Transcranial Electrostimulation and Obstructive Sleep Apnea Surgery

Postoperative pain after major surgery for obstructive sleep apnea (OSA), such as palatopharyngoplasty (PPP) and maxillomandibular advancement (MMA) is moderate-to-severe, and may persist for weeks. Control of this pain may be difficult, because OSA patients are very sensitive to traditional opioid pain medications, and their side effects. Poorly controlled pain slows down patients' recovery after surgery, including a return to normal daily activities and work, and may also delay wound healing. This study will investigate whether pain relief and recovery after surgery may be improved with the application of a weak electrical current to the skin of the patient's head (transcranial electrostimulation, TES). The TES works by blocking pain in the central nervous system through multiple mechanisms, which result in non-pharmacological pain relief, without drug-associated side effects.

Inclusion Criteria: Patients with moderate-to-severe OSA, presenting for PPP and MMA surgeries. All patients will be American Society of Anesthesiology (ASA) physical status II-III. The subjects should understand informed consent and study instructions. Exclusion Criteria: 1. Patients with a known or suspected genetic susceptibility to malignant hyperthermia, or known sensitivity to Sevoflurane, an inhaled anesthetic agent. 2. Pregnant patients. 3. Patients who are unable to understand the questionnaires or the visual analogue scale (VAS) pain scores, or to keep home diaries. 4. Patients with clinically-significant psychological disorders, psychiatric illness or treatment. 5. Alcohol and drug-abusing patients. 6. Patients with the history of seizures. 7. Patients with the documented or suspected organic brain or psychiatric disease, in particular with the history of hallucinations and delusions. 8. Patients with history of significant eye disease, or head or eye injury, which led to alteration of the cranial anatomy or metallic intracranial implants. 9. Patients with the history of significant surgery of the head and/or eye. 10. Patients with skin lesions and/or defects over the areas where TES electrodes will be applied. 11. Patients with implanted medical devices, including cardiac pacemakers. 12. Patients who participate in other research protocols that may interfere with the study outcomes and objectives. 13. Other patients that may be excluded by the investigator, based on medical history and physical examination.