Retrospective Multicenter Review of Efficacy and Practices of Botulinum Toxin a Trigger Point Injections for Chronic Pelvic Pain

INTRODUCTION: Chronic pelvic pain (CPP) is defined by the American College of Obstetricians & Gynecologists as “pain symptoms perceived to originate from pelvic organs/structures typically lasting more than six months.” It is a common disorder with significant burden to patient quality of life, affecting approximately 5.7–26.6% women worldwide with a lifetime prevalence of 33%, although this number is likely underreported. CPP is associated with high healthcare costs and its multifactorial nature often requires extensive diagnostic testing and multiple treatment modalities. Trigger-point injections for myofascial trigger points have been used as an adjunct to pelvic floor physical therapy with studies demonstrating shortened time to improvement. Botulinum toxin A has been used off-label to induce muscle paralysis for high tone pelvic muscle dysfunction and may be used in combination with traditional trigger point injections. While its use is widely accepted, there is no consensus on the location, number, or dosage of injections of botulinum toxin A. OBJECTIVE: The objective of this study was to evaluate the treatment outcomes and practices of trigger-point injections with and without Botox for the treatment of female pelvic pain within the Kaiser Permanente Southern California region. METHODS: This was a multi-center retrospective cohort study within Kaiser Permanente Southern California region comparing treatment outcomes in female patients aged 18–65 with diagnosed pelvic pain treated with trigger-point injections containing Botox compared to the traditional steroid-local anesthetic combination between 2022 and 2025. Primary outcome was requirement of repeat injections and duration of time between injections, as a corollary to patient outcome. Secondary outcomes included an evaluation of current practices of Botox trigger-point injections including dose, locations, and frequency of injections; presence of concomitant pudendal nerve block; and treatment setting (clinic versus operating room). Kruskal–Wallis and chi-square tests were performed to assess for statistical significance which was defined as p<0.05. RESULTS: Patients who received trigger point injections with Botox (N=69) had overall fewer repeat injections and a statistically significant increase in the amount of time between injections (148 days vs 112 days, p value 0.04731) compared to the non-Botox group (N=103). The average dose used was approximately 150 units of Botox with a range from 50 units to 500 units and a median dose of 100 units. Approximately 75% of patients who received Botox trigger-point injections also received concomitant pudendal nerve blocks. Approximately 80% of patients who received Botox trigger-point injections were treated in the operating room. Only 10% of patients in both groups underwent pelvic floor physical therapy during the study period. CONCLUSIONS: The results of this study may indicate a longer duration of treatment effect of trigger-point injections containing botulinum toxin A. Further research is needed to create a standardized protocol for botulinum toxin A trigger-point injections with concurrent use of validated questionnaires to evaluate patient reported outcomes following treatment. Patient education is required to ensure understanding that trigger-point injections are optimally used as an adjunct to pelvic floor physical therapy for long-term benefit.