Anterior Cervical Corpectomy

Surgical intervention is generally reserved for patients who have intractable pain or progressive neurologic symptoms in the presence of documented compression of the cervical cord, nerve roots, or both. Pain relief and resolution or reduction of neurologic deficits can be expected in the vast majority of patients (if patients have been judiciously selected). The prognosis for patients with myelopathy is the most variable. Some studies suggest that increased preoperative disability, an increased number of involved levels, myelopathic symptoms > 1 year in duration, bilateral motor deficit, spinal canal area < 30 mm², absence of Lhermitte’s sign, and possibly advanced age adversely can impact outcome. Given the progressive natural history of cervical spondylotic myelopathy, intervention to halt the neurologic decline before incapacitation occurs is often the goal of surgery. ¹ The criteria for selecting an appropriate surgical procedure should be based on both the patient’s symptoms and adjunctive study findings. Emphasis should be placed on treating the symptomatic cervical levels rather than the levels corresponding to the most abnormal anatomy on the imaging studies. In general, we reserve cervical corpectomy for patients who have multilevel disease with stenosis, severe anterior osteophytes, vertebral body deformities that are either traumatic or degenerative, or compression that occurs behind the entirety of the vertebral body.

10.2 Patient Selection

The purpose of operative intervention is to decompress the neural and vascular elements by removing the offending osteophytes, ligament, and disk material, stabilizing the spine against hypermobility and re-establishing spinal balance. Because spondylotic disease is frequently located anteriorly, an anterior approach is frequently indicated. Anterior approaches afford the benefits of superior decompression of the ventral spinal cord. Anterior approaches allow for safe, reliable access from C2–3 to T1–2, with operation at each extreme a bit more technically challenging. Given that most root and cord compressions occur as a result of herniated disk fragments, anterior cervical diskectomy and fusion (ACDF) is typically the procedure of choice. Cervical corpectomy is a more extensive approach for the treatment of cervical myelopathy and radiculopathy and is indicated in cases of multilevel stenosis secondary to anterior pathology. It is most often the procedure of choice in patients with cervical kyphosis because the spinal cord becomes draped over osteophytic bars ventrally, resulting in myelopathy ( ▶ Fig. 10.1). ² We perform multilevel diskectomies instead of corpectomies for cervical disk disease when stenosis is limited to the disk spaces and is not confluent behind the adjacent vertebral bodies. Park et al found no significant difference between fusion in multilevel ACDF verses single-level diskectomy, with patients undergoing diskectomy specifically for compression pathology posterior to the vertebral body. ³ Diskectomy and corpectomy may be performed in the same patient if the disease process is not confluent at the affected segments ( ▶ Fig. 10.2).

Fig. 10.1 T2-weighted magnetic resonance imaging demonstrating confluent stenosis of the cervical spine.

Fig. 10.2 Lateral postoperative cervical anterior diskectomy and fusion and corpectomy spine X-ray.

A combined anteroposterior (AP) approach to the cervical spine may be appropriate if both anterior and posterior pathologies coexist and are severe or occasionally if corpectomy is performed at three or more levels ( ▶ Fig. 10.3). The prolonged operative time and complications associated with multiple wounds may preclude performance of these procedures in some patients.

Fig. 10.3 Anteroposterior and lateral postoperative multilevel cervical corpectomy and posterior cervical fusion X-rays.

Internal fixation of the cervical spine is thought to prevent the AP translation of the vertebrae and graft material, thereby obviating the need for the patient to wear the rigid collar necessary in noninstrumented grafted fusions. Patients undergoing cervical diskectomy and fusion with instrumentation may receive a soft collar to help with pain relief, but rigid bracing for stability is not necessary in most situations.

10.3 Preoperative Preparation and Patient Positioning

Patient positioning, as with all surgical approaches, is critical during surgery on the cervical spine. The use of tongs for traction and spinal cord monitoring should be considered if the patient’s spine is unstable or if there is evidence of position-dependent neurologic compromise. The shoulders may be retracted inferiorly, as deemed necessary, with wide tape to help expose the neck on both sides; alternatively, wraps may be placed around the wrists to apply intermittent traction. It is exceptionally important not to pull the shoulders down to the limits of their range of motion because this may cause traction injury to the superior roots of the brachial plexus. A rolled towel or support may be used beneath the neck to help maintain a normal cervical lordosis.

Before incision is made, the bony landmarks of the neck should be identified. The angle of the mandible is lateral to C2–3, and the hyoid bone traverses anterior to the cervical spine at C3, as the thyroid cartilage does at C4 and the cricoid cartilage at C6. The carotid tubercle can be used to help identify the C5–6 interspace. These landmarks become especially important for transverse incisions, where the exposure offers a limited view of the structures within the operative field.

The cervical spine may be approached anteriorly from the right or left side. Although many surgeons are right-handed and prefer to operate on the patient’s right side, some surgeons prefer a left-sided approach. This is because of the predictability of the left recurrent laryngeal nerve as it tracks through the carotid sheath and enters the thorax, looping under the aorta before ascending back into the neck adjacent to the trachea and esophagus. The right recurrent laryngeal nerve has a more inconsistent course. It passes beneath the subclavian artery and enters the tracheoesophageal groove at a more rostral level than on the left side. Consequently, it can be readily injured, especially during an approach to C6–7, although the literature documents the rate of recurrent laryngeal injury to be the same regardless of the side of approach.

The incision for a single- or two-level anterior approach to the cervical spine is best performed for cosmetic purposes by a transverse incision, preferably in a natural skin crease. Multilevel fusions or corpectomies at three or more levels or patients with a long, thin neck may require a more extensive exposure, best performed through a longitudinal incision. Alternatively, a transverse incision may be extended upward at the lateral aspect. The patient should be prepared in an appropriate sterile fashion, and the choice of incision should be marked on the neck before draping.

10.4 Operative Procedure

Local anesthesia is applied to the dermis using a small gauge needle. The incision is made with a scalpel down to the platysma and is followed by electrocautery for hemostasis. The platysma is then incised longitudinally in parallel with its fibers. Blunt dissection is then used to identify the parasagittal plane between the sternocleidomastoid and the carotid sheath laterally and the trachea, esophagus, and strap muscles medially.

The carotid artery is identified during the approach to ensure its integrity. The thyroid vasculature may be visualized anterior to the cervical spine and can be ligated during the exposure. The omohyoid, although a useful landmark, may obstruct the operative field and can be retracted or divided if necessary. Care is taken to protect the esophagus, which is retracted to the side opposite the exposure. The loose, middle cervical fascia layer that bridges the sternocleidomastoid and the strap muscles of the larynx is then dissected to reveal the anterior portion of the cervical spine ( ▶ Fig. 10.4).