Indications and Clinical Considerations
Hyoid syndrome is caused by calcification and inflammation of the attachment of the stylohyoid ligament to the hyoid bone. Tendinitis of the other muscular attachments to the hyoid bone also may contribute to this painful condition. Hyoid syndrome also may be seen in conjunction with Eagle syndrome or as a sequela of traumatic injuries of the hyoid ( Figure 11-1 ). The pain of hyoid syndrome is sharp and stabbing and occurs with movement of the mandible, turning of the neck, or swallowing. The pain starts below the angle of the mandible and radiates into the anterolateral neck. The pain of hyoid syndrome often is referred to the ipsilateral ear. Some patients also may report a foreign body sensation in the pharynx. Injection of the attachment of the stylohyoid ligament to the greater cornu of the hyoid bone with local anesthetic and corticosteroid will serve as both a diagnostic and a therapeutic maneuver.
Clinically Relevant Anatomy
The styloid process extends in a caudal and ventral direction from the temporal bone from its origin just below the auditory meatus. The stylohyoid ligament’s cephalad attachment is to the styloid process, and its caudal attachment is to the hyoid bone. In hyoid syndrome, the stylohyoid ligament becomes calcified at its caudal attachment to the hyoid bone ( Figure 11-2 ). Tendinitis of the other muscular attachments to the hyoid bone may also occur, contributing to the pain symptomatology.
The key landmark for injection when treating hyoid syndrome is the cornu of the hyoid bone at a point between the mandible and the larynx. This osseous process is more easily identified if the greater cornu of the hyoid on the opposite side is steadied. Given the relationship of the great vessels of the neck to the greater cornu of the hyoid, care must be taken when placing needles in this anatomic area.
The patient is placed in the supine position. The angle of the mandible on the affected side is then identified. The greater cornu of the hyoid bone should lie approximately 1 inch inferior to the angle of the mandible. Gentle pressure at the same point on the contralateral side of the neck will steady the hyoid bone and make identification of the greater cornu and subsequent injection easier ( Figure 11-3 ). The skin is prepared with antiseptic solution. A 22-gauge, 1½-inch needle attached to a 10-mL syringe is advanced at the point 1 inch inferior to the angle of the mandible in a plane perpendicular to the skin. The greater cornu of the hyoid bone should be encountered within 2.5 to 3 cm (see Figure 11-2 ). After contact has been made, the needle is withdrawn slightly out of the periosteum or substance of the calcified ligament. After careful aspiration reveals no blood or cerebrospinal fluid, 5 mL of 0.5% preservative-free lidocaine combined with 80 mg of methylprednisolone is injected in incremental doses. Subsequent daily nerve blocks are performed in a similar manner, substituting 40 mg of methylprednisolone for the initial 80-mg dose.