Shattered Glass and Painful Illusions

     Thanks to an unfortunate yet interesting event today, I was reminded just how complex the brain’s regulation of pain can be. Distracted by the Georgia Bulldogs football game, I dropped a glass while taking it out of the cabinet. Before I had time to react, the glass shattered all over the counter and floor, making a mess you would think came from a glass three times its size. Being my stubborn self, I refused to put sandals on before cleaning the mess, despite pleas from my fiancée.

      Sure enough a minute later I stepped on a razor sharp piece of glass, or so I thought. I felt a sharp piercing sensation followed by immediate pain and a flexor withdraw because of a piece of glass under my left heel. As I frantically reached for my left foot to examine the damage I was immediately surprised and let out a laugh as I brushed a small crumb of food from my heel. All that pain sensation from something that any other time I would have hardly noticed.

     Despite the empty space now in the cabinet, this was a great reminder of just how well the nervous system can modulate pain. The brain is constantly on the lookout to maintain our survival and the sensation of pain is an extremely effective means to accomplish this (Melzack, 2001). Pain is the implicate perception that tissue is in danger (Moseley, 2007). Put more simply, pain is perceived threat. My glass shattering experience is a great example of this. As I was cleaning up the glass my brain was on high alert trying to save my feet from being damaged by a piece of glass. As soon as my brain received the slightest afferent signal from my heel, it immediately output a painful sensation. Even though this response was maybe a little over the top, it was exactly what my brain should have assumed given the potential threat of the situation. Our brains first priority is to keep us safe.

     However, I couldn’t help but remember a great two part blog post by David Butler, PT, PhD (Part 1, Part 2). As health care professionals we should take great care in how we educate our patients about why they are having a painful experience. We should try to assure patients that, while pain has many uses, it DOES NOT provide a measure of the state of the tissues (Moseley, 2007). In fact, believing that pain accurately reflects the state of the tissues has been shown to increase the perception of pain in subjects with persistent low back pain (Moseley et al 2004, Moseley, 2004). Additionally, neurophysiology education ALONE has been shown to significantly decrease pain ratings in subjects with persistent low back pain. (disclosure: while the results were statistically significant, they were not considered clinically significant) (Moseley et al, 2004)

     In conclusion, understanding pain and being able to provide effective pain education to patients should be considered a high priority clinical skill.

Just Move,

Tank


References:

1. Melzack R. Pain and the neuromatrix in the brain. J Dent Educ. 2001;65(12):1378-1382.
2. Moseley GL. A pain neuromatrix approach to patients with chronic pain. Man Ther. 2003;8(3):130-140.
3. Moseley GL. Evidence for a direct relationship between cognitive and physical change during an education intervention in people with chronic low back pain. Eur J Pain. 2004;8(1):39-45.
4. Moseley GL, Nicholas MK, Hodges PW. A randomized controlled trial of intensive neurophysiology education in chronic low back pain. Clin J Pain. 2004;20(5):324-330.
5. Moseley GL. Reconceptualising Pain According to Modern Pain Science. Physical Therapy. 2007; 169-178