PALM DESERT, CALIF. — More than one in seven healthy parturients report residual pain 6 months after undergoing an elective cesarean section, a Belgian research group reported at the annual meeting of the Society for Obstetric Anesthesia and Perinatology.
Three characteristics distinguished patients suffering chronic postoperative pain from those who reported no pain at 6 months: higher pain scores 24 hours after surgery; a greater likelihood of reporting wound hyperalgesia at 24 and 48 hours; and a previous history of a genitourinary infection.
Patricia M. Lavand'homme, M.D., said her 100-subject study is one of the first to address the issue, despite the rising rate of elective C-sections and the importance of identifying risk factors that may point to preventive strategies.
“I think we really, really need to have more studies,” she remarked.
One previous study included all C-sections, including emergency procedures, and found that 12% of patients still suffered residual pain and discomfort after an average of 10 months, and among these patients, 6% had daily pain. General anesthesia appeared to induce more residual pain and discomfort than did spinal anesthesia (Acta Anaesthesiol. Scand. 2004;48:111–6).
She and her associates at the Université Catholique de Louvain in Brussels prospectively followed 100 healthy women who had undergone elective C-section.
At 6 months, 15 reported chronic pain around the scar. In four women, the pain was intense enough to require analgesics, including codeine and NSAIDs, at least three times a week. The pain was associated with a visceral component in two of the subjects with chronic pain.
No significant differences were found in women with or without chronic pain in terms of previous C-sections or other abdominal surgeries, age, number of pregnancies, endometriosis, or obstetric procedures.
Eight of 15 patients who had chronic pain reported previous genitourinary infections, compared with just 14 of 85 patients with no pain at 6 months. This difference was statistically significant.
At 24 hours, patients who would go on to experience chronic pain rated their pain at rest as a 30 and with movement as a 72 on a 100-point visual analog scale. Patients whose pain resolved before 6 months averaged visual pain scores of 17 at rest and 46 with movement. These differences between groups were also significant.
Chronic pain patients also experienced postoperative wound hyperalgesia at far higher rates than other patients (10 of 15 patients at 24 hours, compared with 20 of 85 in the no chronic pain group, and 8 of 15 patients at 48 hours, compared with 12 of 85 patients).
In response to a question from an audience member, Dr. Lavand'homme said the type of C-section incision used might play a role in rates of residual pain. All patients in the study received a Pfannenstiel incision with peritoneal layer closure. This incision is more comparable with the incision for an inguinal hernia repair—a surgery linked to high rates of residual pain—than is a vertical incision, she said.
However, much more study is needed to determine what specific factors contribute to chronic post-C-section pain and discomfort, Dr. Lavand'homme stressed.