Pathogenesis and Pathologies

In spinal concussion, there is a functional rather than pathologic disturbance, usually with return of function within hours [Tator, 1996]. Extravasation of potassium from neurons into the extracellular space, after direct injury of nerve cell membranes or secondary nerve cell damage from vascular disruption, is the most likely mechanism of spinal cord concussion. Ischemia of the spinal cord can occur from anterior spinal artery or other vascular compression during spinal cord trauma, but also can occur when the trauma does not involve the spinal cord directly. Hypotension, systemic shock, and vascular injury to the aorta or a vertebral artery are the most common causes of this type of injury. With compression of the anterior spinal artery, the anterior two-thirds of the spinal cord is affected, causing weakness and loss of pain and temperature perception, with preservation of proprioception and light touch. Contusion results from a blunt injury of the spinal cord without continued compression or disruption of nerve tissue, resulting in transient paresthesias and dysesthesias in the upper limbs, especially the hands (burning hands syndrome), accompanied by transient long tract signs. Recovery is incomplete, however, distinguishing contusion from concussion. Central cord necrosis (hemorrhagic or ischemic) is a common sequela that often can be seen on magnetic resonance imaging (MRI) [Bailes et al., 1991; Jellinger, 1976]. Compression of the spinal cord can be caused by vertebral dislocation or by pressure from bony fragments, a herniated disc, or extramedullary bleeding [Jellinger, 1976]. Laceration occurs when there is interruption of spinal cord tissue by bony fragments, knife or bullet wounds, fracture-dislocation, or severe stretching. In older children, the most frequent cause of laceration is a penetrating agent, whereas in newborns, hyperextension of the neck during breech delivery is the most likely cause [Allen et al., 1969; Bresnan and Abroms, 1974; Byers, 1975; Crothers, 1923]. Intramedullary hemorrhage, which can extend over several spinal cord segments (hematomyelia), is believed to result from direct injury to blood vessels or from altered vascular permeability, as from acidosis.

The pathology of intraspinal intramedullary injuries has been studied in detail in experimental animals and in human postmortem examination material [DeLaTorre, 1981; Dumont et al., 2001a; Jellinger, 1976; Kakulas, 1984; Norenberg et al., 2004; Park et al., 2004; Profyris et al., 2004]. To mimic most events that lead to various forms of human spinal cord injury, several experimental models have been developed, the most common being transection, compression, or contusion [Rosenzweig and McDonald, 2004]. Because there are striking pathophysiologic similarities between human spinal cord injury and experimental models of spinal cord injury, particularly in the rat, findings in experimental spinal cord injury are commonly extrapolated to human injury. Such extrapolation requires caution, however, because regulation of secondary events after spinal cord injury varies greatly among different animal species and strains [Profyris et al., 2004]. The pathologic changes observed in the spinal cord after trauma can be subdivided into early, late, and very late.

The pathophysiology of spinal cord injury is biphasic. First is the primary injury, which is mechanical (e.g., spinal fracture and/or dislocation), directly disrupting axons, blood vessels, and cell membranes. This is followed by the delayed onset of secondary injury, involving vascular dysfunction, edema, ischemia, excitotoxicity, electrolyte shifts, free radical production, inflammation, and delayed apoptotic cell death. While neurologic deficits are seen immediately following the initial injury, the secondary injury phase results in a protracted period of tissue destruction [Rowland et al., 2008].

Almost all of our detailed understanding of spinal cord injury pathophysiology has been obtained from animal studies. Important to understanding the pathophysiology of human spinal cord injury is that each injury is unique in cause and resultant damage. Further, the contrast between the homogeneity of experimental spinal cord injury models, as in widely used rodent models, and the highly heterogenous human spinal cord injury population adds to the challenge of successfully translating treatments to the clinic.

Phases of secondary injury

Secondary injury can be divided temporally into multiple contiguous phases: immediate, acute, subacute, intermediate, and chronic stages of spinal cord injury.

Immediate Phase (0–2 Hours)

During the immediate phase of spinal cord injury, which can last for up to 2 hours, traumatic severing of axons, the immediate death of neurons and glia, and accompanying spinal shock result in immediate loss of function at and below the level of complete injury. Pathological changes consist of swelling of the spinal cord, often with hemorrhage in the central gray matter and surrounding white matter, and necrosis (Figure 78-5) and spinal cord ischemia extending for many segments rostral and caudal to the injury site. Activation of microglial cells begins almost immediately, with the upregulation of the proinflammatory cytokines tumor necrosis factor (TNF)α and interleukin (IL)-β, detectable within minutes of injury. Also within minutes, levels of extracellular glutamate can reach excitotoxic levels.

Fig. 78-5 Severe traumatic injury to the spinal cord with secondary hemorrhage and coagulation necrosis.

Acute Phase (2–48 Hours)

It is in this phase that the secondary injury processes become dominant. For practical reasons, it is the phase likely to be most amenable to neuroprotective interventions, as it is typically the earliest point at which patients arrive at an appropriate treatment center.

The acute phase of spinal cord injury lasts from 2 to 48 hours. It is characterized by continuing hemorrhage, increasing edema and inflammation, and the onset of additional secondary injury processes, including free radical production, ionic dysregulation, glutamate-mediated excitotoxicity, and immune-associated neurotoxicity, which cause vascular disruption, hemorrhage, and resulting ischemia, with further axonal injury and cell death. The ischemia results in cytotoxic cell swelling, affecting neurons and glia, and axonal swelling. Loss of ion homeostasis immediately following spinal cord injury and excitotoxicity both contribute significantly to the propagation of cell injury after spinal cord injury. Ion dysregulation is also a central feature of necrotic and apoptotic cell death. Excitotoxicity results from excessive activation of glutamate receptors and is believed to play a role in the death of neurons and glia. Production of free radicals gives rise to lipid peroxidation, contributing to axonal disruption and death of neurons and glia. The modest protective effect of methylprednisolone treatment following acute spinal cord injury is believed to be due, at least in part, to the inhibition of lipid peroxidation [Kwon et al., 2004]. An additional acute-phase change is a marked increase in permeability of the blood–brain barrier. Death of neurons at all stages of injury occurs mainly from necrosis; by contrast, oligodendroglia readily undergo apoptosis. Loss of oligodendroglia results in axonal demyelination; persistent demyelination and other forms of axonal injury can then cause death of associated cell bodies. Animal studies have provided strong evidence that spared demyelinated axons are present following contusive spinal cord injury, and represent an important therapeutic target for spinal cord injury treatments that either remyelinate (cell transplants) or improve axonal conduction in demyelinated fibers (4-aminopyridine) [Hayes et al., 2004; Nashmi and Fehlings, 2001]. On the other hand, postmortem human studies and a limited number of animal studies [Lasiene et al., 2008] have not convincingly shown significant numbers of spared demyelinated axons to be present after human spinal cord injury [Kakulas, 2004; Norenberg et al., 2004].

