Coital Urinary Incontinence Induced by Impairment of the Dorsal Nerve of the Clitoris in Rats

Animal models, treatment options, and biomaterials for female stress urinary incontinence

In the quest to tackle stress urinary incontinence (SUI), the synthesis of cutting-edge biomaterials and regenerative materials has emerged as a promising frontier. Briefly, animal models like vaginal distension and bilateral ovariectomy serve as crucial platforms for unraveling the intricacies of SUI, facilitating the evaluation of innovative treatments. The spotlight, however, shines on the development and application of novel biomaterials-ranging from urethral bulking agents to nano-gel composites-which aim to bolster urethral support and foster tissue regeneration. Furthermore, the exploration of stem cell therapies, particularly those derived from adipose tissues and urine, heralds a new era of regenerative medicine, offering potential for significant improvements in urinary function. This review encapsulates the progress in biomaterials and regenerative strategies, highlighting their pivotal role in advancing the treatment of SUI, thereby opening new avenues for effective and minimally invasive solutions.

Does Sexual Intercourse Position Have a Role in Occurrence of Coital Urinary Incontinence?

INTRODUCTION AND HYPOTHESIS

This study was aimed at investigating the hypothesis that sexual intercourse positions may have an impact on the occurrence of coital urinary incontinence (CUI) in women.

METHODS

This case-control observational study enrolled 360 married, heterosexual, sexually active female participants with CUI. Each patient was evaluated using medical and sexual histories, questionnaires, physical examinations, and laboratory tests, including urodynamics. Participants were asked whether or not their intercourse positions had an impact on the occurrence of their CUI. Patients with intercourse position-dependent CUI were included in group 1, and those independent of it were allocated to group 2. The clinic and laboratory findings of the patient groups were compared.

RESULTS

The patients' mean age was 47.24 ± 0.57 years. Of these women, 28.9% (n = 104) were in group 1, and 71.1% (n = 256) were in group 2. Group 1 had a lower mean age, body mass index, Charlson comorbidity index, number of urinary incontinence episodes, severity of CUI and incontinence, and pad weight than group 2 (p < 0.05). The rates of detrusor overactivity and penetration type of CUI were higher in group 1 than in group 2 (p < 0.0009, p = 0.009 respectively). According to logistic regression analysis, the likelihood of sexual position-related CUI was 3.5 times higher in women with detrusor overactivity.

CONCLUSIONS

In certain patients, intercourse position is associated with the occurrence of CUI. This condition seems to be related to detrusor overactivity and is inversely associated with incontinence severity. However, further studies are necessary to explain this phenomenon.

Time course for urethral neuromuscular reestablishment and its facilitated recovery by transcutaneous neuromodulation after simulated birth trauma in rats

The aims of the study were to determine the time-course of urinary incontinence recovery after vaginal distension (VD), elucidate the mechanisms of injury from VD leading to external urethral sphincter (EUS) dysfunction, and assess if transcutaneous electrical stimulation (TENS) of the dorsal nerve of the clitoris facilitates recovery of urinary continence after VD. Rats underwent 4-h VD, 4-h sham VD (SH-VD), VD plus 1-h DNC TENS, and VD plus 1-h sham TENS (SH-TENS). TENS or SH-TENS were applied immediately and at days 2 and 4 post-VD. Micturition behavior, urethral histochemistry and histology, EUS and nerve electrophysiology, and cystometrograms were evaluated. VD induced urine leakage and significantly disrupted EUS fibers and nerve-conduction (VD vs SH-VD group;p < 0.01). Urine leakage disappeared 13 days post-VD (p < 0.001). Structural and functional recovery of EUS neuromuscular circuitry started by day 6 post-VD, but did not fully recover by day 11 post-VD (p > 0.05). TENS significantly decreased the frequency of urine leakage post-VD (days 5–7;p < 0.01). We conclude that rat urinary continence after VD requires 2 weeks to recover, although urethra structure is not fully recovered. TENS facilitated urinary continence recovery after VD. Additional studies are necessary to assess if TENS could be used in postpartum women.

[Coital incontinence]

INTRODUCTION

Urinary incontinence may seriously impact quality of life, self-image and subsequently the sexual life. Beside this fact, urinary leakage can specifically occur during sexual intercourse, formally named coital incontinence, and thus lead to specific alteration of the sexual life.

