Year : 2022 | Volume
: 5 | Issue : 2 | Page : 41--45
A critical review of interventional treatments for myofascial pelvic pain
Aaron Lin1, Hadeer Abbas2, Maryam Sultan3, Tony Tzeng4,
1 Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center McGovern Medical School, Houston, Texas, USA
2 Texas Southern University, Houston, Texas, USA
3 Department of Physical Medicine and Rehabilitation. University of Texas Health Science Center McGovern Medical School; Director, UT Physicians Pelvic Disorders Clinic; Attending Physician, TIRR Memorial Hermann Hospital, Houston, Texas, USA
4 Louisiana State University Health New Orleans School of Medicine, New Orleans, Louisiana, USA
Dr. Aaron Lin
John P and Katherine G McGovern Medical School, University of Taxas McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
Chronic pelvic pain affects between 6% and 25% of women. It is a complex condition that has multifactorial etiologies, including but not limited to conditions arising from the gynecologic, urologic, gastrointestinal, musculoskeletal, neurologic, and psychologic systems. In this literature review, we examine and summarize evidence for interventional treatments compared to conservative treatments for women with musculoskeletal or myofascial pelvic pain. Searches were performed in PubMed and Embase databases. Studies were included if they were randomized controlled trials with a treatment arm of physical therapy, dry needling, trigger point injection (TPI), or injection with botulinum toxin. A total of 106 studies were returned with our search terms, and six articles were included in this review. These studies suggest that pelvic floor physical therapy, dry needling of abdominal wall trigger points, and TPI to abdominal wall and pelvic floor trigger points have some evidence as being effective for treatment of pelvic pain. The evidence for treatment with botulinum toxin was not as robust and also had higher rates of adverse events when compared to other interventions. Most of these studies are limited by small sample sizes and varied baseline demographics, which makes generalization of these findings to different patient populations difficult. In general, treatments for myofascial pelvic pain are low-risk and are effective in reducing myofascial pelvic pain.
|How to cite this article:|
Lin A, Abbas H, Sultan M, Tzeng T. A critical review of interventional treatments for myofascial pelvic pain.J Int Soc Phys Rehabil Med 2022;5:41-45
|How to cite this URL:|
Lin A, Abbas H, Sultan M, Tzeng T. A critical review of interventional treatments for myofascial pelvic pain. J Int Soc Phys Rehabil Med [serial online] 2022 [cited 2022 Nov 28 ];5:41-45
Available from: https://www.jisprm.org/text.asp?2022/5/2/41/345157
Chronic pelvic pain is reported in 6%–25% of women. It is defined as pain in the area below the umbilicus and superior to the proximal thighs for at least 6 months. It is a complex condition that usually has multifactorial etiologies, including but not limited to conditions arising from the gynecologic, urologic, gastrointestinal, musculoskeletal, neurologic, and psychologic systems. In this review, we focus on myofascial pelvic pain. This specifically refers to pain of the pelvic floor muscles, connective tissue, and surrounding fascia. The hallmark of myofascial pain is the presence of trigger points. These are defined as hard, palpable, discrete, localized nodules within taut bands of skeletal muscle that are painful on compression. The conundrum of myofascial pain is that it can be either a primary or secondary pain generator. The objective of this review is to evaluate and contrast interventional treatment options with conservative treatments for women with myofascial pelvic pain.
Literature searches were performed in both PubMed and Embase databases. The following MeSH and Emtree terms and keyword searches were used: myofascial pain, pelvic pain, chronic pelvic pain, treatment, physical therapy, and physiotherapy. Articles were included if they were randomized controlled trials (RCTs) where the treatment arm was pelvic physical therapy, dry needling, trigger point injection (TPI), or injection with botulinum toxin. Subjects needed to have a diagnosis of pain in the pelvic region of the body. If mentioned, studies included in the screening protocol a physical examination by a trained professional and showed tenderness or taut bands of musculature and/or trigger points. These findings served as a proxy for the diagnosis of pelvic pain that is myofascial in etiology. Although the muscles of the pelvic floor are sufficiently separate from the lower abdominal musculature, given the definition of pelvic pain used in this review, the decision was made to include interventions to these muscles alongside those to the muscles of the pelvic floor proper. Articles were excluded if they did not include an outcome related to pain, were not in the English language, were studied on men, were published prior to 2000, or were review articles, posters, case reports, case series, or retrospective studies. These studies were evaluated with the American Academy of Neurology (AAN) classification of evidence for therapeutic studies. In the body of this review, assignments of evidence classification refer to AAN classification. Evaluations of quality of evidence, bias, and limitations of studies were evaluated with the help of an attending physician specializing in Pelvic Rehabilitation.
