Chronic pain after surgery is a major health problem but little is known about individual pain experiences and how and why pain usually resolves. A leading pain researcher reported at this year's American Pain Society Scientific Summit that recent studies yield clues about mechanisms believed to be responsible for pain resolution variability and how they might be manipulated to speed recovery and diminish likelihood for long-lasting severe pain.
Dr. James C. Eisenach, professor of anesthesiology and physiology at Wake Forest University School of Medicine, explained in a plenary session talk that physical, metabolic or chemical injury to tissues typically cause acute pain followed by resolution, but individuals vary considerably in the degree and speed of resolution.
“In most cases, post-surgical pain completely resolves, but in many patients, pain may fluctuate in severity up to three weeks following surgery and we need better understanding of the psychosocial, genetic, and neurobiologic factors that underlie this variability,” said Eisenach. “Studying time courses of acute pain might be useful in assessing the efficacy of interventions aimed at speeding recovery and reducing the incidence of chronic post-surgical pain.”
Eisenach reported data from a Wake Forest study of women undergoing Cesarean section births. Patients were given routine surgical, anesthetic and postoperative care. Following discharge, they completed surveys covering pain duration and severity until 60 days post-surgery. “Daily diary entries allow for analysis of change points in response to complete resolution or development of a new pain state,” explained Eisenach.
Data from the study, according to Eisenach, showed that less than one per cent of Cesarean section patients developed post-surgical chronic pain. However, individuals reported a wide variety of day-to-day experiences, ranging from very fast resolution of pain (six days) to much slower courses (40 days or more). “The important question is how these two types of patients differ and how best to predict which are which category,” said Eisenach.
Further, Eisenach said that different procedures in different patient populations will result in different initial pain severity and time of resolution.
“Understanding shifting time courses of pain recovery may be useful in assessing efficacy of interventions aimed at speeding recovery for surgical patients or reducing the incidence of chronic postsurgical pain.