When working to pinpoint which patients may experience long-lasting pain after orthopedic shoulder surgery, study results suggest cognitive coping style and genetic predisposition to pain sensitivity may play a bigger role than size or intensity of the operation.

The findings stem from a University of Florida (UF) Health study and appear in a recent issue of the journal PAIN.

It can be challenging to know which patients will continue to have pain postsurgery, says lead investigator Steven George, PT, PhD, an associate professor and director of the Doctor of Physical Therapy program and Brooks Rehabilitation research collaboration at the UF College of Public Health and Health Professions, part of UF Health. The number of individuals having surgery to relieve pain compounds this challenge, he adds.

“Some of the factors that you would think might predict the outcome, such as the size or intensity of the surgery, aren’t as strong as people would have wanted them to be. It has led to researchers looking into individual factors that help determine response to surgery,” George states in a university news release.

The release notes that researchers found among a group of patients who underwent shoulder surgery, those who had both a high pain sensitivity variant in a specific gene, as well as worrying thoughts about pain on a questionnaire, were twice as likely to still have pain one year after surgery.

The UF team’s article included a psychologist, statistician, geneticist, exercise scientist, and surgeons. It describes two studies supported by funding from the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health.

According to the release, the first study aimed to help researchers hone in on the genetic and psychological factors that may be the best predictors of pain intensity and duration. The study indicates nearly 200 healthy participants developed a minor shoulder injury through targeted exercises and had their pain levels measured daily until pain resolved.

During a second study, the release says researchers tested 150 patients undergoing shoulder surgery. The participants responded to two questionnaires that assessed their attitudes and beliefs about pain. One was designed to measure fear of various painful situations, ranging from a paper cut to slamming a hand in a car door, and a second assessed what is known as pain catastrophizing, characterized by beliefs that pain will worsen and nothing can be done to stop it. One week prior to surgery, and 3, 6, and 12 months postsurgery, researchers assessed participants’ pain using a measure of pain intensity that asks respondents to rate their pain on a scale of 0 to 10. Zero indicates no pain and 10 represents the worst pain imaginable.

The release reports that researchers say patients who had a high pain sensitivity variant of the COMT gene and high levels of pain catastrophizing had a more than 40% risk of continued pain 1 year after surgery, compared with less than 20% among patients without those factors.

George explains that the researchers’ goal is “not necessarily to prevent someone from having surgery, it’s to provide information that may help them decide whether they need to look into alternative pain management approaches.”

The release notes that the ability to customize pain treatments remains a long-term research goal and is the topic of a study George is planning to start this year. In the upcoming study, researchers will evaluate whether a medication that targets COMT, in combination with behavioral strategies to address pain beliefs, results in improved pain management for high-risk participants with the minor shoulder injury.

George adds that future research should also examine whether the pain risk factors in this study can be applied to patients undergoing other types of musculoskeletal surgeries.

[Source: University of Florida]