The literature search returned 106 results; 100 were excluded. Six articles met our criteria and are critically reviewed below.
Therapy (2 randomized controlled trials)
The evidence for physical therapy for the management of various pelvic floor pain syndromes shows that pelvic floor physical therapy (PFPT) is an effective treatment option. As in other domains of physical medicine and rehabilitation, therapy should be the first-line treatment. Due to the broad skills of physical therapy training, PFPT has a wide scope of treatments. This could involve: education to the patient, pelvic floor muscle exercises, training, and/or stretches with or without biofeedback, manual therapy of internal and external structures of muscles and connective tissues of the pelvic floor, hip girdle, and abdomen, vaginal dilatation, electrical stimulation, and dry needling. These articles do not explicitly state if dry needling is utilized as a part of therapeutic treatment or not. This potentially confounds conclusions in articles that discuss PFPT as a treatment.
In a 2012 study by FitzGerald et al., 81 women aged 18–77 with interstitial cystitis (IC) were treated with PFPT or global therapeutic massage (GTM) over a period of 12 weeks. This study included women who had a clinical diagnosis of IC and symptoms of bladder pain, frequency, and urgency present between 3 months and 3 years. They could not have been treated with PFPT in the past. They also had pelvic floor tenderness on physical examination conducted by the study physician and physical therapist. Primary or secondary outcomes included “moderate or marked” improvement in a 7-point global response assessment (GRA) or change in visual analog scale (VAS). At 3 months, there was a 59% response rate of “moderate or marked” improvement in GRA with PFPT versus a 28% response rate in the GTM group. There was no significant change in the reported VAS between the two groups. Adverse events included pain (14%), infection (12%), constitutional symptoms (11%), and gastrointestinal disturbances (10%). The type of infection is not defined, and so it is difficult to determine the cause of infection and if it was related to the intervention. These patients were followed for up to 3 months, and then offered the opportunity to continue with PFPT for another 3 months. There were too few participants who continued with treatments, so the durability of the intervention is limited. This study was assigned Class III level of evidence as the patients and individuals providing intervention were not blinded and because the baseline characteristics of the patients were not well defined.
In a 2020 parallel group, assessor-blinded RCT by Morin et al., 212 nulliparous women aged 18–45 with vestibulodynia >6 months duration and rated at least 5/10 on the numeric rating scale (NRS) were treated with PFPT or nightly application of topical lidocaine for a duration of 10 weeks. They were evaluated for 6 months. Patients were included if they reported pain during sexual intercourse for >6 months and then evaluated for the diagnosis of provoked vestibulodynia by a physician. Primary outcomes included NRS ratings showing a difference of 30%. At 6 months, results showed 89% improvement in the PFPT group versus 55% in the lidocaine group. No adverse outcomes were reported except for 15% of women reporting irritation/burning sensation from lidocaine, and one participant developed dermatitis from topical lidocaine. The strengths of this study are the large number of participants, with adherence rates of 85% for the home exercise program with PFPT and 91% for those in the lidocaine arm. Limitations include participant inclusion criteria of nulliparous and premenopausal women, though this may also serve to strengthen the study by limiting etiologies of pain associated with vaginal deliveries and genitourinary symptoms associated with menopause. Additionally, by definition, multimodal PT indicates a delivery of personalized treatments at the level of the therapists' abilities. This study emphasized that all PTs who participated were certified with postgraduate training in women's health and pelvic pain. This study did not specifically study one aspect of PFPT, so this could be difficult to generalize to clinical practice. This study was assigned Class II level of evidence as the patients and individuals providing intervention were not blinded, but the assessors were blinded. In addition, baseline characteristics were well defined and showed no significant differences.
Dry Needling (1 Randomized Controlled Trial)
Dry needling is a well-known treatment option in orthopedic physical therapy, especially for the treatment of myofascial trigger points. This treatment is not as well-documented in the pelvic physical therapy treatment toolbox.
