Priapism is a pathologic condition consisting of prolonged penile erection unrelated to sexual arousal or desire. Incidence rates of 0.34 to 5.34 per 100,000 person-years have been estimated among the general population. Priapism has been attributed to diverse etiologies, including neurologic conditions, pharmacologic exposures, trauma, hematologic disorders, and idiopathic presentations. Priapism is classified based on diagnostically distinct presentations. Of the two major types, ischemic (also known as low-flow or venoocclusive) and nonischemic (also known as high-flow or arterial), the ischemic type represents 95% of all presentations and has been notably observed to occur in nearly 40% of patients with sickle cell disease (SCD). Nonischemic priapism episodes often spontaneously resolve and are not medical emergencies. However, ischemic priapism episodes represent a urologic emergency because of the potential for devastating consequences such as cavernosal tissue necrosis and fibrosis, which can result in permanent erectile dysfunction (ED) and other complications.
Ischemic priapism is characterized by reduced or absent cavernous blood flow, corporal rigidity, and pain. This condition is similar to a compartment syndrome in that increased pressures develop within the enclosed cavernosal space and compress the circulation. Because irreversible corporal tissue damage has been shown to occur in episodes lasting more than 6 hours (major priapism), patients are advised to seek immediate medical care for a priapism episode of 4 hours or longer. If episodes persist beyond 24 hours, tissue necrosis and fibroblast proliferation occur, resulting in ED. Recurrent ischemic priapism (RIP), also known as stuttering priapism, is a variant involving repeated episodes of ischemic priapism. Typically, these episodes last for less than 3 hours with intermittent periods of detumescence. Although often transient and self-remitting, nearly 30% of RIP episodes may progress to major episodes. Consequently, this variant may also necessitate emergent management.
Nonischemic priapism is caused by disruptions of the cavernous arterial supply and consequently unregulated cavernous arterial inflow. These disruptions involve mechanisms of injury, including arterial aneurysm, arteriovenous fistula, iatrogenic needle injury, or pelvic trauma resulting in arteriolar-sinusoidal fistula formation. Fistula formation permits cavernous arterial blood to enter the lacunar spaces rather than the helicine arteries, giving rise to unregulated penile engorgement. Although the corpora are usually tumescent, they typically lack rigidity and pain. These episodes may spontaneously resolve with little or no long-term complications.
Given the severe nature of the complications that follow ischemic priapism episodes, accurate diagnosis of the presentation-type is critical in order to determine appropriate management.
Preoperative Preparation and Planning
The initial step in preoperative preparation is discerning between ischemic and nonischemic priapism. Persistent pain is typically associated with and is an important predictor of ischemic priapism. A clinical history detailing the episode duration, degree of pain, priapism-predisposing conditions (e.g., SCD), history and course of previous episodes, history of genital injury or trauma, and use of pharmacotherapy may provide useful diagnostic insights. Physical examination should entail inspection and palpation of the phallus to evaluate the extent of tumescence as well as for signs of trauma. Ischemic priapism is characterized by the presence of cavernosal body rigidity and tenderness without glanular involvement.
Blood gas analysis is a helpful diagnostic tool. An aspirate is obtained directly from the corpora cavernosa and sent for analysis. The presence of acidosis (pH <7.25), hypoxia (pO 2 <30 mm Hg), and hypercarbia (pCO 2 >60 mm Hg) is indicative of ischemic priapism. In the setting of nonischemic priapism, cavernous blood gases will resemble arterial blood (pH >7.40, pO 2 >50 mm Hg, pCO 2 <50 mm Hg). Patients should also be evaluated for the presence of hematologic or coagulation disorders because they may be unaware of underlying conditions. The use of urine toxicology and drug screens can also help in assessing for the use of pharmacotherapeutic and recreational drugs.
Penile color duplex ultrasonography can be used independently of corporal blood gas analysis to aid in the diagnosis of ischemic priapism. The penile shaft and the perineum should be examined using ultrasonography while the patient is in a frog-leg position. Fistulas or other anatomic malformations, as well as straddle or scrotal injuries may be identified in this manner. Ischemic episodes are characterized by decreased or absent cavernosal arterial flow, but nonischemic episodes will have normal to high arterial flow velocities.
First-line management of major ischemic priapism requires immediate decompression through the use of corporal aspiration and irrigation. Antibiotics should be administered, preferably before the initiation of treatment. A local penile shaft block or dorsal nerve block using lidocaine, bupivacaine (without epinephrine), or both is used for local pain control. Blood is then aspirated using a 16- or 18-gauge needle inserted directly into the corpus cavernosum at the lateral aspects of the proximal penile shaft. This needle can also be used for diagnostic and therapeutic evacuation of blood, irrigation with saline, and injection of an α-adrenergic sympathomimetic agent. Evacuation and irrigation of stagnant blood allows for corporal decompression and promotes recovery of arterial blood flow within the corpora. The use of α-adrenergic sympathomimetics in concert with aspiration and irrigation has been reported to improve the rate of priapism resolution from 30% up to 80%. Phenylephrine, a selective α 1 -adrenergic agonist, is typically preferred for its potency, selectivity, and relatively low risk of systemic cardiovascular effects through its decreased β-adrenergic activity. It is injected at a dose of 100 to 200 mcg every 3 to 5 minutes until detumescence, with a maximal dosage of 1000 mcg/hr. Although the systemic side effects are limited by the intracavernosal delivery, patients should be hemodynamically monitored for the development of hypertension, headache, tachycardia, and cardiac arrhythmias. Successful management can be determined when freshly oxygenated blood can be aspirated, pain is resolved, and penile detumescence is noted. If tumescence persists, reevaluation using penile ultrasonography may be performed. Occasionally, high-flow priapism follows an episode of ischemic priapism that has been successfully treated. This is typically self-limiting and requires only close observation.
