Endometriosis-associated nerve fibers and pain

The assessment and diagnosis of endometriosis remain elusive targets. Patient and medical-related factors add to delays in the detection and treatment. Recently, investigators have revealed specific nerve fibers present in endometriotic tissue, with existing parallels between density and pain severity. The aim of this review is to compile a comprehensive review of existing literature on endometriosis-related nerve fiber detection, and the effects of medical therapy on these neural fibers. We performed a systematic literature-based review using Medline and PubMed of nerve fibers detected in eutopic endometrium, endometriotic lesions, and the peritoneum. Various arrangements of significant medical terms and phrases consisting of endometriosis, pelvic pain, nerve fiber detection/density in endometriosis, and diagnoses methodology, including treatment and detection were applied in the search. Subsequent references used were cross-matched with existing sources to compile all additional similar reports. Similar nerve fibers were detected within lesions, endometrium, and myometrium, though at varying degrees of density. Hormonal therapy is widely used to treat endometriosis and was shown to be related to a reduction in fiber density. A direct result of specific nerve fiber detection within eutopic endometrial layers points to the use of a minimally invasive endometrial biopsy technique in reducing delay in diagnosis and subsequent possible preservation of fertility.