In a 2018, parallel group, assessor-blinded RCT by Gaubeca-Gilarranz et al., 56 nulliparous women aged 18–25 with primary dysmenorrhea and trigger points of the inferior rectus abdominis muscle were treated with either trigger point dry needling, placebo needling, or no treatment. These individuals had to exhibit active trigger points on physical examination. It is worth pointing out that this study was unique in that the target of intervention was not in the pelvic floor. Rather, the target was in myofascial trigger points of the inferior rectus muscle. Placebo needling was performed with sham needles, called Dong Bang, that do not penetrate the skin. All groups were assigned a stretching program to be performed 3–5 times a day of the rectus abdominis and oblique musculature. Their allocations were then revealed after baseline assessments and before follow-up assessments at 1 and 2 months. Primary and secondary outcomes of interest included the change of VAS >50% and quality-of-life measures. Data were collected up to 2 months after delivery of one session of treatment, which included one cycle of menstruation and the duration of several weeks. At 2 months, results showed a significant decrease in the VAS of the dry needling group versus placebo and control arms. There were no adverse events reported. There was a reported 97% adherence to the stretching program. This study was assigned a Class III level of evidence. The patients were blinded to initial treatment allocation and treatment. Some limitations include relatively small numbers of participants in each arm, young age of participants, and short duration of the study. These factors could limit generalizability to the public when trying to adopt this intervention in clinical practice.
Trigger Point Injection (2 Randomized Controlled Trials)
TPI are well studied and shown to be effective in treating myofascial pain and perhaps in treating myofascial pelvic pain as well. It is worth mentioning that in these studies, the targets for intervention are either the abdominal wall muscles or pelvic floor muscles.
In a 2015, parallel group, RCT by Montenegro et al. on 30 women, whose average age was 37, and who were diagnosed with chronic pelvic pain, subjects were treated with either TPI with anesthetic or ischemic compression to lower abdominal wall TPs. The patients were screened for trigger points with a calibrated device called an algometer, which delivers precise levels of pressure. Ischemic compression is a noninterventional therapy that consists of a therapist applying direct pressure to a trigger point. TPIs were conducted with 2 mL of 0.5% lidocaine and administered weekly for 4 weeks. The outcome of interest was whether there was a “satisfactory response,” defined as at least a 50% reduction in VAS. The duration of data collection was 12 weeks. At 12 weeks, results showed an 80% response rate in the TPI arm versus 13% in the ischemic compression arm. No adverse events were reported. The main limitation of this study was that it initially intended to enroll 60 subjects total; however, due to the striking difference between the response rate of the two arms, it was terminated early. This study was assigned a Class II level of evidence. However, it should be noted that this was a well-constructed study, with strict eligibility criteria to exclude medical etiologies of pelvic pain, well-defined baseline characteristics, collaboration with two OB/GYN physicians, and blinding of both the providers of intervention and the assessors. In a 2015 RCT by Zoorob et al., 29 women, whose average age was 41, diagnosed with chronic pelvic pain were treated with TPI of the pelvic floor muscles or PFPT with the Thiele method. Patients were screened for trigger points in the pelvic floor by one of two female pelvic medicine and reconstructive surgeons. TPIs were administered with 1 mL of triamcinolone (40 mg/mL) mixed in 9 mL of 0.5% bupivacaine, with a minimum of 5 mL injected per site with up to four sites injected per patient. The patients did not have a set number of treatments. Rather, they needed to have between 1 and 6 weekly administrations of TPIs and between 3 and 10 weekly PFPT sessions. The number of total treatments was determined by a subjective report of adequate pain control or by the maximum allowed sessions. Outcomes of interest included pain score by NRS, whether there was a change of >50% in the NRS, sexual function, and sexual dysfunction. Duration of evaluation was up to 1 month post treatment. At 1 month, results showed improvements in pain scores in both arms as they had more treatments. There was no significant difference in the average pain scores at 1 month. Howeer, patients did report feeling “a little better” at 4.4 weeks in the TPI group versus 7.3 weeks in the PT group. With regard to sexual function and dysfunction, there was an improvement of sexual pain and decreased sexual dysfunction in the PT group. Limitations of this study include a small sample size, partially due to high drop-out rate of 29% in the TPI arm after randomization, which created a difference in the number of participants in each arm (12 in the TPI arm and 17 in the PFPT arm). It should be noted that the subjects included in the study by Zoorob et al. had complicated gynecologic histories, including histories of endometriosis, hysterectomy, sling surgery, rectocele repair, and pelvic organ prolapse. While these factors could make the results more generalizable, it does introduce more confounding biases to the mix. This study was assigned Class II level of evidence. Subjects and providers of intervention were not blinded while assessors were. Baseline characteristics were matched, with the exception of a difference in subjects who had insurance versus who did not.