Subacute Phase (2 Days to 2 Weeks)

The subacute phase of spinal cord injury lasts from 2 days to 2 weeks, and is the time period in which future cell-based therapeutic strategies are most likely to be applied. Transplantation of adult neural precursor cells 2 weeks following spinal cord injury in rats promotes remyelination and functional recovery, whereas cells transplanted at chronic time points either fail to survive, or fail to migrate and differentiate to promote functional recovery. A phagocytic response is maximal during the subacute phase; it helps to remove cell debris and may promote axon growth. An astrocytic response begins in the subacute phase, when astrocytes at the periphery of the lesion become hypertrophic and proliferative, and form an astrocytic (gliotic) scar. This scar presents both a physical and chemical barrier to axonal regeneration. Despite the production of a scar, astrocytes also serve beneficial functions following spinal cord injury, including re-establishment of ion homeostatis and reestablishing the integrity of the blood–brain barrier.

Intermediate Phase (2 Weeks to 6 Months)

The intermediate phase of spinal cord injury lasts from 2 weeks to 6 months. It is characterized by the continued maturation of the astrocytic scar and by regenerative axonal sprouting.

Chronic Phase (6 Months or More)

The chronic phase of spinal cord injury begins 6 months after injury and continues through the patients lifetime. Scar formation continues, and the central portion of the spinal cord is replaced by a cystic cavity extending for several segments above and below the point of impact, resulting in post-traumatic syringomyelia; this extension can continue over many years, significantly increasing the patient’s neurological deficit, including ascending paralysis, brainstem symptoms, and neuropathic pain [Barnett and Jousse, 1976; Profyris et al., 2004; Rowland et al., 2008; Tator, 1996]. Wallerian degeneration of ascending and descending tracts occurs within 6–12 months [Kakulas, 1999], and nerve roots at the level of the lesion become atrophic. The cord becomes thin in the area of injury, with fibrosis and thickening of the overlying meninges [Kakulas, 1984]. At this chronic phase, therapeutic strategies are directed to encouraging regeneration/sprouting of disrupted axons, promoting plasticity with rehabilitative strategies, and improving function of demyelinated axons. Despite much success with stem cell-based approaches when applied subacutely, use of stem cells during this chronic phase of injury has not been shown to be successful [Rowland et al., 2008].

Pathogenesis and Pathologies

The mode of spinal cord injury from intraspinal extramedullary conditions is primarily by spinal cord compression, although secondary vasospasm and ischemia also play a role. The causative pathologies include hemorrhage, infection, cystic fluid, and solid tissues. The degree of resultant injury to cord depends on the location and size of the mass and the duration of cord compression. Post-traumatic intraspinal extramedullary mass lesions occur relatively infrequently and, when present, are often small, causing little, if any, cord compression. Included among these disorders are spinal epidural, subdural, and subarachnoid hemorrhages; spinal epidural abscess; arachnoid cyst; epidermoid tumor; herniation of the nucleus pulposus; and cauda equina injuries.

Radiographic Evaluation

Radiographic evaluation of the child suspected of having spinal cord injury should begin in the emergency department with plain films of the entire spine. The purpose of the evaluation is to look for evidence of unstable fractures or vertebral dislocations that may require emergency surgical intervention. Radiography of the entire spine is important because approximately 15 percent of patients have injury at multiple sites [Hadley, 1992; Hadley et al., 1988]. Radiological evaluation of the spine is often neither possible nor desirable in an emergency situation, however, and may need to be deferred until the spine is stabilized. In such circumstance, only the spinal area clinically involved needs immediate imaging. In cases in which the patient cannot be assessed adequately by plain radiography, MRI may be required early in the evaluation. Stringer and Andersen suggested a diagnostic algorithm for spinal injury combining the findings on neurological examination and results of radiographic studies [Andersen and Stringer, 1996; Stringer and Andersen, 1996].

Children with spinal cord injury routinely have sandbag and tape fixation of the head and neck, making optimal radiographic examination more difficult. Nonetheless, it is crucial to obtain anteroposterior, lateral, and oblique views of the spine. All seven cervical vertebrae and the C7–T1 interspace must be visualized. Swimmer’s views are often necessary to visualize all of the lower cervical vertebrae, and an open-mouth view may be needed to visualize the odontoid process [Goldberg et al., 1990], although the open-mouth view can be safely omitted if the other views are normal [Dias, 2004]. Flexion/extension cervical x-rays and fluoroscopy are sometimes indicated to exclude ligamentous instability when there is still suspicion of cervical spine instability after static x-rays have been obtained [Hadley, 2002b]. Care must be taken not to misinterpret normal variations in cervical spine films of a child. These variations include pseudosubluxation of C2 on C3 (seen in 20 percent of normal children age 1–7 years) and the cartilaginous plate at the base of the odontoid (normally seen in children <3 years old and often mistaken for a recent fracture) [Cattell and Filtzer, 1965].

In spine-injured children, the upper cervical spine is especially susceptible to injury. Specific injuries to this region include:

Occipitoaxial dislocations can be identified on plain radiographs in some patients using the Powers ratio (distance of the basion [midpoint of the anterior border of the foramen magnum] to the posterior arch of C1, divided by the distance of the opisthion [midpoint of the lower border of the foramen magnum] to the anterior arch of C1). This ratio is usually 0.77. Ratios greater than 1 are abnormal. Most often, MRI is needed to identify occipitoaxial dislocations. Instability of the atlantoaxial region is suspected when the preodontoid space exceeds 5 mm in a child or 3 mm in an adult. Fractures of the atlas often can be stabilized by using a rigid (Philadelphia) collar [Alker et al., 1975]. Odontoid fractures and hangman’s fractures are rare in childhood and, if present, usually can be treated nonoperatively (halo brace) [Anderson and D’Alonzo, 1974].

Measurements made to assess alignment of the spinal column follow the “rule of 2”: that is, the allowable displacement between vertebrae in any direction should not exceed 2 mm in adults, with a greater allowance in children. The evaluation of bony integrity can be difficult at times, especially of the odontoid process and C1. If adequate quality cannot be obtained by plain radiographs, computed tomography (CT) is indicated [Andersen and Stringer, 1996; Stringer and Andersen, 1996].

