Hyoid Syndrome

Hyoid Syndrome

Hyoid syndrome is caused by calcification and inflammation of the attachment of the stylohyoid ligament to the hyoid bone. The stylohyoid ligament’s cephalad attachment is to the styloid process, and its caudal attachment is 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. The pain of hyoid syndrome is sharp and stabbing and occurs with movement of the mandible, turning of the neck, or swallowing.

What are the Symptoms of Hyoid Syndrome

The pain of hyoid syndrome starts below the angle of the mandible and radiates into the anterolateral neck. It is triggered or worsened with chewing, rotation of the cervical spine, and swallowing. The pain of hyoid syndrome is sharp and stabbing and often is referred to the ipsilateral ear.

Some patients also may complain of a foreign body sensation in the pharynx. Injection of the attachment of the stylohyoid ligament to the greater cornu of hyoid bone with local anesthetic and steroid serves as a diagnostic and therapeutic maneuver.

How is Hyoid Syndrome diagnosed?

A 22-gauge, 1 1⁄2-inch needle is attached to a 10 mL syringe. At a point 1 inferior to the angle of the mandible in a plane perpendicular to the skin, the needle is advanced toward the hyoid bone.

Injection of the ligament with local anesthetic can serve as a diagnostic maneuver to help strengthen the diagnosis.

Differential Diagnosis

Soft tissue injuries to the region may mimic styloid syndrome. Because trauma is invariably involved in the evolution of the painful condition, the strain and sprain of other soft tissues, such as omohyoid syndrome, often exist concurrently with hyoid syndrome.

Hyoid muscle dystonia may also mimic the signs and symptoms of hyoid syndrome. Primary or metastatic tumors of the neck and hypopharynx and mass effect from thyroglossal duct cyst also may mimic the clinical presentation of hyoid syndrome and should be high on the list of diagnostic possibilities if the history of trauma is weak or absent.

Although clinically similar, glossopharyngeal neuralgia can be distinguished from hyoid syndrome in that the pain of glossopharyngeal neuralgia is characterized by paroxysms of shock-like pain in a manner analogous to trigeminal neuralgia, rather than the sharp, shooting pain that occurs on movement associated with hyoid syndrome.

Because glossopharyngeal neuralgia may be associated with serious cardiac bradyarrhythmias and syncope, the clinician must distinguish the two syndromes.

Treatment

Nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors represent a reasonable first step in the treatment of hyoid syndrome.

The use of tricyclic antidepressants, such as nortriptyline, at a single bedtime dose of 25 mg titrating as side effects allow also is useful, especially if sleep disturbance is present. If symptoms persist, injection of the caudad attachment of the stylohyoid ligament is a reasonable next step.

To perform this injection, the patient is placed in the supine position. The angle of the mandible on the affected side is 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 steadies the hyoid bone and makes identification of the greater cornu and subsequent injection easier.

The skin is prepared with antiseptic solution. A 22-gauge, 1½-inch needle attached to a 10-mL syringe is advanced at this 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.

After contact is 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 done in a similar manner, substituting 40 mg of methylprednisolone for the initial 80-mg dose. Ultrasound and color Doppler guidance may improve the accuracy of needle placement and decrease the incidence of needle-related complications.

Complications

The major complication in the treatment of patients thought to have hyoid syndrome is wrong diagnosis. Occult cervical spine fracture or instability after trauma remains an ever-present possibility.

Failure to diagnose such injuries can put the patient at significant risk for permanent neurological sequelae. As mentioned earlier, if the patient is thought to have a history of trauma, the diagnosis of hyoid syndrome should become one of exclusion.

A careful search for tumors of the neck, apex of the lung, anterior triangle of the neck, and hypopharynx is indicated. If a significant history of vomiting is ascertained, esophageal tear should be considered.

Although the injection technique for hyoid syndrome is safe, complications can occur. In addition to the potential for complications involving the vasculature, if the needle is placed too laterally, the proximity of the brachial plexus, the central neuraxial structures, and the phrenic nerve can result in side effects and complications.

Although these complications should be rare if proper technique is observed, the potential for inadvertent epidural, subdural, or subarachnoid injection remains. Phrenic nerve block also can occur when using this injection technique to treat hyoid syndrome if the needle placement is too posterolateral. In the absence of significant pulmonary disease, unilateral phrenic nerve block should rarely create respiratory embarrassment.

Blockade of the recurrent laryngeal nerve with its attendant vocal cord paralysis combined with paralysis of the diaphragm may make the clearing of pulmonary and upper airway secretions difficult. Because of the proximity of the apex of the lung, pneumothorax is a distinct possibility, and the patient should be informed of this.

Clinical Pearls

The clinician should always evaluate a patient who has pain in this anatomical region for occult malignancy. Tumors of the larynx, hypopharynx, and anterior triangle of the neck may manifest clinical symptoms identical to those of hyoid syndrome.

Given the low incidence of hyoid syndrome relative to pain secondary to malignancy in this anatomical region, hyoid syndrome must be considered a diagnosis of exclusion.

The injection technique described for hyoid syndrome is a simple technique that can produce dramatic relief for patients with the previously mentioned pain problems.

The proximity of the greater cornu of the hyoid bone to major vasculature makes postblock hematoma and ecchymosis a distinct possibility. Although these complications are usually transitory, their dramatic appearance can be quite upsetting to the patient; therefore the patient should be warned of this possibility before the procedure.

The vascularity of this region also increases the incidence of inadvertent intravascular injection. Even small amounts of local anesthetic injected into the carotid artery at this level can result in local anesthetic toxicity and seizures. Incremental dosing while carefully monitoring the patient for signs of local anesthetic toxicity helps avoid this complication.