For major priapism episodes related to underlying SCD, the above approach should be taken without delay. Simultaneous medical optimization of SCD is initiated, which may include hematologic consultation, intravenous hydration, maximizing oxygenation, alkalinization, and exchange transfusion.
When episodes are unremitting, increasingly invasive options are used in an attempt to prevent worsening tissue damage and preserve erectile function or simply provide palliative care when erectile function can no longer be preserved. Surgical intervention is effective as a second-line option in refractory ischemic episodes. Although there is no consensus on when to perform second-line options, it is reasonable to pursue these interventions after first-line treatments have proven ineffective for at least 1 hour. Notably, the effectiveness of first-line therapies decreases as the duration of the priapism episode increases because of the increasingly acidotic and hypoxic corporal tissue. Therefore, surgical intervention may be more immediately considered for episodes of 24 hours or longer.
In contrast, high-flow priapism is not a medical emergency. Initial observation is reasonable because about half resolve spontaneously. The use of ice and pressure in the early posttrauma period may induce vasospasm and thrombosis of the ruptured artery, aiding resolution. If high-flow priapism persists, patients may be counseled in an elective setting on available options. These include continued observation, selective embolization, and androgen ablation. Resolution with selective embolization is approximately 75%. Autologous clot and other nonpermanent biomaterials are preferred because of lower rates of permanent erectile impairment (5% vs. 39%). Androgen ablation carries significant side effects and is infrequently used. In the case of embolization failure, penile exploration with surgical ligation of pseudoaneurysms, sinusoidal fistulas, or both may be required. The use of intraoperative color duplex ultrasonography can aid in the identification of the affected site.
Patient Positioning and Surgical Incision
An episode of major priapism that has failed irrigation and injection of α-adrenergic sympathomimetics will require more definitive management. The primary goal of intervention is providing an outflow of the stagnant, deoxygenated blood of the corpora cavernosa with restoration of normal intracorporal blood flow. Shunting procedures are thus the mainstay of therapy. These can be divided into percutaneous distal shunts (Winter, Ebbehoj, T-shunt), open distal shunts (Al-Ghorab, Burnett), open proximal shunts (Quackels, Sacher), and vein anastomotic shunts (Grayhack, Barry). Typically, a bedside procedure is attempted first. If this proves unsuccessful, open operative intervention with a distal shunting procedure is performed next. Rarely, open proximal shunting or vein anastomosis is required. The placement of a penile prosthesis in the setting of acute priapism is an emerging option for the management of refractory episodes.
The patient should be placed in supine position, with adequate local anesthetic in addition to intravenous or oral pain relief as supplements. Antibiotics targeting skin flora, such as cefazolin, are appropriate. Sterile technique should be meticulously maintained.
Percutaneous Distal Shunts
Winter (Corporoglanular) Shunt
The rigid corpora cavernosa are carefully palpated at the level of the flaccid glans. Local anesthetic is injected directly in the area of anticipated entry. A large bore biopsy needle (18 gauge or larger) is inserted through the glans and directed proximally to the corpus cavernosum. The needle should be inserted parallel to the long axis of the penis, avoiding medial displacement which may result in urethral injury ( Fig. 127.1 ). The needle is inserted several times to allow multiple windows in the tunica albuginea to form. Creation of bilateral fistulas may be required to achieve maximal detumescence. Closure of the skin puncture site is performed with figure-of-eight 3-0 chromic sutures in case of persistent ooze. If priapism is not relieved, the procedure may be repeated or an alternative shunt should be performed.
Ebbehoj (Corporoglanular) Shunt
If a Winter shunt is unsuccessful, larger sized fistulas can be created using a #11 blade. The blade is passed percutaneously through the glans in a similar manner to the Winter technique ( Fig. 127.2 ). The blade may be passed multiple times and bilaterally as needed to achieve the desired effect. 3-0 chromic sutures may be used for skin closure if needed.
A #10 blade is used to enter the corpora cavernosum through the glans similar to the Ebbehoj technique. The blade is inserted parallel to the orientation of the urethral meatus, with care to avoid urethral injury. The sharp portion of the blade is rotated 90 degrees away from the urethra (e.g., on the patient’s left side, the blade is rotated counterclockwise; on the patient’s right side, the blade is rotated clockwise) ( Fig. 127.3 ). The defect created in this fashion is typically larger than with the techniques discussed thus far, facilitating detumescence. In the tunneling modification of the T-shunt, a straight urethral sound (20–24 Fr) is measured along the length the penis for appropriate sizing, then inserted to release stagnant blood from the more proximal penile shaft ( Fig. 127.4 ). The procedure is repeated on the contralateral side. Skin closure with 3-0 chromic suture may be required. If detumescence is not achieved, an open shunt is required.