BACKGROUND Impaired performance on tasks assessing executive function has been linked to chronic pain. We hypothesised that poor performance on tests assessing the ability to adjust thinking in response to changing environmental stimuli (cognitive flexibility) would be associated with persistent post-surgical pain. METHODS We conducted a single-centre prospective observational study in two perioperative cohorts: patients undergoing total knee arthroplasty or noncardiac chest surgical procedures. The co-primary outcome measures compared preoperative performance on the Trail Making Test and the colour-word matching Stroop test between patients who developed persistent post-surgical pain and those who did not. Secondary outcome measures included the associations between these test scores and pain severity at 6 months. RESULTS Of 300 participants enrolled, 198 provided 6 month follow-up data. There were no significant differences in preoperative Trail Making Test B minus A times (33 vs 34 s; P=0.59) or Stroop interference T-scores (47th vs 48th percentile; P=0.50) between patients with and without persistent post-surgical pain (primary outcome). Of those who reported persistent post-surgical pain, poorer baseline performance on the colour-word matching Stroop test was associated with higher pain scores at 6 months in both knee arthroplasty (r=-0.32; P=0.04) and chest (r=-0.44; P=0.02) surgeries (secondary outcome). CONCLUSIONS Preoperative cognitive flexibility test performance was not predictive of overall persistent post-surgical pain incidence 6 months after surgery. However, poor performance on the colour-word matching Stroop test was independently associated with more severe persistent post-surgical pain in both cohorts. CLINICAL TRIAL REGISTRATION NCT02579538.

中文翻译：

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认知灵活性和持续的术后疼痛：FLEXCAPP前瞻性观察性研究。

背景技术在评估执行功能的任务上的表现受损与慢性疼痛有关。我们假设，在评估因应对不断变化的环境刺激（认知灵活性）而调整思维能力的测试中表现不佳将与持续的手术后疼痛有关。方法我们在两个围手术期队列中进行了单中心前瞻性观察性研究：接受全膝关节置换术或非心脏胸腔手术的患者。共同主要结果指标比较了在进行持续性手术后疼痛的患者与未进行手术后疼痛的患者之间进行的Trail制作测试和色词匹配Stroop测试的术前表现。次要结局指标包括这些测试评分与6个月疼痛严重程度之间的关联。结果在300名参与者中，有198名提供了6个月的随访数据。有和没有持续性术后疼痛的患者，术前Trail制作测试B减去A次（33 vs 34 s； P = 0.59）或Stroop干扰T评分（47％vs 48th百分点； P = 0.50）无显着差异。 （主要结果）。在那些报告有持续性手术后疼痛的患者中，彩色词匹配Stroop测试的基线表现较差，与膝关节置换术（r = -0.32; P = 0.04）和胸部（r =- 0.44； P = 0.02）手术（次要结局）。结论术前认知柔韧性测试性能不能预测术后6个月总体持续的术后疼痛发生率。然而，颜色词匹配Stroop测试的不良表现独立地与两个队列中更严重的持续手术后疼痛相关。临床试验注册NCT02579538。