Cervical Arthrodesis

Cervical arthrodesis is a surgical procedure that joins selected bones in the cervical spine.

Surgical pathologies of the cervical spine have commonly been addressed through anterior and posterior approaches. The anterior approach to the cervical spine was developed in the 1950s by Robinson and Smith, ^[1] Bailey and Badgley, ^[2] and Cloward. ^[3] However, the posterior approach to the cervical spine remained the preferred choice of many spinal surgeons until the 1980s, when Meyer reported on the management and treatment of traumatic cervical spine fractures through the anterior approach. ^[4]

Lateral radiograph shows a two-level anterior cervical discectomy and fusion from C 4/5 through 6/7. An anterior plate with carbon fiber intervertebral spacers are used for fusion and internal fixation.

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Postoperative lateral radiograph shows anterior and posterior fusion with instrumentation in a patient with an unstable cervical spine fracture.

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Indications for cervical arthrodesis include the following:

• Trauma and posttraumatic deformity

• Tumors

• Infections

• Cervical spinal spondylosis

• Cervical spinal stenosis

• Degenerative deformity

Complications related to the cervical lateral mass and rods technique include both neurological and vascular causes. ^[5] Neurological injuries can result from direct trauma to the spinal cord and nerve roots. In addition, cerebrospinal fluid leak can occur, especially during the laminectomy portion of the procedure. To minimize these neurological risks, it is recommended to prepare the screw holes prior to the decompressive laminectomy. Iatrogenic injury to the vertebral arteries is rare but possible secondary to misplaced lateral mass screws.

Complications related to the anterior cervical approach can be grouped into neurological, vascular, and visceral complications. These risks may be increased in revision surgeries. ^[6] In addition, grafting and internal fixation also carry risks, including graft failure, pseudoarthrosis, and screw-plate fracture.

Neurological

The most common neurological complication after the anterior cervical approach is hoarseness and/or dysphagia that may result from injury to the recurrent laryngeal nerve. Vocal cord dysfunction is usually present when this nerve is compromised. Hoarseness and dysphagia are usually temporary, and full recovery is expected; however, if the problem persists for more than 3-6 months, swallow barium studies and/or direct laryngoscopy by an ear, nose, and throat specialist should be considered for possible treatment.

Surgeries on the upper cervical spine levels at or above the C3 can be associated with an increased risk of injury to the superior laryngeal nerve. In addition, Horner syndrome can develop the sympathetic trunk is injured during the exposure portion of the procedure if dissection is carried laterally over the longus coli muscles. Finally, injury to the spinal cord is rare but possible.

Vascular

The main arterial systems in the neck are the carotid and vertebral arteries. While the carotid artery is more susceptible to injury during dissection, exposure and placement of the self-retaining retractors, the vertebral arteries are more susceptible to injury during the discectomy and neural foramen decompression. The surgeon should be prepared to deal with these injuries if they arise. Direct arterial repair is ideal but difficult with the vertebral arteries. Tamponade with Gelfoam may be sufficient, and arterial ligation should be considered as a last resort. An immediate postoperative angiogram is necessary if vascular injury is suspected, followed by the appropriate endovascular intervention depending on the pathology.

Visceral

The incidence of esophageal injury is low, and these injuries usually result from malpositioned self-retaining retractors. If perforation of the esophagus occurs, direct repair followed with antibiotic treatment should be considered. A high index of suspicion for this complication is recommended so that early intervention can be performed. Fever and dysphagia are usually early symptoms of esophageal perforation.