile trauma in a 28-year-old man after vigorous sexual intercourse. Sagittal T2 (a) and T1-w (b) images show a 10 mm-long ventral transversely oriented disruption of the low-signal albuginea on the left corpus cavernosum (arrowheads). Axial T2 (c) and T1-w (d) images and coronal T2-w (e) image confirm disruption of the tunica albuginea of the left corpus cavernosum (arrowheads) and show heterogeneous hyperintense collection consistent with associated hematoma (*) extending in the subcutaneous tissue of the base of the penis, antero-laterally to the corpus cavernosum. Note urethral catheter. Sagittal T2-w (f) image better shows the well-marginated, inhomogeneus high-signalintensity hematoma (*).

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Fig. 4: Penile trauma in a 39-year-old man after vigorous sexual intercourse. Sagittal T2 (a) and T1-w (b) images show a small ventral transversely oriented disruption (arrowheads) of the low-signal albuginea on the right corpus cavernosum with associated small hematoma (arrow in a). Axial T2-w (c) image confirms disruption of the tunica albuginea of the right corpus cavernosum (arrowhead).

Fig. 5: Penile trauma in a 30-year-old man previously treated for penile enlargement with filler. False fracture. Sagittal T2 and axial T2 and T1-weighted images show extratunical hematoma (arrowheads) in absence of tunical tear. CS is dislocated (arrow in b). Note high signal focal alterations in the subcutaneous soft tissue, related to the filler treatment.

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Fig. 6: Penile fracture with urethral rupture in a 32-year-old man. Sagittal T2-weighted image (a) shows disruption of the tunica albuginea in the ventral aspect of the right corpus cavernosum (arrowheads) and the resulting adjacent large hematoma extended to the base of the penis. Axial T2 (b, c) and T1-weighted (d) images better show the large etherogeneous hematoma with high T2 and low T1 signal, resulting from urine extravasion from the injured uretra. Note in b the continuity of the urine collection with the disrupted corpus spongiosum. Coronal T2-weighted image(e), demonstrates disruption of the corpus spongiosum sheath and urethral tear (arrowhead). Intraoperative picture (f) confirms the urethral tear.

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Fig. 7: Post-traumatic priapism in a 35-year-old man. MRI (a, b) excluded TA tears and demonstrate low signal lesion, consistent with cavernous artery fistula. Patient underwent superselective angiography (c) and gelfoam embolization, with complete resolution of the contrast medium extravasation (d). See also fig. 8 and 9.

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Fig. 8: Same patient as figure 7. Pre-embolization angiogram show active contrast extravasation consistent with cavernosal artery fistula.

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Fig. 9: Same patient as figure 7. Post-embolization angiogram.

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Conclusion MRI assessment of traumatic penile injury allows correct choice of tailored surgical approach: MRI helps making the diagnosis and suggests the exact site of surgical incision. Moreover MRI confidently excludes rupture of the TA and rules out urethral tears, obviating surgical exploration and suggesting conservative treatment when possible. Superselective endovascular embolization of cavernosal artery fistula, performed with absorbable embolic agents, is the preferred therapy for refractory high-flow priapism.

Personal information G. Pompili, A. Munari, A. Campari, F. Melchiorre, G. Cornalba School of Radiology Department of Diagnostic and Interventional Radiology San Paolo Hospital, Milano, Italy G. Contalbi Department of Urology San Paolo Hospital, Milano, Italy Mail to: [email protected]

References 1. 2. 3. 4. 5.

Kirkham A. MRI of the penis. Br J Radiol. 2012 Nov;85 Spec No 1:S86-93. Choi MH, Kim B, Ryu JA, et al. MR imaging of acute penile fracture. Radiographics. 2000 Sep-Oct;20(5):1397-405. Kirkham AP, Illing RO, Minhas S, et al. MR imaging of nonmalignant penile lesions. Radiographics. 2008 May-Jun;28(3):837-53. Eke N. Urological complications of coitus. BJU Int. 2002 Feb;89(3):273-7. Uder M, Gohl D, Takahashi M, et al. MRI of penile fracture: diagnosis and therapeutic follow-up. Eur Radiol. 2002 Jan;12(1):113-20.

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6. 7.

Eke N. Fracture of the penis. Br J Surg. 2002 May;89(5):555-65. Maubon AJ, Roux JO, Faix A, et al. Penile fracture: MRI demonstration of a urethral tear associated with a rupture of the corpus cavernosum. Eur Radiol. 1998;8(3):469-70. 8. EPOS R-0152 High flow priapism - A painless, yet painful truth. DOI: 10.1594/ ranzcr2011/R-0152. 9. Montague D. et al. American urological association guideline on the management of priapism. The Journal of Urology 2003;170:1318-1324. 10. Kuefer R. Changing diagnostic and therapeutic concepts in high-flow priapism. International Journal of Impotence Research 2005;17:109-113.

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