The following is a summary of “Evaluation of a scoring system for the detection of central sensitization among women with chronic pelvic pain,” published in the NOVEMBER 2023 issue of Obstetrics and Gynecology by Cardaillac, et al.

Chronic pelvic pain often involves central sensitization, characterized by heightened sensitivity to non-painful stimuli. Despite its association with pelvic pain, there was a lack of studies objectively assessing central sensitization through neurophysiological tests in the pelvic and perineal area among women with chronic pelvic pain. For a prospective, assessor-blinded, comparative study, researchers sought to evaluate nociceptive thresholds (primary objective) and the spatial and temporal diffusion of pain in women with chronic pelvic pain, distinguishing between those with high and low scores of central sensitization.

The study included a cohort of women with chronic pelvic pain, categorized into high (>5/10; n=29) and low (<5/10; n=24) central sensitization scores based on the Convergences PP criteria. Participants underwent noninvasive bladder sensory testing, rectal barostat testing, and sensory tests using an algometer and vulvagesiometer. Poststimulation pain (minutes), quality of life (assessed through the Medical Outcomes Study 36-Item Short Form Survey), and psychological state, including anxiety (State-Trait Anxiety Inventory), depression (Beck Depression Inventory Short Form), and catastrophizing (Pain Catastrophizing Scale), were also evaluated.

The participants predominantly suffered from endometriosis (35.8%), irritable bowel syndrome (35.8%), bladder pain syndrome (32.1%), and vestibulodynia (28.3%). Baseline characteristics were comparable between the groups. Women with a high sensitization score were diagnosed with more painful diseases (2.7±1.3 vs 1.6±0.8; P=.002) and had a longer duration of suffering (11±8 vs 6±5 years; P=.028) compared to those with a low score. Bladder maximum capacity was similar (399±168 vs 465±164 mL; P=.18), but pain at each cystometric threshold was significantly higher in women with a high sensitization score. No difference was observed in the rectal pain pressure step (29.3±5.5 vs 30.7±6.5 mm Hg; P=.38). Rectal compliance was reduced in women with a high sensitization score, leading to a substantial increase in pain. Average pain pressure thresholds at vulvar sites and muscles were significantly lower in high sensitization score participants (P=.0003 and P=.0002, respectively). Participants with high sensitization scores required a longer time to achieve a VAS <3 out of 10 after bladder (4.52±5.26 vs 1.27±2.96 minutes; P=.01), rectal (3.75±3.81 vs 1.19±1.23 minutes; P=.009), and muscular stimulation (1.46±1.69 vs 0.64±0.40 minutes; P=.002). Psychological states were equivalent between groups, and no association was found between sensory thresholds and psychological factors. The physical component of the quality of life score was reduced in women with high sensitization scores (P=.0005), with no difference in the mental component.

The study, utilizing neurophysiological tests, demonstrated that objective elements exist for assessing central sensitization independently of psychological factors.

Source: ajog.org/article/S0002-9378(23)00516-1/fulltext