Acute spinal cord injury

Acute spinal cord injury

ORTHOPAEDICS II: SPINE AND PELVIS  neck or back pain  sensory disturbance in the hands or feet  weakness or paralysis of the arms and/or legs. Spi...

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ORTHOPAEDICS II: SPINE AND PELVIS

 neck or back pain  sensory disturbance in the hands or feet  weakness or paralysis of the arms and/or legs. Spinal cord injuries are missed most often because the diagnosis has not been considered and a detailed neurological examination has not been carried out. Spinal injuries are most likely to be missed in those who:  have head injures  are inebriated  have incomplete neurological deficits  have pre-existing neurological diseases and skeletal conditions (e.g. multiple sclerosis, ankylosing spondylitis). In the case of an unconscious patient with a head injury for whom no history can be obtained, and sensation and motor activity cannot be tested, one must remember that forces to the head sufficient to cause unconsciousness are also transmitted to the neck. Hence spinal injury must be assumed until it has been excluded by appropriate investigations. Paradoxical movement of the chest wall with diaphragmatic breathing or the presence of priapism in men may be indicators of a high spinal injury in the traumatized, unconscious patient. The plantar response (movement of the toes in response to an upward stroke with the pointed end of a patellar hammer along the outer edge of the sole) may be down-going and cannot be relied on, in the acute stage, as evidence of the integrity of upper motor neurons. The abolition of the down-going plantar reflex and establishment of a Babinski reflex (up-going plantar response) may not happen for several days. Elderly patients with hyperextension neck injuries and partial cord damage are also difficult to diagnose. Such injuries usually arise from low-velocity injuries (e.g. falls in the home) and are commonly associated with lacerations or abrasions to the forehead. The infarction of the central cord that occurs in these injuries affects the hands more than the legs because the cervical fibres are innermost in the long tracts. Elderly individuals may be confused and complain only of clumsiness or stiffness. There may be little radiological evidence of injury. Radiography sometimes shows an increase in thickness of the prevertebral soft tissue shadow or an opening up of the front of the disc where the anterior longitudinal ligament has been torn. Magnetic resonance imaging (MRI) scans are better at demonstrating oedema and bleeds related to ligamentous injury.

Acute spinal cord injury James P White Pradeep Thumbikat

Abstract Acute spinal cord injuries may arise due to blunt injuries or to penetrating trauma, such as stab or gunshot injuries. The severity of injury is best described in terms of the orthopaedic injury and the sensorimotor pattern of neurological deficit (American Spinal Injury Association category). Advanced Trauma Life Support assessment of all trauma patients includes a thorough neurological examination to identify acute spinal cord injury, the management of which requires discussion with a dedicated spinal injuries unit, and, if appropriate, transfer for specialist care. Spinal injuries centres have multidisciplinary teams that can manage the medical and surgical aspects of patient care together with nursing expertise to avoid decubitus ulceration and other complications of spinal cord injury, and a full rehabilitation team to manage the physical, social, financial, and emotional aspects of rehabilitation. People with medical causes of spinal cord injury (e.g. transverse myelitis) experience many of the same problems as people with traumatic spinal cord injury.

Keywords Bilateral facet dislocation; motor innervation; pressure sores; respiration; respiratory failure; spinal cord; spinal cord injury; thoracolumbar; unifacet dislocation; vertebral fracture

Incidence The incidence of injuries associated with significant spinal cord damage is about 15 per million individuals per year. Young men are most commonly injured:  50% of injuries result from road traffic accidents  40% result from domestic accidents (e.g. falling down stairs) and industrial accidents  10% result from sports accidents (e.g. diving into shallow water, playing rugby, horse riding, gymnastics). The incidence and causes of spinal cord injury vary widely throughout the world. Gunshots and stabbings are common causes in the USA, whereas falls from trees and into wells account for large numbers in developing countries.

Neurological examination A sensory evaluation should be carried out first. Using a disposable pin, the investigation should start at the side of the neck, progress down the outside of the arm, across the fingers, and up the inner arm to the axilla. From the axilla, one should proceed down the side of the chest and move round to the front of the abdomen. It is important to assess sensory awareness along the back of the legs and the perineum. A common mistake in assessing neck injuries is to test sensation on the front of the chest and record a sensory level a few centimetres above the nipples. Sensation to the upper part of the chest is supplied by the fourth cervical nerve through the supraclavicular nerves and is separated from the third thoracic dermatome by an imaginary line (axial line; Figure 1). Thus injuries of the lower cervical spine can be misdiagnosed as being upper thoracic. The last normal sensory segment is considered as

Diagnosis Clinical features A diagnosis of spinal cord injury should be suspected in patients with:

James P White MB ChB is a Clinical Fellow in Spinal Injuries at the Princess Royal Spinal Injuries Centre, Sheffield, UK. Conflicts of interest: none declared. Pradeep Thumbikat FRCS(Glas) is Consultant in Spinal Injuries at the Princess Royal Spinal Injuries Centre, Sheffield, UK. Conflicts of interest: none declared.

