Erectile dysfunction (ED) can occur from arterial insufficiency, bicycle riding or pelvic or perineal trauma if the artery to the penis is partially to totally blocked, leading to inadequate perfusion pressures being delivered to the erection chamber during sexual stimulation. The complaints of a man who has ED from artery blockage are slow-filling of the erection chambers, longer time to achieve erection, lack of spontaneity of erection, less rigid erection and difficulty maintaining the erection.
While ED is much more common in men 50 years or older, men with ED as young as teenagers can have the same artery blockage. The suspected cause in younger men is blunt trauma to the base of the penis, either from a kick to the crotch or a fall onto a hard object such as the bicycle bar or nose protrusion of the bicycle saddle. The artery that perfuses the erection chambers passes in a canal, Alcock’s canal that borders a part of the pelvic bone, the ischiopubic ramus. The force hitting the perineum crushes the artery against the bone. Such trauma can injure the endothelium leading to a localized form of artery blockage. This blockage restricts perfusion pressure in the same way it is restricted in a man with systemic atherosclerosis, which may be from diabetes, hypertension, high cholesterol, cigarette smoking, obesity, metabolic syndrome, or simply aging or family history. The concept that a healthy young man can have the same problem as the older man with atherosclerosis is very confusing to patients and physicians alike.
Diagnosis of artery blockage in a younger man with persistent ED is made with a series of sophisticated tests, one of which measures the perfusion pressure of the penis compared to the perfusion pressure of the arm. Ideally, these pressures would be the same. Once the blockage has been identified it can be bypassed, employing microvascular surgical techniques, to restore proper blood flow to the penis. Those with generalized vascular pathology are poor candidates for this operation as the same disease will likely affect the revascularized segment in the years following surgery.
The surgery is performed under general anesthesia through two incisions and requires an overnight stay. Intercourse is allowed six weeks after surgery.
The success of this operation is based on the selection of the correct operative candidate and the microsurgical capabilities of the surgeon. To this end, the following represents a list of criteria to ensure optimum results. The criteria are as follows:
1. The patient’s history is characterized by (a) intact libido, (b) a consistent reduction in erectile rigidity during sexual activity, (c) variable sustaining capability with the best maintenance of the rigidity during early morning erections, and (d) poor spontaneity of erections, taking much effort and excessive time to achieve the poorly rigid erectile response.
2. Normal hormonal and neurological evaluation.
3. Suspicion of arterial insufficiency as evidenced by reduced peak systolic velocity values during duplex Doppler ultrasonography and increased arterial gradients during cavernosal artery occlusion pressure determination during dynamic infusion cavernosometry.
4. Normal veno-occlusive parameters during and duplex Doppler ultrasonography and dynamic infusion cavernosometry.
5. The presence of a distal occlusive lesion in one or both hypogastric–cavernous arterial beds usually within the common penile artery or cavernosal artery that is amenable to distal bypass (Figures 1a, 1b, 1c, 1d).
6. The presence of an inferior epigastric artery of sufficient length to allow anastomosis to the dorsal artery Figure 2a, 2b).
7. The presence of a communication branch(es) between the dorsal artery and the cavernosal artery distal to the occlusion that will allow the inflow of new blood flow and the development of increased intracorporal pressure.
Nonsurgical treatment options for young men with erectile dysfunction include psychotherapeutic, hormonal, pharmacological, and external device interventions. Surgical treatment options consist primarily of penile prosthesis insertion.
The patient is placed supine on the operating table and his arms secured next to his body to minimize upper-extremity nerve injuries. As this operation may last in excess of 5 hours, great care must be taken in the positioning and padding of the limbs, in particular the neurovascular points on the upper limbs. Sequential compressive devices are placed aouund each calf. General endotracheal anesthesia with complete muscle relaxation provides complete skeletal muscle (especially the rectus muscle) relaxation and facilitates harvesting the donor inferior epigastric artery vessel. The patient’s abdomen and genitalia are carefully shaved, prepped, and draped, following which a 16 Fr Foley catheter is placed using sterile technique. The patient is given one dose of preoperative antibiotics (cefazolin or vancomycin if penicillin allergic). From a technical standpoint, the operation can be divided into three stages: dorsal artery dissection, inferior epigastric artery harvesting, and microsurgical anastomosis.
