Most spinal injuries are the result of high-energy trauma. Road
accidents and falls are the commonest causes of injury, but in the USA gunshot
injuries cause spinal injury relatively frequently. Associated injuries are
common
• Spinal injury at
another level
10—15.%
• Head and face injury
26 %
• Major chest injury
16 %
• Major abdominal injury
10%
• Long bone/pelvic fracture
8%
Ninety per cent of
fractures are simple compression fractures and the majority of these will go
on to heal with little consequence. They are best treated symptomatically,
initially with rest and then with mobilisation and splinting as necessary.
Seventy-five
per cent of patients with an unstable spinal injury will have some sort of
neurological injury. The assessment of spinal stability is difficult,
especially in the patient who is unconscious, and especially in the cervical
spine. Look for general alignment of the spine and for soft-tissue shadows. Is
there widening of the anterior cervical soft tissue shadow, for example? Is
there subluxation or rotation of one vertebra on another? Flexion extension
views can be useful (see above) but should only be done with care by suitably
qualified staff.
A
scoring system has been devised for assessing cervical stability.
•
Anterior element disruption
2
• Posterior element disruption
2
• Sagittal translation >3.5 mm
2
• Sagittal plane rotation >110
2
• Positive stretch test
2
• Cervical cord injury
2
• Cervical root damage
1
• Abnormal disc narrowing
1
• Dangerous spinal loading in the future
1
Unstable
cervical spine injuries
Adequate immobilisation of patients with unstable cervical injuries is
mandatory. The patient should have a hard collar,
Closed
reduction can be best achieved either with halo traction or with Gardner Wells
tongs. These are best applied under local anaesthetic which avoids any risk to
the spinal cord with anaesthesia and intubation. Gardner Wells tongs are easier
to apply, but do not allow correction of flexion or extension of the head once
applied. The other advantage of halo traction is that the halo can then be used
together with a jacket for immobilisation of the cervical spine if required (Fig 33.6 and
Fig 33.7).
Neurological
injury and its management
Some patients with unstable spinal column injuries will sustain damage
to either the spinal cord or nerve roots. Further
A randomised controlled study of a large group of patients has suggested that high-dose steroids may improve recovery after spinal cord injury.
The
suggested regimen is:
• 30 mg per kilogram of body weight bolus of methylprednisolone;
• 5.4 per kilogram of
body weight per hour of methylprednisolone for the first 23 hours.
There
is some debate in the literature about the real efficacy of this regimen, but
serious side effects are rare, and until there is evidence to the contrary it
seems reasonable to offer patients high-dose steroids on presentation. If the
steroids cannot be given within 8 hours, they are not effective and should be
avoided.
It
is important to establish as soon as possible whether the injury is incomplete
or complete. Often the sacral nerve roots are the least affected in spinal
injury probably because they are protected to some extent from the vascular
effects of injury. Sacral sensation is best assessed at the same time as the
patient is log rolled to examine the spine. If sacral sensation is intact, then
the injury is incomplete. If spinal shock has developed, it will not be possible
to assess function below the injury until the spinal shock has resolved. Reflex
arcs can function below the level of the injury without higher functions. The
anal wink and the bulbo-cavernosus reflexes are examples of these. If they are
present, one can assume that the patient is not in spinal shock. During the
period of spinal shock these reflexes will be absent and it is not possible to
assess whether the spinal cord injury is complete or incomplete. Spinal shock
will usually resolve within 24 hours.
Assessment
of neurological injury is best carried out using
MRC
grading:
•
0 — no contraction;
•
1 — flicker of muscle contraction;
•
2 — contracts with motion but not against gravity;
•
3 — contracts with motion against gravity;
•
4 — reduced motor power;
•
5 — normal motor power.
•
A — absent motor and sensory function;
• B — sensation present motor absent;
•
C — sensation present, motor present but not useful (MRC grade 2/3);
•
D — sensation present, motor useful (MRC grade 4/5);
•
E — normal function.
