{"paper_id":"291de9a0-22bd-45e6-9927-5f512066d7ae","body_text":"Vol.:(0123456789)1 3\nArchives of Gynecology and Obstetrics (2023) 308:1803–1809 \nhttps://doi.org/10.1007/s00404-023-07192-5\nGENERAL GYNECOLOGY\nPelvic floor hypertension: possible factors for pelvic floor tenderness \nin endometriosis patients—a pilot study\nJumana Muallem1  · Renata Voltolini Velho1  · Johanna Netzl1  · Jalid Sehouli1  · Sylvia Mechsner1 \nReceived: 17 May 2023 / Accepted: 13 August 2023 / Published online: 6 September 2023 \n© The Author(s) 2023\nAbstract\nPurpose Chronic pelvic pain (CPP) is one of the main problems of endometriosis, leading to a significant impairment of \nquality of life. Understanding the pain mechanisms and the pelvic floor muscles (PFM) changes in these patients is essential \nto integrate additional therapeutic strategies. We hypothesize that endometriosis patients have changes in PFM and that \ntargeted vaginal electrostimulation can be a treatment option for CPP in this disease.\nMethods Fifteen patients with endometriosis and chronic acyclical pelvic pain were included. PFM electromyography with \nthe Multiple Array Probe Leiden (MAPLe) was performed. Mapping of PFM was utilized and targeted electrostimulation of \nthe hypertensive muscles was conducted. Control electromyography was performed afterward to evaluate the electrostimula‑\ntion therapeutic effect.\nResults In 12/15 (80%) patients, the myofascial trigger point could be localized by digital examination. The most frequently \naffected muscle was the puborectalis (10/15—66.7%). Most of the patients showed serious changes in the average resting \ntone (aRT) of PFM. aRT was significantly increased in all patients and decreased after stimulation, whereby the difference \nprior to and after stimulation was not significant (p  = 0.064). The detailed separated analysis of the hypertensive muscles \nshowed a significant (p = 0.026) reduction in their resting tone (hRT), after targeted stimulation.\nConclusion Vaginal electrostimulation is a promising and feasible complementary treatment option for CPP in endometriosis \npatients. Targeted treatment of pelvic floor dysfunction should be included in clinical trials.\nKeywords Chronic pelvic pain · Spinal hyperalgesia · Pelvic floor muscles · Pelvic floor dysfunction · Electrostimulation\nJumana Muallem and Renata Voltolini Velho have contributed \nequally to this work.\n * Sylvia Mechsner \n sylvia.mechsner@charite.de\n1 Department of Gynecology Charité with Center \nof Oncological Surgery, Endometriosis Research Center \nCharité, Campus Virchow‑Klinikum, Augustenburger Platz \n1, 13353 Berlin, Germany\nWhat does this study add to the clinical work \nVaginal electrostimulation is a promising and fea‑\nsible complementary treatment option for chronic \npelvic pain in endometriosis patients. Targeted \ntreatment of pelvic floor dysfunction should be \nincluded in clinical trials.\nIntroduction\nEndometriosis is an unrecognized chronic inflammatory \ngynaecological disease affecting approximately 270 mil‑\nlion women worldwide [1 ]. Chronic pelvic pain (CPP) is \none of the main problems of this condition, leading to sig‑\nnificant impairment of the patient’s quality of life. Patients \nfrequently report a long diagnostic delay and a complex pain \nsyndrome with combinations of pelvic pain and painful blad‑\nder syndrome, irritable bowel syndrome, vulvodynia, pelvic \nfloor tenderness and dyspareunia [1, 2].