Botulinum toxin injection for chronic pelvic pain: A systematic review

Phase 2 randomized study of abobotulinumtoxinA in patients with provoked vestibulodynia: dose-finding results

BACKGROUND

Hypertonicity of the pelvic floor muscles is commonly associated with provoked vestibulodynia (PVD); therefore, patients may benefit from treatments that relax the pelvic floor.

AIM

To define optimal (safe and efficacious) doses of abobotulinumtoxinA (aboBoNT-A) for the treatment of PVD associated with hypertonic pelvic floor muscle dysfunction and to explore use of a novel endpoint for pain assessment for PVD.

METHODS

This phase 2, randomized, placebo-controlled study comprised two steps: dose escalation (Stage 1) and dose expansion (Stage 2). Stage 1 included up to four treatment cycles; Cycle 1 was double blind, Cycles 2-4 open label. Patients were assessed for retreatment every 6 weeks. Stage 2 was not conducted because of early study termination by the sponsor, unrelated to observed safety signals. Enrolled patients-premenopausal women with PVD with associated pelvic-floor hypertonia-were randomized (n = 60) 4:1 to receive aboBoNT-A (doses: 100, 300, 400, or 500 units [U]) or placebo.

OUTCOMES

The primary endpoint was safety. Additionally, a novel composite endpoint, dilator maximum tested size was evaluated. This endpoint combined assessment of vaginal-dilator tolerability with patient-reported pain assessment on an 11-point numeric rating scale, used as a surrogate measure of sexual activity in this study.

RESULTS

All treatment-emergent adverse events (AEs) were mild or moderate in intensity, with no serious AEs or AEs leading to withdrawal reported in the double-blind period. AEs of special interest (urinary incontinence, anal sphincter atonia) were observed at low incidence and predominantly with higher aboBoNT-A doses. The dilator test composite score might be a useful endpoint for pain assessment, with a greater reduction in pain score noted for the 300 U dose group compared with other dose groups and placebo.

CLINICAL IMPLICATIONS

aboBoNT-A was well tolerated in patients with PVD and a novel method for assessing dilator-induced pain was introduced.

STRENGTHS AND LIMITATIONS

The study provided valuable data on use of aboBoNT-A in women with primary or secondary PVD and introduced a novel composite endpoint for assessing dilator-induced pain. Study limitations included the small sample size, limiting formal statistical analysis.

CONCLUSION

aboBoNT-A was well tolerated in patients with PVD with no safety signals reported. Further studies are warranted to demonstrate clinically meaningful benefits with repeated treatment.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03598777.

Chronic pelvic pain and botulinum toxin

Botulinum toxin is being explored as a treatment for chronic pelvic pain, a major cause of suffering and disability in both women and men worldwide. For chronic pelvic pain in women, botulinum toxin may be injected into pelvic floor muscles such as levator ani and obturator internus. For pain associated with genitopelvic penetration disorders (vaginismus, vestibulitis, and vulvar pain, bulbospongioussus and ischiocavernosus may be treated. There have been numerous uncontrolled studies of botulinum toxin for chronic pelvic pain in women showing benefit, however, the few randomized controlled clinical trials published to date have given equivocal results. Chronic pelvic pain in men often implicates the prostate gland, so that the condition is commonly called "chronic prostatitis/chronic pelvic pain syndrome." There are only a handful of clinical trials for male chronic pelvic pain, each using a different site of injection; some with promising results. This paper discusses the use of botulinum toxin in the treatment of chronic pelvic pain in men and women.

Vestibulodynia: Clinical characteristics, first-line treatments, and factors associated with escalation of treatment with EMG-guided injections of botulinum toxin in a retrospective french cohort study

BACKGROUND

Vestibulodynia is a highly prevalent chronic pain disorder affecting the vulva having a major impact on women's physical, psychological, and sexual well-being. It remains an underrecognized disease that responds insufficiently to therapies such as physiotherapy and medication.

AIM

To assess the global efficacy of first-line therapies and factors associated with treatment escalation in women with vestibulodynia.

PATIENTS AND METHODS

This retrospective cohort study was conducted at the dermatology outpatient clinic of the University Hospital in Besancon (France) between 2013 and 2017 and follow-up until 2021.

