Penile Trauma and Priapism

Fig. 48.1

Penile fracture of the right corpus cavernosum. (a) Axial T2-weighted scan shows the lesion as a ventral interruption (arrowhead) of the low-signal-intensity tunica albuginea. There is an associated extraalbugineal haematoma (asterisk). The left corpus cavernosum is intact. (b) Corresponding ultrasonographic scan showing the same features. The injury is identified as a ventral interruption of the echogenic line of the tunica albuginea (arrowhead) with associated extraalbugineal haematoma (asterisk). Curved arrows indicate the corpus spongiosum, which is intact in this patient

In traumas with intact tunica albuginea, extraalbugineal haematomas may result from rupture of the dorsal vessels or their branches [1]. Venous injuries are relatively more frequent than arterial injuries, and rupture of small venous collaterals is more common than injury to the main branches. Torn veins collapse and are not visible directly with ultrasonography, but occasionally they may undergo posttraumatic thrombosis and present at ultrasonography as noncompressible enlarged vessels with echogenic content (Fig. 48.2). If an arterial injury is associated, a posttraumatic arteriovenous fistula may develop [8]. Doppler interrogation shows dilatation of the injured vein; high-velocity, low-resistance arterial flows; and high-velocity turbulent venous flows. Isolated rupture of the deep dorsal vessels usually produce haematomas confined to the space beneath the Buck’s fascia, involving only the penile shaft. When the Buck’s fascia is disrupted, or superficial penile vessels are injured, the haematoma spreads through the subcutaneous tissue and in the space between the Colles’ and the Buck’s fascia involving the pubis, the scrotum and the perineum with characteristic “butterfly” configuration (Fig. 48.3). If an arterial lesion is associated, a posttraumatic arteriovenous fistula may result and be identified at colour Doppler interrogation.

Fig. 48.2

Posttraumatic thrombosis of a superficial penile vein. Axial ultrasonographic view obtained with the transducer on the dorsal aspect of the penis shows blood extravasation in the superficial tissues (asterisks). A noncompressible enlarged vessel with echogenic content is seen (arrowhead) lacking vascularization at colour Doppler interrogation. The tunica albuginea is intact. C corpora cavernosa. Curved arrow indicates the corpus spongiosum

Fig. 48.3

Extracavernosal haematomas. Arrowheads indicate haematoma between the tunica albuginea and the Buck’s fascia. Asterisks indicate haematoma spreading outside the Buck’s fascia

Injury to the erect penis may produce isolated disruption of the penile septum [9]. Ultrasonographic evaluation allows identification of the resulting haematoma as a well-defined cystic-like area in the septal region (Fig. 48.4). Aspiration under ultrasound guidance is recommended to prevent circumscribed septal fibrosis and its associated symptoms, such as penile shortening or focal lack of rigidity.

Fig. 48.4

Isolated septal haematoma. The patient presented with a lump in the mid-shaft 10 days after severe bending of the erect penis during intercourse associated with pain. Axial ultrasonographic scan shows a well-defined cystic-like lesion within the septum (asterisk), consistent with posttraumatic haematoma

48.4 Non-penetrating Injuries to the Flaccid Penis

Non-penetrating traumas to the flaccid penis usually follow blunt perineal injuries. The cavernosal crura are crushed against the pelvic bones. Ultrasonography allows evaluation of extratunical and cavernosal haematomas (Fig. 48.5) and of the tunica albuginea which is usually intact in these patients [1, 8]. Cavernosal artery disruption with formation of an arterial-lacunar fistula presents clinically with high-flow priapism. Colour Doppler ultrasonography is currently considered the imaging modality of choice in patients with high-flow priapism since it is sensitive, non-invasive and widely available [10]. Greyscale ultrasonography demonstrates the area of laceration of the cavernosal tissue as a hypoechoic region within the echogenic corpus cavernosum. In this area, colour Doppler interrogation demonstrates a characteristic arterial colour blush, consistent with extravasation of blood from the torn artery. Doppler interrogation of the fistula results in high-velocity, turbulent flows (Fig. 48.6, Video 48.1). Besides the arterial-lacunar fistula, the penile vasculature can be evaluated to identify the feeding vessels [10].

Fig. 48.5

Intracavernosal haematoma (H) in the right corpus of a patient who crushed the base of the penis against the petrol tank of his motorbike

Fig. 48.6

Posttraumatic high-flow priapism. Duplex Doppler interrogation of the cavernosal artery tear showing high-velocity, turbulent flows

A careful Doppler technique allows a better evaluation of all vascular structures involved. Optimization of the colour Doppler parameters to detect low-velocity flows allows evaluation of the penile vessels and eases identification of the colour blush from the torn artery. However, visualization of high-velocity flows is not correct, and aliasing hampers visualization of the exact site of the cavernosal tear. When colour Doppler velocity scale is increased, depiction of lower-velocity flows is reduced, and the cavernosal tear is immediately recognized as a circumscribed colour spot displaying aliasing [10].

Besides identification of the arterial-lacunar fistula, colour Doppler ultrasonography allows evaluation of the penile vasculature to identify haemodynamically significant feeding vessels, providing useful information in patients undergoing embolization [11]. Usually the main feeding vessel is a cavernosal artery; a variety of collaterals can be associated, however. In particular, dorsal to cavernosal artery communications represent large vascular pathways that are able to feed the fistula and may be responsible to treatment failure after embolization of the torn cavernosal artery. Also intracavernosal arterial communications can connect the proximal portion of the torn artery with the contralateral cavernosal artery and be responsible of treatment failure. Cavernosal-spongiosal communications and other small collaterals can feed the fistula as well [11].

In patients with high-flow priapism, high-velocity systolic flows are observed at Doppler interrogation in both cavernosal arteries also when only one vessel is torn. Large communications exist between the corpora, and nitric oxide released at the level of the fistula diffuses freely in the contralateral side. Diastolic flow is variable, depending on blood pressure within the partially erected bodies. The firmer the erection, the lower the diastolic pressure.

Superselective embolization of the torn artery is currently the treatment of choice for high-flow priapism [12]. After the procedure, colour Doppler ultrasonography is performed to assess the results. Complete closure of the arterial-sinusoidal fistula can be found, or the fistula may be still patent despite arteriographic evidence of occlusion fed by non-obliterated collaterals [10, 11]. In our experience, if the fistula is smaller and penile turgidity is reduced after embolization, spontaneous closure will likely occur within few days due to reduced hyperoxygenation and endothelial shear stress. When a more significant blood supply is demonstrated at colour Doppler interrogation and penile turgidity remains unchanged in the following days, repeat angiography should be considered.

During the follow-up of patients with high-flow priapism, we recommend colour Doppler ultrasound 1–2 months after embolization to rule out the appearance of a recurrent fistula. Recanalization of the embolized cavernosal artery can be observed also when non-reabsorbable embolization material has been used [10, 13]. In patients with erectile dysfunction, the study should be performed after intracavernosal prostaglandin injection to determine whether the functional impairment is caused or not by insufficient penile blood flow [10].

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