\nThe pathogenesis of pain generation is very complex \n[1–3]. A combination of peripheral and central (both visceral \nand somatic) pain sensitization explains the high complex‑\nity of symptoms in patients with endometriosis [3 ]. In case \nof recurrent pain like dysmenorrhea, central sensitization \nmechanisms are activated every month, and pain‑intensify‑\ning mechanisms are upregulated [4, 5]. Unfortunately, only \nlimited data are available regarding pathological changes \n\n1804 Archives of Gynecology and Obstetrics (2023) 308:1803–1809\n1 3\nof the pelvic floor in endometriosis patients and a possible \nimpact of this on pelvic pain. However, various studies on \nthe pelvic floor muscles (PFM) with pelvic pain not caused \nby endometriosis showed a wide range of changes in power, \nability of coordination, speed of coordination, endurance, \ntone and relaxation [6–9]. These data suggest that the pelvic \nfloor may play an important role in the generation of pain in \nendometriosis as well [10]. Myofascial trigger points are a \npossible cause of pelvic pain.\nCurrently, the standard treatment options are not able \nto resolve the chronic pain situation in these women suf‑\nficiently [1, 11]. While hormonal and surgical treatment are \nthe most common treatment options, high recurrence rates \nand ongoing pain after such interventions are frequent [11]. \nAlthough a Cochrane review [12] recommended nonsurgical \ninterventions for the management of CPP in general, studies \nregarding the nonsurgical management of CPP in endome‑\ntriosis are lacking. A thorough investigation of pelvic floor \nchanges in endometriosis patients is necessary to better \nunderstand the pathogenesis of endometriosis‑related pain \nand the development of additional therapeutic management \nstrategies directly targeted at the pelvic floor. Multimodal \ntreatment strategies should be established to improve the \nquality of life of women with endometriosis.\nTo analyze the pelvic floor function in patients with endo‑\nmetriosis, we performed pelvic floor muscle electromyogra‑\nphy (EMG) with the Multiple Array Probe Leiden (MAPLe) \n[13]. In addition, we performed a targeted vaginal electrical \nstimulation of the affected hypertensive muscles as a non ‑\nsurgical pain treatment for endometriosis and CPP patients.\nMaterials and methods\nThis prospective pilot study was conducted at the Endome‑\ntriosis Centre of Charité—Universitätsmedizin Berlin, Ger ‑\nmany, from December 2019 to May 2020.\nFifteen patients with histologically confirmed endome‑\ntriosis and CPP were included (age 18–49). They suffered \nfrom CPP not responding to hormonal, analgesic, and anti‑\ninflammatory treatment. Numerous studies have utilized this \nprocedure on both patients and healthy individuals, and it \nhas been shown to have low risks and side effects. Some \npeople may experience mild tingling or twitching under the \nelectrode area, but this sensation goes away immediately \nonce the stimulation stops. However, individuals with severe \nor untreated internal, neurological, or psychiatric conditions, \nthose who are pregnant or breastfeeding, people with cardiac \npacemakers, myocardial damage, arrhythmias, and epilepsy \npatients were excluded from the study. We assessed the PFM \nof all participants before the intervention using a single‑digit \npelvic examination of the levator ani muscles (Iliococcy -\ngeus muscle, Pubococcygeus muscle, Puborectalis muscle) \nwhich were palpated for tenderness on each side. Tenderness \non each side was rated by the patient as absent or present. \nPatients in whom a pelvic examination could not be per ‑\nformed (e.g., vaginismus) were excluded.\nThe severity of pain was documented using a standard‑\nized questionnaire with a visual analogue scale (VAS) before \nthe intervention. The pain intensity was determined with \nthe help of a visual numerical analogue scale (0 = no pain, \n10 = strongest imaginable pain).