Acute Pain, Postoperative

This prospective observational study aims to evaluate whether rebound pain after peripheral nerve block is associated with the development of chronic postsurgical pain following elective total knee arthroplasty. Adult patients undergoing unilateral total knee arthroplasty under spinal anesthesia and receiving a peripheral nerve block as part of routine multimodal analgesia will be included. No additional intervention, drug administration, or biological sampling will be performed beyond standard clinical care. Rebound pain will be assessed during the early postoperative period using pain diaries, numeric rating scale pain scores, and analgesic consumption records. Chronic postsurgical pain and related outcomes will be evaluated at postoperative 3 and 6 months using validated instruments assessing pain severity, neuropathic pain features, psychological status, functional outcomes, and health-related quality of life. The primary outcome is the presence of chronic postsurgical pain at 3 months after surgery. Secondary outcomes include chronic pain at 6 months, pain intensity, neuropathic pain characteristics, opioid consumption, rescue analgesic requirements, sleep disturbance, and quality-of-life measures. The study also aims to explore demographic and clinical factors associated with rebound pain and chronic postsurgical pain.

This study aims to better understand how acute pain and responses to pain treatment can be measured in children and adolescents using a non-invasive device. Pain is usually assessed using self-reported or observational scales, which can be difficult to interpret, especially in pediatric patients. This study will evaluate whether a novel device, the AlgometRx Nociometer, can provide an objective measure of nociceptive pain. Participants ages 6 to 21 years who are undergoing elective surgery or bone marrow transplantation will be enrolled at Children's National Hospital. The device measures changes in pupil size in response to gentle electrical stimulation, which reflects activity in pain-related nerve pathways. Measurements will be taken before and after procedures and during routine hospital care, alongside standard pain assessments. This is an observational study. Participation will not change or guide any medical treatment, and all pain management will follow standard clinical care. The information collected may help improve future pain assessment and treatment for pediatric patients.