Defining pain is very much one of those subjects that depends on where you come from, and how you look at it.
Mortimer's (1968) famous fable of the blind men and the elephant is a really useful way of seeing this dilemma.
Once upon a time, there lived six blind men in a village. One day the villagers told them, "Hey, there is an elephant in the village today". They had no idea what an elephant was. They decided, "Even though we would not be able to see it, let us go and feel it anyway". All of them went where the elephant was. Everyone of them touched the elephant.
"Hey, the elephant is a pillar," said the first man who touched his leg.
"Oh, no! it is like a rope," said the second man who touched the tail.
"Oh, no! it is like a thick branch of a tree," said the third man who touched the trunk of the elephant.
"It is like a big hand fan" said the fourth man who touched the ear of the elephant.
"It is like a huge wall," said the fifth man who touched the belly of the elephant.
"It is like a solid pipe," said the sixth man who touched the tusk of the elephant.
They began to argue about the elephant and everyone of them insisted that he was right. It looked like they were getting agitated. A wise man was passing by and he saw this. He stopped and asked them, "What is the matter?" They said, "We cannot agree to what the elephant is like." Each one of them told what he thought the elephant was like. The wise man calmly explained to them, "All of you are right. The reason every one of you is telling it differently because each one of you touched the different part of the elephant. So, actually the elephant has all those features what you all said."
"Oh!" everyone said. There was no more fight. They felt happy that they were all right.
The moral of the story is that there may be some truth to what someone says. Sometimes we can see that truth and sometimes not because they may have a different perspective. A neurologist concerned with the physiology of nerves may conclude that abnormal firing patterns may be the cause of the pain. A psychologist may describe how ones past experiences and emotional response is the cause of the pain. A chiropractor may see a dysfunctional vertebral joint. A physiotherapist a muscle imbalances and another alternative health care professional may decide "chi" or energy in the holistic being as the main problem.
They can all be right (or wrong) and is a hallmark of the diversity of pain. The most widely adopted definition is that of the International Association for the Study of Pain (IASP); "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in such terms".
This definition encompasses many components, allowing it to satisfy the blind men and elephant metaphor. There is consideration for the fact that there is definitely an unpleasant feeling we describe when we are in pain, and that how we actually describe it is a factor, a behavioural one. Something many of us, including practitioners, struggle to come to terms with, is that pain and tissue damage are not one and the same. Tissue damage does not mean that there will be a predictable uniform pain response to let you know about it.
Here are some examples from the research, this section may seem heavy but the point is important, please bear with me.
Low backs: Eighty per cent of people with no back pain were found to have one bulging disc and 38% two or more bulging discs on Magnetic Resonance Imaging (MRI)1
It was concluded in a recent systematic review that degenerative changes seen on MRI or spinal x-ray should be viewed as a normal part of ageing and considered common in individuals without pain2.
Tissue damage, no pain.
Shoulders: Thirty-four per cent of people with no shoulder pain or symptoms such as weakness were found to have rotator cuff tears on MRI. This increased to 54% when only considering those over sixty3. Another study found that of people over 30 who have shoulder muscle tears, only 1 in 3 actually experience pain or limited activity4. Further research used ultrasound to image participants shoulders and found 96% had "abnormalities" but no symptoms, no pain5. Among those who have had successful surgery, experience no pain and regain all movement, 1 in 5 still have a muscle tear 6.
Tissue damage, no pain.
Knees: In a group of people with clinical symptoms of knee osteoarthritis, 76% were found to have meniscal tears but no associated pain7. Others have reported that only 50% of people with arthritis of the knee on MRI experience pain 8. In American college basketball players with significant issues identified on their scan, 1 in 3 do not have knee pain 9. An editorial in the British Journal of Sports Medicine stated that degenerative meniscus tears should be looked upon as "wrinkles with age"10.
Tissue damage, no pain.
Hips: A similar story can be found in people with no hip pain, 75% of their scans demonstrate 'issues in the tissues'11. For example, in hockey players with no hip pain, 2 out of 3 have scans that show significant age related changes to their hips12.
Tissue damage, no pain
Necks: A large study of MRIs done on the cervical spines of 1211 participants ages 20-70 found that 88% of them had a bulging disc. For participants in their twenties, 73% of the males and 78% of the females had bulging discs, again, no pain13.
Another study suggested that amongst people with significant ageing on imaging, only 10% actually have neck pain14. Interestingly, in demolition derby drivers who crash 1500 times during their career, only 2% experience long lasting neck pain 15.
Again, tissue damage, no pain.
