The 'P' Word
"Placebo" has had a derogatory connotation in health care, implying that a trusted physician or therapist is knowingly administering -- and charging for -- a treatment that's known to have zero clinical effect.
But when it comes to manual therapy, it might be time to reconsider this complicated physiological and psychological mechanism.
"Placebo is not the same as doing nothing," said Joel Bialosky, PT, PhD, OCS, FAAOMPT, clinical assistant professor at the University of Florida, during his presentation "Manual Therapy: How Does it Work?" at CSM 2012 in Chicago. "It's a physiological and psychological response that involves conditioning and expectation."
"Manual therapy and placebo might work through similar mechanisms," said Dr. Bialosky, who co-presented the session with Joshua Cleland, PT, DPT, PhD, OCS, FAAOMPT, physical therapy professor at Franklin Pierce University in New Hampshire. The effectiveness of manual therapy may arise as much through "nonspecific effects" -- such as the patient-clinician interaction and whether patients expect the intervention to help -- then through orthopedic and biomechanical avenues such as increasing mobility or removing tissue adhesions, he said.
Patient expectation is a large part of placebo's effectiveness. Dr. Bialosky lead-authored a study in the Feb. 2008 issue of the journal BMC Musculoskeletal Disorders that correlated patient expectations to clinical outcomes for spinal manipulation for low-back pain. Randomly assigned patients were told to expect either positive, negative or neutral results from manipulation. Those with "good expectations" and "bad expectations" experienced positive and negative clinical results respectively. The most positive results were witnessed in the neutral expectation group.
"Clearly, expectation may play a role in the clinical outcomes we see in our patients," said Dr. Bialosky.
He went on to use the illustration of World War II soldiers storming the beaches of Normandy to convey the message that pain is a sensory and emotional experience that changes with context and perceived threat. Many of these soldiers sustained catastrophic injuries during maneuvers, but continued to run pain-free until they reached a safe place, when the pain became unbearable. Childbirth is another example.
"Pain is multidimensional, and context-related," said Dr. Bialosky. "We get focused on the sensory component." Rather than thinking of manipulation and other manual interventions as operating in solo, its effects are multilayered. "We don't know what the magnitude of the placebo response is in manual therapy," he said.
"I'm not advocating that we knowingly give our patients placebo," concluded Dr. Bialosky. "But we can use it to our advantage."
Leverage the power of patient expectation in your clinical decision making process -- ask whether the patient has had this problem before, and what treatments were successful. If an intervention that you know to be evidence-based has not worked for them in the past, take special care to explain the rationale behind it. Reduce anxiety levels, which have a negative effect on placebo responses.
"Placebo is an active agent," said Dr. Bialosky. "Future research and clinicians should embrace -- not avoid -- its effect."