RESUMO
BACKGROUND: Preoperative pain sensitivity (PPS) can be associated with postsurgical pain. However, estimates of this association are scarce. Confirming this correlation is essential to identifying patients at high risk for severe postoperative pain and for developing analgesic strategy. This systematic review and meta-analysis summarises PPS and assessed its correlation with postoperative pain. METHODS: PubMed, Scopus, Cochrane Library, and PsycINFO were searched up to October 1, 2023, for studies reporting the association between PPS and postsurgical pain. Two authors abstracted estimates of the effect of each method independently. A random-effects model was used to combine data. Subgroup analyses were performed to investigate the effect of pain types and surgical procedures on outcomes. RESULTS: A total of 70 prospective observational studies were included. A meta-analysis of 50 studies was performed. Postoperative pain was negatively associated with pressure pain threshold (PPT; r=-0.15, 95% confidence interval [CI] -0.23 to -0.07]) and electrical pain threshold (EPT; r=-0.28, 95% CI -0.42 to -0.14), but positively correlated with temporal summation of pain (TSP; r=0.21, 95% CI 0.12-0.30) and Pain Sensitivity Questionnaire (PSQ; r=0.25, 95% CI 0.13-0.37). Subgroup analysis showed that only TSP was associated with acute and chronic postoperative pain, whereas PPT, EPT, and PSQ were only associated with acute pain. A multilevel (three-level) meta-analysis showed that PSQ was not associated with postoperative pain. CONCLUSIONS: Lower PPT and EPT, and higher TSP are associated with acute postoperative pain while only TSP is associated with chronic postoperative pain. Patients with abnormal preoperative pain sensitivity should be identified by clinicians to adopt early interventions for effective analgesia. SYSTEMATIC REVIEW PROTOCOL: PROSPERO (CRD42023465727).
RESUMO
As electrically generated solitons in liquid crystals, directrons represent intriguing structures promising extensive application prospects in the areas of microcargo vehicles, microreactors, and logic devices. However, manipulating directrons along elaborate predetermined trajectories still remains to be largely explored. In this work, the strategy of constructing high-resolution periodic alignment fields for directrons via the polarization holography photoalignment technique is presented. The optimum exposure dose for directrons to form over a broad range of electric fields is determined to be 32.4 J cm-2 for the alignment layers with 1 wt% azo dye SD1. Zigzag and fishhook-shaped trajectories of directrons are realized with two orthogonal polarized beams. The resolution for zigzag steering of directrons is evaluated to be approximately 56 µm to 80 µm, about three to four times the length of directrons. These results not only enrich the forms of motion of directrons, but also lay the foundations for customized trajectories of directrons in future developments.