\nFor the EMG measurement, we utilized the MAPLe \ndevice. The probe from this device contains a matrix of 24 \nelectrodes (six levels, 10 mm apart, on six depths and four \nsides) that measure EMG signals from the different layers \nand sides of the PFM as shown in Fig. 1. The MAPLe Probe \nwas placed intravaginally, with a grounding electrode on \nthe spina iliaca anterior superior. The patients were asked \nto perform three consecutive tasks: (i) 1 min rest, where \npatients were instructed to feel the pelvic floor in rest (aver‑\nage rest tonus—aRT); (ii) 10 maximum voluntary contrac‑\ntions, where patients were instructed to perform a controlled \ncontraction and relaxation of the PFM; and (iii) 3 endurance \ncontractions, where patients were instructed to contract the \nPFM at such a level that they could hold for 30 s. During \nthese examinations, no instructions were given on how to \nperform a pelvic floor muscle contraction. A visual represen‑\ntation of the PFM activity is presented in a tablet application \n(app) developed for the MAPLe device (Fig. 2). Color scales \n(white–red–blue) represent the microvolt (EMG ampli‑\ntude) readings for the 24 electrodes, which are graphically \npresented in a “bull’s eye” pattern. Red means hypertonic \n(2–12 µV), blue means hypotonic (−1 to −8 µV), and white \nmeans normal muscle activity (0 µV). In case of hypertonic/\nhyper‑tense muscles, a RT of these muscles (hRT) was eval‑\nuated separately before and after intervention.\nAfter the affected painful and hypertensive muscles had \nbeen identified through the process described, a targeted \nfocal electrostimulation (intervention) based on the control \ngate theory [14] was applied for 10 min to these muscles \nas a possible treatment. To evaluate the effect of the elec‑\ntrostimulation on the whole PFM, a new EMG measurement \nat rest (aRT) of the PFM was performed.\nStatistical analyses were performed using IBM SPSS Sta‑\ntistics, Version 26 (IBM Corp. IBM SPSS Statistics for Win‑\ndows, Version 26.0. 2019). Data were described by median \nand percentiles. A non‑parametric Spearman correlation \nanalysis was performed to examine the association between \nthe Resting tone (RT) before and after intervention. Two \none‑sample Wilcoxon sign rank tests were conducted to test \nif the RT before and the RT after intervention differed from \nthe critical value for an increased RT of 2 µV [13]. Finally, \na paired sample Wilcoxon sign rank test was performed to \ntest if the RT had improved after the intervention. All these \nanalyses were performed for the general RT (aRT) and the \n\n1805Archives of Gynecology and Obstetrics (2023) 308:1803–1809 \n1 3\nRT of the affected hypertensive muscle (hRT). Statistical \nsignificance was defined as p ≤ 0.05.\nResults\nFifteen patients were recruited from daily practice \nand analyzed. Demographic characteristics are sum‑\nmarized in Table  1. The mean age of participants was \n32.93  ± 8.49 years (range 18–49 years). Three (20%) \npatients were parous. Most participants (12–80%) were \nunder hormonal therapy with either a levonorgestrel‑\nreleasing intrauterine device (2), GnRHa (3), or pro ‑\ngestogen‑only pill (7). The CPP duration ranged from 5 \nto 15 years (7.5; P25 = 6; P75 = 10) with a median pain \nintensity of 6 (P25 = 5; P75 = 7).\nIn 12 (80%) patients, the myofascial trigger point could \nbe localized by digital examination. In 3 (20%), it was not \npossible to identify the myofascial trigger point, but the tout \nbands of PFM. The most frequently affected muscle was the \npuborectalis (10/15—66.7%). In one endometriosis woman, \nthe Pubococcygeus muscle was affected.