Anterior Transcervical Approach to the Cervical Spine

History of present illness

• Pain

  Patients may have pain in the neck or shoulders from nerve root compression from cervical spondylosis; it may radiate to the upper extremities. Pain may also be exacerbated by movement of the neck.

• Neurologic dysfunction

  Patients may have sensory and motor loss from spinal cord compression. Patients should be questioned about sensory loss or weakness of the extremities (decreased grip strength, difficulty ambulating).

• Hoarseness

  Patients who have had prior cervical surgery should be questioned about hoarseness following prior surgery. Hoarseness may signal vocal cord paresis from injury to the recurrent laryngeal nerve. Decreased vocal range with coughing due to aspiration may be associated with injury to the superior laryngeal nerve.

• Dysphagia

  Dysphagia is often multifactorial. Large osteophytes can cause compression of the esophagus with dysphagia for solids. Dysphagia with regurgitation of undigested food is suggestive of a Zenker’s diverticulum.

Past medical history

• Prior cervical spine surgery

  In patients with a prior history of cervical spine surgery, it is important to inquire about the indications for the previous surgery, the operated spine levels, postoperative complications, and the duration of postoperative symptoms. Prolonged hoarseness after surgery may indicate injury to the recurrent laryngeal nerve.

• Other neck surgery or trauma to the cervical spine

  Other operations in the cervical region such as thyroidectomy should be noted.

Inflammation

Inflammatory conditions such as osteomyelitis or retropharyngeal abscess can result in erythema and edema of the soft tissues. Rarely, crepitus from subcutaneous air is palpable if there is communication with the pharynx or esophagus.

Range of motion

Cervical osteophytes may limit the range of motion of the neck (flexion, extension, rotation). Patients with Forestier’s disease or diffuse idiopathic skeletal hyperostosis (DISH) often have limited flexion/extension due to extensive calcification of the anterior longitudinal ligaments.

Mass in the neck

A mass in the neck may be inflammatory or neoplastic. A large Zenker’s diverticulum is rarely palpable. A large thyroid goiter may interfere with a low cervical approach.

Evidence of prior surgery

The side and level of prior surgical approaches to the cervical spine should be noted, since this may have an impact on the surgical approach. If a new level is targeted, it may not be possible to use the same incision.

Upper airway

The upper airway should be examined by endoscopy to assess the safety of the airway for intubation. Large osteophytes posterior to the pharyngeal mucosa may limit access to the airway.

Neurologic function

The function of the larynx should be assessed by laryngoscopy. If there is paresis of a vocal cord, this should be clearly documented.

Lateral plane radiograph

Anterior-posterior and lateral spine radiographs provide basic details of bone anatomy and are good for visualization of spinal hardware. The optimal placement of the skin incision can be determined based on the relationship of the cervical spine level to the bony/cartilaginous landmarks of the hyoid bone and thyroid cartilage.

Esophagram

If there is suspected perforation of the esophagus, an esophagram is obtained using a water-soluble contrast agent. An esophagram or modified barium swallow is also helpful in assessing the severity and contribution of osteophytes to dysphagia.

Computed tomography (CT)

A CT scan with contrast should be considered in patients with associated symptoms or physical findings suggestive of a neoplasm or osteomyelitis. A sagittal view provides optimal viewing of cervical hardware: cervical spine levels, displaced hardware, compression of esophagus ( Fig. 77.1 ).

Magnetic resonance imaging (MRI)

MRI is superior for delineating the level of cord compression from a herniated disc ( Fig. 77.2 ).

Cervical spondylosis

The most common indication for an anterior approach to the cervical spine is cervical spondylosis ( Fig. 77.2 ). Revision surgery is sometimes necessary when there is infection or displacement of plating hardware. Bulky hardware may also contribute to postoperative dysphagia and may be removed electively to improve swallowing function. Large osteophytes occur most commonly at the C4-C6 levels in approximately 12% to 30% of the elderly and may be associated with symptomatic dysphagia and aspiration. It can be difficult to demonstrate that the patient’s symptoms are due to the osteophyte, however, since dysphagia is frequently multifactorial in these patients. Patients with Forestier’s disease or DISH can develop extensive calcification of the anterior longitudinal ligaments with resultant dysphagia ( Fig. 77.3 ). The calcifications usually span multiple levels.

