CROPS Study: Chronification of Post-Surgical Pain and Risk Assessment

Chronic post-surgical pain (CPSP) represents a major clinical problem associated with impaired functional recovery, reduced quality of life, prolonged opioid use, and increased healthcare utilization. The mechanisms underlying pain chronification are multifactorial and involve complex interactions among surgical trauma, inflammatory responses, central sensitization, neuroimmune activation, and psychosocial risk factors. The CROPS study (Chronification of Post-Surgical Pain and Risk Assessment) is a prospective multicenter randomized controlled trial designed to evaluate the impact of perioperative analgesic strategies on the development of chronic post-surgical pain and to validate a novel questionnaire-based pain chronification risk assessment tool in adult patients undergoing cardiac surgery. Participants will be randomized to receive either standard multimodal opioid-based perioperative analgesia or regional anesthesia-based perioperative analgesia incorporating chest wall plane block techniques, including erector spinae plane block, paravertebral block, or PECS block, according to institutional practice. The study will compare postoperative pain intensity, opioid consumption, postoperative recovery, postoperative complications, health-related quality of life, and the incidence of chronic post-surgical pain at 3 months after surgery. In parallel, the predictive performance of the pain chronification risk assessment questionnaire will be evaluated using discrimination and calibration analyses. The study is conducted as an investigator-initiated academic collaboration between the East Slovakia Institute of Cardiovascular Diseases, Košice, Slovakia, and Uppsala University Hospital, Uppsala, Sweden.

Inclusion Criteria: * Age ≥18 years * Elective cardiac surgery requiring median sternotomy, including: * coronary artery bypass grafting (CABG) * aortic valve replacement or repair * mitral valve replacement or repair * ascending aorta surgery * Ability to understand study information * Ability to provide written informed consent * Expected postoperative hospital stay longer than 3 days * Availability for follow-up at 1 week and 3 months after surgery Exclusion Criteria: * Emergency surgery * Cognitive impairment preventing study participation * Serious psychiatric illness interfering with study participation * Language barrier preventing questionnaire completion * Participation in another interventional study affecting pain outcomes * Reoperation for postoperative bleeding * Severe chronic renal failure * Allergy or contraindication to study medication or regional anesthesia techniques * Pregnancy or breastfeeding * Chronic opioid therapy exceeding 60 mg morphine equivalents daily * Extensive emergency aortic surgery (e.g., Thoraflex implantation for acute aortic dissection)