Further limitations of plain radiographs of the spine include 40 percent false-positive and 20 percent false-negative interpretations. Also, significant spinal cord injury frequently occurs in children without radiographic abnormality (SCIWORA) (e.g., vertebral fracture or dislocation) [Burke, 1974; Pang and Wilberger, 1982], with this discrepancy observed in 15–70 percent of all pediatric spinal cord injuries [Hadley et al., 1988; Menezes et al., 1989; Pang and Wilberger, 1982]. Based on radiographic findings, spinal column injuries can be classified as follows:

SCIWORA, as first described, referred to cases of spinal cord injury with objective signs of myelopathy in the absence of abnormalities on static and dynamic flexion/extension films, CT imaging, and plain or CT myelography [Gore et al., 2009]. With modern MRI, many such cases show radiological evidence of injury to the spinal cord or spinal cord ligaments [Caviness, 2004; Davis et al., 1993; Matsumura et al., 1990; Proctor, 2002], with MRI abnormalities seen in about two-thirds of cases [Massagli, 2000]. Pang found MRI in 50 SCIWORA patients to have high prognostic value. The findings were complete transection or major hemorrhage (both with profoundly poor outcomes); minor hemorrhage (40 percent improved to mild disability); edema only (75 percent improved to mild disability); and normal (all recovered completely) [Pang, 2004].

Because the vertebral column in early life is quite elastic, allowing for significant flexion, hyperextension, and vertebral distraction without accompanying fracture or dislocations, SCIWORA is seen most often in infants and young children, in whom the frequency is three times greater than in children older than 10 years of age [Massagli, 2000]. Also predisposing to SCIWORA in young children is the greater elasticity of the spinal column than of the spinal cord; the bony spine can tolerate 5 cm of distraction, whereas the spinal cord can tolerate only 5 mm before disruption [Caviness, 2004]. Spinal cord ischemia from vertebral artery injury may also be contributory [Gore et al., 2009]. SCIWORA most often affects the cervical spine, typically producing signs of a central cord syndrome [Babcock, 1975]. In children less than 8 years, SCIWORA is more likely to be more rostral and more severe; from 8 to 16 years, it tends to be more caudal and less severe [Gore et al., 2009]. In some cases, transient neurologic symptoms may be the only indication that the cervical spinal cord has been injured; in other cases, permanent deficits may result, reflecting more severe spinal cord injuries that can be partial or complete [Caviness, 2004; Massagli, 2000]. In one study, 52 percent of children with SCIWORA had delayed onset of paralysis 4 days after their injury [Pang and Wilberger, 1982]. Children with spinal trauma must be examined frequently for signs of clinical deterioration in the days after their injury, even when plain radiographs of the spine are normal. Cervical immobilization of patients with SCIWORA is controversial. If dynamic films demonstrate stability of the cervical spine, the role of cervical immobilization is unclear. With only extraneural findings on MRI, neurological recovery, and no neck pain, 2 weeks of hard collar immobilization is recommended, followed by dynamic films; but with neural findings on MRI, the recommendation is for 12 weeks of hard collar immobilization before dynamic films are obtained [Gore et al., 2009]. Avoidance of high-risk activities for 6 months is recommended [Gunnarsson and Fehlings, 2003].

CT is the best means of detecting subtle spinal fractures and clarifying equivocal areas seen on plain films. CT also should be used when plain films are normal, but clinical suspicion of instability or fracture still exists [Andersen and Stringer, 1996; Stringer and Andersen, 1996], or when fracture/ displacement is seen on plain radiography [Caviness, 2004]. More recently, MRI of the spine has replaced CT and myelography as the preferred means of imaging the injured spinal cord (Figure 78-7) [Goldberg et al., 1988; Greenberg, 1991; Hyman and Gorey, 1988]. Many MRI sequences can be used, depending on the type of injury and the spinal cord area of concern, including spin-echo, fast-spin-echo, gradient-recall-echo, and inversion-recovery sequences. Excellent review articles on the use of these different sequences in specific situations are available [Andersen and Stringer, 1996; Stringer and Andersen, 1996]. MRI can distinguish intramedullary lesions from extramedullary ones, and early pathologic changes from later ones [Davis et al., 1993; Kalfas et al., 1988; Levitt and Flanders, 1991; Sett and Crockard, 1991]. In general, findings on MRI correlate well with the degree of deficit found on neurological examination [Bondurant et al., 1990; Davis et al., 1993; Flanders et al., 1990]. Additionally, the type and severity of spinal cord injury seen on MRI correlate well with the degree of recovery. In one study, MRI findings were classified into the following three categories:

type I, inhomogeneous on T1-weighted image, large central hypointensity with thin hyperintense rim on T2-weighted image

type II, normal T1-weighted image, hyperintense cord on T2-weighted image

type III, normal T1-weighted image, isointense center with thick hyperintense rim on T2-weighted image.

Fig. 78-7 Imaging studies of the thoracic spine in a 19-year-old male after a car accident in which he was an unrestrained passenger.

A, Computed tomography shows a fracture of the right lamina of T3, with a burst fracture of the body of T4, causing deformity and anteroposterior narrowing of the spinal canal. B, Magnetic resonance image of the thoracic spinal cord in the same patient, obtained the same day (T1-weighted image). There is a wedge fracture of T4 (arrow), producing compression of the underlying spinal cord.

Neurological recovery was insignificant in patients with intraspinal hemorrhage, while patients with cord edema or contusion recovered significant neurological function [Kulkarni et al., 1987] (Figure 78-8).

Fig. 78-8 Radiographs of the cervical spine in a 16-year-old boy who, 10 weeks previously, fell from a one-story roof, sustaining fractures of his 6th and 7th cervical vertebrae.

A, Computed tomography of the cervical spine, showing anterior subluxation of the body of C6 on C7 (arrow). B, CT scan of cervical spine showing fracture of the right articular mass of C6, with forward displacement of the C6 pedicle (circled). C, Magnetic resonance image of the cervical spine (T2-weighted image), showing narrowing and T2 hyperintensity of the cervical spinal cord at the C6 level (arrow), the site of the displaced C6 fracture.

In general, spinal cord injuries in which there is no identifiable MRI abnormality carry a better prognosis for recovery than injuries in which MRI abnormalities are found [Davis et al., 1993]. The usefulness of MRI in visualizing spinal cord injury in neonates, in whom neurologic abnormalities can be difficult to find and in whom significance can be difficult to interpret, has been documented [Lanska et al., 1990]. MRI also is useful in showing abnormalities that may not be seen with other imaging modalities, including ligamentous instability and disruptions, other soft-tissue injuries, disc herniations, intraspinal hemorrhage, and nerve root injuries [Kadish, 2001; Proctor, 2002]. In some cases, it may be necessary to use a combination of MRI and CT to identify coexisting injuries of the spinal cord and bony spine [Levitt and Flanders, 1991; Wittenberg et al., 1990]. MRI can be useful in predicting outcome in intramedullary lesions because it can differentiate hematoma (which often has a poor prognosis) from spinal cord edema, which usually has a better outcome [Schaefer et al., 1992]. In 49 patients who underwent MRI within 72 hours of sustaining a cervical spinal cord injury, the imaging features that correlated with a poor functional recovery included hemorrhage, long segments of edema, and high cervical lesions [Flanders et al., 1999].

