Usefulness of electromyography of the cavernous corpora (CC EMG) in the diagnosis of arterial erectile dysfunction.

Electromyography (EMG) of the corpora cavernosa (CC-EMG) is able to record the activity of the erectile tissue during erection, and thus has been used as a diagnostic technique in patients with erectile dysfunction (ED). The present study examines the usefulness of the technique in the diagnosis of arterial ED. A cross-sectional study was made of 35 males with a mean age of 48.5 years (s.d. 11.34), referred to our center with ED for >1 year. The patients were subjected to CC-EMG and a penile Doppler ultrasound study following the injection of 20 μg of prostaglandin E1 (PGE1). The patients were divided into three groups according to their response to the intracavernous injection of PGE1: Group 1 (adequate erection and reduction/suppression of EMG activity); Group 2 (insufficient erection and persistence of EMG activity); and Group 3 (insufficient erection and reduction/suppression of EMG activity). Patient classification according to response to the intracavernous injection of PGE1 was as follows: Group 1: six patients (17%), Group 2: 18 patients (51%), and Group 3: 11 patients (31%). Patients diagnosed with arterial insufficiency according to Doppler ultrasound (systolic arterial peak velocity <30 mm s(-1) in both arteries) were significantly older than those without such damage (54.5 versus 41.8 years, respectively; s.d. 11.12). The patients in Group 3 showed a significantly lower maximum systolic velocity in both arteries than the subjects belonging to Group 2. Likewise, a statistically significant relationship was observed between the diagnosis of arterial insufficiency and patient classification in Group 3. The confirmation of insufficient erection associated with reduction/suppression of EMG activity showed a sensitivity of 66.7% (confidence interval between 50 and 84%) and a specificity of 92.9% (confidence interval between 84 and 100%) in the diagnosis of arterial ED. Owing to the high specificity of CC-EMG response to the injection of PGE1, this test is considered useful as a screening technique in the diagnosis of arterial ED.