Dorsal Artery Dissection
A curvilinear incision is made, in general on the side opposite to the planned abdominal incision for the donor inferior epigastric artery harvesting (Figure 3a). The advantages of this incision are that it offers (a) excellent proximal and distal exposure of the penile neurovascular bundle, (b) the ability to preserve the fundiform ligament preventing penile shortening, and (c) the absence of unsightly postoperative scars on the penile shaft or at the base of the penis. Use of a Scott ring retractor with its elastic hooks maximizes operative exposure of the penis with a minimum of assistance.
The incision is made 2 finger breadths from the base of the penis, from a point opposite the ventral root of the penis, to the scrotal median raphe. This incision is carried down through the dartos layer using blunt dissection. The ipsilateral tunica albuginea is subsequently identified at the midpenile shaft. With the penis stretched, blunt finger dissection along the tunica albuginea is performed in a distal direction deep and inferior to the spermatic cord structures along the lateral aspect of the penile shaft, avoiding injury to the fundiform ligament.
The penis is then inverted through the skin incision, with care taken to push the glans in fully (Figure 3b). The penis must not be tumesced during this maneuver. If a partial erection is present, intracavernosal a-adrenergic agonist (100 mg phenylephrine) should be administered. Blunt finger dissection around the distal penile shaft enables a plane to be established between Buck’s fascia and Colles’ fascia, and a Penrose drain is secured in this plane.
Exposure of the neurovascular bundle and, in particular, the right and left dorsal penile arteries is now performed. The arteries are usually obvious, located on either side of the deep dorsal vein and surrounded by the dorsal nerves. Isolation of the dorsal penile arteries for such arterial bypass surgery requires limited dissection at this time in the procedure; thus, ischemic, mechanical, and thermal trauma to the dorsal penile arteries may be minimized. To avoid injurious vasospasm, topical papaverine hydrochloride irrigation is applied frequently. In this way, preservation of endothelial and smooth muscle cell morphology during dorsal artery preparation is ensured. This is very critical as the room temperature of the operating room, the use of room temperature irrigating solution, and even the skin incision can induce vasoconstriction, spasm, and possible endothelial cell damage.
The pre-selected right or left dorsal penile artery is identified. The course of the appropriate dorsal artery is followed proximally underneath the fundiform ligament, with care being taken to leave the fundiform ligament intact (Figure 3C). Blunt dissection is performed under the proximal aspect of the fundiform ligament above the pubic bone toward the external ring. This dissection enables the inferior epigastric artery to pass from its abdominal location to the appropriate location in the penis while simultaneously preserving the fundiform ligament. The penis is placed back on its normal anatomic position and the inguinoscrotal incision is temperately closed with staples.
Harvesting of the Inferior Epigastric Artery
A transverse semilunar abdominal incision following Langer’s lines is the preferred incision. The transverse incision provides excellent operative exposure of the inferior epigastric artery and heals with a more cosmetic scar compared to those observed with paramedian skin incisions. The starting point of the transverse incision is approximately 3/4 of the total distance from the pubic bone to the umbilicus in the midline (Figure 4). It extends laterally along Langer’s lines for approximately 5 cm. The rectus fascia is incised vertically. The junction between the rectus muscle and underlying preperitoneal fat is identified and the preperitoneal space is entered. The rectus muscle is reflected medially.
