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43. Surgical Treatment of Erectile Dysfunction: Historical Perspective and Overview
Keywords
Erectile dysfunctionPenile prothesisSemi-rigidInflatableErosionInfectionPenile revascularization43.1 Historical Perspective
The first modern report of a surgical treatment for erectile dysfunction (ED) dates back to 1873 when Francesco Parona from Italy first reported the sclerosis of the dorsal penile vein with hypertonic saline in a young man [1]. In the late 18th and early 19th centuries other reports followed depicting deep dorsal vein ligation or sclerosation [2]. Later on, Oswald Lowsley combined deep dorsal vein ligation with plicature of the ischiocavernous muscles [3]. However, results, such as today, where erratic and short-lived [4–6]. In 1936, Nikolai Bogoraz was the first to report the utilization of rib cartilage during penile reconstructive surgery in order to facilitate erection [7]. The report of this technique sparked a revolution and Bogoraz was soon followed-up by others authors such as Frumkin, Bergman and Henninger [8–10]. Nonetheless, poor long-term results due to rib cartilage reabsorption played down the early success of this technique and led to its almost complete abandonment. In 1950 Peter Scardino performed the first single and unpaired rigid penile prothesis made of acrylic but never published his work [10]. At the time this prothesis was inserted under the penile skin dorsally and soon other authors such as Goodwin followed on his technique [11]. However, the initial enthusiasm was short-lived as the lack of firm proximal support, difficulty in penetration and poor sexual activity derailed its utilization by others.
One of the most important milestone in the surgical treatment of erectile dysfunction occurred in 1966 when Beheri from Egypt reported a case-series of over 700 man who had undergone a paired implantation of rigid penile prothesis made of polyethylene inside the corpora carvernosa paving the way for intra-cavernosal insertion [12]. However, satisfaction was also limited due to the rigidity of the material used as well as other complications such as extrusion and infection and also the fact that Beheri was a plastic surgeon and published in plastic surgery journals did not drawn attention from the urology community [8, 10].
Another important milestone occurred outside the field of medicine when the National Aeronautics and Space Administration developed a high-grade silicone as part of the space program that was subsequently used until today in penile prothesis. In 1973 when Brantley Scott, who would later help found American Medical Systems (AMS), first presented the three-piece inflatable paired penile prosthesis and would later be named “AMS 700” a name which has been carried over until today [13]. A year later in 1974 the Small-Carrion prothesis was also introduced by Mentor which would later be bought by Coloplast [14]. It was a paired semi-rigid penile prothesis which became widely used and was the most implanted penile prosthesis during the 70s and 80s. In 1983, Mentor also introduced a competing three-piece inflatable penile prosthesis. Mentor main difference was the use of different materials like polyurethane and later Mentor’s patented Bioflex® material [15, 16].
While the focus of attention was on the development of penile prosthesis in the 70s and 80s, Vaclav Michal from Czech Republic in 1973 first introduced penile revascularization (Michal I and II procedures), as a non-pharmacological and non-device-related reconstructive surgical strategy for men with erectile dysfunction [17–19]. These technique used microvascular arterial bypass surgical techniques not well known at the time by urologists. Although with more limited indications, contemporary penile revascularization still stands today as an attempt to cure arteriogenic erectile dysfunction in young men with arterial pathology secondary to blunt pelvic, perineal or penile trauma [20].
Since the 90s penile prothesis have been the mainstay surgical treatment of erectile dysfunction with both AMS and Mentor/Coloplast continually improving existing models or introducing new ones. Two-piece inflatable penile prosthesis have been introduced by both AMS and Mentor. In 2000, AMS introduced the InhibiZone™ coating [21], composed of minocycline and rifampin, in order to reduce infection, while Mentor responded with the Titan® in 2002 [22], which has cylinders coated with a hydrophilic substance that decreases bacterial adherence and can absorb and release antibiotics. Pumps have also been improved as in 2000 Mentor introduced the lock-out valve in order to prevent auto-inflation [23] while AMS later in 2013 responded with the Momentary Squeeze preventing both unintentional inflation/deflation [24]. Reservoir design has also been subject to new developments which allowed ectopic reservoir placement as AMS introduced the Conceal® reservoir in 2006 and more recently, Coloplast unveiled the Cloverleaf® reservoir.