Functional MRI has been used to assess the degree of spinal cord damage in 27 patients with complete and incomplete cervical and thoracic spinal cord injuries. With thermal stimuli applied to the inner calf (L4 sensory dermatome), activity in ipsilateral dorsal gray matter was diminished with complete and incomplete injuries; in the ventral regions, however, activity was increased with complete injuries, but with incomplete lesions, it was similar to or diminished compared with healthy subjects (i.e., it was notably less than in subjects with complete spinal cord injuries) [Stroman et al., 2004].

Serial MRI studies also can be helpful in following the evolution of traumatic spinal cord lesions [Sato et al., 1994; Sett and Crockard, 1991]. The need for metrizamide CT, used previously in evaluating post-traumatic spinal cord cysts and syringomyelia [Mace, 1985; Quencer et al., 1983; Rossier et al., 1983], has diminished substantially with the accuracy of MRI in showing these lesions. Also, because of the availability of MRI, the need for myelography to identify surgically remediable spinal cord injuries (e.g., extramedullary hematomas and major fracture-dislocations) has diminished greatly. When the patient’s clinical condition permits, most centers currently advocate early MRI for acute spinal trauma.

Electrophysiologic Evaluation

Motor-evoked potentials (MEPs) provide a means to assess descending spinal tract function. MEPs are induced by transcranial magnetic stimulation of the motor cortex and are recorded on muscles of interest using surface electrodes to determine the level and extent of the spinal cord injury. It has been shown that MEP amplitudes improve with spinal cord injury recovery but latencies do not [Xie and Boakye, 2008].

The usefulness of somatosensory-evoked potentials (SSEPs) and electromyography in evaluating the level of spinal cord injury and predicting clinical outcome is controversial. SSEPs are often useful in identifying the level of spinal cord injury [Louis et al., 1985] and in identifying areas of spinal cord damage that have been clinically unapparent [Toleikis and Sloan, 1987]. This test can be especially helpful in infants and young children in whom the degree of deficit often cannot be determined confidently by clinical examination [Kamimura et al., 1988]. It is unknown, however, whether SSEPs are superior to MRI in identifying the extent of a spinal cord injury and predicting clinical outcome. Some investigators have noted a high degree of correlation between abnormal SSEPs and potential for neurological recovery [Curt et al., 1997; Li et al., 1990; Perot, 1973; Rowed et al., 1976; Spiess et al., 2008; Ziganow, 1986], but others have not [Katz et al., 1991; York et al., 1983]. One study of experimental spinal cord injury revealed no correlation between the absence of SSEP waveforms and the degree of spinal cord injury [Singer et al., 1977]. In that study, animals demonstrated good return of function at 8–9 days, even though SSEP waveforms were not recordable 3–19 days after injury. Other studies have suggested, however, that patients with absent SSEPs after spinal cord injury are unlikely to have any meaningful recovery of neurologic function [Shurman et al., 1996].

The sympathetic skin response (SSR) is another noninvasive electrophysiological test, in which EMG electrodes placed on the skin surface record responses to electric or magnetic stimulation above the spinal lesion. These recordings can be used to assess damage to the spinal and peripheral efferent sympathetic pathways subserving corresponding skin areas. While SSR has been used less than MEPs and SSEPs to assess completeness of spinal cord injuries, the addition of sympathetic nervous system testing may provide a more complete picture of the spinal cord injury [Curt and Dietz, 1999; Xie and Boakye, 2008].

The presence of F-waves and H-reflexes depends on the integrity of the motor neuron pool. H-reflexes disappear in the first 24 hours of spinal shock, but return thereafter; F-waves disappear below the level of injury during spinal shock and reappear with its resolution [Horowitz and Patel, 2003]. F-wave and H-reflex latencies and electromyogram can show lower motor neuron unit abnormalities 3–4 myotome levels beyond the site of a spinal cord lesion [Shefner and Tun, 1991]. Based on such electrophysiologic findings, the extent of deficit, whether functional or anatomic, is often found to be more extensive than indicated by clinical examination. As with SSEPs, it is uncertain whether abnormalities on electromyogram can increase significantly the predictability of clinical outcome in spinal cord injury.

Lumbar Puncture

Lumbar puncture can provide useful diagnostic information in certain types of spinal injury. The presence of extramedullary hematomas should be suspected with bloody or xanthochromic cerebrospinal fluid. Conversely, spinal epidural abscess usually causes a mild cerebrospinal fluid pleocytosis with an elevated cerebrospinal fluid protein concentration and a normal glucose concentration. Very low cerebrospinal fluid pressure at the time of lumbar puncture suggests the presence of a spinal block.

Complete Spinal Cord Injuries

Complete loss of spinal cord function, as defined by the ASIA/IMSOP Spinal Cord Impairment scale, can be either physiologic or pathologic. In physiologic loss, there is no morphologic alteration of the spinal cord, which becomes dysfunctional after impact. This dysfunction may occur with transient compression of the cord by a dislocated vertebra. With more sustained compression of the spinal cord, anatomic disruption of spinal cord elements may result, with accompanying pathologic loss of function. The frequency of complete spinal cord injury in pediatric patients varies widely, depending on the series reviewed, ranging from 20 to 95 percent of all pediatric spinal cord injuries [Anderson and Shutt, 1980; Burke, 1974].

The initial phase of complete loss of spinal cord function is characterized by spinal shock [Green and Eismont, 1984; Kiss and Tator, 1993]. The truncal and extremity muscles below the level of the lesion are flaccid, deep tendon and superficial reflexes are depressed or lost, plantar responses are absent, anesthesia is present to all modalities, and autonomic dysfunction (hypotension and bradycardia) is present. The mechanism of spinal shock is unknown, but its physiologic effects must be differentiated from the more permanent pathologic effects of spinal cord injury. Motor and sensory deficits resulting from spinal shock alone resolve within 1 hour. Persistence of motor and sensory deficits beyond 1 hour implies that pathologic, more permanent injury has occurred. After 6–13 weeks in adults and within 1 week in children, tendon reflexes return, and muscle tone improves. The reflexes later become pathologically active, and spasticity ensues if the injury is more permanent, and there usually is no significant return of motor or sensory function. A four-phase model of the sequential clinical changes seen in spinal shock and the neuronal mechanisms that may underlie those changes has been described:

phase 1 (0–1 day), areflexia/hyporeflexia (from loss of descending facilitation)

phase 2 (1–3 days), initial reflex return (from denervation supersensitivity)

phase 3 (1–4 weeks), initial hyperreflexia (from axon-supported synapse growth)

phase 4 (1–2 months), final hyperreflexia (from soma-supported synapse growth) [Ditunno et al., 2004].

