Electrical activity of the corpus cavernosum in denervated rats

Persistent erectile dysfunction following radical prostatectomy: the association between nerve-sparing status and the prevalence and chronology of venous leak

INTRODUCTION

. Failure to recover erectile function after radical prostatectomy (RP) may result from venous leak as a sequela of neuropraxia-induced erectile tissue damage. Venous leak portends a poor prognosis for erections recovery as well as phosphodiesterase type 5 inhibitor (PDE5i) response.

AIMS

To define the impact of RP nerve-sparing status on venous leak prevalence and chronology.

METHODS

STUDY POPULATION

men who underwent RP for localized prostate cancer, had functional erections prior to RP, developed postoperative erectile dysfunction (ED), had a Doppler ultrasonography within 6 months of RP, and did not receive any ED treatment for the first 6 months after RP other than on-demand PDE5i.

MAIN OUTCOME MEASURES

Venous leak prevalence and erectile function recovery at different time-points.

RESULTS

Data on 142 patients were analyzed, mean age: 58 +/- 16 years. Sixty percent had bilateral nerve-sparing (BNS) surgery, 20% unilateral nerve-sparing (UNS) surgery, and 20% non-nerve-sparing (NNS) surgery. Eleven percent and 21% had venous leak by 3 and 6 months, respectively. Venous leak prevalence by 6 months was 7%, 11%, and 75% for BNS, UNS, and NNS surgery (P < 0.001). Mean end-diastolic velocity was 1.8, 2.1, and 7.2 cm/second for the three groups (P < 0.01). The only patients developing venous leak prior to 3 months were NNS patients, one-third of NNS-associated venous leak occurring before this time-point. At 18 months, the proportion of men having return of unassisted erections was 49%, 42%, and 7% with mean erectile function domain scores of 21, 18, and 12, and PDE5i response rates were 72%, 64%, and 12% for the three groups, respectively.

CONCLUSIONS

Nerve-sparing status impacts heavily upon the prevalence and the chronology of venous leak development post-RP. NNS RP is associated with early development of venous leak, increased prevalence of venous leak, and reduction in return of natural erections.

The value of corpus cavernosum electromyography in erectile dysfunction: current status and future prospect

In the last decade, several investigators have tried to develop corpus cavernosum electromyography (CC-EMG) as a direct clinical method to evaluate the state of the penile autonomic innervation and the cavernous smooth muscle. Both basic and clinical studies have shown promising results. However, its application as a diagnostic tool with clinical relevance was hindered by insufficient knowledge of cavernous smooth muscle electrophysiology, lack of standardization, technical and practical difficulties and problems in the interpretation of the results. Recently, the European Commission created the so-called COST Action B18 (corpus cavernosum EMG in erectile dysfunction), aiming to strengthen the coordination of the European research groups and give the development of CC-EMG a new impetus. This review presents an overview of the physiological background, the current status of CC-EMG, and discusses possibilities for further developments.

The role of corpus cavernosum electromyography

Although corpus cavernosum electromyography presents great theoretical appeal as a possible direct clinical measure of penile neurogenic function, it has still not been adopted as a routine diagnostic test in the evaluation of patients with erectile dysfunction. This is because of the considerable technical and interpretative problems associated with the method. This review covers some of the more important research and clinical papers published since its first description in 1989, with a special focus on recent advances in this field.