Description

Men with erectile dysfunction (ED) refractory to medical therapies are often recommended to undergo placement of an inflatable penile prosthesis (IPP). However, men commonly report a perceived loss of penile length following IPP implantation. This is likely due to one of several factors, including the underlying disease process which resulted in loss of penile length, effects of aging on penile length (loss of elasticity; increased fibrosis), changes in abdominal physiology (development of pre-pubic fat pad that obscures the penis), and recall bias (incorrect recollection of prior penile length).

Several attempts have been made by investigators to optimize penile length prior to placement of the penile prosthesis, including adjunctive surgical maneuvers (excision of suprapubic fat pad, release of suspensory ligament, direct penile extension), use of injectable materials, and pre-operative use of penile traction therapy (PTT). In a small pilot study of 10 men undergoing IPP, Levine and colleagues recommended the use of the Andropenis PTT ≥2 hrs daily for 2-4 months. At 15 months follow-up, patients achieved a +1.6 cm increase compared to pre-traction stretched length, and +0.9 cm increase following prosthesis implantation. Results from a non-validated satisfaction questionnaire demonstrated that no patients reported loss of length following surgery. Unfortunately, the study did not include a control group, thus limiting the conclusions which may be drawn.

Compared to other options, PTT offers several potential advantages in that it is minimally invasive, does not increase the morbidity of surgery, and has not been shown to result in any long-term side effects. RestoreX is a commercially available PTT device that was developed by the Mayo clinic and has been licensed to PathRight Medical. It has been designated as a Class I device that does not require clinical human trials. The device is currently utilized in 30-minute intervals, with up to 3 sessions performed per day, and has demonstrated efficacy at increasing stretched penile length in patients with postprostatectomy penile shortening and diabetes mellitus.

Given the clinical issue of dissatisfaction with penile length post IPP, the potential role for PTT, and the limited amount of data that are currently available, we seek to perform a clinical trial evaluating the effect of PTT stretched penile length, size of prosthetic implantation at time of surgery, and patient satisfaction following implantation.

The device has two functional aspects. The first is the ability to provide direct traction on the penis. The second is the ability to provide counter-bending forces, to treat conditions such as Peyronie's disease. In the current study, only the direct traction aspects of the device will be investigated. Men randomized to treatment will be recommended to utilize the device for 30 minutes, 3 times daily for 3 months prior to placement of an IPP, with up to 1.3 additional months to account for variability in surgical timing.

To date, the efficacy of the RestoreX device has been studied in multiple clinical trials, the results of which are briefly outlined below:

• In a randomized, controlled clinical trial, 82 men who underwent prostatectomy for prostate cancer revealed an average increase in stretched penile length of 1.6 cm after 5 months of RestoreX use vs no change for controls (P=0.001). Adverse events were transient and mild, with 87% of men reporting a desire to repeat therapy and 93% of participants reporting that they would recommend it to others.
• In the open-label phase of the study, the benefits of therapy were found to be maintained even after therapy was discontinued.
• In a randomized, single-blind, controlled trial, 110 men with Peyronie's disease were assigned 3:1 to penile traction therapy for three months vs no therapy. At three months, penile traction therapy was associated with a 1.5 cm increase in penile length and 11.7 degree reduction in penile curvature relative to controls. Further, erectile function scores improved 4.3 points relative to a loss of 0.7 points in the control group. The therapy was well tolerated; adverse events were transient and mild.
• Preliminary data also suggest that the RestoreX device can increase penile length on men with diabetes who did not undergo surgery.

Very limited data are available on the efficacy of PTT in men undergoing placement of an IPP. As noted above, a small pilot study of 10 men undergoing IPP demonstrated a +1.6 cm increase in penile length compared to pre-traction stretched length and 0% of men reporting loss of length following surgery.