Introduction

The geriatric cervical spine is prone to injury. The susceptibility to bony, ligamentous, and neurological injury may be associated with age-related changes including osteoporotic bone, stiffened spinal articulations, preexisting stenosis, and altered spinal cord vasculature and morphology. Because of these factors, which influence injury susceptibility in the elderly patient, the majority of subaxial cervical and upper thoracic spine injuries occur secondary to low-energy mechanisms. Even within the geriatric population, age is an important predictor of injury location based on mechanism.

Although atlantoaxial fractures are more common than subaxial fractures in the elderly, there is considerable morbidity associated with subaxial cervical and upper thoracic spine fractures. These more caudal spine injuries are more likely to be associated with neurological deficits, in comparison to atlantoaxial injuries, and more likely to be associated with higher-energy mechanisms.¹

Apart from the nearly ubiquitous osteoarthritic spondylosis seen in geriatric patients, other etiologies of severe cervical and thoracic spine ankylosis can alter the biomechanics of the cervical spine, causing increased susceptibility to fracture from minor traumatic events. These include ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH). Both conditions result in a stiff and often osteoporotic spine. With injury, both the anterior and posterior columns may be completely disrupted, causing frank instability. Fractures of the ankylosed spine are associated with 50% morbidity and 30% mortality.² For this reason, a high level of suspicion is required not to overlook potentially unstable fracture patterns.

The lateral cervical spine radiograph is widely used as a screening tool in the nongeriatric trauma patient. Because of the susceptibility of injury, the significant consequences of injury, and the potential for occult injury in the geriatric population, however, more extensive imaging may be warranted. This is particularly relevant in the spondylotic or ankylotic spine, to avoid missing injuries.

The treatment of subaxial cervical and upper thoracic spine fractures continues to be evaluated. The subaxial cervical spine injury classification system (SLIC) has been established to provide clinicians with standardization for making nonoperative versus operative decisions and, ultimately, how to surgically approach the injuries.³ The traditional thinking regarding the most optimal timing of surgical treatment of injuries is also changing. Specifically, there is now good evidence that early surgical treatment of central cord injuries is superior to late treatment for certain categories of patients. Geriatric surgical techniques are also evolving; the complex and overlapping pathologies of osteoporosis and ankylosis present challenges for which meticulous preoperative planning may prevent certain postoperative complications.

Basic Science

Cervical spine fractures occur in approximately 2% to 3% of blunt trauma patients. Subaxial fractures account for 40% to 60% of the cervical spine fractures. Of these, it has been found that nearly 20% involve the C7-T1 junction. Many subaxial cervical and upper thoracic spine fractures can be overlooked in the multiply-injured trauma patient. Geriatric patients, in particular, have characteristics that may make injury recognition difficult. These include preexisting spondylosis with or without degenerative deformities, as well as patient factors that make the physical examination difficult, including dementia, baseline weakness, and neuropathies. In the ankylosed spine, even minimally displaced segments can be unstable. The failure to recognize these sometimes subtle injuries can lead to devastating neurological consequences.

The radiographic and clinical evaluation of the cervical spine in the patient following trauma continues to be evaluated. There are ongoing modifications of recommendations regarding the role of radiographs, multiplanar CT, and MRI to rule out cervical spine injuries in the trauma patient. Multiplanar CT and MRI have been shown to have very high sensitivity for detecting cervical spine injury. Despite a high sensitivity, there are reports of cervical spine injury in obtunded patients with an unremarkable multiplanar CT.⁴ Brandenstein and colleagues recently reported on four patients with negative cervical CT scans and MRIs who later had evidence of cervical instability.⁵ They estimated that 0.2% to 0.4% of their patients would have cervical spine instability despite normal CT and MRI findings. Not surprisingly, three of the four patients with instability were geriatric. It is prudent to have a high degree of suspicion for cervical spine injuries in the geriatric patient despite seemingly normal imaging.

Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a seronegative (RF-negative) spondyloarthropathy that predominantly affects the sacroiliac joints and spine. It typically, but not exclusively, affects HLA-B27–seropositive patients. The prevalence ranges from 0.1% in African and Eskimo populations to as high as 6% in Haida Native Americans in northern Canada. The white populations of the USA and UK have a prevalence of 0.5% to 1.0%. AS typically has its onset in the third decade of life, with a mean age of onset of 26. It rarely begins after the age of 40, although the diagnosis may be made at a later age because earlier symptoms are ignored or benign. A juvenile form of AS is described, but it does not affect the spine.

