Persistence of dysmenorrhea and nonmenstrual pain after optimal endometriosis surgery may indicate adenomyosis.

OBJECTIVE: To evaluate whether persistence of pelvic pain after excision of endometriosis was associated with adenomyosis as defined by a thickened uterine junctional zone (JZ) on magnetic resonance (MR) imaging.

DESIGN: Prospective clinical trial.

SETTING: Government research hospital.

PATIENT(S): Fifty-three women with chronic pelvic pain.

INTERVENTION(S): Preoperative MR imaging to measure uterine JZ thickness, surgical excision, and pathologic diagnosis of endometriosis. Those with biopsy-proven endometriosis were randomized to raloxifene or placebo. Visual analog scale (VAS) was used to rate dysmenorrhea and nonmenstrual pain severity before surgery and 3 months later.

MAIN OUTCOME MEASURE(S): Comparison of JZ thickness and pain severity before and 3 months after surgery in women with endometriosis controlling for medical treatment.

RESULT(S): Forty of the 53 patients had biopsy-proven endometriosis, and 6 of these 40 women with endometriosis had a thickened JZ. Overall, dysmenorrhea at 3 months was positively correlated with preoperative JZ thickness (r = 0.47, P=.01). Dysmenorrhea pain severity showed no significant decrease in those patients whose JZ measured >or=11 mm compared with those with JZ <8 mm (P<.0001; VAS decreased 4.3 +/- 0.6), or >or=8 and <11 mm (P<.02; VAS decreased 4.8 +/- 1.3). Nonmenstrual pain severity was correlated with JZ thickness (r = 0.51, P=.004) at 3 months with a significant decrease in nonmenstrual pain only in women with a JZ <8 mm (VAS decreased 4.0 +/- 0.7, P<.0001). The association between dysmenorrhea and nonmenstrual pain reduction and thinner JZ remained after controlling for medical treatment.

CONCLUSION(S): Following surgical excision of endometriosis, chronic pelvic pain was significantly more likely to persist with JZ thickness >11mm on preoperative MR imaging. This suggests that myometrial JZ abnormalities or adenomyosis may contribute to chronic pelvic pain in women with endometriosis.