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Novel concept to enable an old idea: a flexible electrode array to recover neurogenic erectile dysfunction

Sturny, M1; Skoufias, S2; Adamakis, I2; Fraga-Silva, R1; Papaioannou, TG3; Stergiopulos, N1; Constantinides, CA2

1: Ecole Polytechnique Fédérale De Lausanne, Institute of Bioengineering, Lausanne, Switzerland; 2: National and Kapodistrian University of Athens, Medical School, 1st Urology Dept., Laikon Hospital, Athens, Greece; 3: National and Kapodistrian University of Athens, Medical School, 1st Cardiology Dept., Biomedical Engineering Unit, Hippokration Hospital, Athens, Greece

Introduction: Scientific reports have shown that electrostimulation of the cavernosal nerve can induce and maintain penile erection in animals and humans. Since then, neurostimulation to activate erectile response has been considered as a marvelous solution for erectile dysfunction (ED), particularly for spinal cord injury and post-prostatectomy patients. However, despite the recognized potential, this technology has not been further developed. The barrier is the complex anatomy of human cavernous nerve, which challenge the intraoperative identification of the cavernosal nerves for electrodes placement. To overcome this major barrier, we envisioned a practical solution: a 2D flexible flat patch with multiple electrodes which can cover the entire plexus area, so that at least one of the electrodes will be in optimal contact with the cavernosal nerve, without the need of intraoperative identification. The aim of this study was to evaluate the present concept intraoperatively.

Material and Methods: Twenty-four (24) patients enrolled for open radical prostatectomy were recruited. During the surgical procedures, the multi-electrode patch was positioned on the pelvic-plexus (on the prostatic apex or pelvic wall) and electrical stimulation was applied to induce penile erection, while the erectile response was assessed by (i) visual change of penile tumescence and (ii) by continuous measurement of the penile circumference variation using a penile plethysmograph system (PPS). The IIEF-5 erectile function score and cardiovascular risk factors of each patient were evaluated pre-operatively.

Results: Remarkably, electrical stimulation produced immediate penile response in all cases (100%) when tested before (on prostatic apex) or after prostate removal (on pelvic wall). Clear visual penile engorgement was observed in 68%, whereas 32% showed a small penile tumescence. As expected, patients with IIEF-5 score higher than 22 presented enhanced response (73% visual engorgement, n = 15). Importantly, erectile response was potentiated by bilateral stimulation (circumference increase [mm]: 2.9 ± 1.5 vs. 9,1 ± 2.7, p = 0.04).

Conclusion: These results demonstrates that the multi-electrode array concept can guarantee the cavernosal nerve stimulation, without the need to locate it intraoperatively. Importantly, it brings sufficient proof of concept of a conceivable novel medical implant for the treatment of ED caused by mechanical nerve injury, such as prostatectomy and spinal cord injury.


Work supported by industry: no. The presenter or any of the authors act as a consultant, employee (part time or full time) or shareholder of an industry.

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