Perioperative Management of Orthognathic Surgery in Patients with Neurally Mediated Syncope

Neurally mediated syncope is characterized by a sudden and transient loss of consciousness without specific cardiovascular or central nervous disease.It includes vasovagal syncope, carotid sinus syndrome, situational syncope, and emotional syncope.The syncope is usually triggered by prolonged standing, pain, fear, stress, fatigue, and dehydration.The disruption of the balance between the sympathetic and vagal nerves leads to decreased sympathetic tone and increased vagal tone, resulting in decreased blood pressure, bradycardia, and cardiac arrest, followed by loss of consciousness and syn-cope.Here, we report the perioperative management of a 27-year-old woman with jaw deformity, who was diagnosed with neurally mediated syncope.The use of a temporary external pacemaker allowed for safe circulation control during the orthognathic surgery and the perioperative period, to prevent bradycardia and sinus arrest.Even in patients with jaw deformities complicated by hemodynamic instability, orthognathic surgery can be performed safely through close interdisciplinary collaboration. Key words: neurally mediated syncope( 神 経 調 節 性 失神) ，orthognathic surgery(顎矯正手術) ，temporary external pacemaker(体外式ペースメーカー) ［Received Nov. 11, 2025］ 緒 言 神 経 調 節 性 失 神(neurally mediated syncope， 以 下 NMS)は，器質的な心疾患がなく，心血管系や中枢神経 系などの原因が解明できない失神であり 1-3) ，