If you have made it this far and not drifted off then congratulations! Some heavy text there but hopefully it has made for a strong message. The research is clear, injury does NOT equal pain. You may have been told you have any of the above mentioned 'issues in the tissues' (bulging disc in the neck / back, rotator cuff tear in shoulder, torn meniscus in knee, worn cartilage in hip.....), and they may well be true and present, but not necessarily explaining the pain you have. Of course they could be involved but might be analogous to only looking at the tail, or the tusk of our metaphorical elephant that is pain.
So often is the case that chronic pain (pain >12 weeks) sufferers have their hopes pinned on an issue in the tissue, but when those issues resolve and their pain doesn't it leaves them frustrated and confused.
If pain isn't caused by an injury in my body, what is causing my pain??
Find out in part two...
Luke R. Davies
1. Jensen, M. C., Brant-Zawadzki, M. N., Obuchowski, N., Modic, M.T., Malkasian, D., Ross, J. S. (1994). Magnetic Resonance Imaging of the Lumbar Spine in People Without Back Pain. N Engl J Med. 331(2):69-73.
2.Brinjikji, W., Luetmer, P. H., Comstock, B., Bresnahan, B. W., Chen, L. E., Deyo, R. A., Halabi, S., Turner, J. A., Avins, A. L., James, K. (2014). Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations. AJNR Am J Neuroradiol. [Epub ahead of print].
3.Sher, J. S., et al.(1995). Abnormal fFindings on magnetic resonance images of asymptomatic shoulders. J Bone Joint Surg Am. 77(1):10-5.
4. Reilly, P., Macleod, I., Macfarlane, R., Windley, J., Emery, R. J. (2006). Dead men and Radiologists dont lie: a review of cadaveric and radiological studies of rotator cuff tear prevalence. Annals of the royal college of surgeons of England, 88(2): 116-121.
5.Girish, G., Lobo, L. G., Jacobson, J. A., Morag, Y., Miller, B., Jamadar, D. A. (2011). Ultrasound of the Shoulder: Asymptomatic Findings in Men. AJR Am J Roentgenol., 197(4):713-9.
6. Spielmann, A. L., Forster, B. B., Kokan, P., Hawkins, R. H., Janzen D. L. (1999). Shoulder after Rotator Cuff Repair: MR Imaging Findings in Asymptomatic Individuals - Initial Experience. Radiology, 213(3), 705-708.
7.Bhattacharyya, T., Gale, D., Dewire, P., Totterman, S., Gale, M. E., McLaughlin, S., Einhorn, T. A., Felson, D. T. (2003). The Clinical Importance of Meniscal Tears Demonstrated by Magnetic Resonance Imaging in Osteoarthritis of the Knee. J Bone Joint Surg Am. 85-A(1):4-9.
8. Munk, B., Lundorf, E., Jensen, J. (2004). Long Term Outcome of Meniscal Degeneration in the Knee: Poor Association Between MRI and Symptoms in 45 Patients Followed More than 4 Years. Act Orthopaedica Scandinavia Journal, 75(1): 89-92.
9. Major, N. M., Helms, C. A. (2002). MR Imaging of the Knee: Findings in Asymptomatic Collegiate Basketball Players. American Journal of Roentgenology, 179(3): 641-644.
10. Risberg, M. A. (2014) Degenerative Meniscus Tears Should be Looked Upon as Wrinkles with Age–and Should be Treated Accordingly. Br J Sports Med, 48(9):741.
11. Register, B., Pennock, A. T., Ho, C. P., Strickland, C. D. Lawland, A., Philippon, M. J. (2012). Prevalence of Abnormal Hip Findings in Asymptomatic Participants: a Prospective, Blinded Study. American journal of Sports Medicine, 40(12): 2720-2724.
12. Silvis, M. L., Mosher, T. J., Smetana, B. S. (2011). High Prevalence of Pelvic and Hip Magnetic Resonance Imaging Findings in Asymptomatic Collegiate and Professional Hockey Players. American Journal of Sports Medicine, 39(4): 715-721.
13. Nakashima, H., Yukawa, Y., Suda, K., Yamagata, M., Ueta, T., Kato, F. (2015). Abnormal Findings on Magnetic Resonance Images of the Cervical Spines in 1211 Asymptomatic Subjects. Spine (Phila Pa 1976), 40(6):392-8.
14. Okada, E., Matsumoto, M., Fujiwara, H., Toyama, Y. (2011). Disc Degeneration of Cervical Spine on MRI in Patients With Lumbar Disc Herniation: Comparison Study With Asymptomatic Volunteers. European Spine journal: Official Publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical spine Research Society, 20(4): 585-591.
15. Simotas, A. C., Shen, T. (2005). Neck Pain in Demolition Derby Drivers, Archives of Physical Medicine and Rehabilitation, 86(4): 693-696.