Giant 90-mm Ossified Stylohyoid Chain Associated with Restricted Mouth Opening.

Abstract

A 62-year-old man was referred with a six-month history of right submandibular pain followed by dysphagia. At presentation, maximal interincisal opening was 25 mm. Computed tomography angiography demonstrated an ossified right stylohyoid chain extending from the skull base to the hyoid region. It measured 90 mm in length and 17.5 × 10.5 mm at maximal cross-section. The chain contacted the external carotid artery, lay 1.1 mm from the internal carotid artery, and was associated with focal narrowing of the internal jugular vein between the chain and the transverse process of the atlas, with preserved venous patency. Because of restricted mouth opening, tracheal intubation required combined fiberoptic and videolaryngoscopic guidance. Under general anesthesia and neuromuscular blockade, maximal passive interincisal opening, measured with a ruler by the operating surgeon, remained 25 mm before resection and increased immediately to 45 mm after transcervical resection using a diamond burr. Distally, the chain was attached to the lesser horn of the hyoid bone by a residual stylohyoid ligament, which was released without hyoid bone osteotomy. The two excised fragments measured 80 mm in combined length, with an approximately 10-mm proximal segment intentionally retained. Pain was resolved, and maximal interincisal opening was 42 mm at six months. This case highlights the value of vascular imaging, precise definition of stylohyoid measurements, and consideration of Eagle syndrome in unexplained restriction of mouth opening.