You decide that surgical intervention is indicated for this patient. This would allow for safe and expedient mobilization, as well as preservation of the neural elements. Prior to surgical intervention, an angiogram of the cervical vessels was completed, which demonstrated a dissected left vertebral artery (Fig. 81.3).

The patient successfully underwent a combined anterior and posterior cervical fusion. Antiplatelet therapy was initiated to treat the vertebral artery dissection. Gabapentin was initiated for the treatment of the patient’s neuropathic sensory complaints.

• Magnetic resonance imaging (MRI) is helpful in this patient to determine whether ligamentous injury is present. Injury to the anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), posterior interspinous and supraspinous ligaments, facet capsules, and disk spaces can be appreciated. It is critical to identify injury to these structures because this affects the surgical approach.
  
• Additionally, MRI is the study of choice to evaluate the neural elements if neurologic signs or symptoms are present.
  
• Magnetic resonance angiography or CT angiography should be considered in these individuals to assess for cervicocephalic arterial dissections given the patient’s distracting injury and complaint of occipital-based headaches and neck pain.1,2

• Superimposed upon chronic diskogenic changes at C5–C6 and C6–C7 is an acute injury at C6–C7 with fluid in the intervertebral disk space and disruption of the interspinous ligaments.
  
• There is extensive fluid beneath the ALL throughout the cervical spine.
  
• A cord contusion is present at the level of C6–C7. Additionally, there is an absent left vertebral artery flow void on axial slices (Fig. 81.2B).
  
• Significant posterolateral muscle trauma with edema is present.

• Anterior column components include the ALL, inter-vertebral disk and annulus fibrosis, vertebral body, and PLL.
  
• The posterior column components include the pedicles, posterior neural arch, and the posterior ligamentous tension band.
  
• In 1982, Allen and colleagues³ introduced a comprehensive classification system of injuries. This system includes three common mechanisms of spinal trauma: compression–flexion, distraction–flexion, and compression–extension. Distraction–extension and lateral flexion subtypes are less common. Vertical compression injury results in anterior column failure or a burst-type injury. These are further classified into stages of progressive injury.³

• The patient’s ASIA impairment scale is D–Incomplete: Motor preservation below the neurologic level (C5), and at least half of the key muscles below the neurologic level have a muscle grade of 3 or more.

• Radiographically, there are multiple sites of injury including the ALL, PLL, intervertebral disk space at C6–C7, and posterior ligamentous structures.
  
• The discoligamentous injury at C6–C7 in conjunction with an incomplete spinal cord injury justifies the need for a combined anterior and posterior fusion.
  
• We performed an anterior cervical diskectomy with allograft bone graft and anterior cervical plating at the C6–C7 level using fluoroscopic guidance and electrophysiologic monitoring. Two days later an adjunctive posterior instrumentation was completed using polyaxial lateral mass screws and rod fixation (Fig. 81.4).
  
• Note that posteriorly, one could have also done a C6–C7 fusion only instead of fusing C5 to C7.
  
• The left-sided screws were placed first, and extra care was taken during placement secondary to the known vertebral artery injury.

• Awake fiberoptic intubation technique should be considered, given the cervical spine instability.
  
• Prevention of intraoperative hypotension and possible ischemia is critical given the patient’s spinal cord injury and unilateral vertebral artery injury.

• The most common complications of anterior approaches to the cervical spine include recurrent laryngeal nerve palsy with subsequent hoarseness, dysphagia, and odynophagia.⁴ Complete paralysis of the vocal cords is rare and is estimated to be around 0.5%.⁴
  
• Other less common complications include hematoma, large vessel arterial or venous injury/thrombosis, esophageal injury, dural sac manipulation with neurologic injury, dural tear, breathing difficulties or delayed extubation secondary to soft tissue swell ing, traction C5 palsy, peripheral and cranial nerve injury (hypoglossal), vertebral artery injury, Horner syndrome from sympathetic chain injury, and thoracic duct injury.5

• One can attempt a primary repair utilizing microsurgical techniques.
  
• Frequently, Gelfoam (Pfizer Pharmaceuticals, New York, NY) or collagen matrix (preferably inlay) and fibrin glue or hydrogel sealant can be placed over the defect, with care not to compress or manipulate the cord.
  
• Lumbar drainage can be used as an adjunctive measure.⁵

• The segments of the vertebral arteries are as follows.
  
  
  
  • Segment I runs from the subclavian artery to the transverse foramina of cervical vertebra C5 or C6.
    
  • Segment II runs within the transverse foramina of C5/C6 to C2.
    
  • Segment III is tortuous and begins at the transverse foramen of C2 then C1, runs posterolaterally to loop around the posterior arch of C1, and passes subsequently between the atlas and the occiput.
    
  • Segment IV is the intracranial segment and begins as it pierces the dura at the foramen magnum and terminates at the vertebrobasilar junction.
  
  
• Neurologic injury from posttraumatic vertebral artery dissection is often preventable with early diagnosis and therapy. Moreover, the diagnosis of a vertebral artery thrombosis may change the surgical plan, to prevent bilateral vertebral artery compromise.
  
• If indicated, the use of systemic anticoagulation may be protective against cerebral thromboembolism.
  
• Miller et al.⁶ found that patients with vertebral artery injury treated with anticoagulation or anti-platelet therapy had a stroke rate of 2.6%, whereas untreated patients developed stroke 54% of the time.
  
• If anticoagulation or antiplatelet therapy is contraindicated, then interventional embolization or surgical ligation can be considered.

• If the vertebral artery is injured from a posterior approach, then direct repair is not feasible. The screw should be kept in and intraoperative or immediate postoperative angiography is then performed.
  
• Endovascular obliteration is a good option for the management of a pseudoaneurysm after vertebral artery injury as long as the vertebral artery injured is not dominant.⁷

• The patient should initially follow up in the first 2 weeks for wound observation and preservation of spinal alignment.
  
• Radiographically, fusion can be appreciated over the course of ~3 months.
  
• Follow-up appointment may occur every month with plain cervical radiographs. Flexion and extension views can be performed to confirm spinal stability.
  
• A hard collar should be maintained for at least 6 weeks. At the time of radiographic fusion, remove the collar and begin isometric exercises and physical therapy.

• Delayed complications following cervical fusion include pseudoarthrosis, hardware failure, and post-surgical kyphosis.
  
• Pseudoarthrosis is a known cause of persistent neck pain and radiculopathy following anterior cervical discectomy and fusion.⁸ Pseudoarthrosis rates increase with multilevel constructs and may be as high as 50% for three-level fusions.⁴ In patients who undergo anterior cervical surgery with resultant symptomatic pseudoarthrosis, a posterior fusion may be more effective than anterior revision.⁹ Additionally, anterior cervical plating has reduced the incidence of pseudoarthrosis.
  
• Hardware failure or screw loosening typically can be seen at the caudal end of a multilevel construct.¹⁰ Graft displacement can be seen in 2–8% of cases.
  
• These complications may be avoided by maximizing screw purchase, preparing a well-fitting graft under compression, and possibly by the use of dynamic anterior cervical plating.^4,10
  
• Postsurgical kyphosis may result in patients suffering significant two-column injuries who undergo anterior cervical surgery alone. Adjunctive-instrumented posterior fusion can reduce the incidence of this complication.
  
• Adjacent segment disease can occur above or below the fusion.