Hidden Sensory Systems a contributor to pain ??
The link below discusses a very interesting article published in the December 15th issue of the journal Pain (sorry, I am not allowed to post the actual article). The authors describe a case of two individuals who have been diagnosed with congenital insensitivity to pain that surprising led normal lives (those affected by the condition usually have excessively dry skin, often mutilate themselves accidentally and usually have severe mental handicaps). What was even more surprising was the fact that during testing performed on these individuals, while all of their skin sensations were severely impaired, the did retain adequate sensations required for daily living! Further multi-molecular microscopic analysis of skin samples revealed that while they indeed have feeling….their skin lacked all of the nerve endings that are normally associated with skin sensation! So how were these individuals feeling anything?
The proposed answer was due to the presence of sensory nerve endings found on the small blood vessels. It is know that vessels are innervated by nerve endings, the Vasa Nervorum. However it was previously thought that this innervation was simply a means of regulating blood flow. Due to the results from this case, they discovered another level of sensory feedback that can provide conscious tactile information. They also propose that “these nerve endings may contribute to mysterious pain conditions such as migraines headaches and fibromyalgia.”
Why would a manual therapist find this interesting??? In theory it might help us to understand the source of pain associated in cases of tendonopathy (which is not well established). It is well established that in cases of degenerative tendonopathy, or tendinosis, that one of the associated histological findings is angiogenesis – an infusion of new blood vessels into the degenerating tendon. Thus as new vessels are created, an increased number of innervating nerve endings accompany them possibly contributing to the hypersensitivity and pain. Another important fact that builds strength in this hypothesis is the fact that studies have shown that with eccentric training, improvement in reported pain levels are matched by a decrease in the number of infusing vessels (which are “killed” off due to the training).
Link to the article summary: