Newswise — Surgeons predict at least moderate improvement for almost all patients undergoing back surgery, yet nearly 40 percent of patients have little or no improvement one year after their operation, reports a study in the June 15 issue of the journal Spine.
At least for some patients, the results suggest a "curabo effect," with physician expectations influencing treatment outcomes.
Led by Dr. Bertrand Graz of University of Lausanne, Switzerland, the researchers analyzed 197 patients undergoing surgery for low back pain or sciatica. Before the operation, surgeons were asked to predict how much the surgery would improve each patient's quality of life. The surgeons predicted "a great deal of improvement" for 79 percent of patients and "moderate improvement" for 20 percent.
However, patients were generally less satisfied than the surgeons had expected. Of patients whose surgeon predicted "a great deal of improvement," 56 percent reported no significant improvement in their general health one year after surgery. Whereas surgeons had predicted at least moderate improvement for 99 percent of patients, 39 percent achieved no "minimally clinically important" difference.
In contrast, the surgeons' predictions were related to better outcomes for patients who were not necessarily appropriate candidates for back surgery. Among patients whose surgery was deemed "inappropriate or equivocal"—based on strictly defined criteria—higher surgeon expectations were linked to greater improvement on subjective measures of mental health and general health.
The ability to make a correct individual prognosis is obviously important for doctors recommending any form of treatment, especially surgery. Recent reports have suggested that surgeons predict the outcomes of surgery for sciatica as better than they actually are.
The new study also suggests that surgeons tend to overestimate the benefits of surgery for low back pain and sciatica. On average, patients do have significant improvement one year after back surgery; however, the overall impact on their lives may not be as great as predicted by surgeons.
Ironically, the exception may be patients who don't meet strict criteria for back surgery. Dr. Graz and colleagues suggest that this finding might be explained by a "curabo effect." As opposed to the well-known "placebo effect"—in which improvement results from patients' confidence in treatment—the curabo effect is attributed to the doctor's confidence in his or her own work. The curabo effect might be a kind of "self-fulfilling prophecy": physicians may invest more time and energy in their work with a patient; patients may rate the final results higher when the physician has expressed higher expectations.
Other explanations are possible—in particular, surgeons may truly be able to predict which patients have a better than average chance of cure, even if they're not "ideal" candidates for back surgery. Either way, it may be that physicians tend to get the improvement they expect for some subjective outcomes, despite the fact that the treatment doesn't meet "objective" criteria for appropriateness. "Physician expectation may have by itself an influence on patient outcome," the authors conclude.
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