Clinical Case Examples

CASE 1

A 58-year-old male fell from standing and struck the back of his head. This resulted in temporary loss of consciousness and neck pain. He was transferred from an outside hospital when abnormal neurological findings were appreciated. On presentation at our institution, he was immobilized in a rigid cervical collar and was hemodynamically stable. His exam revealed weakness (4/5) of bilateral upper extremities muscle groups. He also had 4/5 strength in his quadriceps but other lower extremity strength was 5/5. His past medical history was significant only for hypertension.

Imaging evaluation revealed extensive degenerative changes. Posterior osteophytes from C3 to C7 and calcification of the posterior longitudinal ligament were demonstrated on CT scanning. There was no fracture, malalignment, or prevertebral edema appreciated (Figure 29-1). An MRI revealed C3-4 disc osteophyte complex associated with spinal cord compression and T2 hyperintensity of the cord. Additional disc protrusions were seen at more caudal cervical levels (Figure 29-2).

FIGURE 29-1 Case 1: Midsagittal CT of cervical spine shows multilevel degenerative changes without evidence of fracture.

FIGURE 29-2 Case 1: MRI performed after physical examination consistent with central cord syndrome. A, Midsagittal T2-weighted cervical spine MRI shows anterior cord compression from the C3-4 disc. B, Axial T2-weighted cervical spine MRI at the C3-4 disc level shows cord edema and central canal stenosis.

He was initially treated with cervical collar immobilization. His neurological examination was monitored. The patient showed no improvement in his neurological examination. The recommendation to decompress and stabilize the cervical spine was accepted by the patient. A posterior direct decompression with instrumented fusion was performed from C3 to T1 (Figure 29-3).

FIGURE 29-3 Case 1: C3-C7 laminectomy and C3-T1 instrumentation and fusion show hardware in correct position and adequate laminectomy. A, Lateral postoperative x-ray. B, AP postoperative x-ray.

Postoperatively, his upper extremity weakness resolved. Two weeks later, however, he presented to the emergency department with recurrent weakness in elbow flexion bilaterally. His examination revealed 4/5 strength in bilateral deltoids and 3/5 strength in biceps and forearm supination. Otherwise his upper and lower extremity motor strength had improved to 5/5. He did not have any sensory deficits. Examination was consistent with C5 nerve palsy. He was treated with observation and analgesic medications. At latest follow-up, he is ambulatory with a fluid narrow-based gait and with resolved weakness in elbow flexion and supination.

Case 2

A 51-year-old male with known diffuse idiopathic skeletal hyperostosis (DISH) had a syncopal event and fell from the stands at Fenway Park, impacting his face and forehead. He had transient paralysis of bilateral upper extremities and severe neck pain. He was stabilized in a cervical collar at Fenway and transferred to our emergency department for evaluation.

On initial examination, he was found to have recovered motor function, and to have intact sensation to pain and light touch in bilateral upper extremities. He had persistent severe neck pain and severe burning pain and sensitivity to light touch in both hands, refractory to intravenous pain medications.

Imaging evaluation demonstrated several disc osteophyte complexes. The largest was observed at C3/C4, where there was 50% narrowing of the central canal. Extensive flowing nonmarginal osteophytes were also well characterized by CT scan (Figure 29-4). While no obvious unstable injuries were appreciated on CT, a subsequent MRI revealed extension distraction fractures with three column disruption at both C3-4 and C6-7. Each level of injury was associated with dissociation of the anterior longitudinal ligament and osteophytes (Figure 29-5). The spinal cord was compressed at C3-4 and C6-7.

FIGURE 29-4 Case 2: Initial midsagittal and axial CT reveals many aspects of DISH. There are four continuous ankylosed vertebrae, the osteophytes are nonmarginal, and it spares the posterior elements, Due to the degree of DISH, it was difficult to say if there was a fracture or instability base on CT scan alone. A, Midsagittal CT scan. B, Axial CT scan at C3 level shows central cord compression from osteophyte.

FIGURE 29-5 Case 2: A, Sagittal STIR MRI with increased signal at C3-4 and C6-7 consistent with acute injury. B, Axial T2-weighted image at C7 shows cord compression.

A C3 to C7 laminectomy and C3 to T1 instrumented fusion were performed. He tolerated the procedure well and was extubated in the operating room (Figure 29-6). Since the patient’s body habitus limited the adequacy of intraoperative radiographs, a CT scan was performed immediately postoperatively to evaluate the spinal alignment and instrumentation (Figure 29-7).

FIGURE 29-6 Case 2: Postoperative AP and lateral cervical spine x-rays with good sagittal and coronal alignment. Hardware in appropriate position without evidence of complications.

FIGURE 29-7 Case 2: Postoperative CT scan. A, Axial CT at C3 level with lateral mass screws. B, Sagittal CT scan demonstrates pedicle screws within the C7 and T1 pedicles.

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