Avoiding Complications in Penile Prosthesis Surgery

Santiago Richter, M.D.
Chairman, Israeli Society of Sexual Medicine
February 2009


Throughout history, many attempts to correct erectile dysfunction (ED) have been recorded. These have been either non invasive or invasive. Non invasive modalities include the administration of different medications such as hormones (Hormone replacement therapy) in those men with low Testosterone level, or PDE-5 inhibitors (PDE5i). Invasive therapy includes intracavernosal injection of vasoactive drugs and implant of a penile prosthesis (PP). Other means to treat ED such as oral yohimbine, vascular surgery, transurethral therapy or vacuum devices bear a rather low effectiveness, or are indicated for specific etiologies.

During the 1990s almost every treatment for all types of ED management was dominated by the appearance of PDE5i. Nevertheless, penile prosthesis remains one of the most effective.
The idea of implanting a PP goes back many years through the history of medicine. The first reported technique of a Penile Implant was published in 1936 [1]. The author described the creation of a pedicle skin graft supported by a costal cartilage in a young man after partial traumatic amputation of his penis. Scott et al. published the first experience with the use of an inflatable prosthesis for the management of erectile impotence [2].
There are different types of Penile Prosthesis manufactured mainly by two American companies, American Medical Systems® and Mentor Corporation®. Many other countries have developed their own type of PP, mainly due to economic reasons, for a lower cost of production. The currently available penile prostheses mostly used are described in Table 1.

Prosthesis Type
American Medical Systems*
Mentor Corporation#
Semirigid Rod
AMS Malleable 600
Acu-Form

AMS Malleable 650

Positionable
Dura II

Two-piece inflatable
AMS Ambicor

Three-piece inflatable
AMS 700 CX
Alpha I

AMS 700 CXM
Titan

AMS 700 CXR
Titan Narrow Base

AMS Ultrex


AMS 700 InhibiZoneTM

* American Medical Systems (AMS), Minnetonka, MN.
# Mentor Corporation, Santa Barbara, CA
Adapted from Campbell-Walsh Urology. Section VI – Reproductive and Sexual Function, Chapter 23:
Prosthetic Surgery for Erectile Dysfunction.

Semirigid devices have the advantage of very low mechanical failure rates and ease of use. On the other hand, disadvantages include constant penile rigidity and fixed length and girth. As compared with malleable prostheses, the positionable Dura II is better able to maintain its downward position for rest and upward position for intercourse. Inflatable PP may be two-piece or three-piece. They all have inflatable/deflatable cylinders implanted in the Corpus Cavernosum (CC), managed through a pump implanted in a scrotal pouch developed behind the testicles. The pump of the Ambicor AMS works as pump and partial reservoir. The three-piece PP has a separate pump that is implanted in the scrotum and a fluid reservoir that is usually implanted in the paravesical space. Inflatable devices provide penile girth expansion and rigidity similar to that of a normal erection. One device, the AMS 700 Ultrex, also provides length expansion. Once deflated, the cylinders collapse and the penis resembles a normal resting organ.
Patient-centered evaluation and selection
Before implanting a PP, the first step should be to evaluate the patient willingness to undergo the procedure and partner acceptability. The surgeon should refrain as much as possible from "recommending" a specific type of PP.  According to the Second International Consultation on Sexual Medicine (ICSM), the approach to the management of ED should be built on a patient-centered and evidence-based principle, rather than on a disease-centered approach [3]. The implanting surgeon will explain to the couple (not always achievable) the different solutions to treat his ED, the different types of PP, its advantages and disadvantages and finally, let the patient/couple decide what kind of implant to choose. The treating professional should examine the dexterity of the patient using his hands to depress a scrotal pump. A man suffering from Rheumatoid Arthritis will have no strength or flexibility in his fingers as to activate an inflatable PP, unless his partner is ready to do it for him.

