Provoked vestibulodynia: Inflammatory, neuropathic or dysfunctional pain? A neurobiological perspective

Innervation of the human vulvar vestibule: A comprehensive review

Pain of the vulvar vestibule, including provoked vestibulodynia, is prevalent among women, yet challenging to treat due to its multifactorial etiology. Recent evidence indicates a neuroproliferative subtype in which hypersensitivity of the vulvar vestibule is due, in part, to hyperinnervation. Detailed knowledge regarding the innervation of the vulvar vestibule is crucial to understanding and treating pain conditions impacting this region. The purpose of this review is to consolidate the current evidence regarding the innervation of the human vulvar vestibule and discuss the implications of this innervation for pathological conditions affecting this tissue. A comprehensive review of the literature was conducted using keywords including vulvar vestibule, innervation, and vestibulodynia to identify articles concerning the innervation of the vulvar vestibule. Fifteen studies published between 1998 and 2017 were reviewed. Evidence from immunohistochemical investigations support that the vulvar vestibule has nociceptive, mechanosensory, sympathetic, and parasympathetic innervation. In pathological samples, hyperinnervation supports the neuroproliferative etiology of provoked vestibulodynia. Additionally, there is some evidence supporting the role of the pudendal nerve in vulvar vestibule innervation, although no cadaveric studies have been reported to date. Progress has been made in our understanding of the innervation of the vulvar vestibule, though further research into the origin of sensory and autonomic innervation of this region is needed. Advancing the knowledge of vulvar vestibule innervation is crucial towards improving our understanding of the function of this tissue, in addition to informing the etiology and management of pain syndromes impacting this region.

Vulvodynia-It Is Time to Accept a New Understanding from a Neurobiological Perspective

Vulvodynia is one the most common causes of pain during sexual intercourse in premenopausal women. The burden of vulvodynia in a woman's life can be devastating due to its consequences in the couple's sexuality and intimacy, in activities of daily living, and psychological well-being. In recent decades, there has been considerable progress in the understanding of vulvar pain. The most significant change has been the differentiation of vulvar pain secondary to pathology or disease from vulvodynia. However, although it is currently proposed that vulvodynia should be considered as a primary chronic pain condition and, therefore, without an obvious identifiable cause, it is still believed that different inflammatory, genetic, hormonal, muscular factors, etc. may be involved in its development. Advances in pain neuroscience and the central sensitization paradigm have led to a new approach to vulvodynia from a neurobiological perspective. It is proposed that vulvodynia should be understood as complex pain without relevant nociception. Different clinical identifiers of vulvodynia are presented from a neurobiological and psychosocial perspective. In this case, strategies to modulate altered central pain processing is necessary, changing the patient's erroneous cognitions about their pain, and also reducing fear avoidance-behaviors and the disability of the patient.

Methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a systematic review

ABSTRACT

Mechanism-based classification of pain has been advocated widely to aid tailoring of interventions for individuals experiencing persistent musculoskeletal pain. Three pain mechanism categories (PMCs) are defined by the International Association for the Study of Pain: nociceptive, neuropathic, and nociplastic pain. Discrimination between them remains challenging. This study aimed to build on a framework developed to converge the diverse literature of PMCs to systematically review methods purported to discriminate between them; synthesise and thematically analyse these methods to identify the convergence and divergence of opinion; and report validation, psychometric properties, and strengths/weaknesses of these methods. The search strategy identified articles discussing methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system. Studies that assessed the validity of methods to discriminate between categories were assessed for quality. Extraction and thematic analysis were undertaken on 184 articles. Data synthesis identified 200 methods in 5 themes: clinical examination, quantitative sensory testing, imaging, diagnostic and laboratory testing, and pain-type questionnaires. Few methods have been validated for discrimination between PMCs. There was general convergence but some disagreement regarding findings that discriminate between PMCs. A combination of features and methods, rather than a single method, was generally recommended to discriminate between PMCs. Two major limitations were identified: an overlap of findings of methods between categories due to mixed presentations and many methods considered discrimination between 2 PMCs but not others. The results of this review provide a foundation to refine methods to differentiate mechanisms for musculoskeletal pain.

Efficiency and Cost: E-Recruitment Is a Promising Method in Gynecological Trials

BACKGROUND

Recruitment of participants is crucial to the success of any trial as it can have a major impact on study costs, the duration of the study itself, and, more critically, trial failure. Given that vulvodynia particularly affects young women, the use of social media and e-recruitment could prove efficient for enrollment.

AIM

To compare the efficiency, effectiveness, and cost-effectiveness of three different recruitment methods.

