The anterior approach can be used for a variety of pathologic conditions from C3 to C7, including:

Preoperative evaluation should include examination of the resting head position, the patient’s protective range of motion of the cervical spine without neurologic symptomology, the carotid pulses (decreased or bruits), and thyroid gland (for thyromegaly, which can inhibit exposure). If previous anterior surgery was performed, the patient must be evaluated carefully for a recurrent laryngeal nerve (RLN) palsy (using direct laryngoscopy) if the surgeon decides to approach using the contralateral side. Appropriate imaging studies should confirm the exact location of the pathology to be addressed. Any previously placed hardware should be identified and appropriate planning for removal must be made, if indicated. The course of the vertebral arteries on both sides should be followed and noted for any anomalies.

The patient is placed supine on a flat operating table. Endotracheal tube placement should occur within the safe range of extension demonstrated by the patient in the preoperative evaluation. If safe visualization of the larynx cannot be achieved with standard methods, then intubation can be performed using direct fiberoptic visualization. The endotracheal tube should be secured to the opposite side of the approach. A small bump or roll can be placed between the scapulae to extend the neck slightly within the safe range of extension and drop the shoulders posteriorly. The head is rotated about 10 to 15 degrees away from the side of the surgical approach. The medial border of the sternocleidomastoid (SCM) is palpated and marked. This represents the location of the longitudinal incision, if so desired, which is useful for multilevel, extensile approaches. If one-level or two-level surgery is planned, a transverse incision within the natural skin folds can be used and is centered over the desired vertebral level, which results in a more cosmetically acceptable scar. Surface landmarks are used to decide on the incision location, as follows:

After skin incision, the skin flaps are undermined, and the platysma is identified. It is divided in line with the incision. A plane deep to the platysma is developed to ensure adequate visualization of the medial fascial border of the SCM and to help minimize the force needed to retract the soft tissues. Depending on patient age and muscular physiology, it may be difficult to identify the contours of the platysma. The trachea is palpated medially through the overlying strap muscles, which include the sternohyoid and sternothyroid. Dissection, through an investing fascial layer, between the strap muscles and the SCM is developed bluntly. In total, the anterior cervical approach proceeds through three fascial layers:

Staying medial to the carotid sheath (by feeling the pulse), blunt dissection is continued in a posteromedial direction toward the spine. At lower levels of dissection (e.g., C6–T1), the omohyoid can be tagged and transected if needed to aid in greater visualization. The anterior aspect of the spine can be palpated through the alar and prevertebral fascia within this interval (Fig. 27.1). The trachea and esophagus are retracted gently to the contralateral side, allowing visualization of the alar fascia, which overlies the prevertebral fascia. These fascial layers are cut to expose the anterior surface of the spine. A peanut dissector now can be used to sweep the tissue from the midline to reveal the anterior longitudinal ligament, longus colli, and underlying disk spaces. Identification of the disk spaces in the arthritic spine may be impeded by large protruding osteophytes. In general, the disk spaces are located at peaks, whereas the midvertebral bodies are in the “valleys.” The correct level can be confirmed with a lateral radiograph by marking the disk space with an 18-gauge spinal needle with two 90-degree bends (with the first 1 cm from the tip).

With the desired levels identified, the longus colli is elevated subperiosteally off the anterior cervical body and disk space to protect the overlying sympathetic chain; this is stopped laterally as soon as the vertebral body starts to curve posteriorly. The vertebral arteries can be injured with more posterolateral exposure. Up until this time, blunt hand-held retractors, such as Cloward retractors, are used. Once dissection is complete, a deep-bladed, self-retaining retractor can be inserted deep to the longus colli with toothed blades on the lateral side and smooth blades on the medial side to reduce the risk of accidental esophageal puncture.

Before closure, the wound is irrigated copiously with normal saline, the esophagus is inspected for possible injury, and a drain is placed if deemed necessary. Indigo carmine (or blue food coloring) can be infused orally into the esophagus to show subtle tears. Strict hemostasis must be achieved to minimize hematoma formation and potential respiratory compromise. If the omohyoid was cut, it is repaired in standard fashion. If the platysma can be repaired, it is reapproximated with 2-0 interrupted vicryl and the skin is to be closed with a running 4-0 subcuticular stitch.

After short procedures, the patient usually can be extubated safely in the operating room. After longer procedures, extubation may be delayed until airway swelling has resolved. The need and type of postoperative immobilization are determined by the stability of the spine and the extent of surgical intervention. If a drain was placed, it is typically removed when the output is less than 10 mL per 8-hour period. The patient’s diet is advanced from a soft mechanical to a regular diet when it is determined that they can safely tolerate solid foods.

Dysphonia, from RLN or superior laryngeal nerve injury, occurs in about 4% to 5% of cases. The risk of RLN palsy is extremely low with surgery performed above C5. The RLN is thought to be at more risk in the following situations:

On the left side, the RLN is located more consistently within the carotid sheath and has less medial–lateral variability than on the right side. Although the left RLN descends in a fairly consistent manner to loop under the arch of the aorta, the right RLN does not extend as far distal before looping around the subclavian artery back toward the larynx. Despite these anatomic differences, a study showed no difference in the incidence of RLN palsy between right-sided and left-sided exposures.

Horner syndrome can arise from injury to the sympathetic plexus, which lies on top of the longus colli
muscle and is at greatest risk at the level of C6. It is diagnosed clinically by the presence of:

Unrecognized esophageal tears can be a cause of late wound infection and mediastinitis. An esophageal tear must be considered with any late presentation of infection following anterior cervical surgery. The risk of infection after uncomplicated anterior cervical spine surgery is less than 1%.