AMS has been bought by Boston Scientific in 2015 and new brands like Promedon, Zephyr Surgical Implants(ZSI) and Rigicon® appeared in the market. Recently, in 2012 ZSI has introduced the first inflatable and semi-rigid models specifically for female-to-male transgender surgery.
43.2 Penile Prothesis
In the last four decades, penile prothesis implantation has been the standard for surgical treatment of erectile dysfunction. In the following subchapter, surgical technique, intra-operative complications, post-operative complications and outcomes will be discussed.
43.2.1 Types of Penile Prosthesis
There are two major type of penile prosthesis, the semirigid prosthesis and the inflatable prosthesis. Although the purpose of both models is to reestablish erection and penetrative ability in erectile dysfunction patients, there are noticeable differences in flaccidity, cosmetic results and complications between these two major types.
Semirigid prosthesis are usually paired solid cylinders which can be further subdivided in malleable or positional accordingly to the mechanisms that allows positional change. Individual cylinders can be made in different lengths and/or girths and some models can be trimmed or added rear tip extensors in order to achieve the ideal length. These prosthesis are known for being much less expensive, easy-to-use by patients, easy to implant by surgeons and with a much lower mechanical failure rate. However, these prosthesis simulate a permanent erection that patients find it hard and difficult to conceal, while not allowing for neither girth or length expansion has some inflatable prothesis allow. Moreover, even though mechanical failures are very low over time, their permanent stiffness can loosen up the tunica albuginea leading to poor quality of erection and decreased patient satisfaction as well as distal erosion.
Currently, there are a number of models available from several brands being the AMS 600 Spectra and the Coloplast Genesis the most well known and used worldwide.
Inflatable prosthesis are characterized by the ability to allow flaccidity when not in use and expansion with pump activation. These can be subdivided in two- and three-piece prothesis according to the number of components. Three-piece components are constituted by cylinders, pump and reservoir while in two-piece prothesis the omitted third component, usually the reservoir, is incorporated in the rear tip of cylinders. These prosthesis mimic more closely a natural erection, yet it comes at the cost of more expense, more complexity and higher rates of mechanical complications. Moreover, they also require more patient or partner dexterity and comprehension in order to function.
Cylinders are also sold marketed on different sizes of length and girth. These can usually be adjusted with rear extenders. These cylinders allow girth expansion and some models, like the AMS 700 LGX, even allow length expansion.
Pumps from different manufactures may present specific characteristics. AMS has introduced the Momentary Squeeze which requires only a quick squeeze in order to deflate the cylinders. Coloplast has introduced the lock-out valve to prevent auto-inflation and also the one-touch release in order to facilitate and speed cylinder deflation [23].
Reservoirs are also manufactured in different volumes according to cylinder size and manufacture specifications. New design concepts have been introduced in the last decade in order to allow ectopic reservoir placement in patients with previous history of inguinal and/or pelvic surgery. Reservoirs like the Conceal® from AMS and the Cloverleaf® from Coloplast allow safe ectopic placement between the transversals fascia and rectus abdominis muscle.
43.2.1.1 Pre-operative Patient Evaluation
Although penile prothesis implantation is associated with the highest reported patient satisfaction and is highly effective in treating erectile dysfunction, it is an irreversible procedure with known intra-operative and post-operative complications that range from mild to life-threatening such as penile prothesis infection. All patients should undergo medical and psychiatric evaluation [25] prior to penile prosthesis implantation and should also be educated and informed about the various types and models of penile prothesis, and their intrinsic characteristics and disparities. Providing images and videos of the cosmetic and functional end-result of an implanted penile prosthesis as well as allowing the patient to handle a sample of the different models can help ease the patient and partner informed decision and consent [26]. A penile doppler ultrasound with an vasoactive agent should also be performed for both medical and legal reasons as it can confirm irreversible organic etiology. During the physical examination stretched penile length should also be documented and shown to the patient in order to avoid unrealistic expectations, patient dissatisfaction and legal litigation [27].
