Associations of Preoperative Cerebrospinal Fluid Acetylcholine, BDNF, and IL-1β with Acute Postoperative Pain Across Educational Strata

Purpose

Educational attainment is commonly used as a proxy for cognitive reserve, but whether associations between central pain-related biomarkers and acute postoperative pain differ across educational strata remains unclear. We examined associations of preoperative cerebrospinal fluid (CSF) acetylcholine (ACh), brain-derived neurotrophic factor (BDNF), and interleukin-1 beta (IL-1β) with postoperative pain and explored whether their shapes differed by educational attainment. Patients and methods: This cross-sectional study included 160 adult male participants in China who underwent anterior cruciate ligament reconstruction between September 2014 and January 2016. Educational attainment was categorized as <15 or ≥15 years. Acute postoperative pain was assessed using a visual analog scale (VAS). CSF ACh, BDNF, and IL-1β were quantified by ELISA. Associations with VAS scores were examined using multivariable linear regression, generalized additive models (GAMs), and exploratory two-piecewise linear regression.