METHODS

The comparison data were collected as part of a bicentric randomized controlled trial evaluating the efficacy of physiotherapy in comparison with topical lidocaine in 212 women suffering from provoked vestibulodynia. The recruitment methods included: (i) conventional methods (eg, posters, leaflets, business cards, newspaper ads); (ii) health professional referrals, and (iii) e-recruitment (eg, Facebook ads and web initiatives). Women interested in participating were screened by telephone for eligibility criteria and were assessed by a gynecologist to confirm their diagnosis. Once included, structured interviews were undertaken to describe their baseline characteristics.

MAIN OUTCOME MEASURES

The outcomes of this study were the recruitment efficiency (the number of patients screened/enrolled), recruitment effectiveness (the number of participants enrolled), cost-effectiveness (cost per enrolled participant), and retention rate, and baseline characteristics of participants were monitored for each method.

RESULTS

The conventional methods (n = 101, 48%) were more effective as they allowed for greater enrollment of participants, followed by e-recruitment (n = 60, 28%) and health professional referrals (n = 33, 16%) (P < 0.007). Recruitment efficiency was found to be similar for e-recruitment and referrals (60/122 and 33/67, 49%, P = 0.055) but lower for conventional methods (101/314, 32%, P < 0.011). Nonsignificant differences were found between the three groups for baseline characteristics (P ≥ 0.189) and retention rate (91%, P ≥ 0.588). The average cost per enrolled participant was fairly similar for e-recruitment ($117) and conventional methods ($110) and lower for referrals ($60).

CLINICAL IMPLICATIONS

Our results suggest that having a variety of recruitment methods is beneficial in promoting clinical trial recruitment without affecting participant characteristics and retention rates.

STRENGTH & LIMITATIONS

Although recruitment methods were used concomitantly, this study gives an excellent insight into the advantages and limitations of recruitment methods owing to a large sample size.

CONCLUSION

The study findings revealed that e-recruitment is a valuable recruitment method because of its comparable efficiency and cost-effectiveness to health professional referrals and conventional methods, respectively.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, number NCT01455350. Benoit-Piau J, Dumoulin C, Carroll MS, et al. Efficiency and Cost: E-Recruitment Is a Promising Method in Gynecological Trials. J Sex Med 2020;17:1304-1311.

Recovering from provoked vestibulodynia: Experiences from encounters with somatocognitive therapy

Although provoked vestibulodynia (PVD) represents a significant challenge for many young women in the Western world, little is known about how these women experience therapeutic efforts. The aim of this paper is to enhance our knowledge of the way that the therapeutic process is experienced by women with PVD undergoing somatocognitive therapy (SCT). The study enhances insight into this recently developed therapy through a detailed description of the physiotherapy approach. The empirical data are based on interviews with six women who participated in SCT. The empirical data analysis is guided by thematic analysis. Our findings demonstrate how the women experience SCT as a bodily process of wholeness. The process of wholeness relates to new experiences in the women's own bodies, awareness of muscular and mental tension and relaxation, breathing patterns, and perceptions focusing on pain. The findings are presented as three interrelated themes: 1) sensitizing the body as an interconnected unit; 2) incorporating the painful pubic region into the body; and 3) developing a new understanding of oneself. The women who participated in this study found that SCT contributed significantly to the process of their recovery from PVD.

Sexual Assertiveness Mediates the Associations Between Partner Facilitative Responses and Sexual Outcomes in Women With Provoked Vestibulodynia

Provoked vestibulodynia (PVD) is a recurrent idiopathic vulvo-vaginal pain associated with negative sexual and psychological consequences. Facilitative partner responses to pain are currently receiving empirical attention because they are positively associated with women's sexual outcomes. However, the mechanisms through which facilitative responses to pain are associated with these outcomes have not been examined. One potential mechanism is sexual assertiveness, which has been found to be associated with better sexual function and satisfaction in women with PVD. The present study examined whether women's sexual assertiveness mediated the association between women's perception of facilitative partner responses and women's sexual function and satisfaction. Women (N = 140) with PVD symptomatology completed self-reported questionnaires evaluating their perception of their partners' facilitative responses, and their own sexual assertiveness, sexual function, and sexual satisfaction. Dependent measures were sexual function measured by the Female Sexual Function Index and sexual satisfaction assessed by the Global Measure of Sexual Satisfaction Scale. Results indicated that women's higher sexual assertiveness mediated the association between their greater perceived facilitative partner responses and their improved sexual function and satisfaction. Findings suggest a potential mechanism through which partner responses may be associated with women's sexual outcomes.

Recent advances in understanding provoked vestibulodynia

Vulvodynia refers to pain in the vulva of at least 3 months’ duration in the absence of a recognized underlying cause. Provoked, localized vestibulodynia is the term used to describe superficial pain confined to the vulvar vestibule, provoked by touch. This review will focus on provoked vestibulodynia with regard to its suggested causative factors and will discuss the role of inflammation, vulvovaginal infections, mucosal nerve fiber proliferation, hormonal associations, central pain mechanisms, pelvic floor muscle dysfunction, and genetic factors.