Autonomic dysfunction can persist for weeks to months. Also, ventilation may be compromised if the intercostal muscles are involved. Flaccid paralysis of the bladder can develop, with urinary retention and overflow incontinence. The gastrointestinal tract can be atonic. Vasomotor dysfunction can develop, with orthostatic hypotension, impaired shivering, sweating, and disturbances in temperature regulation persisting for weeks to months.

After complete injury of the cervical or upper thoracic spinal cord, an acute syndrome of bradycardia, hypotension, and hypothermia can occur, probably because of disturbed sympathetic outflow at the cervical and upper thoracic levels; most patients with quadriplegia after spinal cord injury have chronic hypothermia with poor temperature control related to loss of sympathetic peripheral vascular control [Green and Eismont, 1984]. Recovery from complete spinal cord injury is rare. The prognosis is poor. Tator estimated that less than 2 percent of patients with complete injury recover some distal cord function [Tator, 1996]. More encouraging was a comprehensive review of several large series of patients with complete spinal cord injury, which found that about 2 percent of the patients became ambulatory [Hansebout, 1982].

Incomplete Spinal Cord Injuries

Incomplete spinal cord injuries warrant special attention because children with these injuries often demonstrate significant recovery of function with a relatively good prognosis. Included among incomplete spinal cord injuries are cervical nerve root/brachial plexus neuropraxia, cervical spinal cord neuropraxia, the cervicomedullary syndrome, central spinal cord syndrome, syndromes of the anterior spinal cord and posterior spinal cord, Brown–Séquard syndrome, conus medullaris syndrome, and catastrophic spinal cord injuries (see p.1211).

Spinal Epidural Hematoma

Spinal epidural hematoma can occur with substantial trauma to a normal spine, particularly in a newborn after breech delivery, or with mild trauma to the spine in a patient with a bleeding diathesis, with a spinal epidural hemangioma, or after multiple lumbar punctures [Bruyn and Bosma, 1976; Hehman and Norrell, 1968; Robertson et al., 1979]. In contrast to most intracranial epidural hematomas, spinal epidural hemorrhage is of venous (not arterial) origin [Bruyn and Bosma, 1976]. The main venous structure within the spinal epidural space lies ventrolateral to the cord and comprises a “rope ladder” plexus of thin-walled veins lacking true valves. This internal plexus connects with an external plexus of veins around the spinal column, with segmental spinal veins draining into the inferior vena cava, and with intracranial dural sinuses [Bruyn and Bosma, 1976]. Signs of spinal epidural hematoma can be acute, chronic, or intermittent. A newborn with acute spinal epidural hematoma typically manifests respiratory depression, hypotonia, areflexia, and other signs of spinal shock [Francisco, 1970; Towbin, 1964]. The occurrence of clinically significant traumatic spinal epidural bleeding is uncommon after infancy. When it occurs in older children (as with minor trauma complicating a blood dyscrasia), there is usually severe back pain that is worsened by pressure over the spine, neck flexion, or the Valsalva maneuver. Over the ensuing hours to weeks, signs of spinal cord compression usually develop [Bruyn and Bosma, 1976].

Spinal Subdural Hematoma

Spinal subdural hematoma occurs much less commonly; the source of bleeding in this hematoma is unclear. Similar to spinal epidural hematoma, it occurs mainly in the neonatal period, although it too is occasionally observed in children and adolescents with bleeding diatheses who sustain an otherwise insignificant injury to the spine, such as that occurring at the time of lumbar puncture [Edelson, 1976; Edelson et al., 1974; Towbin, 1964; Walter and Tedeschi, 1970]. Clinical features include back and radicular pain [Edelson, 1976].

Spinal Subarachnoid Hemorrhage

Traumatic subarachnoid hemorrhage caused by injury to the spine also is uncommon. This hemorrhage can occur after penetrating injury, but most often occurs after birth trauma (frequently with accompanying epidural, subdural, or intraspinal hemorrhage) [Plotkin et al., 1966; Towbin, 1964]. The amount of blood that accumulates is usually not great, and significant compression of the cord is rare. Signs of spinal subarachnoid hemorrhage are difficult to distinguish from signs of other spinal hemorrhages (e.g., epidural) that often coexist. Spinal subarachnoid hemorrhage should be suspected when back pain, meningismus, or fever occurs. The diagnosis is indicated by the presence of blood in the spinal fluid or by cerebrospinal fluid xanthochromia. Occasionally, the blood obstructs the subarachnoid space, resulting in a “dry tap.” Spinal subarachnoid hemorrhage must be differentiated from subarachnoid bleeding of intracranial origin and from blood caused by a traumatic lumbar puncture.

Spinal Epidural Abscess

Infections of the skin overlying the spine or of the bony spine itself (osteomyelitis) can occur after spinal trauma and may result in a spinal epidural abscess [Baker et al., 1975; Browder and Meyers, 1941; Hancock, 1976; Heusner, 1948]. Staphylococcus aureus is the organism most often responsible for such infections [Joshi et al., 2003; Pereira and Lynch, 2005]. The signs and symptoms of spinal epidural abscess are difficult to differentiate from the signs and symptoms of spinal epidural hematoma. Usually, other signs of inflammation and local infection of the overlying skin or bone can be identified.

Spinal Arachnoid Cyst

Spinal arachnoid cyst can develop after spinal trauma or may appear idiopathically and can cause significant spinal cord compression [Elsberg et al., 1934; Herskowitz et al., 1978; Nugent et al., 1959; Swanson and Fincher, 1947]. These cysts produce progressive signs, with lower limb weakness in neonates, and recurrent gait and sensory difficulties in older children. Scoliosis may accompany these cysts. The diagnosis is suggested on plain films by widening of the interpeduncular distances [Elsberg et al., 1934; Herskowitz et al., 1978; Nugent et al., 1959; Swanson and Fincher, 1947].

Spinal Epidermoid Tumor

Epidermoid tumors are infrequent complications of lumbar puncture [Batnitzky et al., 1977; Gibson and Norris, 1958; Manno et al., 1962; Shaywitz, 1972]. These tumors may develop 1–20 or more years after a lumbar puncture, and have been attributed to skin and subcutaneous tissues implanted intraspinally at the time of a spinal tap. The symptoms are slowly progressive and usually manifest with back and leg pain followed by gait difficulties [Batnitzky et al., 1977; Gibson and Norris, 1958; Manno et al., 1962; Shaywitz, 1972].

Herniation of the Nucleus Pulposus

Herniation of the nucleus pulposus (protrusion of central intervertebral disc tissue) can result from severe flexion/compression of the spine and can cause compression of the underlying spinal cord [Burke, 1976; Herkowitz and Samberg, 1978; Swischuk, 1969]. The symptoms and signs are similar to those of any intraspinal extradural mass: pain and dysesthesias in radicular distribution, loss of tendon reflexes, muscle weakness, and atrophy [Burke, 1976; Herkowitz and Samberg, 1978; Swischuk, 1969].

