Penile Fracture

Etiology

A penile fracture is typically the result of direct trauma to the penis during sexual intercourse. In one study, 57.2% of patients with confirmed penile fractures reported such direct blunt trauma to the erect penis during intercourse.[1] The erect penis may slip from the vagina and be thrust directly into the perineum or pelvic bone. This active thrusting results in markedly increased pressure inside the blood-filled corpus cavernosa, where the tension causes a rupture of the tunica albuginea. The tearing causes an acute loss of the erection together with immediate swelling, bruising, angulation, hematoma formation, and pain.

Additionally, there may be an associated tear of the penile urethra and urinary retention. The urethra is involved in about 20% of cases, and the corpora spongiosum in up to 30%.[2] The most commonly associated sexual positions are "female superior" or "rear entry," however, one study noted that meta-analyses showed no particular sexual position had an increased risk.[3][4] 

Masturbation injuries and falls landing on an erect penis are other notable causes of penile fractures.[5] Bending or angulation of the penis while attempting vigorous vaginal penetration, rolling over during sleep, and anal intercourse, are other reported causes.[6] Forcefully bending the erect penis downwards to cause rapid detumescence (called taqaandan) is a common practice in many Middle Eastern, North African, and Central Asian cultures, which can also lead to penile fractures.[7][8][9]

Epidemiology

This injury is isolated to persons with phenotypically male genitalia for obvious reasons. Penile fractures most commonly occur in middle-aged men; multiple studies note that the average age of patients is between 30 and 50 years of age.[1][10][11] 

Patients are typically heterosexual males. However, this injury can also occur in men who have sex with men. In one study, 1.8% of penile fractures occurred in homosexual men.[12] As such, for all men who report urogenital trauma, a penile fracture should remain in the differential diagnosis regardless of sexual orientation.[1] 

One study has noted a disproportionately higher number of penile fractures occurring during the summer months and on weekends.[2] The reported yearly overall incidence in the United States is 1 case per 175,000 men.[4][13] In parts of the world where taqaandan is practiced, this is often the most frequent cause of penile fractures.[7][8][9][14]

Pathophysiology

During an erection, the corpora become pressurized and filled with blood, which causes them to become rigid, firm, and erect. The strength, stiffness, and expansion of the tunica albuginea, which covers the corpora, block the venous return and is therefore responsible for maintaining rigidity during an erection. The tunica albuginea of the corpora cavernosa is extremely strong and inflexible. The typical intracavernosal pressure during a normal, full, rigid erection is only about 100 mmHg, whereas the tunica has such tensile strength that it can withstand a bursting pressure of 1,500 mmHg.[13][15]

The circular fibers of the tunica albuginea that form the corpora cavernosa become stretched and thin during an erection. Their normal thickness is 2 mm, but this decreases to just 0.25 mm when the corpora are fully engorged, and the penis is erect.[13] Their weakest point is generally on the ventral side of the penile shaft immediately adjacent to the urethra, where most ruptures occur. It explains the mechanism of any associated urethral injuries. Urethral injury is more likely when both corpora are ruptured.[16]

Immediately after the penile fracture, there is pain, bruising, immediate significant swelling, angulation, and rapid detumescence. Frequently, patients will remember a sudden, audible snapping or cracking sound at the exact time of the injury. As the corpora are engorged with blood and pressurized, then subjected to a sudden, sharp increase in pressure, it is easy to understand how the acute extravasation, pain, swelling, and the other symptoms associated with the injury can develop so quickly. The mechanism is similar to overfilling a balloon to bursting or a sudden blowout on a car tire, where there is immediate explosive decompression from a pressurized enclosure. 

If the urethra is damaged, urination will be affected, and hematuria or urethral blood may be seen. Buck's fascia will confine the hematoma, bruising, and swelling to the penile shaft. If the fascia is damaged, blood and possibly urine can spread into the retroperitoneum, perineum, scrotum, or suprapubic spaces, often leaving a "butterfly" pattern.[17]

Injuries to the penile dorsal vein associated with penile fractures are rare but have been reported.[18][19] Isolated penile dorsal vein ruptures clinically appear similarly to penile fractures but without any audible snapping.[18][19] Treatment is similar.

