The problem with pain scores

If you realize this question, you probably know this scenario: you are sitting in a healthcare facility and after telling your doctor about back pain (or anywhere) they ask, how bad is it?

As a pain medicine specialist, I always have the feeling that the pain score (as it’s called) is a strange ritual. On the one hand, a patient who tells me that he has “seven out of 10” gives me little to work with, because “seven” is a number, but not an objective, reproducible measure of pain. I ask patients to think of “10” as the worst pain they have ever felt or imagined. However, since people’s experiences and ideas differ significantly, one patient may have a broken little finger while another has a broken femur and both report (correctly and accurately from their point of view) “seven out of ten” pain .

If it’s my job to find and fix the cause of a person’s pain, a pain score won’t help me. Why, exactly, became clearer to me on a recent road trip when I ended up at the Les Schwab Tire Center in Walla Walla, Washington State’s wine country.

As I was driving down Highway 12, I noticed a wvoooping sound coming from the rear left side of my Subaru. Thinking a window or door was open, I stopped and found that when I bumped my toe against the left rear tire, the entire wheel wobbled. That seemed bad. I took a closer look and noticed that all of the wheel nuts were loose and that one nut and the bolt behind it were completely missing. So I jacked up the car, tightened the remaining four nuts and made my way to Les Schwab.

Leonel (a mechanic in his twenties whose starched white shirt was as sharp as his mind) listened carefully as I told myself the noise, my bump test, diagnosis, and on-site treatment. After Leonel pretended to be impressed with my mechanical abilities, Leonel responded with a series of reasonable questions: When did it start (about 30 km ago), had it ever happened before (no), when was the last time I had mine Tires? Looked at Costco about two weeks ago) and what I wanted to do (repair). At no point did Leonel ask me how intense the noise was or how much I felt that the left rear wheel pathology was affecting the rest of my Subaru or my life – on a scale of zero to 10. I suspect the idea never would Leonel’s mind was crossed.

And why should it? My perception of the noise or the bike sickness had no influence on what Leonel would do. Leonel’s goal was to find the problem and fix it.

After about an hour he called me back to his bay, where my Subaru was raised to eye level. A pathological report: he handed me the broken bolt, showed me with his only flashlight where my bike was damaged and explained to me why I had to buy a new bike. Leonel was a good doctor. He found the problem and fixed it – and quickly.

Of course, back pain is not as easy as having a tire problem. On my Subaru, the strange noise (a symptom) was a sure sign that something had gone wrong (damage). However, many of my patients believe that their back must be damaged because they have back pain. In fact, the more severe their back pain, the more convinced people are that their back is damaged. Similar to what I expected from Leonel – my patients expect me to find and fix their back injuries.

But back pain and back damage do not necessarily belong together. A large-scale review showed, for example, that 3,110 asymptomatic people had disc degeneration in 27 percent of 20-year-olds up to 96 percent of 80-year-olds. Disc protrusions were found in 30 percent of 20-year-olds to 84 percent of 80-year-olds. However, none of these people reported back pain.

Radiologists love this paper. When I order a lumbar MRI for a patient with back pain, the radiologist often leaves me a short note at the end of their report citing this study and suggesting that the MRI results be interpreted with “caution”. The radiologist reminds me that an MRI doesn’t work like Leonel’s pen light – it immediately shows the problem and how to fix it. Why? While back damage can certainly cause back pain, the presence of one does not require the other. If someone without back pain can have a back injury, the pain they’re having may be caused by something else.

What this “other” is remains unclear, which puts me in a bind as a clinician, because like Leonel, in order to be able to solve a problem effectively, I have to find it first. This is where my training in psychiatry has proven helpful.

Depression and anxiety are extremely common in people with chronic pain: An analysis of 5,381 pain patients showed that a third had either depression or anxiety and about half had both depression and anxiety. It could be that back pain is depressing, but it could also be that depression can manifest as back pain, or maybe some types of depression and back pain have the underlying causes. Patients insist that I look at their back because it hurts there. But with some patients, I may be looking in the wrong place.

Note that patients with chronic musculoskeletal pain who also have depression or anxiety are usually not helped by acute pain medication (e.g., opioids, NSAIDs), but many respond well to drugs used to treat depression and anxiety. What this suggests is pretty obvious: depression, anxiety, and pain all emanate from the brain and nervous system. So it makes sense that improving or restoring healthy brain function would improve a wide variety of problems.

But how do I identify these patients? How could I more clearly define someone’s clinical problem to make my find-and-fix routine more effective?

There has to be a better way of asking the patient to describe zero to ten different facets of their experience. Questions like that make me feel like I’m just stepping on the tires with a much bigger and complex problem.

This is an opinion and analysis article; the views expressed by the author or authors are not necessarily those of Scientific American.