Penile prosthesis: functioning principle and indications

Penile prosthesis: a surgical management of erection troubles

There are many oral medication to treat erection troubles: pills, cream, intra-cavernous injections… It also exists non-oral therapies, such as vacuum devices. When all these therapies failed or if the patient is not happy with, surgical approach can be offered: a penile prosthesis surgical insertion.

It is a 3rd-line therapy, that is to say when 1st-line oral medications (ex: sildenafil) and 2nd-line (ex: intra-cavernous injection of alprostadil) failed or are not enough effective or can’t be offered to the patient (ex: heart disease)

Penile prosthesis : an irreversible procedure

A well-informed patient is the key-point of a penile prosthesis procedure. Indeed, this approach is irreversible:

As showed in previous pages, corpora cavernosum are the erectile part of the penis. Penile prothesis (malleable or inflatable) is placed directly inside the 2 corpora cavernosum, and consequently are irreversibly destructed. Erections will result from a mechanical effect and spontaneous erections won’t be possible, even if prosthesis is removed.

Which patients should be offered penile prosthesis insertion ?

Frequent indications are severe erection disorders associated with:

  • severe cardio-vascular disorders
  • neurolo-vascular diabetic complications
  • radical prostatectomy with erection rehabilitation and pro-erection treatments failure.

There is no strict age limit to offer a penile prosthesis insertion; patient must be fit for a surgical procedure and must be approved by anesthesiologists.

Different kind of penile prosthesis

There are two main type of penile prosthesis:

Malleable penile prosthesis (or half-rigid):

Silicon coated, a malleable penile implant is a surgical device that allows an impotent male to have an erection.  The malleable implant consists of two cylinders that are always hard but pliable.  All components are concealed within the body and cannot be seen from the outside.

The penile implant cylinders reside in the penis on either side of the penis.  No tissue is removed to place the cylinders; the cylinders simply occupy spaces that were previously filled with blood, when one was potent.  The cylinders do not disrupt the flow of urine or ejaculate.  The cylinders do not alter the sensation of the penis.  The cylinders also do not affect tumescence of the glans (i.e. head) of the penis.
malleable prothèse

Advantages:

  • Simple and quick procedure
  • Low infectious risks associated.
  • Easy to use

Disadvantage :

  • Always rigid, even after a sexual intercourse when penis is bended down
  • Aesthetic appearance: does not look realistic when flacid (half-hard)
  • Can disturb end-urologic procedure (ex: cystoscopy).

Intrinsic risks :

  • Prosthesis fracture after a traumatic event; implant must be changed
  • Chronic pain: rare, can be caused by wrong penile implant size or glans erosion
  • Phimosis : foreskin is too narrow when prosthesis is inserted, circumcision or foreskin-plasty may be necessary.

Inflatable penile prosthesis (2 pieces or 3 pieces)

The inflatable penile prosthesis consists of two cylinders — a reservoir and a pump — which are placed surgically in the body. The two cylinders are inserted in the penis and connected by tubing to a separate reservoir of fluid. The reservoir is implanted under the groin muscles. A pump is also connected to the system and sits under the loose skin of the scrotal sac, between the testicles.

To inflate the prosthesis, the man presses on the pump. The pump transfers fluid from the reservoir to the cylinders in the penis, inflating them. Pressing on a deflation valve at the base of the pump returns the fluid to the reservoir, deflating the penis

It exists 2 different types of inflatable devices:  2 or  3 pieces :

  • 2 pieces prosthesis: fluid is placed in the rear part of the cylinder; no reservoir is needed

2 pieces prothèse

  • 3 pieces prosthesis: fluid is placed a proper reservoir, placed in the abdomen.

3 pieces prothèse

Advantages :

  • Very realistic aesthetic appearance when flacid
  • Easy to use for a trained patient.

Disadvantages and intrinsic risks:

  • Sometimes hard to manipulate
  • Pump are sometimes visible in the scrotum.
  • Possible leaks or mechanical failure, an implant revision may be needed.
  • Implants lifetime are 10 to 15 years (depending on using frequency)

Patients information

The choice of type of penile prosthesis is made following:

  • patient past medical and surgical history
  • patient own choice (aesthetic…)
  • patient dexterity: arthrosis or obese patients may need a malleable device to easily use the prosthesis

Patient partner must also be informed about the implant and

Procedure generally last less than an hour, complications are moslty the same of every prosthesis insertion and surgical procedures.

Main complications:

  • Infections: post operative, from 6 to 7% for all patients, more prequzent in case of diabetes, pelvic radiotherapy, pelvic trauma with urethral injuries, chronic infections (urinary tract infection…In case of infection implant must be removed, antibiotics are used; a new device can be placed after several weeks after infectious episode; surgery is more difficult and failure-rate is more important
  • Haematoma: may require a surgical approach to remove it or just a follow-up
  • Mechanical failure: 60% of implants fail after 15 years and must be changed
  • Penile shortening: can be possible

Satisfaction rate is often high, up to 90%.

Post-operative care, management once at home :

Dressing and catheter are generally removed the day after the surgery, scars management can be done at home by trained nurses if patient condition is good enough.

Pain-killers are prescribed for a couple of days; patient must avoid sexual intercourse for 6 weeks.