A rare case of an unexpected difficult airway management in a diffuse idiopathic skeletal hyperostosis patient and post-operative airway evaluation with 3D printing technique

Diffuse idiopathic skeletal hyperostosis (DISH), asymptomatic in most cases, is a degenerative condition that commonly leads to anterior cervical osteophytes in most elderly patients. Clinically significant airway compression is rare. However, in some cases, the seemingly insignificant osteophytes could become a threat to airway management during intubation. Here we present a case of an 82-year-old man diagnosed as DISH and scheduled for cervical surgery. Radiographic imaging did not indicate the airway compromise. Preoperative airway assessment indicated modified Mallampati scoring of class III. However, an unexpected large bulge protruding from posterior pharyngeal wall blocked video laryngoscopy assisted intubation. Intubation with direct laryngoscope, laryngeal mask airway (LMAD) and Shikani optical stylet were failed. Only flexible fiberoptic nasal intubation was performed successfully. After surgery, an anatomically matched and patient-specific 3D printed model was made to help more direct and comprehensive estimation of the size and the location of the osteophyte. The relationship of the airway compromise and osteophytes was revealed in DISH patients for the first time with the aid of 3D printed model. The eccentric growth of the cervical osteophytes occupied large portion of the laryngopharynx space and prohibited the direct placement of the tracheal tube. This case is a rare presentation of the management of a DISH patient with unexpected difficult airway. We propose for the first time that different intubation strategies should be considered for potential difficulty airway in DISH patients according to the size and location of the osteophytes. For potential difficult airway management of DISH patients, 3D printing technique is a promising way of preoperative airway assessment.