\nFig. 1  The MAPLe system. \na The MAPLe probe has \nelectrodes on six depths and \nfour sides. The MAPLe grid \nis displayed. This is used in \nthe figures showing the results \nof the analyses in this study. \nb Graphical representation \nthe pelvic floor muscles and \nstructures (vaginal) with respect \nto the MAPLe electrodes in a \nvisualization Grid. The four \ncompartments represent the \nanterior (12 o’clock), left (3 \no’clock), posterior (6 o’clock) \nand right side (9 o’clock) of the \nPFM. The most outer rings are \nlocated at the most superficial \nparts of the PFM, the most inner \nring (nearest to the center) is \nlocated at the most deeper parts \nof the PFM\nFig. 2  A visual representation of the PFM activity presented in a tab‑\nlet application (app) developed for the MAPLe device. Color scales \n(white–red–blue) represent the microvolt (EMG amplitude) readings \nfor the 24 electrodes, which are graphically presented in a “bull’s \neye” pattern. Red means hypertonic (2–12 µV), blue means hypotonic \n(− 1 to − 8 µV), and white means normal muscle activity (0 µV)\n\n1806 Archives of Gynecology and Obstetrics (2023) 308:1803–1809\n1 3\nBefore the intervention, the median aRT was 3.30 \n(P25 = 2.50; P75 = 4.40), which was significantly higher \nthan the critical value for an increased RT (p  = 0.002). \nAfter the intervention, the median aRT decreased to 3.00 \n(P25 = 2.10; P75 = 3.80), but was still higher than the criti‑\ncal value (p = 0.017) (Fig. 3). All patients who initially had \nan increased aRT (12/15, hyper‑tense muscles) still showed \nafter the intervention (p = 0.05). The difference between the \nmedian aRT before and after the stimulation was not signifi‑\ncant (p = 0.064).\nA RT of the hyper‑tense muscles (hRT—12 patients) was \nevaluated separately before and after the intervention. The \nmedian RT of the affected hypertensive muscle before the \nelectrostimulation was 4.00 (P25 = 4.00; P75 = 10.50), sig‑\nnificantly higher than the critical value for an increased RT \n(p = 0.002). After the targeted stimulation, the median hRT \ndecreased to 3.00 (P25 = 0.00; P75 = 3.75) and did not dif‑\nfer from the critical value for an increased RT (p  = 0.937). \nA statistical significance was obtained with the difference \nbetween hRT before and after the stimulation (p  = 0.026) \n(Fig.  4).\nDuring the targeted electrostimulation, most patients \n(14–93.3%) recognized the targeted area as one of the pain‑\nful points. All patients (15–100%) relate the experience as \npleasant; 12 (80%) felt pain relief a couple of hours later; 14 \n(93.3%) patients felt pain relief a day after the intervention \nthat lasted for a couple of hours.\nDiscussion\nIn this pilot study, a new intravaginal device was used for \ntargeted electrical stimulation of myofascial trigger points \nto relieve CPP in women with endometriosis. Using MAPLe \nallowed us to analyze the different parts of the PFM sepa‑\nrately. As expected, the analysis has shown a significant \nincrease in the aRT of the PFM in this group of patients \ncompared to the aRT in healthy volunteers in the validation \nstudy [13]. Although we did not find a significant decrease \nin the total aRT after the intervention, the value of p (0.064) \nis promising as it suggests that an effect of the interven‑\ntion would be obtained in a larger sample or after the elec‑\ntrostimulation repetition, thus underlining the importance of \nthe continuation of this study. The detailed analysis of the \nhypertensive muscle groups showed a higher RT (hRT) in \nendometriosis patients compared to healthy controls [13]. \nMoreover, the difference in hRT before and after