Cauda Equina Injuries

A special category of extramedullary injury comprises injury involving the cauda equina, which is technically not a spinal cord injury. The level of spinal column and ligament displacement in these injuries varies with age, depending at which vertebral level the spinal cord terminates (L2 in infancy and L1 in adulthood). When any of the extramedullary pathologies just discussed are localized below the spinal cord, they can cause injury to the cauda equina. In incomplete injuries of the cauda equina, there is always preservation of sensation, often with only a partial motor deficit [Tator, 1996]. Bowel and bladder involvement is common. The prognosis in cauda equina injury is better than the prognosis in spinal cord injury because the lower motor neuron apparently has a greater capacity to recover than the upper motor neuron [Tator, 1996].

Spine Immobilization and Supportive Care

The treatment of acute spinal cord injury must include stabilization of the spine to prevent further injury, in addition to maintenance of vital signs. First aid at the scene of the accident should include placement of the child on a rigid stretcher or firm backboard, and fixation of the head by sandbags or towel rolls with tape over the forehead to prevent movement of the head on the spine. A cervical collar alone does not accomplish this goal adequately [Green and Eismont, 1984]. Restriction of movement manually with the arm on the chest and hand on the mandible, exerting slight extension and traction on the head, can help stabilize the cervical spine until the head is taped. Care must be taken not to exert too much spinal distraction with this maneuver [Benzel and Doezema, 1996]. The disproportionately large head of a young child places the child into flexion when he or she is put on a neutral board. Because the high cervical region is the most likely level of injury, neck flexion is particularly dangerous. Flexion can be avoided with a special board with a recess for the occiput, allowing the head to rest in line with the body, or by placing something under the child’s shoulders to elevate the neck in line with the head [Proctor, 2002]. It has been estimated that careful attention to stabilization of the spine before moving the patient has reduced occurrence of complete spinal cord injury by approximately 10 percent [Gunby, 1981]. More recently, it has been suggested that this type of immobilization is painful and potentially harmful (restricted breathing, tissue ischemia, decubiti, intracranial hypertension), offering little, if any, benefit. Although a spine board eases transfer of a patient with a potentially unstable spinal injury to and from an ambulance stretcher, when the patient arrives at the hospital, a hard cervical collar and a firm mattress adequately immobilize the patient before application of traction or definitive stabilization [Hauswald and Braude, 2002].

A patent airway must be established, which may necessitate endotracheal intubation; this is frequently required in complete cervical cord injury (with impairment of diaphragmatic and intercostal muscle function). Intubation should be accomplished by chin lift without or with minimal neck extension. Tracheostomy and cricothyroidotomy should be avoided. Cardiac rate and rhythm should be monitored, and intravenous, central venous, and arterial lines should be placed. Cervical spinal cord trauma is often associated with significant hemodynamic deficits, including hypotension. In addition, injury to other organs (e.g., a ruptured liver or spleen) can cause significant blood loss and hypotension, which must be treated promptly by intravenous crystalloid or blood. Intravenous atropine, glycopyrrolate, phenylephrine, or dopamine may be needed to maintain normal blood pressure after volume depletion is corrected. Aggressive treatment of hypotension after spinal cord injury may improve outcome significantly [Levi et al., 1993; Vale et al., 1997]. The stomach should be emptied by a nasogastric tube. With urinary retention, the bladder should be catheterized. Radiologic studies usually should be performed (see section on radiologic evaluation earlier). In the case of cervical spine trauma, if the child is alert and interactive and has no neurologic deficit, no midline cervical tenderness, no painful distracting injury, and no evidence of intoxication, cervical spine films are probably not needed [Hadley, 2002b]. Spinal alignment is an important next step that usually can be accomplished with skeletal traction [Ducker et al., 1983] (see section on long-term management later).

Surgical Management of Acute Spinal Cord Injury

It is surprising that a question as fundamental as whether early decompression for acute spinal cord injury is or is not beneficial for neurological recovery remains incompletely answered. A significant body of animal research has demonstrated neurological benefit from early decompression of the injured spinal cord, but some clinicians prefer to delay decompression in patients with multiple trauma because of medical instability often seen in the acute post-injury phase. Earlier studies comparing surgical and nonsurgical management in acute spinal trauma come mainly from adult series. In patients with complete spinal cord lesions treated conservatively, 27–34 percent showed some improvement [Frankel et al., 1969; Guttmann, 1963]. Of 27 patients with complete lesions who were managed surgically, 25 improved, but this improvement was seen only in nerve-root function at the site of the injury [Stauffer, 1984]. In patients with incomplete spinal cord lesions, 64–90 percent have improved with conservative treatment [Guttmann, 1963; Meinecke, 1964]. In 22 cases of cervical spine dislocation with neurological changes, recovery (complete in 213) occurred in 82% of cases treated with early spinal fusion [Forsyth et al., 1959]. Thus, in incomplete and complete spinal cord lesions, there would appear to be no clear differences in neurological outcome between surgical and nonsurgical management. The Surgical Treatment of Acute Spinal Cord Injury Study (STASCIS), initiated in 2003 at the University of Toronto and Thomas Jefferson University, was designed to be randomized, but resistance to randomizing to an intentionally delayed decompression led to restructuring as a prospective observational study. The study has an accrual target of 450 patients with traumatic cervical spinal cord injuries ranging in age from 16 to 70 years. A 2-year follow-up period post injury is planned. Preliminary analysis suggests a benefit to decompression in less than 24 hours of injury [Hawryluk et al., 2008].

A Medline search of experimental and clinical studies describing on the effect of decompression on neurological outcome following spinal cord injury was reported in 2005 by Fehlings and Perrin. Animal studies consistently show that neurological recovery is enhanced by early decompression. One randomized controlled trial showed no benefit to decompression in less than 72 hours, but several prospective studies suggested that decompression in less than 12 hours could be performed safely and may improve neurological outcome. A recent meta-analysis showed that decompression in less than 24 hours resulted in statistically better outcomes than both delayed decompression and conservative management. In summary, there currently are no standards regarding the role and timing of decompression in acute spinal cord injury [Fehlings and Perrin, 2005].

One reasonable approach to spinal surgery in acute spinal cord injury might be to limit surgery to patients with partial cord injuries and a progressing neurological deficit and patients with bilaterally locked facets, an unstable fracture, and/or dislocation; surgery in the latter group would minimize the risk of curvature of the spine developing later. Additional appropriate indications for surgery might include the following:

Fig. 78-9 Lateral film of a C5 fracture – dislocation in a 12 year old female (A). Pre- and post operative radiographs of a C5 fracture dislocation in a 19 year old male (B,C).

