Perioperative airway management for aortic valve replacement in an adult with mucopolysaccharidosis type II (Hunter syndrome)

We herein report anesthetic management during aortic valve replacement for aortic valve regurgitation in a patient with adult mucopolysaccharidosis type II (MPS type 2) (Hunter syndrome). This disorder is rare and related to the accumulation of a mucopolysaccharide in lysosomes. It affects various organs, including the airways, heart, and central nerves. In children with MPS type 2, the risk of airway obstruction during anesthesia/sedation is high, and the degree of difficulty increases with aging. The patient described herein was a 33-year-old male without mental retardation. Before surgery, trismus, megaloglossia, and the disturbance of cervical vertebral excursion were noted, suggesting difficulties with ventilation/intubation. Anesthesia was induced under sedation/spontaneous respiration. A laryngeal deployment was conducted using a video laryngoscope; however, the Cormack grade was III. Nasotracheal fiber intubation was performed, and airway obstruction occurred. A muscle relaxant was administered, facilitating ventilation. However, subglottic stenosis, which was not detected before the surgery, made the tracheal tube insertion difficult. Aortic valve replacement was performed without complications. A detailed postoperative examination of the airways revealed oropharyngeal soft tissue outgrowth, narrowing of the upper airway, subglottic stenosis, and displacement/circumflex of the airway axis. Either awake intubation or rapid induction can be selected for this patient; however, either way have risks of airway obstruction. It is important that strategies under light anesthesia or incomplete neuromuscular blockade should be avoided for such our patient as suggested in the JSA airway management guidelines. A preoperative multidisciplinary airway assessment and simulation are important.