the tar ‑\ngeted stimulation was statistically significant. This showed \na positive effect of the targeted stimulation in reducing the \ntension in these hypertonic muscles. The patients identified \nTable 1  Characteristics of the study participants\nCharacteristics N = 15\nAge (years)\n Median (range) 33 (18–49)\nYears of pain\n Median (range) 7.5 (5–15)\nHormone use\n Contraceptive pill 7\n Intrauterine device 2\n GNRH analog 3\n None 3\nVAS\n Median (range) 6.0 (4–8)\nPregnancy 3\n Parous 3\nFig. 3  Resting tone (aRT) for the entire pelvic floor muscle before \nand after the intervention (n = 15)\nFig. 4  Difference in resting tone of the affected, hypertone (hRT) \nmuscle before and after the intervention (n = 12)\n\n1807Archives of Gynecology and Obstetrics (2023) 308:1803–1809 \n1 3\nthe localized hypertensive muscle groups according to their \npainful trigger points. This result is of high clinical rele‑\nvance as it suggests the possibility of pain relief for a patient \ngroup heavily burdened by pain symptoms.\nFor the better development of treatment strategies for \nCPP in endometriosis, the underlying mechanisms of the \npathogenesis of the disease need to be studied in more detail. \nOne of the underestimated sources of pelvic pain is not the \npelvis itself, in terms of the comprised visceral organs and \nthe peritoneum, but the pelvic floor and its layering of differ‑\nent levator ani muscles. As a result of endometriosis‑related \npain, patients search for pain‑resolving positions, however, \nmalposition leads to asymmetric reflector contraction of the \nPFM, resulting in CPP and PFM dysfunction. In 2015, Strat‑\nton was one of the first who raised the possible influence \nof the pelvic floor on pain generation [15]. However, still, \nlimited data on pelvic floor activity in patients with endo‑\nmetriosis is available.\nMost of the few trials published are based on invasive \ntherapies. Myofascial trigger points injection, with or \nwithout a topical anesthetic (wet or dry needling, respec‑\ntively), is another common form of myofascial treatment \nbeing studied. Direct injection of a local anesthetic such as \nlidocaine is thought to diminish the ability to transmit pain \nsignals through these hyperactive neural networks, provid‑\ning additional pain relief that may be more durable than \nmyofascial trigger points needling alone [16, 17]. Prospec‑\ntive studies using dry needling have not been performed in \nthe pelvic region. Nonetheless, dry needling in other body \nregions has been shown to reduce pain and is non‑inferior \nto wet needling [18, 19]. The injection of botox (a brand \nname for botulinum toxin) into the myofascial trigger points \nhas also been investigated. This neurotoxin can temporarily \nparalyze muscles by blocking the release of acetylcholine, \na neurotransmitter that signals muscles to contract. In a \ndouble‑blinded randomized study, symptom improvement \nin 7 patients was observed. Patients from the placebo group \nalso experienced pain relief, although the duration of the \npain mitigation was longer lasting in those who received \nbotox [20].\nSeeking alternatives for a more efficient treatment of \nendometriosis and CPP, physical activity and exercises come \nto light. In a recent review [21], the authors emphasized that \nphysiotherapy in its various forms can be an excellent com‑\nplement to the gynecological treatment of endometriosis, \nreducing inflammation, alleviating pain, and thus signifi‑\ncantly improving women’s quality of life. Small studies tout \nthe effectiveness of these techniques in the treatment of myo‑\nfascial pelvic pain, including one retrospective study which \nshowed