A pilot study to evaluate the clinical relevance of endometriosis-associated nerve fibers in peritoneal endometriotic lesions

Objective To investigate the clinical relevance of endometriosis-associated nerve fibers in the development of endometriosis-associated symptoms. Design Prospective nonrandomized study. Setting University hospital endometriosis center. Patient(s) Fifty-one premenopausal patients underwent surgical laparoscopy because of chronic pelvic pain, dysmenorrhea, or for ovarian cysts. Endometriosis was diagnosed in 44 patients. Intervention(s) The preoperative and postoperative pain scores were determined using a standardized questionnaire with a visual analogue scale from 1–10. Patients with peritoneal endometriosis were divided into two groups depending on their preoperative pain score: group A with a pain score of at least 3 or more and group B with a pain score of 2 or less. Patients without peritoneal endometriosis were classified as group C and patients without endometriosis were classified as group D. Immunohistochemical analysis of neurofilament and protein gene product 9.5 were used for nerve fiber detection. Occurrence of endometriosis-associated nerve fibers was correlated with the severity of pelvic pain and/or dysmenorrhea. Result(s) Peritoneal endometriosis-associated nerve fibers were found significantly more frequently in group A than in group B (82.6% vs. 33.3%). Conclusion(s) The present study suggests that the presence of endometriosis-associated nerve fibers in the peritoneum is important for the development of endometriosis-associated pelvic pain and dysmenorrhea.