Hypnosis and anesthesia: back to the future.

Hypnosis is a physiological mind activity characterized by focused attention, absorption, dissociation and plastic imagination. In the early 19th century, several hundred surgical interventions were described with hypnosis as the sole anesthetic, in an epoch when no anesthetic drugs were available; then hypnosis was prejudicially abandoned and forgotten after its introduction. In the past two decades, an increasing number of studies on hypnosis has shown its capacity to modify the activity of the prefrontal cortex, default mode network and pain neuromatrix (including the anterior cingulate cortex, amygdala, thalamus, insula and somatosensory cortex) and increase pain threshold up to the level of surgical anesthesia. Hypnotic analgesia also prevents pain-related cardiovascular response: therefore, it may stand comparison with pharmacological anesthesia, yielding true protection from stress for the patient. The wealth of data available in the literature provides clear evidence of its meaningful effects on perioperative emotional distress, pain, medication consumption, physiological parameters, duration of surgery and outcome. Hypnosis may be used as follows: 1) as sole anesthetic, in minor surgery and invasive maneuvers and/or selected patients; 2) as adjuvant of pharmacological anesthesia (local anesthesia and/or sedation); 3) as an adjuvant technique in both pre- and postoperative phases in patients submitted to general anesthesia. Hypnosis, unlike any other therapeutic tools, does not call for drugs or equipment and is an attractive technique: it is free of charge, not burdened with proved adverse events and promises to help improving cost/benefits ratio.