Anesthetic Management of a Patient With Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-Like Episodes Syndrome During Extensive Spinal Surgery With Both Motor Evoked Potentials and Somatosensory Evoked Potentials: A Case Report.

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a complex and infrequently encountered mitochondrial cytopathy. Patients with MELAS often present with multi-systemic manifestations, making their anesthetic management particularly challenging. In this case report, we describe in detail our anesthetic approach for a 19-year-old male with confirmed MELAS linked to an m.3243A>G mutation. The patient had been diagnosed with MELAS at age 12 following a stroke-like episode and presented with progressive spinal deformities. He exhibited a 70° thoracic spine curvature and an 80° kyphosis, requiring a T1-L2 posterior spinal fusion. The surgical plan included neuromonitoring with both somatosensory and motor evoked potentials. Intravenous anesthetics such as propofol are typically preferred in this context due to their reduced interference with neuromonitoring compared to volatile anesthetics. Anticipating a surgical duration of six to seven hours, however, we hesitated to rely on propofol for this extended period due to its potential risks of lactic acidosis in the context of MELAS. Given that propofol infusion for extended periods (>48 hours) or at high doses (≥5 mg·kg