Chondronecrosis of the larynx following use of the laryngeal mask airway.

This case describes the development of laryngeal chondronecrosis after use of the laryngeal mask airway (LMA). A 69-year-old male with prior laryngeal irradiation underwent total knee replacement with general anesthesia via LMA. Postoperatively, he developed laryngeal chondronecrosis, bilateral vocal fold immobility, and aspiration, necessitating tracheostomy and gastrostomy placement. He improved with hyperbaric oxygen therapy, intravenous antibiotics, and endoscopic repair of a residual fistula. Vocal fold motion returned and he was decannulated. Chondronecrosis of the larynx may occur with the use of the LMA, and caution should be used in patients with a history of prior laryngeal irradiation.

The role of the craniospinal nerves in mediating the antinociceptive effect of transcranial electrostimulation in the rat.

Transcranial electrostimulation (TES) has been reported to elicit significant analgesia, but its mechanism of action has not been elucidated. In a recently introduced clinically relevant rat model of TES we have validated and characterized the TES antinociceptive effect, suggesting involvement of the sensory nerves of the rat's scalp in mediating that effect. In this study, we have further investigated the role of the craniospinal nerves by attempting to block the TES antinociceptive effect with local anesthetic injected under the TES electrodes. We also applied different transcutaneous electrical nerve stimulation modalities through the TES electrodes and compared the elicited antinociceptive effect to that of TES. The antinociceptive effect was assessed by measuring nociceptive thresholds in the tail-flick latency test in awake, unrestrained male rats. Data were analyzed by one-way analysis of variance followed by the Bonferroni t-test. The TES antinociceptive effect was significantly reduced after local anesthetic injection, and administration of 100 Hz transcutaneous electrical nerve stimulation was, over time, capable of eliciting the same degree of antinociceptive effect as TES. We conclude that sensory craniospinal nerves play a critical role in mediating the TES antinociceptive action and offer a hypothesis on the underlying mechanism(s) responsible for this action.

The antinociceptive effect of transcranial electrostimulation with combined direct and alternating current in freely moving rats.

UNLABELLED: Transcranial electrostimulation (TES) has been reported to elicit significant analgesia, allowing a substantial reduction of intraoperative opioids. Acceptance of TES into clinical practice is hampered by lack of controlled clinical trials and inconclusive animal data regarding the TES antinociceptive action. This inconclusive data may be explained, in part, by failure in rat experiments to simulate the variables used in humans when TES electrodes are positioned on the skin. In this study we validated the TES antinociceptive effect in a novel animal model of cutaneously administered TES, when the stimulating conditions mimic the ones used in clinical practice. The antinociceptive effect was assessed by measuring nociceptive thresholds in the tail-flick and hot-plate latency tests in awake, unrestrained male rats. Data were analyzed by analysis of variance and mixed-effects population modeling. The administration of TES at 2.25 mA produced an almost immediate, sustained, frequency-dependent (40-60 Hz) antinociceptive effect, reaching approximately 50% of the maximal possible value. We conclude that an antinociceptive effect of cutaneously administered TES can be demonstrated in the rat. Some characteristics of the effect suggest an important role of the sensory nerves of the rat's scalp in mediating the TES antinociceptive response. IMPLICATIONS: Transcranial electrostimulation produces a significant, frequency-dependent antinociceptive effect that may be mediated by cutaneous nerves of the scalp.