In complex cases such as Peyronie's disease and ED, history of pelvic/perineal trauma, complicated endocrinopathy, complicated psychiatric disorder, complex relationship problems, and medicolegal concerns, a proper pre-operative evaluation is of extreme importance.
Prevention of complications
Although they present with a low incidence, the most feared complications after PP implant are infection and corporeal perforation. Other rare complications include device malfunction, due mainly to fluid loss in inflatable PP, poor glans support (SST deformity) and cylinders auto-inflation.
Peri-operative prevention of infection
The patient should arrive for surgery with no foci of infection, especially skin or urinary tract infection. On his way to the operating suite he will receive prophylactic antibacterial such as a combination of gentamicin in a dose of 1.0-1.5 mg per body weight and vancomycin 1.0 gr IV. The area from the umbilicus down to both groins and perineal area is carefully shaved. It is recommended to shave immediately before starting surgery in order to prevent small skin abrasions and penetration of bacteria. A ten minutes thorough skin disinfection is performed. I personally do not use povidone-iodine solutions as they can become intrinsically contaminated and cause outbreaks of infection and/or pseudoinfection [4]. I use Chlorhexidine gluconate 0.5%. Cloth drapes are permeable to bacteria when wet, thus paper drapes are preferable. If there are no paper drapes available, one can stick over the cloth drapes a 56 x 64 cm adhesive drape (3M Steridrape®) after cutting a hole in the middle, over the external genitalia.
Surgical approaches for PP implant include subcoronar (for malleable and positional PP only), transverse infrapubic and longitudinal penoscrotal, being the last one the most frequently used because it provides a wider surgical field, a better approach to the CC and a good urethral identification. Moreover, it is far from the penile dorsal nerve and vessels. A transverse penoscrotal incision has also been described, arguing that it facilitates a better approach to the proximal end of the CC. The various surgical techniques used have been well described in the medical literature [5].
Once incised, the surgical area should be flushed several times with a NaCl solution containing gentamicin 80 mg/lt. Penile prostheses come always in a dry (malleable) or fluid filled (inflatable) package. The package is open immediately before implanting and the device simmered in antibacterial solution, except the AMS 700 InhibiZoneTM, that should be kept dry and covered by a towel. This device underwent a special surface treatment combining rifampin and minocycline (InhibiZone). In a cohort of 2261 coated compared to 1944 non coated implants the incidence of infection was 0.68% and 1.61%, respectively [6]. Mentor introduced a hydrophilic surface coating with polyvinylpyrrolidone (PVP), for their three-piece inflatable prosthesis (Mentor Titan). This coating reduces bacterial adhesion and absorbs the antibiotics in which the prosthesis is submerged by the surgeon just before implantation, reducing the infection rate from 2.07% in the control group to 1.06% in the Mentor Titan group [7].
Bleeding should be carefully controlled in order to prevent hematoma that may get infected later on. The use of electrocoagulation of large areas is not recommended as it may develop necrotic tissue, another reason for infection. After placing all parts of the PP and closing the corporotomies, the superficial subcutaneous tissue is closed in two layers of interrupted absorbable suture. The need for wound drainage placement at the end of surgery is controversial. It has been reported that there is no clear evidence that using drains surgical wound significantly improves patient outcomes and drains may be associated with an increased length of hospital stay [8]. One should take into consideration that primary non complicated PP implant surgery is a "clean" procedure. Approaching the operated tissue with gentleness, achieving good hemostasis and using a mild compressing dressing makes the use of drainage unnecessary. This is at least, my personal opinion and experience. Antibacterial coverage should continue for a period of 7-10 days with oral cefalosporin. The first post operative check up is scheduled one week after surgery to remove the skin sutures. Do not use staples to close the skin; there is danger of stabbing part of the implant.
Prevention of corporeal perforation
Corporeal perforation may occur proximal or distal. The surgeon may, inadvertently, perforate the intercavernosal septum developing a "pass" between one corpus to the other. If he succeeds to find the way again, he may continue to implant. While dilating proximally, the surgeon should remember the anatomy of the CC. He should take into consideration that both CC separate laterally towards the crura in a kind of open semicircle. Using metal dilators in a careless way may perforate the CC at its bending. Never use force while dilating, if you got a "stop" remove the dilator and look for another entrance some millimeters away, not in the middle of the corporeal tissue but close to the tunica albuginea laterally, to avoid damage to the urethra. Even if you perforate the CC laterally or proximally, you may continue your surgery provided that you found your way at last, unless there is a perforation to the urethra in which case you may see some blood in the meatus. In this event, the prosthesis should be removed and a urethral catheter inserted. I personally never implant a PP without intubating the urethra first. When dilating distally, remember that the CC goes to the midglans only, do not try to force your way to the end. It is always better to dilate under the lateral part of the CC immediately under the tunica albuginea, far from the urethra. It has been reported that the most frequent perforations occur using thin dilators. One of the best ways to avoid perforation while dilating is the following: start with a number eight or nine dilator, if there is no fibrosis or tissue resistance, skip the lower numbers, you can "jump" every other number.