RESULTS

Among 132 patients, the mean [standard deviation] age at diagnosis was 27.2 [±9.45] years, with an average duration of symptoms of 42.3 [±37.92] months. Most cases comprised provoked (75.0%) or secondary (72.7%) vestibulodynia. At least one comorbid pain or psychologic condition was identified respectively in 63 (47.7%) and 23 patients (54.5%). Vulvar hyperesthesia associated with pelvic floor muscle dysfunction was present in 121 patients (91.6%) and vulvar erethism was noted in 94 patients (71.2%). First-line treatments consisted of pelvic floor physiotherapy with biofeedback in 85% of patients, associated with amitriptyline in 36% of cases, and of additional lidocaine cream in 17%. Fifty-two patients (39%) presented at least a good response to first-line treatment, with only 21 (15%) being in complete remission, irrespective of therapeutic strategy (p = 0.25). Botulinum toxin injections were performed in 54 patients. Patients with either primary vestibulodynia (p = 0.04) or spontaneous vestibulodynia (p = 0.03) were more likely to receive this treatment.

CONCLUSION

Our study highlights the current lack of efficacy of first-line treatments in vestibulodynia. Considering the high prevalence of muscular dysfunction, botulinum toxin injections are of particular interest despite a lack of randomized controlled trials in this indication.

Guideline No. 445: Management of Chronic Pelvic Pain

OBJECTIVE

To provide evidence-based recommendations for the management of chronic pelvic pain in females.

TARGET POPULATION

This guideline is specific to pelvic pain in adolescent and adult females and excluded literature that looked at pelvic pain in males. It also did not address genital pain.

BENEFITS, HARMS, AND COSTS

The intent is to benefit patients with chronic pelvic pain by providing an evidence-based approach to management. Access to certain interventions such as physiotherapy and psychological treatments, and to interdisciplinary care overall, may be limited by costs and service availability.

EVIDENCE

Medline and the Cochrane Database from 1990 to 2020 were searched for articles in English on subjects related to chronic pelvic pain, including diagnosis, overlapping pain conditions, central sensitization, management, medications, surgery, physiotherapy, psychological therapies, alternative and complementary therapies, and multidisciplinary and interdisciplinary care. The committee reviewed the literature and available data and used a consensus approach to develop recommendations. Only articles in English and pertaining to female subjects were included.

VALIDATION METHODS

The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

Family physicians, gynaecologists, urologists, pain specialists, physiotherapists, and mental health professionals.

TWEETABLE ABSTRACT

Management of chronic pelvic pain should consider multifactorial contributors, including underlying central sensitization/nociplastic pain, and employ an interdisciplinary biopsychosocial approach that includes pain education, physiotherapy, and psychological & medical treatments.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Pain Specialist Management of Sexual Pain-II: Interventional

INTRODUCTION

Treatment of female sexual pain often requires the use of diverse modalities crossing multiple medical disciplines. Interventional procedures are important in the diagnosis and treatment of female sexual pain. Pain specialists and other medical specialties can provide these capabilities.

OBJECTIVES

To provide a current summary of the procedures used in the diagnosis and treatment of female sexual pain.

METHODS

The internet, PubMed, and the Cochrane Library were searched for relevant articles on female sexual pain within the clinical purview and scope of the practice of pain management.

RESULTS

A thorough review of the literature was conducted to include basic science studies, clinical trials, systematic reviews, consensus statements, and case reports. An effort was made to also include a sampling of information on real-world patient self-directed therapies. Descriptions of interventional procedures for the diagnosis and treatment of sexual pain were made and clinical studies reviewed. The evidence for the use of various interventional treatment strategies for sexual pain was assessed.

CONCLUSIONS

The process of care for female sexual pain employs an interdisciplinary biopsychosocial model that includes a role for interventional procedures commonly performed by pain management specialists. These specialists are a resource of knowledge, skills, and abilities that can be used to improve the care of women with chronic sexual pain.

Treatment of Dyspareunia with Botulinum Neurotoxin Type A: Clinical Improvement and Influence of Patients' Characteristics

The treatment of chronic pelvic pain (CPP) with botulinum neurotoxin type A (BoNT/A) has increased lately, but more studies assessing its effect are needed. This study aimed to evaluate the evolution of patients after BoNT/A infiltration and identify potential responders to treatment. Twenty-four women with CPP associated with dyspareunia were treated with 90 units of BoNT/A injected into their pelvic floor muscle (PFM). Clinical status and PFM activity were monitored in a previous visit (PV) and 12 and 24 weeks after the infiltration (W12, W24) by validated clinical questionnaires and surface electromyography (sEMG). The influence of patients' characteristics on the reduction in pain at W12 and W24 was also assessed. After treatment, pain scores and the impact of symptoms on quality of life dropped significantly, sexual function improved and sEMG signal amplitude decreased on both sides of the PFM with no adverse events. Headaches and bilateral pelvic pain were risk factors for a smaller pain improvement at W24, while lower back pain was a protective factor. Apart from reporting a significant clinical improvement of patients with CPP associated with dyspareunia after BoNT/A infiltration, this study shows that clinical characteristics should be analyzed in detail to identify potential responders to treatment.