This approach is typically used for resection of anterior processes, such as the odontoid with basilar invagination, infection, tumors, irreducible odontoid fractures in chronic dislocations, and congenital disorders of the anterior axis or atlas.

As its name implies, this approach uses the oral cavity as its pathway to the upper cervical spine. Visualization can be difficult due to the constraints of the jaw and oral cavity, but it can allow direct access from the clivus to the upper portion of C3. Although there is little vascularity encountered when approaching the spine through this midline approach, infection and cerebrospinal fluid leakage have been considerable problems in the past. The heightened chance of infection and historically poor outcome of bone grafting with the transoral approach make it a questionable choice for use during
anterior cervical fusions (1). The limitations in exposure with this approach can be reduced by the use of mandibular osteotomies. Morbidity from these techniques can be substantial; however, the approach does allow unique anterior exposure from the clivus to C6. It is typically useful for lesions within the bodies of C2-3, and when the oral cavity cannot be easily traversed, such as with severe temporomandibular joint arthrosis or an interdental distance less than 25 mm.

As with all spine surgery, medical comor-bidities should be ascertained, but particular focus must be paid to nutritional status. Total lymphocyte count and albumin are generally useful markers of nutritional status. Dental evaluations should be performed preoperatively to ensure an oral cavity that is free from ongoing infection. Standard preoperative antibiotic recommendations currently include an intravenous cephalosporin and metronidazole.

A padded headrest or Gardner-Wells^TM tongs are used to stabilize the head with the patient in the supine position. Awake, nasotracheal intubation may be performed with or without fiberoptic assistance depending on the perceived stability of the cervical spine. Once a neurologic examination is performed, anesthetic can be administered, and then the patient can be placed in a mild reverse-Trendelenberg position to prevent aspiration (2). Various retractors can be used for widening the interdental gap, such as the Codman Crawford or the Spetzler-Sonntag transoral retractors (Figs. 12-1, 12-2 and 12-3). The soft palate can often be elevated with a malleable self-retainer. Alternatively, two Red Robin catheters can be fed through the nares (one on each side) and brought out through the mouth. Once both catheters have been placed, the two ends on each side are tensioned superolaterally and secured to the drapes. Prepare the oropharyngeal area with betadine solution, and place a throat packing to prevent debris from falling into dependent laryngeal spaces or the trachea. Obtain localizing radiographs once the posterior pharyngeal area is exposed, and then inject epinephrine solution along the site of planned incision. Although surgical loupes with overhead illumination can be used in these cases, an operating microscope provides a clearer image and allows for easier assistant participation.

The tubercle of the atlas can be palpated to discern the midline, and a vertical incision is carried out 1 to 2 cm above and below the tubercle in the midline (Fig. 12-4).

Once the resection portion of the procedure has been completed, CSF containment should be confirmed with a Valsalva maneuver, and then reconstruction or closure can proceed. If possible, the longus colli is reapproximated in the midline, followed by absorbable suture approximation of the pharyngeal layer. Intubation is typically continued for 1 to 2 days due to the risk of swelling postoperatively. Antibiotic regimens vary in the literature, but we typically use cefazolin and metronidazole for 5 to 7 days starting immediately preoperatively. The metronidazole can be administered through a nasogastric feeding tube placed intraoperatively after wound closure. Clear liquids are begun approximately one week after surgery, but a regular diet should be withheld until 3 weeks postoperatively (6).

Rates of complication with the transoral approach have been quoted between 18% and 26%, including a mortality rate of 6%, according to one source (7). Although early use of the approach led to very high infection rates (above 50%), more recent studies demonstrate infection rates below 3% (8, 9, 10). CSF leakage during the procedure should be addressed with attempted closure, grafting, fibrin glue, and a meticulous closure, as the persistence of leakage can result in fistula formation (11). A lumbar drain should be strongly considered in this situation, as the persistence of CSF leakage can be exceptionally troublesome. Other potential complications include bleeding from injury to the vertebral or internal carotid arteries, craniocervical instability, lingual swelling, and postoperative infection.

The high retropharyngeal approaches allow access to the anterior upper cervical spine, and may be indicated for debridement of tumors or infection, and stabilization of the atlantoaxial segment. It is possible to expose the C1-2 facet articulations at the upper end of the approach, while the most caudal access afforded by the primary incision is the upper end of C3. An extensile vertical incision can be employed to allow access to the mid and lower cervical regions.

Although this approach can be carried out medial (anterior approach) or lateral (anterolateral approach) to the carotid sheath, we favor the use of the method described by McAfee and colleagues, termed the anterior retropharyngeal approach (12). It is an extension of the Southwick and Robinson approach initially described for use in the lower cervical spine (13). By accessing the retropharyngeal space medial to the carotid sheath, one avoids the risk of injuring the carotid vessels or cranial nerves at the skull base, but there is a higher risk of injury to the superior laryngeal or glossopharyngeal nerves than when approached lateral to the carotid sheath. Additionally, the anterior approach allows access to both vertebral arteries, while exposing lateral to the carotid sheath compromises access to the contralateral vertebral artery. Finally, anterior decompression and reconstructive measures may be more easily performed when visualizing the spine from the anterior approach than the anterolateral approach.

Particular attention should be focused on any compromise of swallowing or respiratory function. In the revision setting, it may be necessary to have the patient undergo vocal cord evaluation. A preoperative tracheostomy may be warranted to avoid airway problems, and an otolaryngologist can assist with this determination. When attempting tumor resections, angiography or a CT angiogram should be obtained to define the locations of the vertebral arteries.

The patient is placed in a supine position, and cranial traction should be strongly considered. If postoperative halo-vest immobilization is planned, the use of a halo ring can be substituted for Gardner-Wells tongs. Before traction is applied, baseline evoked potentials from neuromonitoring should be obtained (if used). The patient should be awake for fiberoptic nasotracheal intubation, so neurologic assessment can be performed following the intubation and positioning. Oral placement of tubes or devices should be avoided, as they may inferiorly displace the mandible and compromise maximum exposure of the upper-most aspects of the cervical spine. Finally, place the patient in a slight reverse-Trendelenberg position to aid in visualization and improve venous drainage.

Unlike lower areas of the cervical spine, the side of approach need not be dictated by underlying anatomical variations. A right-sided approach may be easier for those surgeons with right-handed dominance, but if there is a foreseeable need to extend below C5 then one should consider a left-sided approach to avoid injury to the recurrent laryngeal nerve. Tumor location predominantly on one side may also influence the need for approach on a particular side. Mild head rotation can facilitate the exposure. If performing the anterolateral high retropharyngeal approach, the ipsilateral earlobe should be prepped and then sutured to the cheek anteriorly. Otherwise, it will be an obstruction during the exposure.

Extubation may be performed immediately after surgery, but longer cases or those with greater likelihood of significant edema should be considered for a day or two of continued intubation. Less commonly, tracheostomy might be required immediately or in a delayed fashion if there is more serious airway compromise or concern. Drains are typically left in for approximately 24 hours, but higher outputs may necessitate longer durations or exploration in cases of persistent heavy bleeding. It is generally advised to keep the head of the bed elevated to encourage more rapid resolution of edema. Dietary advancement should begin with sips of water or clear liquids, and then slow progression may ensue if tolerated on the first postoperative day.