With
this information available it is possible to define a neurological injury, to
assess improvement or deterioration, and to communicate with others in a
meaningful way about the injury.
Cervical
spine injuries
Upper
cervical spine in juries
Severe neurological injury is rarely seen in practice because it is not
usually compatible with life.
Occipital
condyle injuries. These are unusual injuries which are difficult to diagnose on
plain films. If this type of injury is suspected, CT scanning is the best method
of investigation. Some of these injuries are unstable, and if so occipitocervical
fusion should be considered.
Jefferson
fractures. This is a fracture of the ring of C1 and is usually caused by
axial loading (Fig. 33.8). The ring can be split in two, three or four places.
The amount of displacement can be assessed on the open mouth view, and if
there is more than 6.9 mm of displacement, one can assume that the transverse
ligament is ruptured, which suggests that the fracture is very unstable.
Although the fracture can usually be seen on plain films, CT scan is useful to
define the fracture pattern and to be sure that there is no associated injury at
adjacent levels.
If
the transverse ligament is divided a period of traction may be advisable. We
usually treat these fractures in a halo jacket for 3 months; CT scan followed by
supervised flexion extension radiographs is advisable at that point to be sure
that healing has occurred and that there is no residual instability.
Occasionally one part of the ring may fail to heal but the spine may still be
stable. Persistent instability or failure to heal requires posterior
occipitocervical fusion.
Odontoid
fracture. This is the most commonly missed fracture in the cervical spine
and comprises 10 per cent of cervical injuries. Failure to diagnose these
fractures can result in spinal cord damage and death. Three types of fracture
are described (see Fig. 33.9). Type 1 fractures are rare and ate usually stable
and can be treated symptomatically. Type II fractures (Fig.
33.10) cause the
most problems because there is a high incidence of nonunion, especially in
displaced fractures (up to 70 per cent). Undisplaced fractures can be treated
with halo-jacket immobilisation, although it is also possible primarily to
internally fix the fracture with one or two screws through an anterior approach.
Displaced fractures can also be treated with anterior fixation which is quite
Type
III fractures have a much better ability to heal and immobilisation in a halo
jacket for 3 months will usually allow the fracture to heal. Again in the very
old immobilisation in a SOMI brace or even in a Philadelphia collar may be
adequate to allow healing. During treatment the position of the fracture should
be monitored, and adjustments made to the position of the head as required to
hold the fracture reasonably reduced.
Atlantoaxial
instability. This is a common presentation in children and usually presents
as inability to straighten the head, which tends to look right or left and
slightly up, the so-called cock-robin position. The rotation may be fixed and
often follows minor trauma, although it can present spontaneously, or
occasionally as a result of local infection in the neck or oropharynx, so a
careful examination of the head and neck is required. The diagnosis is made with
radiographs and CT scans with the patient looking right and left. If the
position of the axis is fixed in relation to the atlas on the two views, then
fixed atlantoaxial rotation can be diagnosed. The subluxation can usually be
corrected by a short period of halter traction, but occasionally surgery in the
form of fusion is required.
Hangman’s
fracture (Fig. 33.11). This is really a fracture of the pedicle of C2. It
comprises 5—10 per cent of cervical injuries, and is caused by hyperextension
of the spine. There are three types, type I being the most stable, and type III
the most unstable. Type I fractures can be immobilised for 3 months in a halo
jacket or in a suitable brace, and they will usually heal. The more unstable the
fracture the more likely
Lower
cervical spine in juries
Wedge fractures. These are the commonest fractures, and are
caused by hyperflexion of the spine, but they must be differentiated from burst
fractures (see below). This can be done with CT scan. Symptomatic treatment is
the rule, and surgery is rarely indicated.
Burst
fractures and teardrop fractures. Burst fractures are caused by hyperflexion
of the spine with or without axial compression. Fragments of bone are pushed
circumferentially, whereas in wedge fractures the bone is simply compressed.