that physical therapy benefits up to 63% of patients \nwho attempt it [22, 23]. In a recently published meta‑anal‑\nysis, the available evidence for the effect of physical activi‑\nties and exercise on endometriosis‑associated symptoms was \nsummarized [24]. Three interventional studies involving 109 \nwomen were identified and included. Each included study \nfound some improvement in pain intensity, stress levels, \nwell‑being, or self‑image. However, due to confounding \nfactors, the effect of physical activities and exercise alone \ncould not be determined. Nevertheless, the authors affirm \nthat these activities might exert a range of beneficial effects \non endometriosis‑associated symptoms [24].\nPrevious studies using electrotherapy demonstrated the \nbenefits relieving CPP related to endometriosis. Self‑applied \ntranscutaneous electrical nerve stimulation (TENS) involves \nthe application of adhesive electrodes to the skin with sub‑\nsequent electrical stimulation of painful areas [25]. Inter ‑\nferential current (IFC) therapy involves the application of \nmedium‑frequency alternating currents, which are thought to \nincrease blood flow and reduce pain [26, 27]. Seems advan‑\ntageous over TENS as it generates an amplitude‑modulated \nfrequency, allowing it to penetrate more deeply than TENS. \nDespite the efficacy, both methodologies have been demon‑\nstrated to be similar and beneficial in endometriosis‑related \nCPP [28].\nTo the best of our knowledge, only our group has evalu‑\nated a target vaginal electrical stimulation (using MAPLe). \nEven though our pilot study has some limitations, such as \nthe short therapy duration (one session of electrostimula‑\ntion) and the small number of participants, promising results \ncould be seen. Vaginal electrostimulation is an encourag ‑\ning and feasible complementary treatment option for CPP \nin endometriosis patients, and future clinical trials should \ninclude this approach. Endometriosis is an under diagnosis \nand undertreated complex disease. Multimodal treatment \nstrategies should be established to improve the quality of \nlife of these patients.\nAuthor contributions JM: project development, data collection, manu‑\nscript writing/editing. RVV: project development, manuscript writing/\nediting. JN: data analysis, manuscript editing. JS: project development, \nmanuscript editing. SM: project development, manuscript writing/\nediting.\nFunding Open Access funding enabled and organized by Projekt \nDEAL. This study was sponsored by Medizintechnik Rostock GmbH.\nDeclarations \nConflict of interest All the machines used in this study as well as finan‑\ncial support (JM) where provided by Medizintechnik Rostock GmbH. \nAll the other authors declare no potential conflict of interest.\nEthical approval This study was performed in line with the principles \nof the Declaration of Helsinki. Approval was granted by the Institu‑\ntional Review Board of the Charité University Medical Centre (Ethic \nvote EA1/211/20).\nConsent to participate Informed consent was obtained from all indi‑\nvidual participants included in the study.\n\n1808 Archives of Gynecology and Obstetrics (2023) 308:1803–1809\n1 3\nOpen Access This article is licensed under a Creative Commons Attri‑\nbution 4.0 International License, which permits use, sharing, adapta‑\ntion, distribution and reproduction in any medium or format, as long \nas you give appropriate credit to the original author(s) and the source, \nprovide a link to the Creative Commons licence, and indicate if changes \nwere made. The images or other third party material in this article are \nincluded in the article’s Creative Commons licence, unless indicated \notherwise in a credit line to the material. If material is not included in \nthe article’s Creative Commons licence and your intended use is not \npermitted by statutory regulation or exceeds the permitted use, you will \nneed to obtain permission directly from the copyright holder. To view a \ncopy of this licence, visit http://creativecommons.org/licenses/by/4.0/.