Implementar la infraestructura de red.

228        PART II Systematic Evaluation of the Traumatized Patient

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Hangman's Fracture. This is a fracture through the pellicles and laminae of C-2 with occasional subluxation between C-2 and C-3, which commonly results from a hyperextension injury to the upper cervical spine.

Teardrop Fracture. This fracture usually occurs in response to a hyperextension injury in which the anterior longitudinal ligament is ruptured or avulsed, fracturing and displacing a small triangular fragment of the vertebral body.

Clay-Shoveler's Fracture. This is an avulsion fracture of the spinal processes of C-6 and C-7 induced by ligamentous stresses associated with extreme weight bearing and does not result in neurologic injury.

Dens/Odontoid Fracture. This fracture can occur from either hyperextension or hyperflexion and results in displacement of the dens anteriorly or posteriorly. Three types of fracture have been described:

1. Fracture through the upper dens—a stable fracture
2. Fracture through the waist of the dens—an unstable fracture
3. Fracture extending into the C-2 body—an unstable fracture

Compression Fracture. A vertical blow to the head or axial loading injury causes this fracture, and it can occur at any vertebral level. Mild forms consist of a wedge compression fracture with a teardrop-shaped chip broken off the anterior lip of the vertebral body. A severe form consists of a "burst" fracture, in which the entire vertebral body is crushed, usually with intraspinal bone fragments.

SOFT TISSUE INJURIES

Musculoskeletal Strain. Musculoskeletal strain constitutes a large portion of soft tissue injury and occurs with hyperextension not associated with fracture and dislocation. Flexion injuries occur with recoil; however, it is usually less forcefill. Some authors have referred to this injury pattern as "whiplash injury."g°

Central Cord Syndrome. This syndrome occurs in the setting of forceful hyperextension and backward thrusting of the neck, usually in an elderly patient with cervical spondylosis and stenosis. Paralysis occurs in this syndrome without vertebral injury. The upper extremities are usually weaker than the lower extremities owing to the somatotropic organization of the corticospinal tracts, with arm fibers medial and leg fibers lateral.

MANAGEMENT

Patients with neurologic deficits are treated with high-dose methylprednisolone as soon as possible, a 30 mg/kg bolus, followed by 5.4 g/kg/hr for 24 hours.`'t Statistically significant improvement in motor function outcomes was reported in the NASCIS-II study when steroids are initiated within 8 hours of injury.'"2

Cervical spine fractures are usually managed best with the patient in skeletal traction, often with

9 Neurologic Evaluation and Management        229

the use of halo traction in a Stryker frame or a rotokinetic bcd.89'93.9' Gardner-Wells tongs can also be applied effectively. The halo ring is attached to the skull by a four-point screw system, placed just above the pinnae of the ears on an imaginary plane connecting the mastoid processes and the external auditory canals.

Weight is applied to the ring to reduce the fracture and align the spine. The general recommendation is a maximum of 5 pounds per vertebral level above the fracture and/or dislocation (e.g., a C5 fracture usually requires 25 pounds of traction). Patients are kept immobilized before definitive treatment. Incomplete injuries and failure to reduce the fracture adequately are indications for early operative intervention .96

Alternatively, patients are placed in a halo vest orthosis, selected for operative fusion, or selected for fusion and immobilization in a halo vest. Unstable cervical spine fractures (i.e., complex fractures involving anterior and posterior elements, multiple levels, or fracture dislocations) should undergo operative fusion and decompression. Anterior vertebrectomy and fusion with plating arc indicated in burst fractures with anterior compression, whereas posterior fusion with instrumentation and autologous bone graft are best for posterior element disruption. Occasionally, both anterior and posterior procedures are required to decompress and stabilize the spine,

Upper cervical spine fractures are better immobilized with the halo vest orthosis than are lower cervical spine fractures.93.97 Hangman's and Jefferson's fractures respond well to immobilization in a halo vest and seldom require- operative intervention. Unstable C1 C2 fracture dislocations commonly require posterior cervical fusion and postoperative immobilization in either a hard collar or a halo vest.98'99 Soft tissue injuries are best treated with hard cervical collars for a brief period of relative immobilization, with analgesics and muscle relaxants administered.9°'m

SPECIAL CONSIDERATIONS

Posttreatment instability can lead to nonunion, malunion, or increased neurologic deficit. Frequently, unstable lower cervical spine fractures managed without operative intervention result in instability, which usually requires operative intervention. Similarly, when ligamentous disruption exists alone and management consists of a halo vest, posterior interspinous instability frequently develops, requiring operative fusion. Most authorities agree that these injuries should be managed surgically, followed by immobilization.93'95'96

PROGNOSIS

Sometimes the patient with an incomplete cord injury can walk again, provided that early surgical care is supplied and rehabilitation is aggressive and well planned. However, patients with complete lesions rarely recover function below the lesion. Rehabilitation fbr these patients is directed toward self-care and vocational readjustment. Most persons with these handicaps can eventually achieve independence. Life expectancy is shortened slightly in paraplegic persons and notably in quadriplegic persons. Long-term problems associated with skin care and recurrent urinary infections account for the shortened life expectancy.

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