A retrospective study of the management of vulvodynia

Botulinum toxin injection in vulva and vagina. Evidence from a literature systematic review

INTRODUCTION

Botulinum toxin (BoNT) administration has been proposed in the gynecologic field for pelvic, vulvar and vaginal disorders. On this regard, we aimed assessing the therapeutic effectiveness and safety of BoNT usage in the treatment of vaginal, vulvar and pelvic pain disorders.

METHODS

We searched for all the original articles without date restriction until 31.12.2021. We included all the original articles which administered botulinum toxin in the vulva or vagina of women suffering from vaginismus, dyspareunia, and chronic pelvic pain. Only English language studies and those performed in humans were eligible. We excluded all case reports and pilot study from the qualitative analysis, although we accurately evaluated them. 22 original studies were finally included in the systematic review.

RESULTS

Botulinum toxin injection was found to be effective in improving vulvar and vaginal dyspareunia, vaginismus, and chronic pelvic pain. No irreversible side effects were detected. Major side effects reported were transient urinary or fecal incontinence, constipation and rectal pain. The risk of bias assessment proved original articles to be of medium quality. No metanalysis could have been performed since lack of congruency in the definition of pathology and methods of botulinum toxin administration.

CONCLUSION

Data extraction pointed out different endpoints and different methods of analysis. Studies focus on different types of participants and use various techniques and timing. According to the best evidence available, different techniques provide evidence about positive outcomes, with the need for a standardized protocol.

Inflammation, lipids, and pain in vulvar disease

Localized provoked vulvodynia (LPV) affects ∼14 million people in the US (9% of women), destroying lives and relationships. LPV is characterized by chronic pain (>3 months) upon touch to the vulvar vestibule, which surrounds the vaginal opening. Many patients go months or years without a diagnosis. Once diagnosed, the treatments available only manage the symptoms of disease and do not correct the underlying problem. We have focused on elucidating the underlying mechanisms of chronic vulvar pain to speed diagnosis and improve intervention and management. We determined the inflammatory response to microorganisms, even members of the resident microflora, sets off a chain of events that culminates in chronic pain. This agrees with findings from several other groups, which show inflammation is altered in the painful vestibule. The vestibule of patients is acutely sensitive to inflammatory stimuli to the point of being deleterious. Rather than protect against vaginal infection, it causes heightened inflammation that does not resolve, which coincides with alterations in lipid metabolism that favor production of proinflammatory lipids and not pro-resolving lipids. Lipid dysbiosis in turn triggers pain signaling through the transient receptor potential vanilloid subtype 4 receptor (TRPV4). Treatment with specialized pro-resolving mediators (SPMs) that foster resolution reduces inflammation in fibroblasts and mice and vulvar sensitivity in mice. SPMs, specifically maresin 1, act on more than one part of the vulvodynia mechanism by limiting inflammation and acutely inhibiting TRPV4 signaling. Therefore, SPMs or other agents that target inflammation and/or TRPV4 signaling could prove effective as new vulvodynia therapies.

Effectiveness of topical gabapentin in the treatment of vulvodynia: a narrative synthesis

Vulvodynia is a leading cause of dyspareunia in premenopausal women, causing considerable morbidity and sexual dysfunction. A multimodal approach is used to treat vulvodynia. Alongside psychosocial interventions and physiotherapy, pharmacological treatment such as oral gabapentin are used in the treatment of vulvodynia. Topical formulations of gabapentin have shown promise in animal models and case reports investigating its use in other pain conditions. The topical route also avoids the systemic complications of gabapentin such as somnolence, dizziness, and peripheral edema. This study aimed to perform a narrative synthesis of studies investigating the use of topical gabapentin in the treatment of vulvodynia. The primary outcome was a change in pain score following treatment with topical gabapentin. A broad literature search was performed, which identified four studies for inclusion. The included studies reported improved pain measures following treatment; however, conclusions cannot be made due to methodological heterogeneity and inherent limitations. These include lack of control arms, small sample sizes, lack of patient randomization, and use of combination treatments. Due to the paucity of evidence, this review supports the future implementation of double-blind randomized controlled trials to further investigate the efficacy of topical gabapentin in the treatment of vulvodynia.

