, Amr Abdel Raheem1, 3 and D. Ralph1
Department of Urology, University College Hospital, London, UK
Department of Andrology, University College London, London, UK
Department of Andrology, Cairo University, Cairo, Egypt
Erectile dysfunction (ED) is the inability to attain and/or maintain an erection sufficient for sexual intercourse. Fifty percent of men aged 40–70 years will be affected by ED. This may result in a significant deterioration in their quality of life and relationships. It is often associated with conditions affecting vascular circulation such as diabetes mellitus, hyperlipidaemia, smoking, obesity and hypertension. However, it may also be due to conditions affecting nerve innervation (pelvic surgery) or smooth muscle. Montorsi et al. provided the first significant evidence linking ED with cardiovascular disease . In their landmark paper, 50% with acute chest pain and proven coronary artery disease also reported ED. Subsequent studies have strengthened their findings and ED should now be considered to precede a cardiovascular event by 3–5 years [2–5]. The reduction of risk factors associated with vascular disease may improve erectile function . The second large group of men who will experience ED are those undergoing pelvic surgery; this group is increasing in numbers every year.
The treatment of ED consists of medical and surgical therapies. The medical treatment of ED was revolutionised in the 1990s with the development and marketing of Sildenafil which was the first phosphodiesterase-5 inhibitors (PDE5i) . This group of drugs has an estimated efficacy of 60% . Second line treatment includes intracavernosal or intraurethral alprostadil and vacuum devices. Men who fail or do not tolerate medical therapies should be offered the insertion of a penile prosthesis (PP) . Prostheses have undergone a variety of innovations since they were first described in 1936 . The 1973 hydraulic silicon prosthesis developed by Scott forms the basis of the modern day PP . The modern day PP has a satisfaction rate of over 80% with complication rates of less than 10% [9–16]. Penile prosthesis implantation results in a significantly higher satisfaction and sexual frequency when compared with Sildenafil, vacuum device and injection therapy .
Types of Penile Prosthesis
There are currently three types of penile prosthesis available which are manufactured by American Medical Systems (AMS) Boston Scientific and Coloplast. The prosthesis available may be classified as (Table 13.1):
2-Piece hydraulic inflatable
3-Piece hydraulic inflatable
Types of penile implant
• AMS spectra, coloplast genesis
• Easy to use and insert
• Need concealment by patient
• Pencil rigidity
2 piece inflatable
• AMS Ambicor
• Easy to insert
• Avoid entry into retroperitoneal space
• More natural appearing erection than malleable
• Patient needs to have good penile size
• Less rigidity compared to other types of implant
3 piece inflatable
• AMS LGX, 700, CXR, CX
• Coloplast Titan
• Three parts: cylinders, reservoir and pump
• Natural appearing erection
• All increase penile girth; LGX also increases penile length
• More complex surgery
• AMS implants are antibiotic coated
• Coloplast implants require soaking in antibiotics prior to insertion
There are two implants within this group: AMS spectra and Coloplast Genesis (Fig. 13.1). These implants are easy to use and insert surgically. They maintain a constant rigidity and therefore the patient must be taught how to manipulate their penis downwards to void. In addition they will need to be counselled about the need to wear concealing clothes as they will usually appear to have a partial rigidity. These implants have a lower satisfaction rate than the other types . This may be as a result of reduced spontaneous filling of the tissues around the implant over time with subsequent reduction in penile girth and a condition known as ‘pencil like erection’ .
A semi-rigid malleable implant
The AMS Spectra™ consists of a central polymer with metal segments and an outer surface of Gore-Tex covered with silicon . The Coloplast Genesis consists of silicon with a central metal core . A hydrophilic coating allows the implants to absorb antibiotic by soaking prior to insertion into the patient.
2-Piece Inflatable (IPP)
The AMS Ambicor (Fig. 13.2) consists of a pair of cylinder attached to the preconnected activation pump . The reservoir is pre-filled and is incorporated into the proximal end of the device. Activation of the pump moves fluid from the reservoir to the cylinders producing penile rigidity. The main advantage of this device is that as there is no intra-abdominal reservoir, it is useful in men who have had previous pelvic trauma, extensive lower abdominal surgery or a renal transplant. It combines the ease of insertion of a malleable prosthesis with the more natural erection observed with a 3-piece IPP. Deactivation of the device requires the downward manipulation of the penis. The disadvantage of this device is that the patient should ideally have a good sized penis as the available diameters are 12.5, 14 and 15.5 mm .
The AMS Ambicor device
3-Piece Inflatable (IPP)
These consist of a pair of cylinders attached to an activation/deactivation pump with a separate reservoir. These implants (Fig. 13.3) have the highest satisfaction rates and allow patients the most natural appearing and rigid erections. However, they are more prone to mechanical failure and infection as there are more components and the procedure is more technically challenging than the malleable implant and 2-piece IPP. AMS and Coloplast both produce a variety of devices in this group.
The 3 Piece Inflatable device
All AMS implants are impregnated with inhibizone (rifampicin and minocycline) to reduce the risk of infection. The cylinders are micro-coated with Parylene to improve durability . All the implants produce girth expansion however the LGX produces both girth and length expansion .
The Coloplast cylinders expand in girth and the implants need to be soaked in antibiotics prior to insertion. The coloplast implants are hydrophilic which aids antibiotic absorption.
Both companies have specific types of implants for men with narrow or fibrotic corpora .
This is vitally important and ideally should take place in a dedicated clinic. Patients’ and their partners’ expectations must be managed to ensure they are aware that the implant will only produce rigidity to enable penetrative sexual intercourse but will not increase penile length and should be considered irreversible. It is therefore important that all other options have been attempted and failed prior to proceeding to PP. The different types of PP are demonstrated and the patient is offered the opportunity to discuss the procedure with a patient who has already had a PP implanted. The session is also useful for the clinician as an opportunity to assess:
These factors will enable the clinician to individualise the type of implant chosen. Patients must be counselled about all the potential risks associated with the procedure.
All patients are reviewed pre-operatively in the Pre-assessment clinic where routine investigations are performed and in high risk patients, a review by a consultant anaesthetist is undertaken. Men with diabetes are optimised to reduce their risk of post-operative infections. In rare circumstances the procedure may be performed under a local anaesthetic (Table 13.2).
Indications for penile prosthesis
Failed medical treatment for ED
Inability or unwillingness to tolerate medical treatment for ED
Refractory non-ischaemic priapism
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