Bulbocavernosus reflex testing: a preliminary study on the prognostic factors for potency and response to sildenafil citrate after bilateral nerve-sparing radical prostatectomy

Erectile dysfunction (ED) following radical prostatectomy is of major concern for both patients and caring physicians. We evaluated the bulbocavernosus reflex latency (BCRL) and amplitude (BCRA) following bilateral nerve-sparing radical retropubic prostatectomy (NS-RRP) to predict the response to sildenafil citrate (SC). Patients were recruited in our ED clinic following NS-RRP. Exclusion criteria included preoperative significant ED, neurological disease, and nitrates treatment. Patients were defined as non-responders only after four consecutive unsuccessful trials of 100 mg SC. Twenty patients at least 3 months after surgery were included in this study. Five patients (25%) regained spontaneous erections, although insufficient for vaginal penetration. All of them had normal BCRL and normal BCRA as well as good response to 100 mg SC. Three patients (15%) lacked spontaneous erections and had prolonged BCRL with normal BCRA. This subgroup eventually regained erections using SC. Twelve patients (60%) lacked spontaneous erections and had prolonged BCRL and low BCRA. They failed SC trials and achieved erections using intra-cavernosal injections (ICI) of 10 mu g PGE(1). Neurophysiologic evaluation consisting of BCRL and BCRA was found to be useful in the prediction of the response to SC following bilateral NS-RRP. Patients who do not regain an erection, and have abnormal BCRL and BCRA 6 months after surgery, will probably be SC non-responders and may benefit from ICI. A subset of patients with preserved BCRA and prolonged latencies has been shown to have a better chance to respond to SC.