Validation of the Surgical Pain Scales in Women Undergoing Pelvic Reconstructive Surgery

Abstract

Surgical pain scales (SPS) consist of 4 items that measure pain at rest, during normal activities, and during work/exercise and quantify unpleasantness of worst pain, which are valid and responsive in men undergoing hernia repair. Our objective was to evaluate the psychometric properties of SPS in women undergoing vaginal surgery for pelvic organ prolapse and stress urinary incontinence. We modified SPS by converting original response scales from a visual analog scale to numerical rating scales. Numerical rating scales have lower error rates and higher validity than visual analog scale. The sample included 169 women with stage II to IV pelvic organ prolapse and stress urinary incontinence in a randomized trial comparing sacrospinous ligament fixation to uterosacral vault suspension with and without pelvic floor muscle training. Participants completed SPS and SF-36 at baseline, and 2 weeks and 6 months after surgery. Construct validity and responsiveness were examined in cross-sectional and longitudinal data using Pearson correlation and analysis of variance. Pain at rest, during normal activities, and during work/exercise worsened at 2 weeks (P<0.05); and all measures of pain improved from baseline to 6 months (P<0.0001). Construct validity was demonstrated by correlations of 0.51 to 0.74 between SPS and the SF-36 Bodily Pain Scale (P<0.0001). Pain worsened on SF-36 between baseline and 2 weeks in 63% of the participants, and this group demonstrated a mean (SD) increase in pain of 1.9 (2.8) on the SPS (effect size, 0.99), confirming responsiveness of the scale. The modified SPS are valid and responsive in women after pelvic reconstructive surgery.