Tracheoesophageal Injuries

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Chapter Synopsis	The anterior approach to the cervical spine has gained worldwide acceptance by spine surgeons to address a variety of pathologic conditions of the cervical spine. Injuries to the trachea and esophagus are rare, but they can result from direct or indirect injury and manifest with early or late clinical findings. Radiographic imaging such as plain radiography, computed tomography or magnetic resonance imaging, and esophagography/swallow studies can help confirm the diagnosis. Because false-negative results can occur, however, a high index of suspicion is necessary. If unrecognized, these injuries can be the source of significant morbidity and mortality, but when they are diagnosed and aggressively treated through a multidisciplinary team approach, a successful outcome can be achieved.
Important Points	Depending on the level approached, injury to various nerves innervating the tracheoesophageal structures can occur during anterior cervical surgical procedures. The diagnosis of tracheoesophageal injuries is based on both imaging modalities and endoscopic studies. Because false-negative results can occur, however, a high index of suspicion is necessary. A multidisciplinary team approach including otolaryngology or thoracic surgeons, infectious disease specialists, and nutritional support should be considered.
Clinical and Surgical Pearls	Patients undergoing revision cervical spine surgery should have a preoperative evaluation to determine the status of the superior laryngeal nerve. In the case of esophageal perforations, consideration for placement of a percutaneous endoscopic gastrostomy tube can provide enteric nutrition while bypassing the perforated esophagus. Primary closure of the esophageal perforation should be considered in both acute and delayed presentations. A multidisciplinary team including otolaryngology or thoracic surgeons, infectious disease specialists, and nutritional support should be considered.
Clinical and Surgical Pitfalls	Surgical approaches to the upper cervical spine place the superior laryngeal nerve, along with its associated structures, at risk. Asymptomatic perforations of the trachea and esophagus have been reported; therefore, a high index of clinical suspicion is required for the diagnosis of tracheoesophageal injuries. False-negative results of diagnostic studies have been reported and can occur. This is another reason that a high index of clinical suspicion is required for the diagnosis of tracheoesophageal injuries. Determination of the resolution period for tracheoesophageal perforations can be challenging.

The anterior approach to the cervical spine is a well-established surgical dissection technique that has been used successfully for the treatment of pathologic conditions of the cervical spine, including traumatic conditions, degenerative abnormalities, deformities, infections, and neoplastic diseases. By virtue of the approach, it provides access to the anterior cervical spinal column and avoids the need for dissecting through the cervical posterior stabilizing elements, including the paraspinal muscles and ligamentum nuchae. However, with this approach, the anterior structures of the neck (e.g., the trachea and esophagus) are at risk for both direct injury (perforation) and indirect injury (traction or compression). This chapter reviews injuries to the tracheoesophageal structure during surgical procedures of the cervical spine.

The anterior cervical approach, championed by Robinson and Smith, uses the interval between the sternocleidomastoid muscle and the neck strap muscles. This approach requires dissection through the deep cervical fascia. The trachea and esophagus are then retracted medially, and the carotid sheath is retracted laterally. The deeper surgical plane poses risks of injuring vital structures, including nerves, blood vessels, and lymphatic vessels, and it risks perforating the trachea and esophagus. For patients who have undergone an anterior cervical approach, one of the most common problems encountered during the postoperative period is dysphagia. Some studies reported that during the postoperative period, these patients presented with dysphagia 47% of the time.

Nerve Injuries

Based on the operative level, nervous structures that can be at risk during anterior cervical dissection are the hypoglossal nerve, the superior laryngeal nerve, and the recurrent laryngeal nerve. Palsy of these nerves can manifest in the following ways: as dysphagia, which is difficulty swallowing; as dysphonia, which is an impairment of sound production as the passive vocal cords interact with the exhaled airstream; and as hoarseness, which is a breathy or harsh voice ( Table 52-1 ).

Table 52-1

Structures at Risk During Anterior Approach to Cervical Spine

Vertebral Level	Structure(s) at Risk	Clinical Correlate
C2	HN	Dysphagia, dysarthria, ipsliateral tongue deviation
C2–C3	HN	Dysphagia, dysarthria, ipsliateral tongue deviation
C3	HN, ISLN, STA, SLA	Dysphagia, dysarthria, ipsliateral tongue deviation, impaired cough reflex
C3–C4	ISLN, STA, SLA	Impaired cough reflex
C4	ISLN, ESLN, STA, SLA	Impaired cough reflex, hoarseness, voice fatigability, impaired high-pitch phonation
C4–C5	ESLN, STA, SLA	Hoarseness, voice fatigability, impaired high-pitch phonation
C5	ESLN, STA, SLA	Hoarseness, voice fatigability, impaired high-pitch phonation
C5–C6	ESLN, STA	Hoarseness, voice fatigability, impaired high-pitch phonation
C6	ESLN, STA	Hoarseness, voice fatigability, impaired high-pitch phonation

ESLN, External superior laryngeal nerve; HN, hypoglossal nerve; ISLN, internal superior laryngeal nerve; SLA , superior laryngeal artery; STA, superior thyroid artery.

Adapted from Haller JM, Iwanik M, Shen FH: Clinically relevant anatomy of high anterior cervical approaches. Spine (Phila Pa 1976) 36:2116-2121, 2011.

At the C1 arch level or in the anterior triangle of the neck, the hypoglossal nerve is at risk as it exits the hypoglossal foramen and passes along the anterior aspect of the C1 arch. Except for the palatoglossus muscle, all motor innervation to the tongue muscles is provided by the hypoglossal nerve; therefore, palsy of the nerve causes ipsilateral tongue deviation with difficulty swallowing as the ability to move the food toward the back of the mouth is impaired.

At the C3-C4 level, the superior laryngeal nerve, along with closely associated structures (e.g., the carotid bifurcation, upper pole of the thyroid, and superior thyroid artery) are at risk. The superior laryngeal nerve is a branch of the vagus nerve (cranial nerve X) that originates in the carotid sheath before it splits into a sensory (internal) branch and a motor (external) branch. The sensory branch innervates both ipsilateral and contralateral larynges, thus preventing aspiration. The motor branch innervates the cricothyroid, a muscle that tenses the vocal cords to produce the high-pitched sounds of singing. Palsy of the motor (external) superior laryngeal nerve branch manifests as a monotonous voice, whereas palsy of the sensory (internal) superior laryngeal nerve may be silent because the pharynx has contralateral innervation. Therefore, patients undergoing revision surgical procedures of the cervical spine should have a preoperative evaluation with electromyography, strobovideolaryngoscopy, or both, to determine the status of the superior laryngeal nerve.

The recurrent laryngeal nerve is vulnerable to traction injury as it loops around the great vessels—the aorta on the left and the subclavian artery on the right—before ascending into the tracheoesophageal groove in the neck ( Fig. 52-1 ). Other postulated causes of recurrent laryngeal nerve injury include direct trauma, pressure neurapraxia from a fixed inflated endotracheal cuff, and stretch from aggressive retractor use; the right recurrent laryngeal nerve is suggested to be more vulnerable than the left because of its more lateral point of fixation on the brachiocephalic trunk.