There are few absolute contra-indication for penile prothesis implantation, namely the inability to underwent anesthesia, untreated or untreatable blood dyscrasia known, known untreated active infection or known hypersensitivity or allergy to prothesis materials. Other potential or relative contra-indications have also been proposed, such as potentially reversible erectile dysfunction, poor compliance with treatment, inability to follow instructions or spinal cord injury. These often do not impede surgery but require extra assurance and ponderation when deciding as potential complications can be more frequent.
43.2.1.2 Pre-operative Care
Penile prothesis implantation , either semi-rigid or inflatable, can be performed under general, spinal and even local anesthesia according to patient condition and surgical team preference. The patient should be placed in a supine position on the operative table. The genitals are shaved and scrubbed with chlorhexidine soup immediately before the incision. Two intravenous broad-spectrum antibiotics should also de administer before the incision and the skin should be prepped with an alcohol-based solutions there is evidence that alcohol-based chlorhexidine solution is better than povidone-iodine in preventing surgical wound site infection [28]. A surgical incision drape should be also placed in order to decrease undesired skin contact.
43.2.1.3 Surgical Technique
Penile prostheses can be implanted using a penoscrotal, infrapubic or sub coronal approach. Our group favors a single-incision penoscrotal approach for both semi-rigid and inflatable approaches. A Foley catheter is placed, caped and a Scott retractor is secured along the base of the penis. Blunt yellow hooks should be used as they minimize damage to prothesis or surgical gloves. A two centimeters median skin incision is performed inferior to the penoscrotal junction along the median raphe. Scrotal fat is swept inferiorly and secured with the help of hook retractors. Following exposure of the Buck fascia an incision is made bilaterally to expose the corpora cavernosa. A vertical corporotomy is made bilaterally. Corporotomy length varies depending on type and model of prothesis but often a 1.5 cm incision is made for inflatable while a larger incision is usually preferred for semi-rigid ones. One or two rows, according to corporotomy length, of 2–0 Vicryl™ should then be placed and needles can be cut are removed from the surgical field. Care should be taken on corporotomy placement in there-piece inflatable prothesis as more proximal corporotomy can lead to unwanted tubing awareness.
A Metzenbaum scissor is then used to initiate the tunneling of the corpora cavernosa. The curvature of the scissors should face away the midline and its tip should be next to the lateral tunica albuginea. Constant traction in the penis is the key to ensure correct tunneling of the corpora while avoiding crossing over. Corporal dilatation can be performed using Brook’s or Hegar dilators if needed as in primary implantation cases dilation may be not necessary. The surgeon must be aware that most of intra-operative complications occur during this step. After finishing corporal dilation two dilators should be placed proximally and distally in order to check for cross-over to proximal or distal tunica albuginea perforation, the so called “field goal test ”. A “distal fluid challenge test” can also be performed. A Furlow inserter is used to measure proximal and distal corporal length. After determining the total corporal length, the appropriate cylinder size is selected.