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Distribution of sensory dermatomes

Motor innervation of muscles

C3 C4 T2/3

T2/3 T4 5 6

C5 C6 T1

C5

7 8

C6

9

T1

10

Muscle

Nerves

Deltoid Biceps Wrist extensors Triceps Finger flexors Hand intrinsics Hip flexors Hip adductors Quadriceps Ankle dorsiflexors Hamstring Ankle plantar flexors

C5 C5 C6 C7 C8 T1 L1, L2 L2, L3 L3, L4 L4, L5 L4, L5, S1 S1, S2

11 12

C7

L1

C8 S5 L3

L4

Table 1

C7 C8 L2

Anterior cord syndrome: the front of the cord is damaged with paralysis and loss of pain sensation, but preservation of touch and joint position sense through the posterior columns of the spinal cord.

L3

L4

Brown-Sequard syndrome: comprises injury predominantly to one side of the spinal cord causing motor loss on that side and pain and temperature loss on the opposite side. L5

S1

Radiological evaluation The thoracic spine is a relatively fixed structure with mobile segments at either end. Thus fractures tend to occur at the cervicothoracic and the thoracolumbar junctions, where mobile segments meet rigid segments.

L5

Radiographs: if a neck injury is suspected, it is essential to obtain anteroposterior, lateral and open-mouth views of the cervical spine. Shoulder pull-down views and swimmer’s views are helpful

S1

Figure 1

the neurological level (sensory) of the patient. In general, changes in muscle power follow the pattern of pain and temperature loss because their nerve fibre tracts (corticospinal and spinothalamic tracts respectively) are closely related in the spinal cord. Knowledge of motor innervation of muscles is important in carrying out an adequate neurological examination (Table 1). By doing a complete motor and sensory examination, it is possible to determine the completeness of an injury and the American Spinal Injury Association (ASIA) impairment scale, which has prognostic and functional significance (Table 2). Although the details of the scoring system are beyond the scope of this article, it is freely available from the ASIA and International Spinal Cord Society (ISCOS) websites. Incomplete injuries may show selective involvement of part of the cord giving rise to well-recognized syndromes.

ASIA impairment scale Description

AIS A

Complete e no motor or sensory function is preserved in the sacral segments S4eS5 Incomplete e sensory but not motor function is preserved below injury level and includes S4 eS5 Incomplete e motor function preserved e half the muscles have less than grade 3 power Incomplete e motor function preserved e half the muscles have less than grade 3 power Incomplete e motor and sensory function are normal

AIS B

AIS C AIS D AIS E

Central cord syndrome: usually follows a hyperextension injury in an elderly patient. Damage to the middle of the cord results in paralysis predominantly affecting the arms and hands.

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Category

ASIA, American Spinal Injury Association.

Table 2

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when the C7eT1 junction is not clearly seen. Oblique views of the lower facets may be informative, especially when dislocations are suspected. If the diagnosis is difficult or there is difficulty in obtaining adequate views, a computed tomography (CT) scan is helpful in providing a reconstruction of the alignment of the lower cervical and upper thoracic spine. Anteroposterior and lateral radiographs of the suspected injury site should also be obtained, preferably before moving the patient from the examination trolley. High-velocity injuries (e.g. from road traffic accidents) have a high incidence of spinal fractures at more than one level (non-contiguous injuries) and so radiographs should be taken of the entire spine. Where available there is a trend towards the use of CT scanning and MRI either as a first line or to confirm plain film findings; such imaging should be considered in all situations but it is prudent to consider the time delays involved in obtaining scans as this should not be allowed to significantly delay intervention. CT scanning and MRI provide additional information on the:  integrity of the posterior elements  stability of the fracture  degree of canal encroachment  ligamentous damage  extent of cord injury (Figure 2).