A, Plain lateral film of the cervical spine in a 12-year-old female. There is a wedge-shaped fracture of C5 (arrow) with posterior dislocation of C5 on C6 and loss of the disc space between those two vertebrae. B, Computed tomography sagittal reconstruction from 2-mm axial scans through the C4–C6 level (unenhanced study) in the same patient as in Figure 78-7. Posterior dislocation of a fracture fragment (arrow) from the inferoposterior margin of C5 has resulted in narrowing of the anteroposterior diameter of the spinal canal. C, Plain lateral film of the cervical spine in the same patient as in Figure 78-7. The spine was stabilized by anterior bony fusion (arrow) and posterior wiring to prevent further narrowing of the spinal canal.

Completed Randomized Controlled Clinical Trials for Medical Treatment of Acute Spinal Cord Injury

Ten randomized controlled treatment trials examining methylprednisolone, naloxone, tirilazad, GM₁ ganglioside, thyrotropin releasing hormone, nimodipine, and gacyclidine have been completed [Hawryluk et al., 2008].

Additional Clinical Trials

Other Investigational Therapies

A variety of substances have been studied in different animal models, most often the rat, to assess their efficacy in promoting repair following experimentally induced spinal cord injury. The results of most of these studies have been encouraging. The agents studied include: brain-derived neurotrophic factor and glial-derived neurotrophic factor [Sharma, 2006]; dynorphin A (1–17) antibodies [Sharma et al., 2006a]; antioxidant compound H-290/51 [Sharma et al., 2006b]; Lipitor [Pannu et al., 2007]; C1 esterase inhibitor [Tei et al., 2008]; activated spinal cord ependymal stem cells [Moreno-Manzano et al., 2009]; adenosine triphosphate (ATP)-sensitive receptor P2X7 antagonist [Peng et al., 2009]; magnesium [Wiseman et al., 2009]; tamoxifen [Tian et al., 2009]; and calpain inhibitor [Colak et al., 2009].

Gene Therapy for Spinal Cord Injury

Although injured axons cannot regrow spontaneously to reach their original targets after spinal cord injury, such regrowth is possible in the presence of a favorable milieu that provides a delicate balance between growth-promoting and growth-inhibiting factors. Such regrown axons will then have the potential to make new synapses necessary for functional restoration.

A major problem in delivering neurotrophic factors to the injured central nervous system is difficulty in providing these proteins in biologically relevant amounts and for prolonged periods of time. As neurotrophins have a very short half-life, are digested in the gastrointestinal tract, and do not cross the blood–brain barrier, various methods have been developed for delivering neurotrophins directly to the spinal cord. These include:

Depending on the vector used, a single injection can result in long-lasting expression, providing a lasting biological effect. Not only does the choice of vector make a difference, but so does the site of injection also; for intrinsic stimulation of growth, the cell body is preferred, while for extrinsic stimulation at the axonal tip, the site of injury is usually preferred.

The simplest and most elegant strategy is the direct gene therapy approach that uses a single injection for delivery of a gene therapy vehicle. Among the vectors used to transduce neural tissue in vivo are nonviral vectors and viral ones (herpes simplex [HSV]; retroviral [RV]; lentiviral [LV]; adenoviral [Ad]; adeno-associated viral [AAV]), each with its own merits and limitations. HSV and Ad vectors have proved to be excessively toxic, but after a decade of work, nontoxic AAV and LV vectors, suitable for neuroregenerative research, have been developed [Blits and Bunge, 2006].

Cervical Spine Immobilization

In spine and spinal cord injuries in children, the main imperatives are to decompress the neural elements and to stabilize the spine to prevent further injury [Proctor, 2002]. Cervical traction serves to immobilize the spine and reduce fractures. Reduction of fractures or subluxation must be undertaken with care in young patients because overdistraction can worsen the patient’s neurologic dysfunction. Manual positioning under fluoroscopy often is required in cases of cervical ligamentous injury. Crown halo rings can be applied in younger patients at a pressure of 2 inches/pound of torque per pin [Pang and Hanley, 1990]. In older patients, cervical traction can be used with relative safety. Many spine-injured children can be managed with external stabilization without a need for later surgery [Hadley, 1992; Proctor, 2002]. Various devices can be used, depending on the level and severity of injury, including the Philadelphia cervical collar, Yale braces, sternal occipital mandibular immobilizer (SOMI) braces, four-poster braces, halo rests, crown halo rings, and thoracolumbar orthoses. When such devices are used, frequent radiographic reevaluations are needed to ensure continuing proper alignment of spinal elements because adequate external (and internal) fixation can be difficult to achieve in a young child [Proctor, 2002]. Specific recommendations for the management of SCIWORA were discussed earlier [Gunnarsson and Fehlings, 2003].

Supportive Medical Care

For patients with midcervical or upper cervical spinal cord injuries, there is a high risk of respiratory failure. Because the lower motor neurons for the phrenic nerve are at cervical levels 3 through 5, patients with severe spinal cord injuries above this level require permanent mechanical ventilation. Although patients with mid cervical spinal cord injuries initially may have adequate spontaneous ventilation, their ventilatory ability may deteriorate within a few days consequent to ascending spinal cord edema [Marion, 1998]. Children with high cervical lesions who are ventilator-dependent may be candidates for phrenic nerve pacing [Massagli, 2000].

In addition to causing respiratory difficulties, spinal cord trauma can result in a variety of other medical problems requiring on-going care [Luce, 1985]. Cardiovascular function can be altered by the trauma and its acute management. In one study, 4 of 9 patients developed pulmonary edema after spinal cord injury, probably from overhydration during acute resuscitation [Meyer et al., 1971]. Patients with spinal cord lesions above T7 requiring long-term management have decreased cardiac output, hypotension, and problems with temperature regulation, limiting adaption to exercise. Nasogastric tube feeding after restoration of normal intestinal activity, antacids, hyperalimentation when bowel atonia persists, and digital stimulation, especially in young children, may be needed [Goetz et al., 1998]. In some children, gentle disimpaction is indicated. The use of enema continence catheters for bowel dysfunction after spinal cord trauma may significantly facilitate bowel care in such patients [Liptak and Revell, 1992]. Intermittent catheterization of the bladder is preferred to placement of an indwelling catheter to reduce the risk of urinary tract infection and renal failure [Luce, 1985; Nygaard and Kreder, 1996; Pannek et al., 1997].

Renal failure is a major cause of mortality in patients with chronic spinal cord injury [Hackler, 1984]. Anticholinergic and botulinum toxin therapy can reduce the effects of detrusor hyperreflexia (neurogenic bladder), present in approximately 60 percent of patients rendered quadriparetic from spinal cord injuries [Curt et al., 1997; Schurch et al., 1997]. Hyperhidrosis, fever, and disrupted temperature regulation are additional autonomic dysfunctions frequently encountered in patients with spinal cord injury. Anticholinergic treatment may help [Canaday and Stanford, 1995].

