Corpus Cavernosum Electromyography Revisited: Defining the Origin of the Signal

A new diagnostic definition for patients with lower urinary tract symptoms evaluated by corpus cavernosum electromyography: 'Pelvic autonomic dysfunction'

This study investigates the use of corpus cavernosum electromyography (CC-EMG) recording as a diagnostic tool for identifying the presence of pelvic autonomic dysfunction (PAD) in patients with LUTS and concurrent ED. Fifty patients were included in the study, and the electromyographic and urodynamic findings were compared. The 50% relaxation degree was accepted as a threshold value for PAD. According to relaxation degree in CC-EMG recordings, patients were grouped as; Group 1 (with PAD) = 23 patients with a relaxation degree of less than 50%. Group 2 (without PAD) = 27 patients with a relaxation degree greater than 50%. The mean age of the patients was 58 ± 3.2 (50-71) years. The comparison of the urodynamic parameters and transrectal ultrasound revealed that the postvoiding residual urine volume (PVR) (p = 0.0007), P det Q_max (p = 0.0005), and P det compliance (0.003) values were statistically significantly lower in Group 2. The mean IIEF-5 and IIEF-15 scores of the patients in Group 1 were 2.5 ± 0.7 and 8.1 ± 1.1 respectively. In Group 2, mean IIEF-5 and IIEF-15 scores were 7.2 ± 2.9, and 17.2 ± 3.5 (p: 0.00023 and p: 0.0009). The mean I-PSS score was 22.8 ± 3 in Group 1 and 16 ± 2.3 in Group 2 (p = 0.001). The mean relaxation degree (RD) in Group I was 30.73 ± 6.8%, and in Group 2 was 66.3 ± 5.1%. The mean amplitude values of the patients in Group I were 261.41 ± 112.97 before papaverine injection, and in Group 2 were 246 ± 101.28 respectively. The inter-group difference was statistically significant (p < 0.05). The mean amplitude value of the patients in Group I after papaverine injection was 182.73 ± 60.71, and in Group 2, that value was 83.2 ± 29.19. The inter-group difference was also significant (p < 0.05). Increased electrical bursts and decreased relaxation responses on CC-EMG indirectly indicated an increase in the contractility of the bladder sphincter. Therefore, we concluded that CC-EMG could be a diagnostic tool for PAD and cavernous autonomic dysfunction.

Establishment of Novel Intraoperative Monitoring and Mapping Method for the Cavernous Nerve During Robot-assisted Radical Prostatectomy: Results of the Phase I/II, First-in-human, Feasibility Study

BACKGROUND

Potency preservation often does not meet expectation despite nerve-sparing prostatectomy.

OBJECTIVE

To set the protocol for intraoperative cavernous nerve monitoring and mapping during robot-assisted radical prostatectomy (RARP), and to evaluate its safety and clinical feasibility.

DESIGN, SETTING, AND PARTICIPANTS

A prospective phase I/II, feasibility study was performed. A total of 30 patients with prostate cancer who underwent RARP at a high-volume tertiary academic hospital were enrolled.

SURGICAL PROCEDURE

Pudendal somatosensory evoked potential, bulbocavernosus reflex, spontaneous corpus cavernosum electromyography (CC-EMG), median nerve stimulation evoked CC-EMG, and neurovascular bundle (NVB)-triggered CC-EMG with various stimulation protocols were assessed during conventional RARP under total intravenous anesthesia with controlled muscle relaxation.

MEASUREMENTS

The primary endpoint was the completion rate of planned surgery and assessment. Adverse events, and erectile and urinary functions were evaluated within 1 yr. CC-EMGs were graded and correlated with functional outcomes.

RESULTS AND LIMITATIONS

The completion rate was 100%. Only one patient experienced adverse events, which were not related to study intervention. Grades of CC-EMGs including NVB-triggered CC-EMG before prostate removal were associated with baseline five-item International Index of Erectile Function (IIEF-5) score (grades 0-1, 4.6±2.7; grade 2, 13.2±6.8; grades 3-4, 16.6±5.9; p=0.003). Furthermore, grades of CC-EMGs including NVB-triggered CC-EMG after prostate removal were significantly associated with potency recovery (grade 0, 12.5%; grade 1, 0%; grade 2, 33.3%; grades 3-4, 100% at 12 mo; p=0.005) and postoperative IIEF-5 scores at all evaluation time points (grades 0-1, 2.6±2.8; grade 2, 4.3±5.8; grades 3-4, 15.7±11.0 at 12 mo; p=0.003).

CONCLUSIONS

We successfully established the protocol for safe intraoperative cavernous nerve monitoring and mapping using CC-EMG during RARP. Its grades were well correlated with erectile function.

PATIENT SUMMARY

In this first-in-human feasibility study, we successfully established the protocol for safe intraoperative cavernous nerve monitoring and mapping method during robot-assisted radical prostatectomy. The results were significantly associated with erectile function. Evaluation of clinical efficacy to preserve potency seems worthy of further optimization and investigation in confirmatory clinical trials.

Measurement of electrochemical conductance of penile skin using Sudoscan®: A new tool to assess neurogenic impotence

OBJECTIVES

To investigate the value of electrochemical skin conductance (ESC) measurement at penile level using Sudoscan^® for the diagnosis of neurogenic impotence in diabetics.

METHODS

The following neurophysiological parameters were assessed in 25 male diabetics who complained of impotence and 25 age-matched normal male subjects without erectile dysfunction (age range: 29-70 years): ESC, sympathetic skin responses (SSR), warm detection thresholds (WDT), and cold detection thresholds (CDT) for the penis and the feet, vibration detection thresholds (VDT) for the penis, and sensory nerve conduction study of the dorsal nerve of the penis (DNP) with sensory nerve action potential (SNAP) recording.

RESULTS

Diabetic patients with impotence differed from controls with regard to most neurophysiological results at both penile and foot levels. Among penile innervation variables in the group of impotent diabetics, penile ESC was found to be the most frequently abnormal (80% of patients), followed by penile WDT, CDT, and DNP-SNAP amplitude (52% of patients), and then penile SSR amplitude and VDT (44% of patients). Various combinations of abnormalities were observed: penile ESC was the only abnormal test in 2 patients, while all tests were abnormal in 2 patients and remained normal in only one patient.

CONCLUSION

Erectile dysfunction is common in diabetic men, but the diagnosis of a neurogenic origin is challenging. This study showed that ESC measurement using Sudoscan^® is feasible and more sensitive than SSR recordings to show penile sympathetic innervation impairment. This new test should be further studied to better define its diagnostic accuracy and clinical correlates.