vagus. Such procedures (e.g. oropharyngeal suction, endotracheal intubation) should not be carried out in the presence of bradycardia unless atropine has been given or is immediately available. It is difficult to differentiate neurogenic hypotension from hypotension related to hypovolaemia. A fall in blood pressure should not be regarded as solely due to altered physiology until causes of acute blood loss (e.g. haemothorax, intra-abdominal trauma, hypovolaemia associated with multiple fractures) have been excluded, especially in high-velocity trauma. Patients with high lesions have a poor respiratory reserve and should not be over-infused because it is easy to precipitate pulmonary oedema and hence respiratory failure. Low blood pressure in neurogenic shock responds well to sympathomimetics (e.g. noradrenaline). Corticosteroids: use of high-dose corticosteroids in the acute stage of cord injury became standard practice following the National Acute Spinal Injury Studies (NASCIS); further analysis and research have failed to demonstrate a significant improvement in outcome. Level 2 evidence suggests that common place use of corticosteroids in the acute stage may adversely affect the rate of morbidity and mortality due to an increased incidence of complications. The use of corticosteroids is no longer standard practice within spinal injury units in the UK.

Acute management

Prophylactic anticoagulation: before the introduction of prophylactic anticoagulation, pulmonary embolism was the most common cause of death in the acute phase following injury of the spinal cord. In the absence of contraindications, such as head injury or significant haemorrhage, anticoagulation should be commenced 24 hours after injury. Initially low-molecular-weight heparin is used as per local policy for venous thromboembolic prophylaxis. If there are no contraindications, and allowing for any initial ileus to resolve this should be converted to full oral therapy with warfarin. Warfarin doses are titrated to maintain the international normalized ratio (INR) between 2 and 2.5. Pharmacological prophylaxis should be combined with careful

Autonomic disturbance Injury to the spinal cord, especially high lesions, has a profound effect on the physiology. Loss of sympathetic tone (consequent to damage to the sympathetic fibres that leave the cord from the T1eT11 segments) results in peripheral vasodilatation. This results in a lowering of blood pressure and an inability to respond to environmental temperature changes, leaving the patients susceptible to hypothermia or hyperthermia. Bradycardia, which results from disturbance of sympathetic outflow to the heart and unopposed vagal activity, can be rendered more profound (even to the point of cardiac arrest), by procedures that may be necessary, but which stimulate the

a

b

c

C6 fracture with a burst component. a Radiograph (lateral view) of the cervical spine, b axial computed tomography (CT) scan and c T2-weighted sagittal magnetic resonance imaging (MRI) scan show fracture extending across the three columns, causing extensive injury to the cord (bright signal within cord). The bright signal change in c along the anterior aspect of the vertebral bodies (arrow) suggests ligament damage. The posterior elements of C4 are seen fractured in a (arrows). CT is most useful in delineating bony injury; MRI helps to identify the extent of cord damage, disc injuries and ligamentous damage. Figure 2

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use of mechanical measures, ensuring regular monitoring of skin integrity; such measures include:  compression stockings  sequential calf compression  frequent turns to provide optimal protection against deep vein thrombosis and pulmonary embolism.

a common complication of acute spinal cord injuries because of the routine use of prophylactic H2-receptor blockers and protonpump inhibitors. These agents are given parenterally for the first few days and then orally while the patient is confined to bed. Perforation of an ulcer may be difficult to recognize because of the paucity of abdominal symptoms and signs. If suspected, a lateral decubitus abdominal radiograph may show the presence of free gas in the abdomen.

Respiration Patients with lesions below the level of C5 are generally able to ventilate adequately, unless they have superimposed chest problems. Paralysis of the intercostal muscles in high lesions results in paradoxical movement of the chest wall with indrawing of the intercostal spaces during inspiration. Such patients are almost entirely dependent on diaphragmatic breathing, and have a considerably reduced vital capacity. Further respiratory insults (e.g. lung contusion, pneumothorax and haemothorax) may lead to respiratory failure (Box 1). Monitoring respiratory rate, vital capacity and oxygen saturation gives warning of respiratory insufficiency. In the case of cervical lesions, respiratory failure may be due to ascent of the neurological deficit with subsequent diaphragmatic paresis. Paralysis of the abdominal muscles prevents effective coughing and clearance of chest secretions. Respiratory physiotherapy, breathing exercises and assisted coughing are commenced at the earliest possible opportunity to minimize the incidence of respiratory complications.