Autonomic dysreflexia (AD) is a well-known clinical emergency in subjects who have had a spinal cord injury, especially at T6 or above. It is characterized by acute elevation of arterial blood pressure and bradycardia, though tachycardia can also occur. Accompanying symptoms include severe headache, blurred vision, feeling of anxiety, profuse sweating, flushing and piloerection above the level of injury, and dry and pale skin below the injury. The higher the injury level, the more severe is the AD. Untreated episodes can have serious consequences, including intracranial hemorrhage, retinal detachment, seizures, and death. Physiologically, AD is caused by a massive sympathetic discharge, triggered by either a noxious or non-noxious stimulus, originating below the level of the spinal cord injury. The more complete the spinal injury, the more likely is AD to occur. The most frequent triggers are irritation of the urinary bladder or colon. Symptoms usually are short-lived, although there have been reports of AD sustained for days to weeks. It is usually evident a month or more post injury, although cases have been reported after 1 week. Management of an episode of AD includes placing the patient upright, loosening any tight clothing, eliminating any precipitating stimulus (bladder distention or bowel impaction in 85 percent of cases) and antihypertensive drugs in the presence of sustained hypertension [Krassioukov et al., 2009].

Other general measures include chest physiotherapy to prevent pneumonia, frequent repositioning of the patient and the use of spinal beds (Stryker frame RotaBed) to avoid decubiti, and the use of Jobst stockings to minimize the risk of deep vein thromboses and the attendant potential for pulmonary emboli. Occasionally, ventilation-perfusion scanning and pulmonary angiography are needed to establish the diagnosis of pulmonary emboli. It is estimated that one-third of the deaths within the first weeks of spinal cord injury are due to pulmonary embolism. The use of mini-heparin treatment (1 μg/kg/hr, continuous infusion) or intermittent low-dose heparin therapy may reduce the risk of pulmonary embolism [Borow and Goldson, 1983]. In patients for whom anticoagulant therapy is contraindicated, placement of an inferior vena cava filter may be necessary. The healing of decubitus ulcers is aided by treatment with vitamin C (15–20 mg/kg/day) [Taylor et al., 1974]. Muscle relaxants, such as diazepam, baclofen, cyclobenzaprine, and intravenous orphenadrine citrate [Casale et al., 1995], may be helpful in the long-term management of spasticity after spinal cord injury. Additional antispasmodic treatments include intrathecal baclofen and tizanidine [Abel and Smith, 1994; Lewis and Mueller, 1993; Nance et al., 1994]. Progressive spinal deformity is common in children after spinal cord injury, particularly after laminectomy [Lonstein, 1995]. Chronic pain is also common, and its management can be difficult, necessitating intervention by pain management specialists [Chiou-Tan et al., 1996; Drewes et al., 1994; Siddall et al., 1995; Yezierski, 1996]. In patients in whom there is delayed deterioration of neurological functioning, the presence of a syrinx should be sought; if one is found, the syrinx may need to be shunted [Proctor, 2002].

Physical Therapy

Physical therapy is an important component in the long-term care of all patients with spinal cord injury [Jacobs and Nash, 2004]. Physical therapy should begin early and continue indefinitely. Measures such as proper limb positioning and passive muscle stretching can be instituted when the patient is medically and surgically stable. Later, after spinal shock has resolved and early spasticity is evident, inhibitive casting can be used to minimize the development of limb contractures. Despite such measures, many patients later require phenol blocks, botulinum toxin injections, tendon lengthenings, and tendon transfers. In the 1970s and 1980s, functional electrical stimulation (FES) raised hopes in many plegic patients, with apparent efficacy in some children and adolescents rendered paraplegic after a spinal cord injury. Electrodes were placed in 9 such patients to provide constant stimulation to their hip and knee extensors and hip abductors and adductors; the 7 who were able to complete their training all gained increased functional abilities over traditional long leg braces, and a decreased need for physical assistance by a caregiver [Johnston et al., 2003]. FES has been used to augment function of the lower limbs, upper limbs, bladder, bowel, respiration, and erection/ejaculation [Creasey et al., 2004; Kirshblum, 2004]. Short-term stimulation can be provided by electrodes on the skin or by percutaneous fine wires, but implanted systems are preferable for long-term use [Creasey et al., 2004]. FES-assisted stepping can be triggered automatically at a fixed rate (autotrigger), by a manual switch (switch-trigger), or by an electromyogram-based gait event-detector (EMG-trigger) [Dutta et al., 2009].

Despite spectacular videos in selected patients, FES has not yet fulfilled expectations with respect to achievable gait function. The best paraplegic patients have covered a maximum uninterrupted gait distance of up to 500 meters at a velocity of approximately 20 meters per min [Hesse and Werner, 2009]. Further, there is an absence of randomized clinical trials to assess the true efficacy of FES in improvement of walking in spinal cord injury patients.

In the early 1990s, treadmill training with partial body-weight support opened new perspectives for patients with incomplete spinal cord injuries – the harness substituted for deficient equilibrium reflexes, the body weight reduction compensated for the paresis, and the moving treadmill enforced locomotion. Numerous open studies have suggested efficacy of body-weight-supported treadmill training in improving gait ability and function in spinal cord injury patients [Hesse and Werner, 2009]. A recent controlled trial in 146 patients with acute incomplete spinal cord injuries, however, failed to show any superiority of manually assisted treadmill training when compared to repetitive gait training on the floor assisted by early use of technical aids [Dobkin et al., 2006].

FES and gait training have often been used together. Twenty-seven subjects with chronic incomplete spinal cord injuries received 12 weeks of body-weight support training, with and without FES, on the treadmill and during over-ground walking. Walking speed was measured before and after training; those subjects with initial slower speed increased their speed in 85 percent of cases, whereas those with initial fast speed showed an increase in only 9 percent of cases [Ditunno and Scivoletto, 2009].

Both human and animal studies show that the spinal cord has the potential to reorganize and/or readjust to the loss of supraspinal input and to utilize the remaining peripheral input to control stepping and standing. Motor training can be used to provide sensory ensembles within the spinal circuitry that are task-specific, i.e., step training improves stepping, and stand training improves standing. The use of robotics for training specific motor tasks has become more prevalent recently. Using an “assist-as-needed” approach for step training after a severe spinal cord injury provides a high probability of successful rehabilitation, enhancing the ability of spinal cord-injured individuals to regain the maximum locomotor ability possible [Edgerton and Roy, 2009].

Psychological Therapy

Counseling should be provided, beginning early in the postinjury period and continuing throughout all stages of rehabilitation, to provide maximal, on-going support for the child and family [Geller and Greydanus, 1979; Talbot, 1971]. Health professionals from many disciplines can assist in providing such support.