McGill Pain Questionnaire: a multi-dimensional verbal scale assessing postoperative changes in pain symptoms associated with severe endometriosis.

BACKGROUND: Objective evaluation of pelvic pain symptoms using a standard pain questionnaire is essential to assessing the treatment of endometriosis and related pain. Aim: To evaluate the McGill Pain Questionnaire (MPQ) as a multi-dimensional verbal scale in providing information about chronic pelvic pain associated with endometriosis, before and after laparoscopic surgery. METHODS: Fifty-five women undergoing laparoscopy for severe endometriosis were asked to complete the MPQ before surgery and at the 6-month follow up. All patients presented with preoperative pain symptoms of variable severity. We obtained the pain indexes and studied their relation with: patients' characteristics (age, body mass index, parity, qualification, occupation); operative findings (number, site and size of endometriotic lesions and presence of pelvic adhesions); and postoperative evolution of variable MPQ pain indexes at the 6-month follow up. RESULTS: Median present pain index (PPI) (index of pain intensity), before surgical treatment was 3 (2-4): preoperative PPI was <2 in 25% of patients while 25% of patients had PPI > 4. Overall median PPI after surgical treatment was 1 (0-2): postoperative index of pain intensity was <1 in 50% of patients, >2 in 25% of patients while 25% of patients did not experience postoperative pain. Overall pain intensity significantly decreased after laparoscopic treatment of endometriosis (Wilcoxon test P < 0.0005). None of the patients' characteristics were found to be significantly correlated with the severity or improvement of preoperative pain at postoperative follow up (P > 0.05), and the intensity of preoperative pain was not correlated to any of the operative variables. There was a significant reduction in all individual MPQ pain indexes; however 18.2% of women did not show improvement of pain symptoms after laparoscopic surgery. An increasing endometrioma diameter was associated with a significant decrease in the difference in evaluative rank score of pain rating index between pain indexes at the 6-month follow up and preoperatively (P = 0.04, Spearman's rank correlation Rho = -0.277). CONCLUSIONS: MPQ appears to be useful as a multi-dimensional scale in describing patients' pain semiology and evaluating pain evolution after surgical treatment. However, due to the extreme variability of pain experience, MPQ results don't clarify the relationship between pain intensity and the severity of endometriosis.