Pain mapping: A mechanisms-oriented protocol for the assessment of chronic pelvic pain and urogenital pain syndromes

Abstract

Objective: Chronic pelvic pain (CPP) and various pelvic dysfunctions are best assessed by consultants with knowledge and training in myofascial pain. The prevalence of myofascial pain is recognised but what is needed is a validated protocol to guide physical examination of pelvic structures. Pain mapping was developed to assist with localising active and passive sources of pain, evaluating its severity, temporal characteristics, topography and mechanisms and guiding therapy. Materials and Methods: This is a prospective study involving the pain mapping of 320 female volunteers, consisting of women diagnosed with chronic urogenital pain (CUP), and of a comparison and control group. The protocol uses three pain maps to guide assessment of the external urogenital area, internal pelvic floor structures and paraurethral region, and follows an established strategy to maintain consistency. Results: The mean age of the CUP group was 34.7±12.1 years; 31.6±10.1 for the gynaecology comparison group; and 35.5±11.5 for the control group. There were no significant differences in age or parity, the groups were well matched for statistical comparison. The highest pain scores from Map A were noted around the vestibule and urethral meatus; from Map B included all of the internal pelvic structures tested; and from Map C all points were painful and accounted for the highest scores of all the points mapped. Logistic regression analysis identified two points from each of the three maps (a total of six points), that provide 94% accuracy in the diagnosis of chronic urogenital pain syndrome. Conclusion: The pain mapping study demonstrates the benefits of using an established protocol for localising and assessing pelvic pain. The results highlight the role of peripheral mechanisms, in the form of myofascial changes associated with pain and organ dysfunction. The paraurethral area appears to be the primary generator of CUP symptoms and diagnostically is the most reliable in differentiating between CUP cases and asymptomatic controls. As an anatomical region the paraurethral area is an overlooked source of pain and rarely tested during diagnostic assessments.