Page 1619 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

1138 PART 10: The Surgical Patient

between 1973 and 1979 to 12 days since 2005. Shorter stays in rehabilita-
TABLE 119-1 Clinical Sequele vs Level of Spinal Cord injury
tion, from 98 to 38 days, are also noted. The increasing life expectancy
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SCi Level Clinical Sequelae of spinal cord injured patients has led to an increased worldwide preva-
C1-C2 Tetraplegia; phrenic nerve paralysis and complete paralysis of respiratory lence of SCI, now approaching 2 million. 4
muscles, requires permanent mechanical ventilation, diaphragmatic pacing Intensivists working in nondesignated trauma center hospitals should
consider the transfer of an acute spine injured patient to a level I trauma
C3-C4 Tetraplegia; phrenic nerve damage and paralysis of respiratory muscles but center as soon as possible. There is level II evidence that trauma centers
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damage at the C4 level and below allows some recovery of respiratory function
and specialized neurocritical care have a positive impact on mortality
C5 Tetraplegia; shoulder and upper arm control preserved; loss of wrist and hand and disability after spinal cord injury.
control. Diaphragmatic function preserved; paralysis of the intercostal and abdominal
wall muscles supplied by the thoracic segments leads to paradoxical respiration
C6 Tetraplegia; wrist control preserved; loss of hand control CLASSIFICATION OF VERTEBRAL INJURIES
C7-T1 Tetraplegia; reduced dexterity of hands and fingers The cervical spine is divided into the upper cervical spine (C1 [atlas]-C2
T1-T8 Paraplegia; upper extremity function typically preserved; loss of abdominal [odontoid or dens]) and lower (subaxial) cervical spine (C3-C7). The
muscle control cervical vertebrae are smaller and very mobile. Common C2 fracture
includes that of the dens and bipedicular (or hangman’s fractures). The
T9-12 Paraplegia; abdominal muscle and trunk control preserved latter are frequently caused by acute neck hyperextension. After trauma
L1-L5 Paraplegia; loss of hip flexor and leg control; early but temporary loss of colonic to the cervical spine, fractures may appear on x-ray, but the stability of
motility; initially hypotonic bladder and external urethral sphincter; later detrusor the spine depends on the ligaments which are not visible on plain x-rays
hyperactivity with loss of external urethral sphincter control with urinary incontinence or computed tomography (CT) scans. The thoracolumbar spine (T1-12;
S1-S5 Paraplegia; loss of foot control; chronic dysmotility; greater risks of fecal impaction; L1-5) vertebrae are larger and less mobile.
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impaired motor output to bladder (S2-S4) leading to a flaccid, distended bladder The Denis three-column theory of spinal stability divides the
vertebral column into anterior, middle, and posterior columns. Together,
these columns form functional units that contribute to spinal stability
Approximately 50% of spinal injuries occur in the cervical spine, the and can explain the effect of various injuries on spinal destabilization.
other half involve the thoracic, lumbar, and sacral areas. SCI may lead to The anterior column contains the anterior longitudinal ligament, the
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significant neurological damage, including paraplegia, tetraplegia, or death. anterior half of the vertebral body, intervertebral disk, and its annulus
Patients with tetraplegia have injuries to one or more of the eight cervical fibrous. The middle column contains the posterior longitudinal liga-
segments (C1-8) of the spinal cord; those with paraplegia have lesions in the ment, the posterior half of the vertebral body, intervertebral disk, and
thoracic (T1-12), lumbar (L1-5), or sacral (S1-2) regions of the spinal cord its annulus. The posterior column contains the bony posterior neural
(Table 119-1). The American Spinal Injury Association (ASIA) has devised arch, the intervertebral articulations, the ligamentum flavum, and the
a scoring system to assess SCI (Fig. 119-1). Complete spinal cord injuries interspinous and supraspinous ligaments.
result in no motor or sensory preservation below the level of injury and The spine can be damaged by blunt or penetrating trauma and
carry a poor prognosis for functional recovery. Partial preservation of motor the forces of flexion, distraction (extension), and rotation. Fractures of the
and or sensory function is termed incomplete injury. An incomplete injury spine can be classified based on the pattern of injury and the forces.