AIM

To analyse the prevalence, pathophysiological mechanisms and possible therapeutic options for coital urinary incontinence.

METHODS

Related terms to urinary incontinence and sexual dysfunction were search on PubMed database.

RESULTS

Whereas at least a quarter of incontinent women have a coital incontinence, this symptom was rarely spontaneously reported. Some women had only coital incontinence (7.6 to 20% of cases). In men, urinary incontinence during sexual intercourse was mainly observed after prostatectomy in 20 to 64% of cases. Coital incontinence requires precise assessment. Indeed, it can occur whatever the phase of coitus: local stimulation (20-30%), excitement (13-18%), penetration (62.9-68%), movements back and forth, orgasm (27-37.1%). Cervico-urethral hypermobility, sphincter incompetence, urethral instability, detrusor overactivity could be the principal physiopathological mechanisms. In men, the main cause was a stress incontinence secondary to sphincter deficiency. Specific therapeutic strategies have proved their effectiveness. The rehabilitative approach (RR=0.25, CI [0.06-1.01]), medicinal (anticholinergic were effective in 59% of cases) or surgical therapeutic (slings with an efficiency of 87%) was proposed to patients.

CONCLUSION

Coital incontinence is a common and troublesome symptom. Its precise assessment may suggest a specific mechanism and thus a specific treatment.

Anatomical organization and somatic axonal components of the lumbosacral nerves in female rabbits

AIM

To determine the anatomical organization and somatic axonal components of the lumbosacral nerves in female rabbits.

METHODS

Chinchilla adult anesthetized female rabbits were used. Anatomical, electrophysiological, and histological studies were performed.

RESULTS

L7, S1, and some fibers from S2 and S3 form the lumbosacral trunk, which gives origin to the sciatic nerve and innervation to the gluteal region. From S2 to S3 originates the pudendal nerve, whose branches innervates the striated anal and urethra sphincters, as well as the bulbospongiosus, ischiocavernosus, and constrictor vulvae muscles. The sensory field of the pudendal nerve is ∼1800 mm² and is localized in the clitoral sheath and perineal and perigenital skin. The organization of the pudendal nerve varies between individuals, three patterns were identified, and one of them was present in 50% of the animals. From S3 emerge the pelvic nerve, which anastomoses to form a plexus localized between the vagina and the rectum. The innervation of the pelvic floor originates from S3 to S4 fibers.

CONCLUSIONS

Most of the sacral spinal nerves of rabbit are mixed, carrying sensory, and motor information. Sacral nerves innervate the hind limbs, pelvic viscera, clitoris, perineal muscles, inguinal and anal glands and perineal, perigenital, and rump skin. The detailed description of the sacral nerves organization, topography, and axonal components further the knowledge of the innervation in pelvic and perinal structures of the female rabbit. This information will be useful in future studies about the physiology and physiopathology of urinary, fecal, reproductive, and sexual functions.

Neuroanatomic and behavioral correlates of urinary dysfunction induced by vaginal distension in rats

The aim of the present study was to use a model of simulated human childbirth in rats to determine the damage to genitourinary structures and behavioral signs of urinary dysfunction induced by vaginal distension (VD) in female rats. In experiment 1, the length of the genitourinary tract and the nerves associated with it were measured immediately after simulated human delivery induced by VD or sham (SH) procedures. Electroneurograms of the dorsal nerve of the clitoris (DNC) were also recorded. In experiment 2, histological characteristics of the bladder and major pelvic ganglion of VD and SH rats were evaluated. In experiment 3, urinary parameters were determined in conscious animals during 6 h of dark and 6 h of light before and 3 days after VD or SH procedures. VD significantly increased distal vagina width (P < 0.001) and the length of the motor branch of the sacral plexus (P < 0.05), DNC (P < 0.05), and vesical nerves (P < 0.01) and decreased DNC frequency and amplitude of firing. VD occluded the pelvic urethra, inducing urinary retention, hematomas in the bladder, and thinness of the epithelial (P < 0.05) and detrusor (P < 0.01) layers of the bladder. Major pelvic ganglion parameters were not modified after VD. Rats dripped urine in unusual places to void, without the stereotyped behavior of micturition after VD. The neuroanatomic injuries after VD occur alongside behavioral signs of urinary incontinence as determined by a new behavioral tool for assessing micturition in conscious animals.