Bladder Until the patient’s condition has stabilized, the bladder should be drained with an indwelling catheter; this will allow close monitoring of urine output. Once the patient’s condition has stabilized, intermittent catheterization can be commenced, with fluid intake controlled to achieve bladder volumes of 500e600 ml. Patients with flaccid bladders who have sufficient dexterity are established on permanent intermittent self-catheterization; men with supraconal cord lesions are established on reflex bladder emptying into a condom urinal system. If the patient develops a urinary tract infection that requires treatment with antibiotics, re-insertion of an indwelling catheter may be necessary until the infection has been eliminated. Bowel In the initial stages of acute spinal cord injury, the rectum is flaccid and evacuation should be carried out manually, beginning 2 or 3 days after injury and continuing daily or on alternate days. With the return of reflex anal activity, evacuation can be achieved using:  digital stimulation  suppositories  micro-enemas. Establishing a regular bowel regimen commonly requires the addition of a bulking agent and stool softener to the diet, along with regular aperients.

Abdomen Major intra-abdominal trauma may be difficult to detect in complete cord lesions because of the absence of pain or guarding. The abdomen should be examined for helpful signs, such as bruising and distension. Haematuria may be indicative of renal trauma, and may suggest injury to other viscera. Ultrasound or contrast-enhanced CT scanning may be used to investigate the stable patient suspected of having intra-abdominal trauma; peritoneal lavage is generally reserved for emergencies. Bowel sounds are usually present in the early stages after injury, though ileus almost always develops. The patient should be kept on ‘nil by mouth’ until the ileus has resolved. Unless there are signs of abdominal distension, it is not usually necessary to pass a nasogastric tube. Abdominal distension must be prevented because it may hinder the free movement of the diaphragm, and cause respiratory insufficiency. Stress peptic ulceration with perforation or haemorrhage is no longer

Physiotherapy Early chest physiotherapy, involving assisted coughing and breathing exercises, is vital for all patients with acute spinal cord injury and more so for those who have a history of chest disease or associated chest trauma. Joint and muscle contractures that may cause movement restrictions can develop rapidly. To prevent this, the patient’s arms and legs are put through a full range of passive joint movements as soon as possible after the injury. It is essential, especially in elderly patients, to maintain a good range of shoulder movements; stiff, painful shoulders can compound subsequent disability. With lumbar fractures, passive flexion of the hips should be limited to 70 to avoid unrolling of the lumbar lordosis. A programme of strengthening of non-paralysed muscles should also be initiated.

Factors that predispose to respiratory failure C C C C C C C C

Pre-existing chest disease Rising neurological level Over-transfusion Paralytic ileus Rib fractures Haemothorax Pneumothorax Pulmonary contusion

Nursing Nursing care of a patient with acute spinal cord injury is directed towards:  maintaining alignment of the spine  preventing damage to the patient’s skin. All manoeuvres (lifts, rolls and twists) required for skin care and pressure relief are carried out by trained staff. The patient should be lifted by three to five persons acting in unison. During turning, alignment of the spine is maintained by the use of

Box 1

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dedicated turning beds (e.g. the StokeeEgerton bed) and specific nursing techniques.

a

Thoracolumbar injury: a patient with a thoracolumbar injury may be ‘log-rolled’ on to their side using a long thin lumbar pillow positioned in the hollow of the back. Cervical injury: the shoulders may be held flat against the bed to maintain alignment of the cervical and upper thoracic spine, while the pelvis is twisted to bring one leg uppermost. This leg and the back are then supported with pillows to relieve pressure on the sacrum and uppermost buttock. If this technique is used, the skin over the shoulder blades should be inspected at regular intervals. Pressure sores e can develop rapidly because the patient is unable to feel or to move. The patient’s position should be changed every 2e3 hours. The skin should be kept clean and dry, and evidence of incipient sore formation should be sought at each turn. Pressure must be kept off any areas of skin where redness persists. b

Fracture management Maintenance of alignment Skull traction should be applied to cervical injuries to establish and to maintain alignment. GardnereWells callipers (which have a built-in tension indicator) are the simplest and safest to apply. The calliper pins are sited about 2 cm above the ears (in line with the external auditory meatus). Traction along this line produces the required extending moment about the neck. A larger extending moment can be applied by positioning the callipers further forward, but fixation of the temporalis muscle by the pins can result in trismus. The force needed to maintain alignment varies; for example, it is:  2 kg in a frail elderly patient with a high cervical fracture  5 kg in a fit young man with a low-neck injury. If there is major disruption, large forces over long periods can cause considerable distraction at the fracture site and put traction on the cord. An alternative to traction for maintaining alignment in selected cases is a well-fitted halo jacket.

a Radiograph (lateral view) of the cervical spine of a unifacet dislocation of C5 on C6. b Facet views of the same injury as in a. The loss of apposition of the facet surfaces (arrows) and the change in rotational alignment of the spine are evidenced by the visibility of the neural foraminae below the level of the dislocation and the facet articulations above.