Alternative Clinical Indications of Botulinum Toxin

Botulinum toxin type A (BoNTA) is a powerful neurotoxin that inhibits acetylcholine release from presynaptic vesicles. The potency and safety profile of BoNTA grant the toxin vast therapeutic potential. It has been used off-label for a variety of dermatologic conditions. This review aims to analyze published literature regarding the benefits and risks of the off-label use of BoNTA beyond facial lines, including eccrine hidrocystomas, enlarged pores, keloids and hypertrophic scars, hidradenitis suppurativa, hyperhidrosis, masseter muscle hypertrophy, and salivary gland hypertrophy, among others. A MEDLINE search from January 2000 to December 2019 was conducted on the off-label uses of botulinum toxin in dermatology.

Treatment of Vulvodynia: Pharmacological and Non-Pharmacological Approaches

Vulvodynia is a common, recurrent, vulvar pain condition with debilitating consequences for affected women's health and quality of life. The heterogeneity of women suffering from vulvodynia as well as its uncertain and likely multifactorial etiology pose a significant challenge to identifying any kind of "gold standard" treatment. Thus, treatment providers must be well versed in the various options and the evidence for each. In this review, we begin with pharmacological treatments, followed by non-pharmacological treatments, surgery, and finally multimodal treatments. For each approach, we briefly discuss the method, mechanism of action, and empirical support for the treatment. In sum, pharmacological treatments that may be beneficial but require further research include antinociceptive agents (lidocaine, capsaicin), anti-inflammatory agents (corticosteroids, interferon), neuromodulating medications (anticonvulsants and antidepressants), hormonal agents, and muscle relaxants (e.g., botulinum toxin). There is strong evidence to support and recommend non-pharmacological interventions including psychological therapy, pelvic floor physical therapy, as well as surgery (i.e., vestibulectomy for provoked vestibulodynia) for the treatment of vulvodynia. We conclude this review with a discussion of issues that may have hindered progress of treatment efficacy and effectiveness, and recommendations for moving the field forward.

Gabapentin for the Treatment of Vulvodynia: A Randomized Controlled Trial

OBJECTIVE

To evaluate whether extended-release gabapentin is more effective than placebo among women with vulvodynia.

METHODS

In a multicenter double-blind, placebo-controlled randomized crossover trial, gabapentin (1,200-3,000 mg/d) was compared with a placebo. The primary outcome was mean pain intensity (0, no pain at all to 10, worst pain ever) on the tampon test (a standardized tampon insertion and removal test used as a surrogate marker for dyspareunia) during the last 7 days of the maintenance phase. Secondary outcomes included sexual intercourse pain and daily pain. A sample size of 53 provided 90% power to detect a 1-point reduction on the tampon test (.05 level, two-sided) between the two treatment phases.

RESULTS

From August 2012 to January 2016, 230 women were screened at three academic institutions and 89 (mean age 37 years; 65% black) were randomized: 45 to gabapentin first and then placebo and 44 to placebo first and then gabapentin. Tampon test pain with gabapentin was not different compared with the placebo (adjusted mean 4.0, 95% CI 3.0-4.9 vs 4.3, 95% CI 3.4-5.2, difference -0.3, 95% CI -0.7 to 0.0; P=.07). Gabapentin also did not improve pain over placebo for sexual intercourse pain (adjusted mean 3.9, 95% CI 2.4-5.3 vs 4.0, 95% CI 2.5-5.4, difference -0.1, 95% CI -0.9 to 0.6; P=.76) and daily pain (adjusted mean 2.7, 95% CI 1.8-3.6 vs 2.9, 95% CI 2.0-3.8, difference -0.2, 95% CI -0.5 to -0.2; P=.36). Subset analyses found that longer pain duration and oral contraceptive nonuse were associated with minimal improvement in tampon test pain with gabapentin.

CONCLUSION

In this cohort, extended-release gabapentin, as compared with a placebo, did not reduce tampon test pain. These data do not support the recommendation of gabapentin alone as treatment for vulvodynia.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT01301001.

