Good Stress Response May Enhance Recovery From Surgery
According to a study led by Stanford University School of Medicine researchers, the proper kind of stress response can lead to a much quicker recover for people who have had knee surgery. These results might be able to be used to develop methods for forecasting how well some patients will manage after they leave the hospital.
The study published today in the Journal of Bone and Joint Surgery, discovered through a blood test that patients whose immune systems responded to the stress recovered more fully. These results bring to light that a very simple and inexpensive blood test performed while patients are on the operating table could predict how well patients will have recovered months after they leave the hospital. Doctors are hoping that this could lead to developing medical interventions to improve that recovery.
“One of the beauties of the tests is that it’s so easy,” said Esther Sternberg, MD, chief of the section on neuroendocrine immunology and behavior at the National Institute of Mental Health, who was not involved in the research. “The information is completely available to any physician pre- and post-surgery.”
Old models of stress and the immune system predicted that stressful situations would suppress immune activity. Firdaus Dhabhar, PhD, Stanford associate professor of psychiatry and behavioral sciences and senior author of the paper, doesn’t believe that and said those models didn’t differentiate between unhealthy chronic stress, which can negatively affect the immune system, and healthier short-term stress. Short-term stress, Dhabhar said, launches the “fight-or flight” response, which he described as “one of nature’s fundamental protective survival mechanisms.”
This is not Dhabhar first study into this. In previous studies he found that when mice are in stressful circumstances for just minutes to hours, their immune cells flood out of the spleen and bone marrow and into the bloodstream, causing a noticeable increase in their numbers within five to 10 minutes.
Dhabhar and his colleagues enlisted 57 patients who were scheduled for surgery to repair damaged cartilage in their knee joints. He made sure all the surgeries were performed by Peter Jokl, MD, professor and vice chair of orthopedics and rehabilitation at Yale University to ensure that the surgical procedure would be as consistent as possible
Three to ten days before the surgery, patients gave blood samples to establish a baseline count of immune cells in their blood. On the morning of surgery, the researchers took another blood sample and a half-hour after surgery the patients gave a final sample while in the recovery room.
Researchers followed up with patients for one year, checking knee inflammation and using the Lysholm scale, a well-respected questionnaire, to rank knee function and pain. What they discovered were patients who showed the positive stress response during surgery showed increased recovery as early as one week post-surgery compared to low responders, an effect that carried all the way through the study period.
Surprisingly, the researchers also discovered that women were less likely to show an adaptive response than men and achieved lower overall knee recovery than men. However, when women did show adaptive immune cell redistribution, their recovery matched that of men with the same adaptive response.
Dhabhar’s next step is to investigate the biological links between the stress-induced immune activation and recovery, and to test the immune measurements in other types of surgery.