Botox (1 Randomized Controlled Trial)
In a 2019 study by Dessie et al., 59 female subjects aged 30–55 with at least 3 months of pelvic pain rated at least 6/10 on the VAS were treated with either injection of pelvic floor TPs with onabotulinum toxin A or saline placebo. The onabotulinum toxin A dose was 200 units diluted into 20 mL saline. Placebo was the same volume of saline. The patients were screened for “short, tight pelvic floor” muscles. The injectors were 1 of 4 female pelvic medicine and reconstructive surgeons. TPs were identified first by intravaginal palpation and prior to injection, all participants received 100 mg of 2% lidocaine jelly inside the vagina. The process of injection with botulinum toxin included 20 injections of 1 mL with a 20 gauge needle in bilateral areas of pelvic floor muscles that contained TPs. Both groups were assigned PFPT 4 weeks after injection for a total of 8 weekly sessions. Method of evaluation included rating pain by VAS on palpation of pelvic floor muscles at weeks 2, 4, and 12. Duration of evaluation was up to 12 weeks after injection. The primary outcome was a change in pain on palpation. The secondary outcomes of interest included overall impression of disease severity. At 12 weeks, results showed that there were small improvements of pain in both groups, but the difference was not statistically significant. Adverse events reported in both groups included new-onset constipation (10%), new urinary incontinence (22%) in the intervention group, and urinary tract infection (9%) in the placebo group. This study was assigned a Class II level of evidence. The strengths of this study included blinding of subjects and investigators. Limitations included small sample size and the injectate volume of 20 mL of saline may have contributed to the lack of statistical difference.
In the literature, there is a relative paucity of rigorous studies performed on first-line interventions for the management of myofascial pelvic pain. In this paper, we reviewed six articles on this topic, in which two investigated the efficacy of PFPT, one did so for dry needling, two for TPI, and one for botulinum toxin injection. In summary, the studies show generally favorable results of pain relief with interventions with minimal side effects. PFPT, dry needling, and TPI show significant differences compared to more conservative approaches. Botulinum toxin injection did not show a statistically significant difference between injection with toxin versus saline. The limitations of these types of studies are all small numbers of subjects; difficulty in generalization to the public; lack of evaluation of durability of pain relief, increase of function, or decrease of pain medication use; and, on a micro scale, variability in injection techniques. It is difficult to generalize these treatments to the public as these studies did not necessarily prioritize certain demographics such as nulliparity versus multiparity, prior history of surgery, organ prolapse, and mental illness or disorders, to name a few. These conditions have both direct and indirect effects on pain generation itself and perception of pain. With regard to PFPT, treatments are highly variable and personalized to each patient. The heterogeneity of treatment and clinician expertise can make a generalization to clinical practice difficult.
One of the main limitations of evaluating such a small number of studies is the participants' type included. While the studies analyzed myofascial pelvic pain, this is often a secondary syndrome rather than the primary pain generator identified. For instance, several studies are in specific populations such as IC, dysmenorrhea, and endometriosis. These conditions have all been identified and implicated in chronic pain syndromes that may result in taut bands. It is prudent to state that chronic pelvic pain does not automatically indicate the presence of hypertonic, taut bands, and myofascial pelvic pain. However, myofascial pelvic pain is often a primary or secondary cause of chronic pelvic pain.
In practice, the best course of action is likely to begin with patient enrollment in PFPT. If myofascial pain is recognized as a barrier to attendance or progression in therapy, then a medication or intervention may be indicated to help the patient proceed with physical therapy. Since so many organ systems are involved in the pelvis and with the sensation of pain itself, a multidisciplinary approach that considers the anatomic, physiologic, neurologic, psychiatric, and psychological basis of the patient's pelvic pain should be employed throughout the diagnosis and treatment plan.
In the future, studies directly comparing injectates, injection sites, and needle size in the treatment of myofascial pelvic pain are necessary to move toward standardization of this treatment protocol. Furthermore, studies comparing injecting medication versus insertion of a needle without injectate would be helpful in evaluating the effect of “dry needling” while performing a trigger point or botulinum toxin injection. Future scientific studies could also focus on specific subpopulations, such as those with widespread pain in addition to pelvic pain versus pain that is isolated to the pelvic region.
This was a critical review of the available randomized controlled trials studying interventions for the treatment of myofascial pelvic pain. Current and common treatments for myofascial pain in musculoskeletal medicine are physical therapy, dry needling, TPI, and botulinum toxin injections. This review shows that there are some data that show that these treatments can be used for pelvic pain. All of these interventions are low-risk procedures but do require specialized training. Although physical therapy, dry needling, and TPIs all have good evidence, they only show short-term benefits on the order of 1 and 3 months. For botulinum toxin injections, though there is an overall effect of pain relief, the available data do not show benefit over placebo with saline injection.
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Conflicts of interest
There are no conflicts of interest.
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