Postsurgical Pain and Opioid Use in Older Adults: Effects of Mild Cognitive Impairment

Older adults account for a growing proportion of patients undergoing major orthopedic and complex spine procedures. As the population ages, increasing numbers of surgical patients present with preexisting cognitive impairment that falls short of dementia but may nevertheless influence recovery after surgery. Mild cognitive impairment (MCI) represents an intermediate stage between normal cognitive aging and dementia and is characterized by measurable cognitive deficits with relative preservation of functional independence. Despite the high prevalence of MCI among older surgical patients, limited information is available regarding how underlying cognitive status may influence the biological and physiological mechanisms associated with postoperative recovery. Pain processing is a complex phenomenon involving peripheral sensory pathways, central nervous system modulation, autonomic nervous system regulation, and behavioral responses. Emerging evidence suggests that neurodegenerative processes associated with cognitive impairment may alter pain perception and pain regulation. Structural and functional changes within brain regions involved in pain processing, including areas responsible for sensory discrimination, emotional appraisal, and descending inhibitory control, may affect responses to acute surgical injury. Consequently, individuals with MCI may experience postoperative pain differently than cognitively intact older adults, potentially influencing recovery trajectories and patterns of analgesic utilization. The relationship between cognitive impairment and postoperative recovery has important public health implications. Persistent postsurgical pain remains a significant cause of morbidity following orthopedic and spine surgery, contributing to impaired physical function, reduced quality of life, healthcare utilization, and prolonged exposure to opioid medications. Understanding mechanisms that contribute to variability in pain experiences among older adults may facilitate development of individualized perioperative pain management strategies and improve recovery outcomes in this vulnerable population. This prospective observational study is designed to characterize biological, physiological, and behavioral factors that may underlie differences in postoperative recovery among older adults with and without MCI. The study incorporates multidimensional assessments of pain-related mechanisms before surgery and during postoperative recovery. These assessments evaluate sensory processing, autonomic nervous system function, genetic and plasma biomarkers associated with neurodegenerative disease risk, and patient-reported experiences across multiple domains of recovery. A central feature of the study is the evaluation of pain modulatory function using quantitative sensory testing methodologies. Quantitative sensory testing provides a standardized approach for examining responses to experimentally applied stimuli and allows investigation of mechanisms that cannot be fully evaluated through self-report measures alone. Repeated assessments over time will permit examination of how surgery may influence pain processing and whether trajectories differ according to preoperative cognitive status. The study also evaluates autonomic nervous system activity through measurements of heart rate variability. Reduced parasympathetic regulation has been associated with impaired inhibitory control of pain and may represent an important physiological mechanism linking cognitive impairment and altered pain regulation. Characterizing autonomic function before and after surgery may provide insight into pathways through which neurocognitive changes influence postoperative recovery. Another objective is to explore the contribution of biomarkers associated with Alzheimer's disease risk and neurodegeneration. Genetic susceptibility and circulating biomarkers may provide information regarding underlying neuropathological processes that are not fully captured through cognitive testing alone. By integrating biomarker data with physiological and clinical assessments, the study seeks to identify factors that may explain heterogeneity in postoperative recovery among older adults. The study further aims to examine relationships among cognitive function, sensory processing, autonomic regulation, and healthcare outcomes. Recovery after surgery is multifaceted and extends beyond resolution of acute postoperative symptoms. A comprehensive understanding of recovery requires evaluation of functional status, healthcare utilization, medication exposure patterns, and changes in cognitive performance. Longitudinal follow-up will allow assessment of these interrelated domains and facilitate identification of factors associated with favorable and unfavorable recovery trajectories. Because cognitive impairment often remains unrecognized in routine clinical practice, findings from this study may also inform future strategies for perioperative risk stratification. Identification of measurable physiological or biomarker signatures associated with altered recovery could support development of screening approaches that help clinicians recognize patients who may benefit from tailored perioperative management. Such approaches could include modifications to pain management strategies, enhanced postoperative monitoring, or targeted interventions designed to promote recovery and minimize treatment-related complications. Data generated through this investigation will contribute to understanding of interactions among cognitive aging, neurodegenerative risk, pain regulation, and postoperative recovery. By integrating cognitive, physiological, sensory, biomarker, and clinical data collected over a six-month postoperative period, the study aims to advance knowledge regarding mechanisms that influence recovery in older surgical patients. The resulting information may provide a foundation for future mechanistic studies and intervention trials designed to improve outcomes for older adults with cognitive impairment undergoing major surgery.