The inferior epigastric artery and its two accompanying veins are located beneath the rectus muscle in the preperitoneal plane. The ring retractor is again utilized to optimize operative exposure. It is critical to harvest an inferior epigastric artery of sufficient length to prevent tension on the microvascular anastomosis. Application of topical papaverine is utilized on the inferior epigastric artery throughout the dissection. Thermal injury is avoided using low-current microbipolar cautery set at the minimum level necessary for adequate coagulation and the vasa vasora are preserved by dissecting the artery en bloc with its surrounding veins and fat. Dissection of the inferior epigastric is required from its origin at the level of the external iliac artery to a point at the level of the umbilicus.
The transfer route of the neoarterial inflow source is prepared from the abdominal perspective prior to transecting the vessel distally (the penile transfer route has previously been dissected). The temporary scrotal staples are removed and the penis is reinverted. The internal ring on the side of the harvested artery is identified lateral to the origin of the inferior epigastric artery. Using blunt finger dissection through the inguinal canal, a long fine vascular clamp is passed through the fenestration in the fundiform ligament, the external and internal inguinal rings, and a Penrose drain is placed to protect this transfer route.
The donor inferior epigastric artery vascular bundle is transected at the level of the umbilicus between two ligaclips and carefully inspected for any proximal bleeding points. This donor artery should pulsate briskly (Figure 5a). All atachments to the retroperitoneal fat are carefully removed prior to artery transfer as any attachments will diminish donor artery length and place the subsequent anastomosis with the dorsal artery at risk for being made under undue tension. The long fine vascular clamp is brought through the internal inguinal ring again, this time to grasp the end of the transected inferior epigastric artery. The inferior epigastric vascular bundle is transferred to the base of the penis (Figure 5b). It should be briskly pulsating and of adequate length. The origin of the inferior epigastric artery should be inspected for kinking or twisting. Following the achievement of complete hemostasis, closure of the abdominal wound is performed in two layers. The rectus fascia is closed utilizing a running 0 polyglycolic acid suture, one suture started at either end of the incision. ON-Q® Silversoaker® catheters (I-Flow Corporation, Lake Forest CA), that stay in place post-operatively for 48 to 72 hours, are placed below and above the rectus fascia and 0.5% Marcaine is delivered at 2 ml/hour through each catheter (Figure 6a). The skin edges are opposed using 4-0 Monocryl and Dermabond is applied over the skin incision. ON-Q catheters are secured to the skin temporarily using steri-strips. (Figure 6b).
A ring retractor and the associated elastic hooks are utilized once again on the inguinoscrotal incision and the fenestration of the fundiform ligament to gain exposure of the proximal dorsal neurovascular bundle. The pulsating inferior epigastric artery is placed against the recipient dorsal penile arteries and a convenient location is selected for the vascular anastomosis. The anastomosis is created based on the arteriographic and duplex Doppler ultrasound findings. An end-to-end anastomosis is best under conditions whereby dorsal penile artery communications exist to the cavernous artery. In addition, an end-to-end anastomosis transfers perfusion pressure more effectively than an end-to-side anastomosis with less turbulence.
For intraluminal arterial irrigation, we utilize a dilute papaverine, heparin, and electrolytic solution believed to be capable of inhibiting the early development of myointimal proliferative lesions during surgical preparation.
The appropriate dorsal penile artery segment is freed from its attachments to the tunica albuginea, with care being taken to avoid injury to any communicating branches to the cavernosal artery. Vascular hemostasis of this segment of the dorsal penile artery may be achieved with either gold-plated (low-pressure) aneurysm vascular clamps under minimal tension for the minimal of operating time. The only location where the adventitia must be carefully removed is at the site of the vascular anastomosis, i.e., the distal end of the inferior epigastric artery and the free end of the dorsal artery, to avoid causing subsequent thrombosis. If segments of adventitia enter the anastomosis, patency of the anastomosis is in jeopardy as adventitia activates clotting factors from the extrinsic clotting system. The remaining adventitia should be preserved in the vessels as the vasa vasorum provide a nutritional role to the vessel wall. The preservation of the adventitia is in addition important in terms of vessel innervation.