\nReferences\n 1. Mechsner S (2022) Endometriosis, an ongoing pain‑step‑by‑step \ntreatment. J Clin Med 11(2):467. https:// doi. org/ 10. 3390/ jcm11 \n020467\n 2. Gruber TM, Mechsner S (2021) Pathogenesis of endometriosis: \nthe origin of pain and subfertility. Cells 10(6):1381. https:// doi. \norg/ 10. 3390/ cells 10061 381\n 3. Morotti M, Vincent K, Becker CM (2017) Mechanisms of pain \nin endometriosis. Eur J Obstet Gynecol Reprod Biol 209:8–13. \nhttps:// doi. org/ 10. 1016/j. ejogrb. 2016. 07. 497\n 4. Hoffman D (2015) Central and peripheral pain generators in \nwomen with chronic pelvic pain: patient centered assessment and \ntreatment. Curr Rheumatol Rev 11(2):146–166. https:// doi. org/  \n10. 2174/ 15733 97111 66615 06190 94524\n 5. Ng SK, Urquhart DM, Fitzgerald PB, Cicuttini FM, Hussain SM, \nFitzgibbon BM (2018) The relationship between structural and \nfunctional brain changes and altered emotion and cognition in \nchronic low back pain brain changes: a systematic review of MRI \nand fMRI studies. Clin J Pain 34(3):237–261. https:// doi. org/ 10. \n1097/ AJP. 00000 00000 000534\n 6. Reissing ED, Brown C, Lord MJ, Binik YM, Khalife S (2005) \nPelvic floor muscle functioning in women with vulvar vestibulitis \nsyndrome. J Psychosom Obstet Gynaecol 26(2):107–113. https:// \ndoi. org/ 10. 1080/ 01443 61040 00231 06\n 7. Gentilcore‑Saulnier E, McLean L, Goldfinger C, Pukall CF, \nChamberlain S (2010) Pelvic floor muscle assessment outcomes in \nwomen with and without provoked vestibulodynia and the impact \nof a physical therapy program. J Sex Med 7(2 Pt 2):1003–1022. \nhttps:// doi. org/ 10. 1111/j. 1743‑ 6109. 2009. 01642.x\n 8. Loving S, Thomsen T, Jaszczak P, Nordling J (2014) Pelvic floor \nmuscle dysfunctions are prevalent in female chronic pelvic pain: \na cross‑sectional population‑based study. Eur J Pain 18(9):1259–\n1270. https:// doi. org/ 10. 1002/j. 1532‑ 2149. 2014. 485.x\n 9. Moldwin RM, Fariello JY (2013) Myofascial trigger points of \nthe pelvic floor: associations with urological pain syndromes and \ntreatment strategies including injection therapy. Curr Urol Rep \n14(5):409–417. https:// doi. org/ 10. 1007/ s11934‑ 013‑ 0360‑7\n 10. Yong PJ, Mui J, Allaire C, Williams C (2014) Pelvic floor tender‑\nness in the etiology of superficial dyspareunia. J Obstet Gynaecol \nCan 36(11):1002–1009. https:// doi. org/ 10. 1016/ S1701‑ 2163(15) \n30414‑X\n 11. Duckelmann AM, Taube E, Abesadze E, Chiantera V, Sehouli \nJ, Mechsner S (2021) When and how should peritoneal endo‑\nmetriosis be operated on in order to improve fertility rates and \nsymptoms? The experience and outcomes of nearly 100 cases. \nArch Gynecol Obstet 304(1):143–155. https:// doi. org/ 10. 1007/ \ns00404‑ 021‑ 05971‑6\n 12. Cheong YC, Smotra G, Williams AC (2014) Non‑surgical inter ‑\nventions for the management of chronic pelvic pain. Cochrane \nDatabase Syst Rev 3:CD008797. https:// doi. org/ 10. 1002/ 14651 \n858. CD008 797. pub2\n 13. Voorham‑van der Zalm PJ, Voorham JC, van den Bos TW et al \n(2013) Reliability and differentiation of pelvic floor muscle elec‑\ntromyography measurements in healthy volunteers using a new \ndevice: the multiple array probe leiden (MAPLe). Neurourol Uro‑\ndyn 32(4):341–348. https:// doi. org/ 10. 