Psychological Factors that Influence Elective Surgical Outcome for Chronic Pain Patients

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An additional important cognitive risk factor to consider is how the patients think about their pain. Is the pain troublesome or is it killing them? The difference between these two descriptive adjectives is clinically significant. I first started to appreciate the clinical significance of catastrophic thinking after reading a study conducted by Wilbert Fordyce and Stanley Bigos, in 1992. It was an extensive and well designed study where over 3,000 Boeing employees were administered the MMPI. The sample was then followed for three years to determine if a profile could predict who would file a back injury claim. An elevated Scale 3 appeared to be a significant predictor of subsequent back injury. In my opinion, Scale 3 is a good indicator of catastrophic thinking or what I refer to as the "Chicken Little factor." Remember, Chicken Little thought the sky was falling after being hit on the head by an acorn. While at OHSU I conducted a study to determine if we could predict, based on a psychological profile, who would fail a trial of spinal cord stimulation. Scale 3 of the MMPI was found to be a significant predictor of trial failure (see bibliography for citations). These patients with catastrophic thinking are easy to identify just by asking them to describe their pain, or by administering the McGill Pain Questionnaire (MPS) with particular attention to group 16. Melzack constructed the MPS based on his model of pain. I would strongly recommend to the reader his book Pain Measurement and Assessment for a more detailed explanation.

Further evidence of catastrophic thinking can be obtained by asking the patient to rate their pain on a 0-10 point scale, with 10 being the highest rating. The catastrophic pain patient will usually rate their pain at a 10 or higher, even knowing that the scale only goes to 10, and will also describe very little variability over the course of a day. These patients will typically present themselves in a dramatic fashion, usually magnifying their symptoms which will not be consistent with physical findings. In addition, they will usually be more antalgic and hyper-responsive to physical testing. If you perform physiological testing, they will generally be colder in the extremities, have elevated sweat gland activity (EDR or GRS), and exhibit higher surface muscle activity (EMG) readings. In the extreme, these patients may be diagnosed with some type of anxiety disorder or elevated psychophysiologic sympathetic arousal. The surgeon who is considering an elective procedure on a pain patient who is consistent with this typology should proceed with caution. The prudent course of action would include a psychological evaluation from a pain psychologist before proceeding with any major invasive procedure.

Updated on: 09/08/16
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Potential Complications and Avoidance: Part 3

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