Image Quiz

Delayed Onset of Neurologic Deficit Following High-Energy Trauma to the Head and Neck1 (continued)

Answer: Comminuted shear fracture of the left occipital condyle and Collet-Sicard syndrome

A computed tomographic scan of the cervical spine showed a comminuted shear fracture involving the inferior aspect of the left occipital condyle with bone fragments immediately inferior and lateral to the left hypoglossal canal. There was rotatory malalignment of the atlas in relation to the axis, with anterior subluxation of the left lateral mass of the atlas in relation to the occipital condyle (Figs. 2-A, 2-B, and 2-C). The patient was treated with halo-vest immobilization.


Fig. 1		 Fig. 1 Open-mouth radiograph of the upper cervical spine showing no obvious fracture; however, there is mild asymmetry in the interval between the dens and the lateral masses of the atlas.

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Fig. 2-A
Fig. 2-B
Fig. 2-C
Figs. 2-A, 2-B, and 2-C Computed tomographic scans of the cervical spine showing a comminuted shear fracture involving the inferior aspect of the left occipital condyle with bone fragments immediately inferior and lateral to the left hypoglossal canal. Rotary malalignment of the atlas in relation to the axis as well as anterior subluxation of the left lateral mass of the atlas in relation to the occipital condyle are also noted.

Laryngeal examination confirmed a true vocal-cord paralysis on the left side, with pooling of saliva on the cords. Video-endoscopic and fiberoptic endoscopic evaluation of swallowing indicated notable dysphagia with frank aspiration of contrast medium, reduced laryngeal sensitivity, and reduced clearing of secretions in addition to associated dysphonia. Magnetic resonance angiography confirmed a normal vertebrobasilar vascular system. Cranial nerve electromyography showed denervation of the vocal cords on the left side, severe left spinal accessory neuropathy, and moderately severe left superior laryngeal neuropathy.

The patient reported immediate reduction in the neck pain following halo application. Because of the severe dysphagia and the risk of aspiration, a gastrostomy tube was inserted and feeding was begun through this tube. The neurologic status remained unchanged during the hospital stay. He was discharged home after five days, and feeding was continued through the gastrostomy tube. Oral secretions required frequent suctioning.

The patient remained in a halo vest for a total of eight weeks and then wore a rigid cervicothoracic orthosis for an additional four weeks. Three years later, the patient was completely asymptomatic. The neurologic symptoms had resolved, and he had regained a full and painless range of motion of the neck. A computed tomographic scan of the neck showed a healed fracture of the occipital condyle with mild residual subluxation of the condyle on the lateral mass of the atlas.

Discussion

Isolated injury to the cranial nerves is occasionally associated with a fracture of the occipital condyle. Cranial nerve deficit may be due to compression of a nerve by bone fragments, stretching of a nerve at the time of injury, or transection of a nerve. Collet-Sicard syndrome is a unilateral lesion of cranial nerves IX, X, XI, and XII, without an associated Horner syndrome. The lower four cranial nerves exit the base of the skull in close association with each other. Cranial nerve IX, the glossopharyngeal nerve, is the afferent limb of the ipsilateral gag reflex and provides taste sensation on the posterior one-third of the tongue. Cranial nerve X, the vagus nerve, is the efferent limb of the gag reflex. It also innervates most of the striated muscles of the larynx and pharynx. Cranial nerve XI, the accessory nerve, provides innervation for the sternocleidomastoid and trapezius muscles. Cranial nerve XII, the hypoglossal nerve, provides innervation to the ipsilateral tongue muscles. Causes of Collet-Sicard syndrome include occipital condyle fracture, gunshot injury, Jefferson fracture of the atlas, carotid and vertebral artery dissections or other vascular causes, and infiltrative tumors.

Our patient was not immobilized initially, and we believe that progressive subluxation of the occipital condyle fragments on the lateral mass of the atlas, coupled with the added insult of secondary trauma, resulted in increased traction on the lower cranial nerves and the subsequent cranial nerve deficits.

Fractures of the occipital condyle are divided into three types on the basis of the mechanism of injury. Type-1 fractures are impaction fractures from an axial load. Type-2 fractures occur as part of a basilar skull fracture. Type-3 fractures are avulsion fractures of the occipital condyle. Our patient had a type-1 fracture, with notable comminution. We propose that in the presence of notable comminution of the occipital condyle fracture fragments, or with an associated cranial nerve deficit, the potential exists for an unstable subtype of the type-1 fracture. We believe that patients with such injuries should be treated with rigid halo immobilization for a minimum of three months.

Sharma et al. described the results of acute surgical intervention in a patient who had Collet-Sicard syndrome following a fracture of the occipital condyle. A portion of the posterior aspect of the occipital condyle was resected to decompress the lower cranial nerves, and the authors reported that there was a decrease in the patient's symptoms at three months. However, most authors have agreed that nonoperative treatment leads to good results in patients with unilateral nerve palsies.

This case illustrates several important points regarding a fracture of the occipital condyle with associated nerve palsies of the lower cranial nerves. Superimposition of the overlying facial bones on plain radiographs makes it difficult to identify a fracture of the occipital condyle, and the diagnosis thus requires a high index of suspicion. Our patient was initially diagnosed as having a cervical sprain. The difficulty in diagnosis is evident in many case reports on fractures of the occipital condyle. Anderson and Montesano reported that, in a series of six patients with a fracture of the occipital condyle, none of the fractures were identified on the initial radiographs. We recommend the use of computed tomography with coronal and sagittal reconstructions to evaluate the area more fully in any patient who has (1) suspected injury to the craniocervical region, (2) persistent neck pain, (3) unexplained increase in prevertebral soft-tissue swelling, or (4) loss of consciousness with substantial head injury or cranial nerve deficit. Examination of the cranial nerves is necessary in any patient who has sustained an injury to the craniocervical region. If a cranial nerve injury is present in conjunction with an occipital condyle fracture, we recommend treatment with a halo vest. It is essential to take precautions against aspiration, including frequent mouth suctioning and the use of medications to increase gastric motility. Adequate nutrition must be provided through a nasogastric tube or gastrostomy. In the management of patients with cervicocranial trauma, a high index of suspicion should be maintained regarding a fracture of the occipital condyle and injury to the lower cranial nerves.

Reference

1. Rao RD, Singhal P. Delayed development of neurological deficit from an occipital fracture: a case report. J Bone Joint Surg Am. 2004;86:1047-50.