1002/ nau. 22311\n 14. Lin T, Gargya A, Singh H, Sivanesan E, Gulati A (2020) Mecha‑\nnism of peripheral nerve stimulation in chronic pain. Pain Med \n21(Suppl 1):S6–S12. https:// doi. org/ 10. 1093/ pm/ pnaa1 64\n 15. Stratton P, Khachikyan I, Sinaii N, Ortiz R, Shah J (2015) Asso‑\nciation of chronic pelvic pain and endometriosis with signs of sen‑\nsitization and myofascial pain. Obstet Gynecol 125(3):719–728. \nhttps:// doi. org/ 10. 1097/ AOG. 00000 00000 000663\n 16. Langford CF, Udvari Nagy S, Ghoniem GM (2007) Levator ani \ntrigger point injections: an underutilized treatment for chronic \npelvic pain. Neurourol Urodyn 26(1):59–62. https:// doi. org/ 10. \n1002/ nau. 20393\n 17. Aredo JV, Heyrana KJ, Karp BI, Shah JP, Stratton P (2017) Relat‑\ning chronic pelvic pain and endometriosis to signs of sensitiza‑\ntion and myofascial pain and dysfunction. Semin Reprod Med \n35(1):88–97. https:// doi. org/ 10. 1055/s‑ 0036‑ 15971 23\n 18. Desai MJ, Saini V, Saini S (2013) Myofascial pain syndrome: a \ntreatment review. Pain Ther 2(1):21–36. https:// doi. org/ 10. 1007/ \ns40122‑ 013‑ 0006‑y\n 19. Ay S, Evcik D, Tur BS (2010) Comparison of injection meth‑\nods in myofascial pain syndrome: a randomized controlled \ntrial. Clin Rheumatol 29(1):19–23. https:// doi. org/ 10. 1007/  \ns10067‑ 009‑ 1307‑8\n 20. Tandon HK, Stratton P, Sinaii N, Shah J, Karp BI (2019) Botuli‑\nnum toxin for chronic pelvic pain in women with endometriosis: \na cohort study of a pain‑focused treatment. Reg Anesth Pain Med. \nhttps:// doi. org/ 10. 1136/ rapm‑ 2019‑ 100529\n 21. Wojcik M, Szczepaniak R, Placek K (2022) Physiotherapy \nmanagement in endometriosis. Int J Environ Res Public Health \n19(23):16148. https:// doi. org/ 10. 3390/ ijerp h1923 16148\n 22. Pastore EA, Katzman WB (2012) Recognizing myofascial pel‑\nvic pain in the female patient with chronic pelvic pain. J Obstet \nGynecol Neonatal Nurs 41(5):680–691. https:// doi. org/ 10. 1111/j. \n1552‑ 6909. 2012. 01404.x\n 23. Bedaiwy MA, Patterson B, Mahajan S (2013) Prevalence of myo‑\nfascial chronic pelvic pain and the effectiveness of pelvic floor \nphysical therapy. J Reprod Med 58(11–12):504–510\n 24. Tennfjord MK, Gabrielsen R, Tellum T (2021) Effect of physical \nactivity and exercise on endometriosis‑associated symptoms: a \nsystematic review. BMC Womens Health 21(1):355. https:// doi. \norg/ 10. 1186/ s12905‑ 021‑ 01500‑4\n 25. Takla MKN (2018) Low‑frequency high‑intensity versus medium‑\nfrequency low‑intensity combined therapy in the management of \nactive myofascial trigger points: A randomized controlled trial. \nPhysiother Res Int 23(4):1737. https:// doi. org/ 10. 1002/ pri. 1737\n 26. Fuentes JP, Armijo Olivo S, Magee DJ, Gross DP (2010) Effec‑\ntiveness of interferential current therapy in the management of \nmusculoskeletal pain: a systematic review and meta‑analysis. Phys \nTher 90(9):1219–1238. https:// doi. org/ 10. 2522/ ptj. 20090 335\n 27. Almeida CC, Silva V, Junior GC, Liebano RE, Durigan JLQ \n(2018) Transcutaneous electrical nerve stimulation and interfer ‑\nential current demonstrate similar effects in relieving acute and \nchronic pain: a systematic review with meta‑analysis. Braz J Phys \nTher 22(5):347–354. https:// doi. org/ 10. 1016/j. bjpt. 2017. 12. 005\n 28. Galasso A, Urits I, An D et al (2020) A comprehensive review \nof the treatment and management of myofascial pain syndrome. \nCurr Pain Headache Rep 24(8):43. https:// doi. org/ 10. 1007/  \ns11916‑ 020‑ 00877‑5\n\n1809Archives of Gynecology and Obstetrics (2023) 308:1803–1809 \n1 3\nPublisher's Note Springer Nature remains neutral with regard to \njurisdictional claims in published maps and institutional affiliations.","source_license":"CC0","license_restricted":false}