The application of analgesic intervention prior to the surgical incision is called preventive analgesia. Animal experiments have shown that a hyper reflects persistent excitability occurs in response to intense or repeatedly, stimulation mediated pathways nociceptive of the dorsal horn that represents central sensitization, with the persistent excitation of afferent fiber C discharge of neurons in dynamic wide limits of the dorsal horn, a phenomenon which is called revivalThis central sensitization is related to the increase in the perception of pain; the pharmacological blockade of nociceptive pathways until there is stimulation decreases or prevent these changes, preventive analgesia may develop with different analgesic substances has tried to demonstrate the benefit of this type of analgesia to reduce postoperative pain, for example they have shown minimal effect potent inhalational agents (26-29).
Infiltration of wound combined with anesthesia by inhalation seems to have some effect. Trials with opioids appear to have some efficacy (28). Studies with the use of NSAIDs along with other substances is not conclusive, but are encouraging, what motivates this study.