Successful Management of Post Prostatectomy Erectile Dysfunction with the Use of a Novel Penile Constriction Ring (MaxErect®)

ABSTRACT. The effect of a novel penile constriction ring on erectile dysfunction in a cohort of post-radical prostatectomy patients was measured utilizing the International Index of Erectile Function (IIEF) before and after the constriction ring was introduced. This group consisted of patients who had failed on a variety of commonly used interventions including most of the pharmacopeia for erectile dysfunction. The ring itself is engineered to maintain a relatively constant resistance across a wide circumference range representing a "constant resistance ring" (CRR) thereby averting the property of current penile constriction rings to tighten exponentially as erection occurs. CONCLUSION: A penile constriction ring with stable resistance across a broad range of circumferences shows promise as a significant improvement in current technology as a safe and inexpensive intervention in conjunction with known pharmaceutical interventions in this difficult group of patients with er ectile dysfunction. Application in other groups of this technology requires additional study, but indications are that this might allow reduction in use and dosage of drugs used for erectile dysfunction. This would confer benefits for function, safety, and costs.
INTRODUCTION. Prostate cancer is the most common cancer among men.1 The highest incidence (27.3%) occurs between the ages of 55 and 64 years of age.2 Radical prostatectomy (RP) has long been established as the standard of care for early stage disease. Improvements in surgical technique, most notably nerve sparing radical prostatectomy (NSRP), have improved the rate of complications. However, the most common complications continue to be erectile dysfunction (ED) and urinary incontinence.3 Considering that age and a previous history of erectile dysfunction are major factors in post operative recovery,4 it is not surprising that the overall 5 year rate of return to normal erectile function is still estimated to b e ~ 28% with 55% of these patients suffering from complete erectile dysfunction.5 Veno-occlusive disease/syndrome is a common consequence of post-radical prostatectomy with an incidence between 45 and 80%.6,7 Patients who undergo NSRP suffer from ED due to physiologic injury of the cavernous nerves resulting in a period of neuropraxia.2 Fabrizio et al, demonstrated that progressive fibrosis in the corpora cavernosa after radical prostatectomy resulted in a loss of elasticity and function of the erectile tissue.8 The progression of cavernosal fibrosis is believed to negatively impact the veno-occlusive mechanism for erection. Treatment for the recovery of erectile function following RP, commonly referred to as penile rehabilitation, is implemented to help prevent or decrease the amount of corporal fibrosis and aid in the recovery of satisfactory erectile function.
Increasingly, concern for the risk of failure to achieve satisfactory erectile function after prostate surg ery may compel many men to consider postponing potentially curative surgery. This concern has led to the exploration of newer treatments that would better ensure the preservation of post-operative erectile function. Today, many institutions utilize currently available therapies such as phosphodiesterase 5 inhibitors (PDE5i), intraurethral suppositories, intracavernosal injections, or vacuum erection devices (VEDs) in various fashions to facilitate increased arterial perfusion to the cavernosal tissue. Failure to successfully help NSRP patients return to baseline function often results in the surgical placement of an internal penile pump (IPP). VEDs have been utilized for nearly four decades and have proven to be a safe and effective method of treating erectile dysfunction of various etiologies.10 Use of VEDs with a constriction band has expanded due to improvements in both the design of the devices themselves and the constriction bands. Furthermore, usage of VEDs following r adical prostatectomy has been reported to aid in the rehabilitation of penile tissue. Raina, et al., reported their experience with early use of VEDs following radical prostatectomy. Their study showed a significant improvement in response to therapy and restoration of erectile function following early usage of VEDs.11 Koehler et al have shown that VEDs are suitable and successful at "reconditioning" erectile function in patients undergoing post radical prostatectomy who have erectile dysfunction, particularly if their use is begun early in the post operative period.9
These devices by necessity utilize penile constriction rings that invariably are unforgiving and which are likely responsible for the attrition most practitioners experience with respect to their long term use. Very little has been published to document the sustainability of using VEDs despite their successful application early in the post operative period. Even if patients can withstand the discomfort as sociated with these rings, many may not achieve satisfactory sexual function as a result of the discomfort associated with the constriction ring itself -- oftentimes regardless of the level of erectile function achieved. However, reasons for discontinuation of therapy remained historically consistent in that many patients complain of penile bruising or discomfort with the use of constriction bands. Despite the efforts of clinicians to provide early penile rehabilitation, many patients will have persistent veno-occlusive disease following RP. Although VEDs invariably employ some form of penile venous constriction (PVC) in order to override "venous leak", very little data is available that objectively characterizes their safety or efficacy. It has been the impression of these clinicians that the penile constriction rings themselves more often create enough discomfort and impairment such that they discourage the use of the VED itself. We report here on the use of a uniquely engineered penile constriction ring utilizing the principle of constant circumferential resistance (Figure 1) or "constant resistance ring" (CRR). This represents a potentially significant advancement in achieving the goal of restored function in the subset of patients with variable levels of post radical prostatectomy erectile dysfunction (PRPED).