has the potential to regain useful function or progress to complete injury. The types of fractures include compression (wedge) fractures, caused by
flexion and compression in the anterior column with variable involvement
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EPIDEMIOLOGY of the middle and posterior column, burst (or crush) fractures involving
the anterior and middle columns characterized by loss of height of the
Acute traumatic spinal injuries occur most commonly in males (80.8%) vertebral body, caused by axial compression forces associated with high
and the average age at injury is 40.2 years, increased from 28.7 years in energy trauma (eg, MVA, falls from a heights, and sports-related trauma),
the 1970s mainly due to an increase in the median age of the general most commonly found at the thoracolumbar junction between levels
population. Excluding those who die at the accident scene, the annual T10 and L2; seatbelt or Chance thoracolumbar spine fractures are the
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incidence of (SCI) in the U.S. is approximately 12,000 new cases each result of flexion and distraction forces and involve middle and posterior
year or 40 cases/million population. Since 2005, the most common eti- columns with injury to ligamentous components, bony components, or
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ologies of SCI are motor vehicle crashes (41.3%), falls (27.3%), violence both; and dislocations that involve all three columns (Figs. 119-2 to 119-4).
(15%), and sports (7.9%). Incomplete tetraplegia occurs in approxi- Chance fractures are often associated with intra-abdominal injuries.
mately 38.3% of traumatic spinal injuries, followed by complete paraple- Lateral flexion and rotation (with or without anterior -posteriorly directed
gia (22.9%), incomplete paraplegia (21.5%), and complete tetraplegia force) result in rotational fracture-dislocations. The posterior and middle
(16.9%). Complete tetraplegia is a devastating injury, with a less than columns are damaged with varying degrees of anterior column insult. The
1% rate of complete neurologic recovery by hospital discharge. Over rotational forces disrupt the posterior ligaments and facet joints. With
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the last 15 years, the percentage of persons with incomplete tetraplegia sufficient rotational force, the upper vertebral body rotates and carries the
has increased while complete paraplegia and complete tetraplegia have superior portion of the lower vertebral body along with it causing a radio-
decreased slightly. Intoxication is a factor in many traumatic injuries. graphic “slice” appearance sometimes seen with these types of injuries. 1
Respiratory complications are the leading cause of death during the Other types of stable fractures include spinous process and transverse
first year after SCI, and the third leading cause of death thereafter. For process fractures, osteophyte fractures, avulsion fractures, and injury to
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patients with injury at age 20, surviving 24 hours and ventilator depen- trabecular bone (Fig. 119-2).
dent from any level of injury, the life expectancy is only 18.1 years and at The grading of the stability of vertebral fractures is based on
1 year postinjury rises to 24.9 years. The life expectancy for older (aged biomechanical stability, fracture morphology, osteoligamentous integrity,
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60) ventilator-dependent patients who survive the first 24 hours after spinal canal or neural foramina deformity, and neurological impairment.
SCI is 1.8 years and at 1 year after injury is only 3.6 years. In the past, Disruption of two or more columns results in a potentially unstable
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renal failure was the leading cause of death after SCI, but due to advances spine, therefore burst fractures, Chance fractures, and dislocations are
in urological management, pneumonia, sepsis, and pulmonary emboli potentially unstable but compression fractures are stable. For example,
currently appear to have the greatest impact on reduced life expectancy. 2 compression fractures do not lead to neurological lesions and are stable;
The median days spent in the acute care unit for those who immedi- burst fractures are potentially unstable but in the presence of neurological
ately enter a “Model Spinal Cord Injury Unit” has declined from 24 days signs related to migration of the vertebral body, they are unstable

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