Penile prosthesis length and penile size
No man would accept to be implanted cylinders shorter than the maximal length of his penis. On the other hand trying to implant a too long device may end in corporeal perforation, penile deformity or at least serious discomfort. The surgeon must carefully measure the total length of the CC. He should feel the proximal end at the crura and the distal end in the midglans. In diabetics and in paraplegics one must be even more careful, as there is usually lower distal sensitivity and less blood supply. All cylinders are sized to a sequence of 0.5 cm in length, it is preferable to implant a half centimeter shorter device instead of forcing the maximal length of the CC. The AMS Ultrex cylinder has length expansion ranging from 1 to 4 cm (mean 1.9 cm); the surgeon should take this fact into consideration and deduct the two centimeters from CC length measurement.
Implanting a too short cylinder will develop the called "SST" deformation. The glans drops down due to a poor glans support. This problem can be corrected, but it will need further, unnecessary surgery.
Closing the Corpus Cavernosum
There are special instruments to protect the cylinder while closing the CC. Some of them are included in the PP kit. It is always advisable to use them but, if the surgeon applies stay stitches immediately after incising the tunica albuginea, even before dilating, he may use these stitches to close the CC at the end of the procedure. In any case it is most advisable to inflate the PP before closing the CC. You will check if the cylinder size is correct, if it fills the whole corpora and you will discover fluid leak if there has been an inadvertent stabbing. I always test the PP at least twice during surgery, once after implanting the cylinders, second time after implanting the whole device, before closing. Of course I test the PP a third time before taking the patient to recovery room.
Avoiding complications in pump implant
The best place to locate the pump of a three-piece PP is behind and between both testicles. A nice pouch should be developed but, be careful to go in the vaginal cavity and not thinning too much the scrotal wall. It will end in pump adhesion and danger of perforation or/and infection. After developing the pouch and introducing the pump, the surgeon should put some stitches above it to prevent upper migration of the pump towards the groin. You must be careful not to stab the pump, since you are working in a narrow, deep and dark surgical field. It is advisable to apply some stitches between the tubes emerging from the pump to the cylinders, to separate among them.
Avoiding complications in reservoir implant
The best place to locate the reservoir is the paravesical space. To that you develop a channel through the upper inguinal canal above the superior border of the superior ramus pubis. This is a blind procedure performed with the help of a sharp instrument (Metzenbaum scisors) and the surgeon must be careful not to perforate any viscera. Thus it is not advisable to use this technique in patients that underwent intraabdominal or especially intrapelvic sugery. In these cases it is better to use a second incision at the lower abdominal quadrant, make the way to the pre-rectus abdominis muscle space and pass the connecting tubes through the deep subcutaneous tissue. It is important to develop a good space for the reservoir to prevent autoinflation.
In summary, the implant of a Penile Prosthesis is an intelligent solution for the management of erectile dysfunction, with high surgical success and satisfaction rate for both the patient and his partner. Nevertheless it is very important to let the patient understand what exactly he is going to expect from the use of his PP. The surgeon should not recommend a specific type of device but should advise the patient not to choosing a PP that he will not be able to manage. The surgical procedure is delicate and the professional should do his best to avoid complications. Herein are described some practical hints and tips to prevent them. Some of these tips are not reported in the medical literature, they are the result of personal experience.

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