Intraoperative Assessment of an Implantable Electrode Array for Cavernous Nerve Stimulation

Introduction. Erectile dysfunction remains a major functional complication of radical prostatectomy in the modern era despite surgical techniques to preserve the penile autonomic nerve supply. Aim. To develop and evaluate a neurostimulation system for cavernous nerve electrical stimulation for future use as a chronic implantation device that neurotrophically promotes erectile function recovery following radical prostatectomy. Method. After radical retropubic prostatectomy, the neurovascular bundle was stimulated using a temporarily placed electrode array of an implantable neurostimulation system (20 Hz frequency, 260 mu seconds pulse width, 5 mA-60 mA amplitude up to 10 minutes), and penile circumference increases were measured. Main Outcome Measure. Increase in penile circumference. Results. Among 12 men (mean age 60.3 years) enrolled in this study, 6 (50%) demonstrated measurable increases in penile circumference in response to cavernous nerve stimulation. Among these six men, the mean increase was 5.0 mm (range 1.6 mm to 7.0 mm). Temporary surgical placement of the device was done with relative ease, and there was no evidence of injury to the neurovascular bundle. Conclusions. A chronic implantable nerve stimulation system for cavernous nerve stimulation having possible neuromodulatory effects on the recovery of penile erections after radical prostatectomy is feasible.