Chronic Pain

Chronic pain presents a number of challenges to researchers and clinicians, leaving many patients to endure and suffer chronic pain for many years and even a lifetime for some. Attempts to understand, treat and alleviate the suffering caused by pain is one of the most important aspects of healthcare and medicine. The subjective nature of the pain experience and the different pathophysiological mechanisms involved in pain all contribute to the challenges in understanding and treating chronic pain. Conventional pharmacological treatment approaches have been providing some relief to patients who suffer chronic pain, but those who suffer may seek alternative treatments for a number of reasons, ranging from the lack of effective analgesia to the

The introduction of modern medical and scientific imaging technologies has allowed researchers and clinicians to gain a much better understanding of acute and chronic pain pathophysiology.

Acute pain is well understood, it functions as a protective warning system and is important for human survival. Pain informs when damage to the body is imminent or has taken place, so that action can be taken to prevent or protect from further damage taking place. Physical response to acute pain is automatic. When one removes a hand from a hot surface to prevent damage to the skin tissue, or shields and injury from further damage, one does not need to think about doing these things. They are automatic unconscious responses that take place through biophysiological processes and mechanisms.

Anatomical, physiological and biochemical mechanisms and processes work together in a complex way to detect damage or potential damage to tissue at a cellular level, sending a message from the peripheral nervous system to the central nervous system which interprets the pain experience and body location. These mechanisms and processes also respond with appropriate control to take action, not only at the site of injury, but also systemically, using other systems, processes and mechanisms of the body, besides just the nervous

Different types of nerve fibres interface with the interneurons and second order neurons in the grey matter laminae of the spinal cord. The laminae is divided into a number of lamina, each providing a specific type of transmission between the nerve fibres and the interneurons/second order neurons. The outermost lamina is where A-delta fibres and C fibres synapse with second order neurons that transmit to the thalamus and then on to the somatosensory cortex and cingulate cortex in the brain, where the perception of the pain experience is processed. In some layers of lamina, A-delta, A-beta and C fibres synapse with interneurons and second order neurons that may synapse with neurons in other lamina. The innermost lamina contain second order neurons that transmit to the locus coeruleus, hypothalamus and amygdala in the brain. Some lamina also contain inhibitory interneurons which prevent signals from transmitting further along the pathway. The dorsal horn of the spinal cord is a complex anatomical structure which needs further explanation, as this is where one of the mechanisms of chronic pain can develop.

As mentioned, different types of nerve fibres synapse in the laminae. A-delta and C fibres synapse with second order neurons that transmit to the thalamus and then on to the somatosensory cortex, cingulate