Vulvodynia: A Review of the Literature

Objective: To evaluate the literature and educate the pharmacy community about the different treatment options for vulvodynia. Data Sources: Searches were performed through MEDLINE (1946-May 2018) using OVID and EBSCOhost, and Excerpta Medica (1974-May 2018) using EMBASE. Search terms included vulvar vestibulitis syndrome, vestibulodynia, vulvodynia, vulvar pain, provoked vulvar vestibulitis, and vulvodynia treatment. References of all relevant articles were then used to find additional applicable articles. Study Selection and Data Extraction: This review includes articles in the English language and human trial literature. Twenty-five trials explored the use of oral and topical medications in the treatment of vulvodynia. Data Synthesis: Vulvodynia is a poorly understood disease with an unknown etiology. Oral tricyclic antidepressants and gabapentin continue to be the most commonly used treatments for vulvodynia pain. This is due to their ease of use and patient preference. Topical treatments that have efficacy data are amitriptyline, gabapentin, lidocaine, baclofen, and hormones. This route of administration avoids systemic adverse effects and interpatient variability that accompanies oral administration. Alternative therapies more commonly used include physiotherapy, psychotherapy, and surgery. Treatment length may vary due to dose titrations and potential changes in medication therapy. Conclusions: Several medication and alternative therapies may be effective in treating vulvodynia. Current studies used wide dosing ranges, making it difficult to standardize therapy. No consistent method of assessing pain was used between studies, as well as a limited number being randomized and placebo controlled. Additional research is needed to increase knowledge and further develop vulvodynia treatments.

Opioid Adjuncts: Optimizing Opioid Therapy With Nonopioid Medications

In this article, we describe a variety of medications that physicians managing outpatient chronic pain should familiarize themselves with to better aid their approach to multimodal pain therapy. Physicians should always consider the use of an adjuvant or coanalgesic drug as first-line treatments. Although many of these medications are not primarily analgesics, in clinical practice they have independent analgesic effects or synergistic analgesic properties when used with opioids. The use of adjunct analgesics reduces opioid-related adverse effects and optimizes pain management. Although there may be some medication overlap with this section and the ERAS section, the purpose of this article is to understand prolonged use in the outpatient setting to reduce opioid use or limit opioid dose with adjuvant therapy.

Therapeutic Approaches of Botulinum Toxin in Gynecology

Botulinum toxins (BoNTs) are produced by several anaerobic species of the genus Clostridium and, although they were originally considered lethal toxins, today they find their usefulness in the treatment of a wide range of pathologies in various medical specialties. Botulinum neurotoxin has been identified in seven different isoforms (BoNT-A, BoNT-B, BoNT-C, BoNT-D, BoNT-E, BoNT-F, and BoNT-G). Neurotoxigenic Clostridia can produce more than 40 different BoNT subtypes and, recently, a new BoNT serotype (BoNT-X) has been reported in some studies. BoNT-X has not been shown to actually be an active neurotoxin despite its catalytically active LC, so it should be described as a putative eighth serotype. The mechanism of action of the serotypes is similar: they inhibit the release of acetylcholine from the nerve endings but their therapeutically potency varies. Botulinum toxin type A (BoNT-A) is the most studied serotype for therapeutic purposes. Regarding the gynecological pathology, a series of studies based on the efficiency of its use in the treatment of refractory myofascial pelvic pain, vaginism, dyspareunia, vulvodynia and overactive bladder or urinary incontinence have been reported. The current study is a review of the literature regarding the efficiency of BoNT-A in the gynecological pathology and on the long and short-term effects of its administration.

A review of the available clinical therapies for vulvodynia management and new data implicating proinflammatory mediators in pain elicitation

Localised provoked vulvodynia (LPV) is a common, chronic, and disabling condition: patients experience profound pain and a diminished quality of life. The aetiologic origins of vulvodynia are poorly understood, yet recent evidence suggests a link to site-specific inflammatory responses. Fibroblasts isolated from the vestibule of LPV patients are sensitive to proinflammatory stimuli and copiously produce pain-associated proinflammatory mediators (IL-6 and PGE₂ ). Although LPV is a multifactorial disorder, understanding vulvar inflammation and targeting the inflammatory response should lead to treatment advances, especially for patients exhibiting signs of inflammation. NFκB (already targeted clinically) or other inflammatory components may be suitable therapeutic targets.

TWEETABLE ABSTRACT

Vulvodynia is a poorly understood, prevalent, and serious women's health issue requiring better understanding to improve therapy.