Cervical osteomyelitis

Rarely infection of the vertebral bodies (osteomyelitis from adjacent infection or hematogenous seeding of the vertebral body; e.g., tuberculosis) may require surgery.

Neoplastic involvement of cervical spine

Malignancies metastatic to the vertebral bodies are usually treated with palliative radiation but may also require surgery for stabilization of the cervical spine.

Retropharyngeal abscess

Infection of deep neck spaces may result in a retropharyngeal abscess. This may result from a suppurative upper respiratory infection with involvement of the retropharyngeal lymph nodes, esophageal perforation, or a foreign body.

Zenker’s diverticulum

Although most cricopharyngeal myotomies for Zenker’s diverticulum are now performed endoscopically, an anterior cervical approach to the cervical spine provides the necessary exposure of the cricopharyngeus and inferior pharyngeal constrictor muscle for performance of a myotomy or excision of diverticulum with a myotomy, especially in patients who are not candidates for an endoscopic approach.

Esophageal perforation

An esophageal perforation may result from intraluminal trauma (e.g., passage of a tube or esophagoscope), erosion by spinal hardware, or iatrogenic injury from neck surgery. A transcervical approach provides drainage of air/fluid to prevent infection and allows primary surgical repair.

Retropharyngeal lymphadenectomy

Neoplasms of the soft palate, pharynx, thyroid, and skull base may metastasize to retropharyngeal lymph nodes. Although the survival is poor in patients with squamous cell carcinoma metastatic to the retropharyngeal lymph nodes, retropharyngeal lymphadenectomy may be beneficial in selected patients with other types of neoplasms (esthesioneuroblastoma, thyroid cancer).

Active neck infection

Untreated neck infection is a contraindication to cervical spine surgery with instrumentation, unless the patient requires surgical treatment of osteomyelitis. Staging of surgery may be necessary with surgical drainage of infection and medical therapy prior to spine surgery.

Major medical comorbidities

If a patient is not a candidate for general anesthesia, limited surgery for biopsy or drainage of an abscess can be performed with minimal sedation and local anesthesia.

Informed consent

Informed consent includes a discussion of potential risks and expected sequelae of surgery. For anterior approaches, the greatest concern is postoperative hoarseness or aspiration due to injury to the superior or recurrent laryngeal nerves. Some degree of dysphagia is expected postoperatively and can persist for months in a minority of patients. The risk of infection or significant bleeding is negligible. Perforation of the esophagus or hypopharynx is a remote possibility, but the risk is increased when displaced hardware or a large osteophyte is being removed.

Neck incision

The laterality of the incision is generally not important. Arguments can be made for either side, depending on the level of exposure, handedness of the surgeon, risk of retraction injury of the recurrent laryngeal nerve, deviation of the esophagus, and prior surgery. Most right-handed surgeons find a right-sided approach to be easier for instrumentation of upper cervical levels and a left-sided approach for instrumentation of lower cervical levels.

Using the same side as a previous incision is preferred if the same cervical spine level is targeted, especially if spinal hardware needs to be removed. If there is paresis of a vocal cord or preoperative examination of the larynx was not performed, it is safer to operate on the same side to avoid possible paresis of the contralateral vocal cord.

Assessment of the anatomic relationship of vertebral bodies to cartilaginous and bony landmarks is assessed with a lateral radiograph of the cervical spine or on CT or MRI (sagittal view; Figs. 77.1 and 77.2 ). The level of upper cervical vertebrae is judged based on their relationship to the hyoid bone. The level of midcervical vertebrae is best judged based on their relationship to the posterior cricoid cartilage and thyroid cartilage. Since cartilaginous landmarks are not well visualized on MRI, the epiglottis is a useful landmark. The anterior ring of the cricoid cartilage is a readily identifiable landmark for localizing the lower cervical vertebrae.

Neurophysiology

Neurophysiologic monitoring of spinal cord function is performed intraoperatively when there is preoperative compression of the spinal cord or when surgery on the spinal cord is performed. If there is severe preoperative compression, a baseline study is performed after induction of anesthesia and prior to positioning. After positioning, the patient is reassessed to confirm that neurologic function has not worsened. Continuous monitoring is performed throughout surgery.

Navigation

Intraoperative image guidance with a navigational system is helpful for pathology of the upper cervical spine and cranial base but is impractical for lower levels. When a navigational system is used, a CT angiogram will provide good visualization of bony anatomy, as well as the course of the vertebral artery.