Comparison of long-term outcomes of penile prostheses and intracavernosal injection therapy.

PURPOSE

Intracavernosal injection therapy is one of the most popular therapies for erectile dysfunction today. Yet, most clinicians consider intracavernosal injection a palliative treatment for erectile dysfunction because of the high patient initiated dropout rate. In contrast, penile prostheses appear to offer a more permanent cure for erectile dysfunction. We compare the long-term outcomes of both therapies in contemporaneously treated patients and determine the reasons for failure of each.

MATERIALS AND METHODS

Telephone survey and chart review was conducted on the first 115 patients treated with intracavernosal injection and 65 patients undergoing insertion of a penile prosthesis during the same period at our institution. Mean patient age was 57 and 60 years, respectively, and mean followup of all patients was 5.4 years (range of 3.3 to 16).

RESULTS

An equal percentage of patients were lost to followup in both groups, including 19% of the intracavernosal injection group and 18% of the penile prosthesis group. Of the intracavernosal injection patients 6 (6%) died during followup and 10 (19%) of the prosthetic patients died (p < 0.05). At the time of contact only 41% of the patients were still using intracavernosal injection. In contrast, 70% of the patients were still sexually active with the prosthesis (p < 0.01). Mean duration of use of the penile prosthetics was 63 months compared to 37 months for intracavernosal injection (p < 0.001). The most common reasons for discontinuing intracavernosal injection were inadequate erections (16 cases), lack of spontaneity (14), side effects (12), lack of partner (10), loss of sexual interest (6) and spontaneous return of normal erections (4). More than half of the patients (61%) who discontinued intracavernosal injection remain sexually active with other therapies, including penile prosthesis in 11, vacuum devices in 4, vascular surgery in 1 and oral medication in 1, and 14 without any therapy. We could not identify any significant clinical parameters that would accurately predict which patients most benefited by the long-term use of intracavernosal injection therapy. In contrast, only 6 patients discontinued use of the implant because of complications (infection, erosion and malfunction) and 7 for reasons independent of the implant (that is lack of partner, loss of sexual interest and co-morbidity).

CONCLUSIONS

Intracavernosal injection serves as only a palliative therapy for the majority of patients with erectile dysfunction but there exists a core group who derives long-term satisfaction with its use. The majority of patients who discontinue intracavernosal injection remain sexually active yet do not progress to more invasive or effective therapies. The reason for discontinuing therapies for erectile dysfunction is often unrelated to the actual therapeutic modality. Our findings suggest that further improvements in intracavernosal injection therapy and the development of alternative methods of delivery of vasoactive agents will have only a limited impact on the overall outcome of therapy for erectile dysfunction and that increased attention to issues separate from the erection is warranted.