Tomada’s manœuvre . After blunt incision of the external inguinal ring, a urethral catheter ballon is placed in the prepubic space and inflated to 80–100 mL to create space for the reservoir
By this time all previously used instruments are considered contaminated and removed from the surgical field, surgical gloves are replaced, and a new skin drape is placed. Following the “no touch” technique principles may further decrease infection rates [29]. In case of two- or three-piece inflatable prothesis tubing, reservoir and pump are flushed in order to completely remove all air. Tubing should then be closed with two protected Kelly clamps in each extremity. Cylinders are then brought to field and positioned distally in the dilated corpora cavernosa using a Furlow insertion tool with a Keith needle while proximally a pusher can be used if needed. The Foley catheter balloon previously placed in the retropubic space is deflated and replaced by the reservoir, which is then filled with the appropriate volume of isotonic normal saline according to cylinder size and manufacturer specifications. After connecting the fluid reservoir and the cylinders to the pump, the device is inflated and deflated to ensure functionality and good cosmetic outcome. The pump is then placed in a subdartos pouch. Previously placed Vicryl™ sutures are used to close the corporotomy as in a mattress suture. A closed suction drain can be placed at this time if there are concerns with hemostasis. There is not a general agreement on drain placement but close suction drains do not increase infection rate while preventing hematoma formation [30, 31]. Dartos fascia and Buck’s fascia are closed using 3–0 Vicryl™, and the incision is closed with a running suture of 4–0 Vicryl rapid™. In case of inflatable prothesis the cylinders are left partially filled in order to ensure hemostasis. After the skin is closed, the patient is placed in a frog-leg position and his penis and scrotum are wrapped with a compressive scrotal dressing. Alternatively, a mummy wrap can be performed.
43.2.1.4 Intra-operative Complications
Ensuring correct surgical technique is essential in preventing and reducing intra-operative, and even post-operative, complications. However, complications do and will happen and the surgeon should be familiar on how to solve them.
Distal perforation or crossover can happen during tunneling and dilation and it is preferable to identify and correct it during dilation than after cylinder placement or post-operatively. This complication can be recognized when asymmetry is identified or a metal rubbing is felt between corporal dilators. The same holds true for proximal perforation. If the surgeon suspects urethral perforation and he/she is not comfortable with repairing, surgery can be terminated and prothesis implantation can be safely rescheduled 6 weeks after, although ensuing corpora fibrosis can add further difficulty and lead to additional penile length loss.
To correct a distal perforation distal perforation a subcoronal incision is performed and the distal tunica albuginea should be incised in order to search for the medial tunical defect. The defect can be closed with separate PDS stitches. The tunica albuginea incision is then closed using PDS. Alternatively tunneling and dilation can be performed again avoiding the false passage, and if successful, the cylinder can then be safely placed.
Proximal perforation is less dangerous as urethral injury is uncommon and can also be identified after the “field goal test”. Reparation can be performed either trough distal tip extensor anchoring to the proximal corpora carvernosa or input tubing fixation to the corporotomy in the case of two- or three-pice inflatable prothesis.
43.2.1.5 Post-operative Care
Patients can be safely discharged on the same or the next day. Urethral catheter and penoscrotal dressing can be safely removed in the next day and cylinders can be deflated in case of inflatable prothesis. Patients are instructed to wear tight underwear and preferably position the penis upward in order to mold capsule formation. Even though the efficacy of post-operative antibiotic therapy has not been demonstrated and remains controversial, the majority of implanters still prescribe antibiotics favoring quinolone, 1 week duration [32]. Patients are taught on how to operate the device 4–6 weeks after the surgery after edema and scarring resolution. Follow-up visits are schedule for 3, 6 and 12 months and thereafter yearly in order to assess complications, device functioning and patient satisfaction.
43.2.1.6 Post-operative Results
Although invasive and irreversible, implantation of a penile prothesis provides long-term cure of erectile dysfunction with the highest patient and partner-reported satisfaction rates. Results have improved in the last decades possibly as a result of improved peri-operative care, surgical technique as well as improvement of penile prothesis material, design and mechanics. Patient-reported satisfaction seems to steadily increase during the first 6 post-operative months as pain and edema subside and patients improve prothesis handling. High satisfaction results seem to be common to all main device manufactures [33, 34].
Factors of postoperative dissatisfaction have been studied and loss of penile length has been reported as the most common complain [27, 35]. Obesity and Peyronie’s disease are also known negative predictors [35], although probably part as a result of loss of penile length. Intra-operative strategies to preserve or increase penile length have been introduced in the last decade notably for patients with erectile dysfunction and Peyronie’s disease [36–41]. Manufactures have also developed models, like the AMS 700 LGX, which also feature length expansion to more closely mimic a natural erection [40].