Similarities between interstitial cystitis/bladder pain syndrome and vulvodynia: implications for patient management

Interstitial cystitis/bladder pain syndrome (IC/BPS) and vulvodynia are chronic pain syndromes that appear to be intertwined from the perspectives of embryology, pathology and epidemiology. These associations may account for similar responses to various therapies.

MicroRNA expression profiles differentiate chronic pain condition subtypes

Chronic pain is a significant health care problem, ineffectively treated because of its unclear etiology and heterogeneous clinical presentation. Emerging evidence demonstrates that microRNAs (miRNAs) regulate the expression of pain-relevant genes, yet little is known about their role in chronic pain. Here, we evaluate the relationship among pain, psychological characteristics, plasma cytokines, and whole blood miRNAs in 22 healthy controls (HCs); 33 subjects with chronic pelvic pain (vestibulodynia, VBD); and 23 subjects with VBD and irritable bowel syndrome (VBD + IBS). VBD subjects were similar to HCs in self-reported pain, psychological profiles, and remote bodily pain. VBD + IBS subjects reported decreased health and function; and an increase in headaches, somatization, and remote bodily pain. Furthermore, VBD subjects exhibited a balance in proinflammatory and anti-inflammatory cytokines, whereas VBD + IBS subjects failed to exhibit a compensatory increase in anti-inflammatory cytokines. VBD subjects differed from controls in expression of 10 miRNAs of predicted importance for pain and estrogen signaling. VBD + IBS subjects differed from controls in expression of 11 miRNAs of predicted importance for pain, cell physiology, and insulin signaling. miRNA expression was correlated with pain-relevant phenotypes and cytokine levels. These results suggest that miRNAs represent a valuable tool for differentiating VBD subtypes (localized pain with apparent peripheral neurosensory disruption vs widespread pain with a central sensory contribution) that may require different treatment approaches.

Vulvodynia

Vulvodynia is a complex disorder reported by up to 16% of women in the general population. While most patients describe it as burning, stinging, irritation, or rawness, it is underreported and underrecognized by providers. Vulvodynia is costly both economically and psychologically due to its negative impact on quality of life. Vulvodynia is a diagnosis of exclusion with unknown etiology and may involve multiple sources of pain in the same woman. Thus, there are no clinical or histopathologic criteria for the diagnosis other than consideration and careful evaluation to exclude other causes of pain. Successful therapy often requires a multidisciplinary approach with more than one therapeutic intervention to address the physical, psychological, psychosexual, and relationship components.

Anticonvulsant pharmacotherapy for generalized and localized vulvodynia: a critical review of the literature

Anticonvulsant therapy has occasionally been recommended to treat vulvodynia. However, convincing evidence to support this therapeutic option is lacking. The goal of this study was to critically review studies published on the effectiveness of anticonvulsants for the treatment of vulvodynia. Evaluation of the methodological quality of relevant publications was the main outcome measure. MEDLINE, PubMED and Cochrane were used to identify studies published in English between January 1999 and February 2013. Searches were performed between December 2012 and February 2013. Articles were appraised with the Oxford Centre for Evidence-Based Medicine - Levels of Evidence. Eight relevant studies were identified: two case reports, three retrospective studies, two non-randomized prospective studies and one open-label pilot trial study. Gabapentin formed the main focus (87.5%) to reduce vulvar pain; success rates ranged from 50 to 82%. Lamotrigine was used in one study (12.5%) to relieve symptoms; satisfaction was reported in 82%. These results seem promising, but the majority of studies have several methodological weaknesses regarding sample size and design. Insufficient evidence was available to recommend anticonvulsants for the treatment of vulvodynia. Further studies are necessary with double-blind, randomized-controlled designs to investigate the effectiveness of anticonvulsant therapy for vulvodynia.

Vulvodynia: An unrecognized diabetic neuropathic syndrome

Vulvar pain syndromes, including vulvodynia, are a common source of morbidity in women and cause much physical and psychological suffering. This brief communication postulates the hypothesis that unexplained vulvar pain may be hitherto undescribed manifestation of painful sensory diabetic neuropathy. It describes the clinical characteristics of vulvodynia and highlights the similarities between this condition and diabetic neuropathy. The hypothesis calls for women presenting with vulvar pain to be screened for diabetes, as well as women with diabetes to be questioned about vulvar symptomatology. The paper hopes to stimulate extensive research in this important, but so far neglected, field of women's endocrine health.