Prior to the anastomosis, it is appropriate to assess the integrity of the donor inferior epigastric perfusion pressure. This is assessed grossly by temporarily removing pressure on the gold-plated (low-pressure) aneurysm vascular clamps under minimal tension (Figure 7a). The donor artery should exhibit brisk arterial inflow. A plastic colored background material is used to aid in vessel visualization under the microscope. An end-to-end anastomosis is performed between the inferior epigastric artery and the dorsal artery using interrupted 10-0 nylon sutures (single-armed, 100-mm, 149-degree curved needle) under 10 fold magnification. Sutures are usually passed from the outside of the inferior epigastric artery (1 mm from the cut edge) to the inside lumen and then from the insode of the dorsal artery lumen to the outside wall of the dorsal artery (1 mm from the cut edge) and then tied. Usually 15 or more interupted sutures are used. All sutures used to complete the anastomosis are inserted equidistant from each other to avoid an uneven anastomosis.
Following release of the temporary occluding vascular clamps on the dorsal penile artery, the anastomosed segment should reveal arterial pulsations along its length and retrograde into the inferior epigastric artery. Such an observation implies a patent anastomosis. At this time, the inferior epigastric artery gold-plated aneurysm clamp may be removed. The intensity of the arterial pulsations in the anastomosis usually increases (Figure 7b). On occasion, the application of a small amount of hemostatic material may be needed to aid in promoting hemostasis from suture needle holes in the vessel walls.
After complete hemostasis has been achieved and correct instrument and sponge counts are assured, closure of the inguinoscrotal incision may begin. The dartos layer is reapproximated using a 3-0 polyglycolic acid sutures in a running fashion. The skin edges are opposed using 4-0 Monocryl and Dermabond is applied over the skin incision. The ON-Q catheters are re-secured to the skin with Tegaderm. A compressive scrotal dressing is placed using fluffs and elastoplast. The Foley catheter is left to closed-system gravity drainage overnight (Figure 8).
Mechanical disruption of the microvascular anastomosis and subsequent uncontrolled arterial hemorrhage may occur from blunt trauma in the first few postoperative weeks following coitus, masturbation, or from accidents. It is recommended that abstention from sexual activities involving the erect penis until 6 weeks postoperatively. Other complications include penile pain and diminished penile sensation from injury to the nearby dorsal nerve. Loss of compliance of the suspensory and fundiform ligaments postoperatively may lead to diminished penile length. Preserving the two ligaments has markedly minimized those complications in our series. Glans hyperemia, once a complication seen when inferior epigastric artery to deep dorsal vein anastomoses (dorsal vein arterialization) were performed, is no longer seen.
Microvascular arteral bypass surgery has been performed in this above fashion since 1981. An estimated 1500 procedures have been performed over more than 25 years. It is estimated that the success rate (clincially relevant improvement in erectile function) is appromimately 65 – 70%. Since relocating to San Diego, a review has been made of the latest microvascular arterial bypass procedures using post-operative validated outcome scales, ultrasonography and arteriography. The scores of the International Index of Erectile Fucntion have improved significantly in the total score, the erectile function domain, the desire domain, the orgasm domain, the intercourse satiusfaction domain and the overall satisfaction domain. There has been marked and significant lowering of the sexual distress scale. Post-operative duplex Doppler ultrasonography has confirmed marked increases in cavernosal artery peak systolic velocity. Post-operative selective inferior epigastric arteriograms have been performed that have documented intact arterial anastomoses between the inferior epigastric artery and the dorsal penile artery with subsequent visualization of contrast in the cavernosal artery (Figures 9a, 9b). Finally use of the ON-Q pump for delivery of Marcaine for 48 to 72 hours has resulted in siginificant lowering of post-operative morphine and percocet while the patients have simultaneously experienced excellent pain relief.