The use of penile injections of clostridium histolyticum collagenase for Peyronie's disease has created a new etiology for penile fractures.[20] The mechanism is a reduction in the strength of the tunica by the collagenase activity. The incidence of penile fractures associated with this treatment is reported as 0.5% to 4.9%.[21][22]

History and Physical

Penile fractures often occur during intercourse. Typical historical findings associated with penile fracture include:[6]

• Angulation of the penis, typically away from the side of the injury
• An erect penis at the time of the trauma
• Bruising and significant swelling of the penis and surrounding area
• Immediate detumescence
• Pain in the genitals
• A "pop" or "shaping" sound (patient-reported)
• Trauma to the genitals

A physical exam should be comprehensive and may include the following findings: [6]

• Angulated penis
• Ecchymotic shaft (an "eggplant" deformity)
• Flaccid penis or asymmetric erection
• Significant penile shaft swelling
• Tenderness of the penis

Evaluation

The diagnosis of penile fractures is typically made clinically by direct examination.[6] The penis will often demonstrate a classic "eggplant deformity" and will tend to deviate away from the side of the rupture.[6][23] The presence of a possible urethral injury may not be readily apparent.[24] 

Blood at the urethral meatus, hematuria, and difficulty voiding should prompt an assessment for a urethral injury.[2] The American Urological Association guidelines recommend provocative testing with the intent to rule out a urethral injury if there is a suspicion that this may be the case.[25] This testing could either be an intraoperative cystoscopy or a retrograde urethrogram.[25] The European Association of Urology guidelines are aligned with these recommendations but suggest intraoperative cystoscopy over preoperative retrograde urethrography since retrograde urethrograms have a higher false positive rate and may delay access to the operating room.[9][26]

The workup surrounding penile fractures should include preoperative laboratory evaluation, and other studies to rule out concomitant urethral injury may be warranted. Suspicion of a penile fracture, based on history alone, should warrant a thorough evaluation to rule out related injuries, including dorsal penile vein and nerve damage, while simultaneously diagnosing the penile fracture. In addition to clinical suspicion for a tunica rupture, multiple imaging modalities are available which can be useful to identify penile fractures and diagnose urethral injuries.

Ultrasound is readily available in most emergency centers, can be performed quickly, and is generally recommended; however, there is some controversy over its true clinical utility as the actual test is very operator-dependent, and successful identification of a penile corporal injury requires specific expertise.[27][28] The ultrasound may show irregular defects at the site of a cavernosal rupture.[29][30] However, if there is a significant hematoma (which is common in these cases), it may increase the difficulty of diagnosing a tunica rupture exclusively by ultrasound.

Although CT is widely available and has been demonstrated to be helpful in the identification of the exact location and size of injury to aid in surgical repair, it exposes the patient to radiation (particularly to the genitals) and incurs extra cost. Additionally, the test rarely affects the surgery and delays the patient's arrival at the operating room.[31] 

MRI, although not the quickest, cheapest, or most readily available test, has been shown to assist in the diagnosis and perioperative management of penile fractures.[32][33] One study demonstrated 100% sensitivity along with 77.8% specificity for the identification of tunica ruptures in the penis by MRI.[32]

Cavernosography can be useful and definitive; however, like MRI and CT imaging, it is generally reserved for those unusual cases where the clinical presentation and physical examination are not adequate for a diagnosis, and a more detailed examination is required.[34]

Treatment / Management

Treatment of penile fractures should be a prompt operative repair of the defect. Preoperative antibiotics should be given.

An initial linear incision is acceptable for the opening of the skin, but many urologists prefer a circumcising subcoronal incision that allows degloving of the penile shaft skin. This provides optimal surgical exposure and avoids leaving a longitudinal suture line along the ventral penile shaft.[35] Access to injuries at the base of the penis may also be accomplished by a midline penoscrotal incision which avoids a full degloving of the shaft.

After opening the skin, the hematoma should be evacuated as completely as possible. The hematoma should be removed, allowing direct and complete visualization of the tunica for any tears or defects. These are typically seen on the ventral surface of the tunica, starting at its juncture with the urethra and extending axially.

The urethra should also be carefully examined even if the preoperative evaluation did not suggest a urethral injury. If there is any doubt, an intraoperative flexible cystoscopy should be performed.

