Systematic review and quantitative trend analysis of scientific quality in preclinical studies using rodent models of...

Post-operative pain management is crucial, yet remains a global healthcare challenge with many patients suffering from unexpectedly severe acute pain, leading to impaired recovery and chronic pain. Post-operative pain models are useful for research and intervention development. However, there is substantial variability in design, reporting, and translational relevance. To provide an integrated map that links preclinical model choice, outcome domains, and methodological safeguards to clinical relevance, we conducted a systematic review and quantitative trend-analysis. We evaluated models, outcomes, methodologies, study details, quality, reporting, and patterns in relation to perioperative domains. Screening of 7519 records identified 674 studies, which were analyzed for methodological quality, risk of bias, and reporting trends. Incision models dominated, while procedure-specific models accounted for 14 %. Sex bias was evident, with 83 % of studies using only males and limited justification for single-sex studies. Most pain-related behavior assessments were mechanical (87 %), with non-evoked (24 %) and movement-evoked (5 %) less utilized. The majority used fewer assessments, but 17 % used three or more outcomes. Methodological rigor remains limited, with randomization and blinding reported in just over half of studies, and sample size calculations in only 18 %. Critical details such as housing enrichment or experimenter sex were rarely reported. Together, these patterns motivate a minimum translational set for further studies: combine different behavioural outcomes aligned to perioperative domains, include both sexes or justify single-sex designs, and predefine and transparently report perioperative regimens alongside randomization, blinding, and sample-size planning. We advocate for these changes to improve translational research in this field.