Factors Contributing to Lingering Pain after Surgery: The Role of Patient Expectations.

BACKGROUND: Pain that lingers beyond the early weeks after the acute postoperative period is an important risk factor for chronic postsurgical pain. This study examined the hypothesis that patients' expectations about their postsurgical pain would be independently associated with lingering postsurgical pain. METHODS: The study included 3,628 patients who underwent diverse surgeries between February 2015 and October 2016 in a single U.S. tertiary hospital and participated in the Systematic Assessment and Targeted Improvement of Services Following Yearlong Surgical Outcomes Surveys (SATISFY-SOS) observational study. Preoperatively, patients were asked about their expectations about pain 1 month after surgery. Patients were considered to have lingering postsurgical pain if they endorsed having pain in the area related to their surgeries during a follow-up survey obtained 1 to 3 months postoperatively. The independent associations between preselected perioperative variables and lingering postsurgical pain were evaluated. RESULTS: Of the cohort, 36% (1,308 of 3,628) experienced lingering postsurgical pain. Overall, two thirds (2,414 of 3,628) expected their postsurgical pain to be absent or improved from baseline, and 73% of these had their positive expectations fulfilled. A total of 19% (686 of 3,628) expected new, unabated, or worsened pain, and only 39% (257 of 661) of these had their negative expectations fulfilled. Negative expectations were most common in patients with presurgical pain unrelated to the reason for surgery, undergoing surgeries not typically performed to help alleviate pain. Endorsing negative expectations was independently associated with lingering postsurgical pain (odds ratio, 1.56; 95% CI, 1.23 to 1.98; P < 0.001). Additional major factors associated with lingering postsurgical pain included recollection of severe acute postoperative pain (odds ratio, 3.13; 95% CI, 2.58 to 3.78; P < 0.001), undergoing a procedure typically performed to help alleviate pain (odds ratio, 2.18; 95% CI, 1.73 to 2.75; P < 0.001), and preoperative pain related to surgery (odds ratio, 1.91; 95% CI, 1.52 to 2.40; P < 0.001). CONCLUSIONS: Lingering postsurgical pain is relatively common after diverse surgeries and is associated with both fixed surgical characteristics and potentially modifiable factors like pain expectations and severe acute postoperative pain.

Cognitive flexibility and persistent post-surgical pain: the FLEXCAPP prospective observational study.

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.