43.2.1.7 Post-operative Complications
Infection
Penile prothesis infection is a serious complication which often requires prothesis explantation or at least a salvage attempt. Reports suggest that most infection were caused by caused by relatively innocuous skin bacteria which adhere to the prothesis at the time of implantation creating a biofilm around the prothesis that can not be completely eradicated with antibiotherapy. Strategies like antibiotic-coated prothesis, peri-operative prophylactic antibiotherapy as well as operative techniques such as the “no touch” approach have allowed a decrease in the infection rates to around 0.46–1.4% in the last couple decades [29, 42]. Although the introduction of antibiotic-coated prothesis, such as the InhibiZone coating from AMS, effectively prevented infection from relatively innocuous skin bacteria [43]. However, there has been a shift from late-appearing less virulent bacteria to earlier infection caused by more virulent bacteria such as Enterococcus faecalis and Pseudomonas aeruginosa [44, 45].
Recently a retrospective study has shown that although around two thirds and one third of penile prothesis infection are caused by gram-positive and gram-negative bacteria, respectively, there are still a significant number of infections caused by fungus, anaerobic bacteria and methicillin-resistant Staphylococcus aureus which are not usually covered by currently recommended peri-operative prophylactic antibiotherapy [45].
Infection presentation can vary in severity and timeline. It can range range from localized pain and swelling to erythema, abscess or tissue necrosis with systemic signs such as fever and elevated white blood cell count. Usually pain and edema are expected during the first two postoperative weeks and lack of improvement or aggravation of symptoms by the third week usually suggest infection. Infection can also manifest months and even years later. Imaging studies are usually unhelpful and the decision has to be made based only on clinical findings.
The surgeon should defer from prescribing antibiotherapy as when clinical signs present it is useless strategy as it can not eradicate biofilm already formed. Instead penile prothesis explantation or a salvage attempted are indicated at the time of infection diagnosis. Penile prothesis explantation implies the removal of all the device parts as well as all the non absorbable material used, such as sutures or grafts used for concomitant penile curvature correction. Usually after infection is treated and inflammatory reaction is resolved, a waiting period ensues if secondary penile prothesis implantation is desired. However, prothesis explanation often leads to severe fibrosis of the corpora cavernosa often complicating secondary implantation and causing loss of penile length that can lead to patient dissatisfaction. Also, secondary implantation is known for having a higher infection rates and less success rate even for experienced surgeons [46].
Salvage protocols, being Mulcahy one of the most known, consist of penile prothesis replacement after profuse wound cleansing with several antiseptic solutions [47, 48]. These procedures have been introduced nearly two decades ago in order to prevent loss of penile length and in properly select patients salvage can have success rates up to 84%. Replacement of a inflatable with a semi-rigid prothesis can also be an alternative as later the semi-rigid prothesis can be safely replaced with an inflatable in case of no reinfection. Even though there are no absolute criteria on who is eligible for early salvage it is commonly agreed that patients with an early detected non purulent infection are optimal candidates while a necrotic infection, infection with Enterococcus spp., uncontrolled diabetes mellitus or cylinder extrusion through the urethra salvage are contra-indications [49, 50].
Prevention is key and adherence to aforementioned strategies such as use of peri-operative intravenous antibiotics, antibiotic-coated or antibiotic irrigated prothesis and a clean surgical technique with adoption of “no touch” principals or similar can decrease post-operative infections.
Mechanical Failure
Related posts:
Changing Scenario of Urethral Stricture Management
Treatment of Male Stress Urinary Incontinence: An Overview
Reconstruction in Female-to-Male Gender Affirming Surgery
Complications of Gender-Affirming Surgery
Reconstruction of Panurethral Stricture Disease
Reconstruction of Pelvic Fracture Urethral Injury
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