Traumatic Atlanto-Occipital Dislocation Presenting With Dysphagia as the Chief Complaint: A Case Report
A 59-year-old male visited the rehabilitation department because of ongoing difficulty swallowing. Two months earlier, a 15-kg piece of iron was dropped on his neck from a height of 10 m. He was admitted and diagnosed with whiplash injury and a compression fracture of the fifth thoracic vertebra. He was treated conservatively, and the neck pain subsided. As the swallowing difficulty continued, he visited the rehabilitation department.\nOn physical examination, there was slight atrophy of the right sternocleidomastoid and upper trapezius muscles. The tongue was deviated to the right, and the gag reflex was impaired but the uvula was not significantly deviated. He complained of mild dysarthria and a hoarse voice. Examination of the upper and lower extremities revealed no weakness, but the power of right scapula elevation, head tilt to the right, and neck rotation to the left were decreased. The sensory examination was normal.\nIn a motor nerve conduction study, the compound muscle action potential of the right accessory nerve was not evoked. Needle electromyography revealed abnormal spontaneous activity in the right trapezius and sternocleidomastoid muscles. Injury of the accessory nerve was confirmed, although the other cranial nerves were not checked because the patient would not cooperate.\nA videofluoroscopic swallowing study (VFSS) revealed that lip closure and jaw movement were normal, but the soft palate and tongue movements were impaired. There were decreased epiglottic inversion, laryngeal elevation and movement of pharyngeal wall and delayed pharyngeal transit time. There was no penetration or aspiration of liquid, semisolid, or solid, but a large amount of material was retained in the right vallecula and pyriform sinus ().\nTo identify the cause of the dysphagia, brain and cervical magnetic resonance imaging (MRI) were performed. Brain MRI showed no abnormal findings in the brain parenchyma, and therefore, a brain lesion was excluded. Cervical MRI showed medullary compression and disruption of ligaments (). The sagittal section of the cervical computed tomography (CT) clearly showed a posteriorly displaced basion with respect to the tip of the dense of axis, and therefore, a posterior atlanto-occipital dislocation was diagnosed. And in the axial view, bony erosion of the atlas on the right side was shown (). For the treatment of the posterior atlanto-occipital dislocation, surgery was recommended, but the patient refused. Consequently, he underwent occupational therapy for the dysphagia. We educated the patient on a compensatory strategy when swallowing (rotation of the neck to the right side while swallowing food) and advised him to have repeated swallows to reduce pharyngeal residues. And he was also encouraged to perform resistance and range of motion exercises for the oral tongue, tongue base, neck, and shoulders to improve swallowing function. We have followed him for one year, and his dysphagia symptoms (choking during liquid swallowing, sensation of retained residual after swallowing, and food leakage into the nasal cavity) have improved. But, the degree of atlanto-occipital dislocation which was evaluated by X-ray was not changed.