Chronic pain commonly involves a mix of nociceptive pain and neuropathic pain.
Nociceptive pain, or tissue pain, is pain that is arising and is modulated via the standard physiological pain mechanisms, says Dr Richard Sullivan, a pain medicine specialist and specialist anaesthetist at the Precision Brain, Spine and Pain Centre.
“Neuropathic pain is differentiated from nociceptive pain because it is pain that is arising as a consequence of some disease or disorder of the somatosensory system.
“So there needs to be some lesion in the somatosensory system for the definition of neuropathic pain. For example, painful diabetic neuropathy, postherpetic neuralgia, or trigeminal neuralgia.”
Around 80% of chronic low back pain has some elements of neuropathic pain, says Dr Sullivan.
This is not necessarily overlapping sciatica from neural irritation, he says.
“It can be because the pain has been there for such a long period of time that you get the central disordered process sensitisation and you can actually demonstrate that there are neuropathic elements to that pain,” says Dr Sullivan.