Clinical observations, epidemiological studies, and data from basic research emphasize the heterogeneity of vulvar pain syndromes. There is a critical need to perform prospective, longitudinal studies that will allow better diagnostic criteria and subgrouping of patients that would lead to improvements in our understanding of provoked vestibulodynia and its treatment.

Genitofemoral neuralgia: adding to the burden of chronic vulvar pain

The vulva is a particularly common locus of chronic pain with neuropathic characteristics that occurs in women of any age, though most women with neuropathic type chronic vulvar pain will remain undiagnosed even following multiple physician visits. Here, we report on an exemplary case of a middle-aged woman who was referred to the Vulvovaginal Disease Clinic with debilitating vulvar burning and itching over the right labium majus that had been persisting for 2 years and was considered intractable. Careful history taking and clinical examination, followed by electrophysiological assessment through somatosensory evoked potentials was consistent with genitofemoral neuralgia, for which no obvious cause could be identified. Adequate pain relief was obtained with a serotonin–noradrenaline reuptake inhibitor and topical gabapentin cream. We briefly discuss the epidemiology, diagnosis, and treatment of genitofemoral neuralgia and provide a series of clues to guide clinicians in obtaining a presumptive diagnosis of specific neuropathic pain syndromes that may underlie chronic vulvar pain. We further aim to draw attention to the tremendous burden of chronic, unrecognized vulvar pain.

Long-term assessment of effectiveness and quality of life of OnabotulinumtoxinA injections in provoked vestibulodynia

BACKGROUND

Provoked vestibulodynia is a relatively common condition that affects sexual activity. Multidisciplinary care is indicated and OnabotulinumtoxinA injections are safe and effective treatment in this indication.

AIMS

To assess the long-term efficacy of OnabotulinumtoxinA in provoked vestibulodynia.

MATERIALS AND METHODS

Twenty-one patients treated with OnabotulinumtoxinA injections (50U in each bulbospongiosus muscle) 24 months prior to the study were included. Data on pain [assessed using a visual analogue scale (VAS)], quality of life [measured by the Dermatology Life Quality Index (DLQI)] and quality of sex life [assessed using the Female Sexual Function Index (FSFI)] were collected before treatment, and 3 and 24 months after injection.

RESULTS

Nineteen patients participated in the study and 37% had no pain after 24 months. Significant improvements were noted in the VAS, DLQI and FSFI scores between baseline and 24 months post treatment (P < 0.0001). After 24 months, 18 patients (95%) were able to have sexual intercourse. This study was open and non-controlled.

DISCUSSION AND CONCLUSION

100U OnabotulinumtoxinA injections constitute an effective treatment in provoked vestibulodynia with results maintained after 2 years. They significantly improve pain, and have a positive impact on patient quality of life and sex life. Beneficial effects continue in the long-term, allowing patients to resume sexual activity.

Acceptance of vulvovaginal pain in women with provoked vestibulodynia and their partners: associations with pain, psychological, and sexual adjustment

INTRODUCTION

Provoked vestibulodynia (PVD) is a common vulvovaginal pain condition associated with negative psychological and sexual consequences for affected women and their sexual partners. Greater pain acceptance has been found to be associated with better functional and psychological outcomes in individuals with chronic pain, and acceptance-based strategies are being increasingly incorporated into treatment protocols. The present study is a novel investigation of pain acceptance in PVD couples.

AIM

The aim was to examine the associations between acceptance of vulvovaginal pain and women's pain during intercourse, as well as the psychological and sexual adjustment of both women with PVD and their partners.

METHODS

Sixty-one couples (M(age) for women = 27.95 years, SD = 5.87; M(age) for men = 30.48 years, SD = 6.70) in which the woman was diagnosed with PVD completed the Chronic Pain Acceptance Questionnaire, in reference to women's vulvovaginal pain. Women also rated their pain during intercourse, and couples completed measures of anxiety, depression, sexual function, and sexual satisfaction.

MAIN OUTCOME MEASURES

Dependent measures were (i) women's self-reported pain during intercourse on a numerical rating scale; (ii) State-Trait Anxiety Inventory trait subscale; (iii) Beck Depression Inventory-II; (iv) Derogatis Interview for Sexual Functioning; and (v) Global Measure of Sexual Satisfaction Scale.

RESULTS

Women's greater pain acceptance was associated with their lower self-reported pain during intercourse, controlling for partner's pain acceptance. Greater pain acceptance among women was associated with their own lower anxiety and depression, greater sexual functioning, as well as their own and their partner's greater sexual satisfaction, controlling for the partner's pain acceptance. Additionally, greater pain acceptance among male partners was associated with their own lower depression.

CONCLUSIONS

Findings suggest that psychological interventions for PVD should target increasing couples' vulvovaginal pain acceptance in order to improve women's pain and the sexual and psychological functioning of both members of the couple.