The main objective of penile microvascular revascularization is to bypass obstructive lesions in the hypogastric-cavernosal system, thereby increasing cavernosal arterial perfusion pressure [13–15, 17, 18]. As will be discussed below, this is best achieved in younger patients who have sustained a traumatic blunt pelvic/perineal injury, resulting in damage to vessels leading to the corpora cavernosa.

The initial experience with penile revascularization surgery is credited to Michal et al. [20] in the 1970s. They initially used the inferior epigastric artery as the donor vessel anastomosed directly to the corpus cavernosum (Michal I procedure). This resulted in flow rates of more than 100 mL/min and intraoperative erections. Unfortunately, nearly all of the cases had anastomotic stenosis and poor success rates [14]. Subsequently, they anastomosed the inferior epigastric artery to the dorsal artery of the penis in an end-to-side manner (Michal II procedure). Here, a 56% success rate was achieved [14, 20]. Virag et al. [21] modified this procedure in the early 1980s by arterializing an isolated segment of dorsal vein. Here, the donor inferior epigastric artery was anastomosed to the deep dorsal vein increasing penile perfusion in a retrograde fashion. They reported a 49% success rate and an additional 20% improvement rate [14, 21]. Furlow and Fisher [22] also reported dorsal vein arterialization with ligation of its circumflex branches to prevent glanular hyperemia. Their success rate was 62% [22]. Sharaby et al. [19] created a side-to-side fistula between the dorsal artery and deep dorsal vein. They then used a spatulated inferior epigastric artery as the input source to this arteriovenous combination realizing an 80% success rate [14]. A variety of modifications were utilized (Table 13.1). A lack of patient eligibility criteria and standardized protocols and techniques likely contributed to the variable results and subsequent low popularity of these procedures. Current microarterial bypass surgical techniques involve anastomosing the inferior epigastric artery to either the dorsal vein or artery [13–15]. Although the artery-to-vein anastomosis is technically easier than that of artery-to-artery, the former is more likely to fail. The dorsal vein has valves that can retard penile reperfusion. These valves may also cause anastomotic thrombosis. A valvulotome or Fogarty balloon catheter can be used to remove the valves but may also cause endothelial injury, resulting in activation of the clotting system’s intrinsic pathway leading to thrombosis and failures. Artery-to-artery microarterial bypass surgery obviates the penile hyperemia seen with dorsal vein arterializations noted earlier [13–15, 17, 18].

Surgical correction of veno-occlusive erectile dysfunction has included penile venous ligation, crural banding, and spongiolysis in a small subset of patients [18, 23, 24].

Microvascular penile venous surgery is utilized to correct venous leak [18, 23, 24]. As the corpora expand during erection, the subtunical venules are compressed creating venous outflow resistance. This is the corporal veno-occlusive mechanism. Venous leak impotence equates with the inability to maintain an erection secondary to abnormal venous outflow from the corpora cavernosa. Penile trauma, Peyronie’s disease, urethral stricture incision/excision, congenital corpora cavernosal venous drainage abnormalities, and priapism surgery can all result in focal defects in the corporal veno-occlusive mechanism.

Penile venous reconstructive surgery to limit the venous outflow of the penis is not recommended according to the American Urological Association Clinical Guidelines Panel on Erectile Dysfunction [16]. The Panel cites the difficulty in distinguishing functional smooth muscle dysfunction from anatomical tunical abnormalities. They also describe the difficulty in determining the proportion of erectile dysfunction secondary to a veno-occlusive etiology independent of general arterial hypofunction and how to diagnose and treat this subset of patients.

Presently, venous leak surgery has been nearly abandoned since the predominant pathology is smooth muscle dysfunction and ligating the draining veins does not remedy the veno-occlusive dysfunction [25].

In appropriately selected erectile dysfunction patients with both poor arterial inflow and veno-occlusive dysfunction, a combination of surgical revascularization and venous ligation procedure can be performed. However, despite a patent anastomosis and adequate veno-occlusion, significant failure rates may be seen secondary to end-organ corporal disease and poor distal arterial runoff beyond the anastomosis [18, 25, 26].

Evaluation of the patient with erectile dysfunction should proceed along a patient-centered evaluation using a goal-directed approach as described by Lue [27] in 2007. Alternative nonsurgical and surgical treatment modalities should be discussed with the patient. Patients with mild to moderate vascular disease may benefit from oral PDE-5 inhibitors or intracavernosal vasoactive injection therapy. Similarly, vacuum devices and penile prostheses are alternative therapies for patients with arterial and/or veno-occlusive dysfunction etiologies.

The optimal patient for penile revascularization is a younger patient, less than 55 years of age, with focal arterial lesions limiting flow to the corpora cavernosa [13–18]. A comprehensive history and physical examination is performed. He should be psychologically stable and understand alternative treatment choices as mentioned earlier. First-line, less-invasive treatments are usually tried first. Blunt perineal trauma or pelvic fracture should be the likely culprit of the arterial lesions. Using a narrow bicycle seat with a protruding nose extension during bicycle riding causes compression of the ischiopubic rami, perineum, and the contents of Alcock’s canal [13, 28–30]. Resultant suprasystolic perineal compression pressures occlude penile perfusion and potentially induce endothelial injury, resulting in arterial vasculogenic erectile dysfunction. A wide bicycle seat without a nose extension results in pressure applied to the ischial tuberosities, thus sparing compression of the perineum allowing penile arterial inflow [30]. Vascular risk factors such as atherosclerosis, diabetes, hypertension, and coronary artery disease should be absent as these portend more diffuse disease with a worse prognosis after revascularization. Tobacco use needs to be eliminated at least 6 months prior to surgery. A normal libido, reduction in erectile rigidity during sexual activity, improved rigidity and sustaining ability in the morning, and poor spontaneous erections requiring increased stimulation to achieve these are characteristics of the ideal patient’s history.