The placement of a Foley catheter at the time of surgery is recommended even in cases where no urethral injury is found or suspected.[36] This stabilizes the corpora and serves as a useful surgical landmark. The catheter is usually removed the day after surgery in patients without urethral damage.[36]

An absorbable suture (polyglactin or polydioxanone, size 00 is the most frequently selected) is used to repair the tunica defect.[9][28][34][37] Interrupted sutures are typically used for strength.[9] Lateral sutures at the edges of the defect are optional. Some surgeons will bury the knots from the tunica repair to further minimize postoperative scarring.[38](A1)

A solution of indigo carmine and normal saline can be injected directly into the corpora cavernosa or through the glans into the corpora spongiosum to evaluate the integrity of the repair and to inspect the area for any unrecognized injuries or leaks.[35] A tourniquet should be placed around the base of the penis immediately before such intraoperative test injections.[35]

Buck's fascia should also undergo repair if it appears damaged. A torn Buck's fascia can result in a scrotal hematoma. Such a hematoma should be surgically evacuated and drained.[39](B3)

This surgical repair should be performed promptly, as delays cause increased extravasation, poorer healing, increased fibrosis, and more complications. Multiple studies have proven a significant change in functional outcomes with delayed repairs of penile fractures.[28][34][37] One study showed that a delay of approximately 8 hours resulted in substantial increases in erectile dysfunction postoperatively.[40](B2)

The one exception to the standard recommendation to perform urgent surgical repair of a penile fracture may be those cases of corporal tearing that follow the administration of clostridium histolyticum collagenase plaque injections for treating Peyronie disease.[41][20][41] In such cases, the recommendation is to treat the injury conservatively if the urethra has not been injured, as the integrity of the tunica has been compromised by the collagenase.[20][41] 

Urethral tears should generally be repaired primarily with smaller, absorbable sutures in a tension-free manner over a Foley catheter.[28][34][37] The catheter should remain in place for at least two weeks, and a periurethral urethrogram should be performed before Foley removal.(B2)

Postoperatively, patients should receive routine postsurgical care instructions, including incisional care and information regarding indications to return to the emergency department. Patients should be instructed to refrain from intercourse during the postoperative period as well.

Differential Diagnosis

The differential diagnoses for penile fracture include:

• Anasarca
• Coagulation disorders
• Dorsal vein rupture
• Dependent penile edema
• Paraphimosis
• Pelvic trauma
• Penile cellulitis
• Penile contusion
• Priapism
• Thrombocytopenia
• Urethral tear

Prognosis

The prognosis for a promptly identified and repaired penile fracture is excellent, although there is a risk for long-lasting sexual effects due to the injury.[4] Immediate surgical repair of a penile fracture and any associated urethral injuries serves to minimize complications.[8][28][34][37] High-volume centers that see this injury frequently tend to have better outcomes.[8]

Complications

The most obvious and concerning complication of penile fracture is sexual dysfunction. All patients who are subject to penile fracture will experience some degree of sexual dysfunction, at least temporarily. Most are limited to the immediate postoperative period; however, some patients will experience long-lasting dysfunction.

Many patients will have anxiety over sexual performance after a penile fracture. Patients may also exhibit changes in sexual practices due to fears of a recurrent injury. Counseling may be needed to help guide a patient through the postoperative period to minimize psychological effects or sexual dysfunction following a penile fracture.[11]

Surgical complications may also include plaques and nodules, scarring, penile curvature or angulation, erectile dysfunction, painful erections, infection, reoperation, urethral stricture, penile induration, corporal aneurysm, wound edema, and urinary disorders.[4] Noticeable or bothersome scarring has been closely associated with the failure to use absorbable sutures.[33][42]

There is a significant risk of a concomitant urethral injury. Special attention is necessary to ensure correct Foley placement intraoperatively if such an injury is present. A missed urethral rupture could lead to a number of additional complications, including:

• Abscess formation
• Curvature of the penis
• Erectile dysfunction
• Extravasation
• Fibrosis and plaque formation
• Fistula formation (arteriovenous, corporourethral, urethrocutaneous, etc)
• Hematuria
• Nodule formation at the injury site
• Painful erections
• Painful intercourse
• Urethral stricture
• Urinary retention
• Urinoma formation
• Weak urinary stream

Conservative management of penile fractures has significantly more complications than immediate surgical intervention, mainly concerning erectile dysfunction.[4] Additionally, the patient may have excessive scar tissue development resulting in curvature of the penis, painful erections, penile angulation, and a consequent loss of penile length during erections. These factors all support early operative repair of penile fractures and should be discussed thoroughly with patients when explaining the risks and benefits of immediate surgical intervention.