Reduction of facet dislocation Reduction of facet dislocation requires traction forces much greater than for maintenance of alignment. Unifacet dislocation: the dislocated facet can be determined by observing the patient from the head of the bed; the chin is often turned away from, and the head tilted towards, the side of the dislocation. Classically, on the lateral radiograph there is a forward shift of about 25% of vertebral body diameter of the upper vertebra on the one below (Figures 3a, b and 4). The initial attempt at reduction comprises the application of axial traction. If, however, the dislocation is unresponsive, the neck may be slightly flexed and the head turned away from the side of the dislocation to unlock the facet. Traction is increased by 2 kg every 10e15 minutes to allow the tissues to stretch. Traction weights of 30 kg or more are often required, and reduction with as much as 70 kg has been reported. Radiographs are taken with each increment in weight until the dislocation is reduced, whereupon the neck is brought into extension and the

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Figure 3

weights reduced to maintenance level. The patient is questioned and examined repeatedly for changes in neurology during this period. The final phase of the reduction may be facilitated by giving intravenous diazepam to relax the paraspinal muscles; the diazepam should be titrated so that the patient is not rendered unresponsive to questioning or examination. Manipulative reduction under general anaesthetic should (if time and neurology allow) be carried out after obtaining MRI scans of the neck to exclude a concomitant disc prolapse. Anaesthesia carries

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the risk of not being able to monitor the patient’s neurology, and is best undertaken by those with experience of the technique. If unilateral facet dislocations cannot be reduced by the above means, emergency surgery is occasionally necessary. There is usually a reasonable degree of stability and, in a neurologically intact patient, traction may be maintained and an elective open reduction may be planned. In patients with partial neurological lesions, reduction is best achieved as soon as possible, as late reduction can cause neurological deterioration; this may be due to the cord having become oedematous and more sensitive to the trauma of manipulation. Bilateral facet dislocation: a patient with bilateral facet dislocation and who is neurologically intact is in an extremely dangerous situation. If traction succeeds in reducing one of the facets, there is some added stability and open reduction can be carried out in a planned manner. If, however, both facets remain dislocated, immediate open reduction should be considered (Figure 5).

Figure 4 Radiograph (anteroposterior view) of unifacet dislocation of C6 on C7, showing an increase in the intraspinous process distance (arrows), and a shift of the alignment of spinous processes above the level of the dislocation towards the side of the dislocation.

Figure 5 Radiograph (lateral view) of the cervical spine showing a bifacet dislocation of C5 on C6. The loss of apposition of the facet surfaces and complete disruption of the posterior ligamentous complex are evidenced by the distance between the spinous processes (arrows).

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Figure 6 Interpedicular fixation of a fracture/dislocation.

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Thoracolumbar injuries The three-column classification of thoracolumbar injuries by Francis Denis in 1983 is the easiest to use in the clinical setting. It emphasizes the importance of distinguishing between stable ‘wedge’ fractures and unstable ‘burst’ fractures. Serious thoracolumbar injuries can be managed conservatively or by internal fixation. Conservative management may involve 6e10 weeks of nursing flat in bed followed by mobilization in a spinal brace. Abandonment of conservative treatment should be considered if:  there is continued progression of a neurological lesion after admission  displacement of the fracture precludes conservative management  surgery may improve nerve root recovery at the site of the injury  associated injuries (e.g. head and chest injuries) can be better managed following fixation of the spine. Whether decompressive surgery aids neurological recovery remains unproven. It certainly carries a small risk of neurological deterioration in patients with incomplete cord injury. Decompressive laminectomy should not be carried out on its own as it increases the instability at the fracture site. Modern anterior and posterior fixation devices (Figures 6 and 7) have reduced, but not totally solved, the problems of implant failure and loss of correction. A

FURTHER READING Denis F. The three column spine and its significance in the classification of acute thoracolumbar injuries. Spine 1983; 8: 817e31. Grundy d, Russell J, Swain A. ABC of spinal cord injury. 3rd edn. London: BMJ Publishing Group, 1996. Sayer FT, Kronvall E, Nilsson OG. Methylprednisolone treatment in acute spinal cord injury: the myth challenged through a structured analysis of published literature. Spine J 2006 MayeJun; 6: 335e43. Review.

Figure 7 Anterior decompression and fixation with a Moss cage and Kaneda fixator.

Surgical fixation: after successful reduction, the ligamentous disruption that occurs with facet dislocation is best treated by some form of fixation. This may be:  a posterior approach with interpedicular fixation  an anterior approach with bone grafting and application of a plate.

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