Physical examination should reveal appropriate penile geometry with normal penile extensibility during stretching maneuvers [17, 18]. No Peyronie’s plaques or intracavernosal lesions should be present. A neurologic examination without evidence of a sensory neuropathy is mandatory [13–15, 17, 18].

Routine endocrinologic evaluation is undertaken to confirm that the hormonal milieu, including serum testosterone, is within normal limits [13–15, 17, 18].

Nocturnal penile tumescence testing is performed to rule out a psychogenic cause [13–15, 17, 18]. Tumescence, rigidity, and number of erectile episodes are recorded. Duplex Doppler ultrasonography with intracavernous vasodilator injection reveals functional and anatomic information [8, 9, 31]. Redosing of the vasodilating agent may be necessary. If the cavernosal artery peak systolic velocity is less than 25 cm/s, a vascular etiology is highly likely and corresponds with abnormal pudendal angiography [8, 9, 13–15, 17, 18, 27, 31]. Peak systolic velocities between 25 and 30 cm/s are borderline for arterial insufficiency but values are age dependent [8, 9, 13–15, 17, 18, 27, 31]. End diastolic velocities less than 5 cm/s are consistent with normal corporo-occlusive function [8, 9, 13–15, 17, 18, 27, 31]. Anatomically, the presence of communicating branches between the dorsal artery and cavernosal artery distal to the occlusive lesions is evaluated. This is necessary so that when new blood flow is restored to the dorsal artery, it will result in increased intracorporal pressure. Dorsal artery diameters and flow direction through septal communicators are also assessed. Hence, the best recipient dorsal artery can be chosen. Subsequently, dynamic infusion cavernosometry/cavernosography (DICC) is performed to demonstrate arterial pressure gradients between the cavernosal and brachial arteries [8, 9, 13–15, 17, 18, 27]. A gradient of more than 30 mmHg between the penile occlusion pressure and mean brachial pressure demonstrates functional arterial disease. DICC is also used to rule out veno-occlusive dysfunction. Flows to maintain less than 5 cc/min and pressure decays less than 45 mmHg over 30 s essentially rule out venous leak [8, 9, 13–15, 17, 18, 27, 31].

A common iliac arteriogram and a selective internal pudendal arteriogram are mandatory to identify the location of the obstructive arterial lesion as well as the best-suited donor vessel usually the inferior epigastric artery [8, 9, 13–15, 17, 18]. The inferior epigastric artery should be of sufficient length to allow a tension-free anastomosis to the dorsal artery. Common trunks between the inferior epigastric artery and the obturator arteries should be absent to avoid diminution of inferior epigastric artery perfusion pressures via the steal syndrome. The distal occlusive lesion in one or both hypogastric-cavernous arterial beds is usually located within the common penile or cavernosal artery and should be less than 2 mm in diameter [13]. Blockages in the internal pudendal arteries that are between 2 and 4 mm can be treated with endovascular stents. However, occlusive lesions in the internal pudendal arteries have a significant association with systemic atherosclerotic disease which portends a worse prognosis with regard to patency and success [25].

A curvilinear inguinoscrotal incision is made on the side opposite to the planned abdominal incision for the donor inferior epigastric artery harvesting (Fig. 13.10). This incision provides optimal proximal and distal exposure of the dorsal neurovascular bundle, and penile shortening is prevented by preserving the fundiform ligament. Additionally, better cosmesis is achieved by obviating postoperative scars on the penile shaft or base. The incision is made approximately two finger breadths from the base of the penis, from a point opposite the ventral root, to the scrotal median raphe. A Scott ring retractor with elastic hooks maximizes exposure. Blunt dissection deepens the incision through the dartos layer. The ipsilateral tunica albuginea is identified at the midshaft. The penis is then stretched and blunt finger dissection along the tunica albuginea is performed distally deep and inferior to the spermatic cord along the lateral aspect of the penile shaft. Injury to the fundiform ligament is avoided. The penis, including the glans, is inverted completely through the incision. A plane is created between Buck’s and Colles’ fascia around the distal penile shaft using blunt finger dissection. A Penrose drain is placed in this area. The neurovascular bundle is exposed. As noted in “Anatomy of the Penis and Male Perineum” section, the dorsal arteries of the penis are lateral to the deep dorsal vein and medial to the respective dorsal nerves. Dissection of the dorsal artery is limited at this point in the procedure to minimize ischemic, mechanical, and thermal trauma to these vessels. Topical papaverine hydrochloride irrigation is applied liberally to the vessels to prevent vasospasm-induced vasoconstriction and resultant endothelial and smooth muscle cell injury. In the past, both dorsal arteries were dissected and anastomosed to the bifurcation of the inferior epigastric artery. However, a significant improvement in erectile function was not made manifest in patients who underwent a bilateral anastomosis compared to those who had a unilateral anastomosis. Hence, the current consensus is that performing a single anastomosis minimizes surgical time and preserves the contralateral dorsal artery in case a second penile revascularization is required. The preselected right or left dorsal artery is identified and its course is bluntly followed proximally underneath the fundiform ligament. The fundiform ligament is left intact during this dissection allowing the penis to maintain elasticity during postoperative erection. Blunt dissection is performed between the proximal fundiform ligament and the pubic bone toward the external ring on the side of the preselected inferior epigastric artery. This dissection creates a transfer route allowing the inferior epigastric artery access to the dorsal artery of the penis while preserving the fundiform ligament. The penis is reverted back to its normal anatomic position and the inguinoscrotal incision is closed temporarily with skin staples.