Widespread myofascial dysfunction and spinal sensitization in women with endometriosis-associated chronic pelvic pain

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Despite optimal surgical/hormonal treatment, some women with endometriosis continue to have chronic pelvic pain (endo-CPP). Comorbid non-pelvic pain, myofascial dysfunction, and sensitization have rarely been reported in this population. We systematically assessed the presence and distribution of pain, myofascial dysfunction, and spinal sensitization in women with endo-CPP. Women (18–50 years) with endo-CPP after optimized surgical/hormonal treatment were evaluated. Participants underwent gynecologic examination of pelvic floor muscles to identify tenderness/spasm. Neuromusculoskeletal examination included assessment of paraspinal tactile allodynia (Von Frey monofilament) and hyperalgesia (Wartenburg pinwheel). Myofascial trigger points (MTrPs) were identified in 13 regions bilaterally. Pressure-pain thresholds (PPTs) were measured over interspinous ligaments and MTrPs. Twenty-eight women with endo-CPP for a median of 12 years (range 1–20) were evaluated. All had pelvic floor muscle spasm on gyn examination. All endorsed the pelvic floor as a major focus of pain, which was described as focal in 19/28. All women had widespread myofascial dysfunction with MTrPs in more than two-thirds of assessed regions. Low PPTs (< 9 b/in 2 ) were found over interspinous ligaments in 24(86%) women. Widespread spinal segmental sensitization (allodynia and hyperalgesia) was present in 15(53%) subjects. Thoracic sensitization was present in 19(68%) women and lumbosacral sensitization related to the pelvic region in 17(61%). While cervical sensitization was detected in only 2(7%), 22(79%) reported recurrent, severe headaches and 14(50%) experienced orofacial pain. Women with endo-CPP can have myofascial dysfunction beyond the pelvic focus of pain, demonstrated by widespread diffuse and regional allodynia, hyperalgesia, MTrPs, and lowered PPTs, likely reflecting central sensitization. Sensitization may be initiated and maintained by pelvic floor spasm and may account for pain persisting after resection of endometriosis lesions and despite continued use of hormonal treatment. These diffuse and focal myofascial and central nervous system manifestations warrant consideration in management of pain in this population.