Pain relief approaches in post-breast cancer surgery and in labor

CHICAGO – As pain physicians, anesthesiologists are committed to conducting research to better understand and treat patients suffering from acute and chronic pain. Two studies from the February issue of Anesthesiology address the relief of pain. The first study examined the link between the type of pain relief provided after breast cancer surgery and the development of chronic pain, while the second study analyzed the connection between the topical drug capsaicin and labor pain.

Breast cancer surgery and chronic pain
Researchers at the Institut Curie-H?pital René Huguenin, Saint-Cloud, France, studied the effectiveness of local anesthetic wound infiltration after breast surgery on chronic pain. “We wanted to determine whether the technique of strong pain relief for a short period of time after surgery reduces the development of chronic postsurgical pain,” explained study authors Aline Albi-Feldzer, M.D. and Christian Jayr, M.D., Ph.D.

More than 230 patients scheduled for breast surgery were randomized to receive local anesthetic wound infiltration or placebo wound infiltration. Acute pain, analgesic consumption, nausea and vomiting were examined every 30 minutes for two hours in the postanesthesia care unit and every six hours for 48 hours. Chronic pain was evaluated at three and six months, and one year after surgery.

Findings revealed local anesthetic wound infiltration after breast surgery significantly reduced the incidence of acute pain in patients (no pain at all) by one half in the first 48 hours after surgery, but did not decrease the incidence of chronic pain at three months (33 percent of patients having had local anesthetic wound infiltration and 27 percent of patients having had placebo wound infiltration). The results question the link that some studies have suggested between the severity of acute pain after surgery and the risk of developing chronic postsurgical pain.

Capsaicin and labor pain
The role of topical application of capsaicin to the uterine cervix in the reduction of labor pain and the expedition of delivery in mice was analyzed by researchers at the American University of Beirut (Lebanon) and Columbia University (NYC). The study analyzed the incidence of four proposed pain behaviors in mice, including no analgesia in labor and the postpartum period, increasing doses of the aJunior