Thus, the spinal cord or nerve roots may be compromised, and the majority of
these fractures should be considered unstable. They should be treated either
with immobilisation or with surgery in the form of fusion and instrumentation.
Teardrop
fractures (Fig. 33.12) are really fracture dislocations where part of the
injury goes through the lower part of the vertebra and part of the injury is
ligamentous. These fractures often look quite benign on radiographs, but they
are very unstable and should be treated with respect. Stabilisation is often
necessary.
Facet
dislocation. These injuries are caused by flexion or flexion and rotation.
Either one or both facets may be dislocated (and this can usually be decided
on plain films, where if there is less than 25 per cent displacement of
one vertebra on the other it is probably one facet, whereas if there is more
displacement it is probably both facets). About two-thirds of these patients
have some sort of neurological injury, and a third have a complete cord injury.
These dislocations should be reduced as soon as possible, provided an anterior
disc
Facet
dislocations are unstable and once reduced, internal fixation and bone grafting
is recommended.
These fractures can be classified according to the mechanism of injury
or according to the classification method developed by the AO. This
classification corresponds with an increasing degree of injury and increasing
incidence of neurological injury. It is helpful for communication and for
classification in research.
Thoracic
fractures (T1 —T9)
The
spine is splinted by the ribs. Other patterns of fracture are often caused by
high-energy injuries, and multiple injuries are not uncommon in these patients.
Thoracic fractures and sternal fractures are often associated with aortic
rupture, and a high index of suspicion is recommended in the patients. CT
scanning will help to make the diagnosis.
Some
thoracic fractures can be very difficult to diagnose, particularly in the upper
part of the thoracic spine. Careful clinical examination should exclude these
fractures in the conscious patient, but in the unconscious patients radiographs
of the spine must be carefully examined, with a low threshold for carrying out
CT scans.
Unstable
thoracic fractures can easily displace in the first few hours after a fracture
and great care must be taken when moving the patient. Early posterior
stabilisation of these fractures is recommended.
Thoracolumbar
fractures (T10—L5)
These fractures are more common than thoracic fractures because this
part of the spine is not splinted by the ribs. The most common fractures are T12
and L1 because these are at the junction between the stiff thoracic spine and
the mobile lumbar spine.
Stable
wedge fractures are commonest and can be treated either with mobilisation alone
or with bracing initially for pain.
Unstable
fractures may cause spinal cord injury or nerve root injury depending on the
level of the injury.
Burst
fractures may be stable or unstable. If the posterior elements are intact, then
the fracture can be considered stable. Unstable fractures can usually be
diagnosed on the plain radiographs, with what may appear to be a fracture
similar to a wedge fracture, but with widening of the distance between the
pedicles (see Fig. 33.14). This implies a fracture of the anterior structures
(the body) and the posterior structures (the pedicles). It may however be
necessary to carry out a CT scan to see whether the posterior elements are fractured.
Clinical examination in the conscious patient will allow some assessment of the
posterior structures. If there is no pain and no palpable defect, then the
injury is probably stable. In the unconscious patient this may be more difficult
and occasionally MRI scans are necessary to assess the whether posterior
elements adequately to see if there is ligamentous damage.
Distraction
injuries are more commonly associated with neurological injury and are usually
unstable injuries. Most of these injuries are a combination of bone and
soft-tissue injury, but some pass through the bone alone, so-called chance
fractures. Many of these fractures are associated with intra-abdominal injury
and careful examination of the abdomen is important.
Rotational
injuries are the most common and are usually caused by a combination of forces.
They are associated with the highest incidence of neurological injury and are
best treated with reduction and internal fixation.
Unstable
fractures are best treated with posterior stabilisanon of the spine but if
there is associated neurological injury, particularly at the level of the conus
(T12/L1), anterior vertebrectomy and stabilisation is probably best in order
to decompress the spinal cord adequately. In the lumbar spine it is important
that fixation is limited to the minimum number of levels in order to maintain
lumbar mobility.