Pathophysiology of postoperative pain
Surgery produces tissue injury with consequent release of histamine and inflammatory mediators, such as bradykinin, substance P, prostaglandins, neurotransmitters (e.g., serotonin), and neurotrophins (e.g., nerve growth factor). Noxious stimuli are transduced by peripheral nociceptors and transmitted by A-delta and C nerve fibers from peripheral visceral and somatic sites to the dorsal horn of the spinal cord. These stimuli are transmitted to higher centers through the spinothalamic and spinoreticular tracts, where they induce suprasegmental and cortical responses to ultimately produce the perception of and affective component of pain.