METHODOLOGY. Forty-six men who had undergone a bi lateral or unilateral nerve sparing radical retropubic prostatectomy (BNSRRP or UNSRRP) were randomly selected from the patient population at Metro Urology in St. Paul, MN. All forty-six men were being treated for PRPED, but were having a suboptimal response from their treatments. Treatment failures included oral PDE5 inhibitors, intra-urethral Alprostadil, commonly used injectable erectogenic agents, VEDs with a standard supplied constriction ring, or combination therapy. Each man was asked to fill out the International Index of Erectile Function (IIEF) Questionnaire, a validated, multi dimensional scale for measuring erectile function. The men filled out the questionnaire routinely throughout their treatment for PRPED thus providing the most current level of erectile function prior to the addition of the CRR (MaxErect, Doctors Naturals Corp.*). Please note that Question 9 of the IIEF evaluating ejaculation was omitted as not being relevant to the test. Each patient was the n evaluated and given a CRR of the correct size and firmness with instructions for proper usage to be utilized in combination with their current therapy. The patients were then seen for follow-up after three months and asked to answer the same IIEF questionnaire.
RESULTS. Cumulative scores of the IIEF were gathered but statistical analysis was performed by examining the cumulative scores of the abridged 5 version of the International Index of Erectile Function (IIEF-5). Baseline IIEF-5 scores were compared to IIEF-5 scores following the addition of the CRR. The mean baseline score for the erectile function (EF) domain was (3.62) prior to the addition of the CRR ring. The mean IIEF EF domain score following the addition of the CRR was (20.81). p<0.001. In every case, the use of the CRR dramatically improved the sexual function of each patient. None of the subject patients reported any discomfort over the test period and none exhibited any palpable tissue damage.
DISCUSSION. Penile constriction rings have been used for many years both as "sexual enhancement" devices and as adjunctive treatment for the newer VEDs. In fact, it is generally acknowledged that without the use of such constriction rings, most of the modern VEDs would work poorly. Consequently, fewer than 44% of patients choose to use these devices under these circumstances.12 Constriction rings have generally involved the use of materials that become exponentially tighter as the penis fills. This results in the common complaint of discomfort or ejaculatory impairment. Although there are no formal studies done on the efficacy or long term use of penile constriction rings, it is felt that in many cases they might cause significant tissue damage as a result of these qualities. Additionally these complaints are often a cause of VED discontinuation or underutilization. This is unfortunate as these approaches to PRPED and ED of other etiologies might otherwise reduce the need f or PDE5 inhibitors or at least reduce dosing strength and attendant side effects and risk. The CRR used in this preliminary study on patients with PRPED employs a material that confers near-constant resistance across a broad range of circumferences thereby eliminating the "exponential tightness" problem. This is one of the major factors differentiating this device from other constriction rings; the material is engineered to provide constant durometric (circumferential) tension throughout the first 400-500% expansion of the ring's circumference. This provides pressure sufficient enough to occlude the veins of the penis and restrict blood flow out of the organ without impairing arterial supply and tissue oxygenation, as well as minimizing trauma to nerves. Although more controlled clinical research trials are needed involving the use of this intervention, it would appear that the relative efficacy of a CRR as a management tool for penile vein constriction and venous leak using its unique material compares very favorably with other, more invasive and expensive interventions for veno-occlusive ED.
CONCLUSION. A constant-resistance penile constriction ring, such as used in the context of veno-occlusive PRPED, appears to offer significant advantages when combined with commonly utilized drug interventions in patients having a suboptimal response to therapy. Furthermore, this intervention may offer unique advantages in efficacy, cost, and safety for the treatment of veno-occlusive erectile dysfunction following radical prostatectomy. The CRR may represent a significant advance in the management of veno-occlusive erectile dysfunction following radical prostatectomy. Given the widespread usage of penile venous constriction rings, further research exploiting the additional feature of constant resistance in the treatment of veno-occlusive erectile dysfunction and other forms of ED is warranted.
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