In the UK, the great majority of spinal injuries are closed and occur from the indirect effect of violence applied to the vertebral column. In military practice open and compound from penetration by missiles of various sorts are found. The distributions of spinal injuries are as follows: 10% occur in the cervical region, 10% in the upper thoracic, 50% in the lower thoracic and 30% in the lumbar. Approximately 50%
are the result of road traffic incidents, 30% from industrial incidents and most of the remainder from sport or falls. Approximately 75% occur in patients under 40 years and 80% are males.
The effects can most easily be described by considering spinal cord and vertebral column injury separately, although clearly these are intertwined.
Spinal concussion is the transient loss of neurological function which may recover quickly and fully, and is similar to minor concussion of the brain. Spinal contusion involves swelling and haemorrhages in the spinal cord and very quickly there may be a central necrosis. The myelin sheaths are broken up, the axons are ruptured and neurons degenerate. Eventually the swelling subsides; some neural tissues may recover but those that have died are replaced by gliosis. An occasional late complication is the development of a syrinx (cyst) within the cord.
If injury is severe, there is an immediate and total loss of function at the level of the contusion and in the distal cord. Paralysis is complete and flaccid and there is total sensory loss. The bladder ceases to function. It is generally agreed that if there is no return of function within the first 48 h after injury, then the lesion is a complete functional transection and there will be no subsequent return of functions running up and down the spinal cord. If the lesion is partial and if there is some distal function remaining or returning, the neurological deficits are variable from one case to the next, as is the extent of recovery.
Spinal shock is the term used to describe the early phase lasting several weeks after injury; muscles are flaccid and there is also paralysis of the bladder and intestinal tract. As spinal shock wears off, distal spinal cord function returns but is shut off from the brain. Spinal cord reflexes return, the major one being the mass reflex, that is limbs reflexively withdraw on stimulation, the rectum and bladder evacuate and there is profuse sweating.
Cervical spinal cord injuries bring particular problems dependent on the level of injury. The lower the lesion in the cervical spinal cord, the more arm function is preserved, remembering that the main neurological supply to the arm is between C5 and T1. The higher the lesion, the greater the problems with respiration, since if the injury is at C4 or above not only are the intercostal muscles paralyzed but so are the diaphragm muscles due to loss of the phrenic nerve innervation and the patient can only survive by artificial ventilation or by electrical pulsed stimulation of the phrenic nerves.
The types of vertebral column injury are many and only a brief account is given here. One important concept to grasp is the difference between a stable injury which will not displace further and an unstable injury which may displace further and cause further neurological damage.
The upper two cervical vertebrae are more complex and different from those lower down the neck. Three main types of fracture occur:
• Jefferson fracture involves the ring of the atlas and is usually a stable fracture;
• Hangman's fracture involves both sides of the neural arch of the axis, thus separating the arch from the body;
• The dens (odontoid) may fracture at variable distances from the body of the axis, which is unstable and may lead to avascular necrosis of the dens above the fracture line.
In the cervical spine, fracture dislocations may occur as well as compression (burst) fractures. Dislocations can also occur when the facet joints dislocate unilaterally or bilaterally. All these injuries should be regarded as unstable and require some form of fixation. In any suspected injury, the whole cervical spine needs to be viewed on radiographically with the neck in a neutral position and this may involve pulling down the shoulders during the examination so that the whole cervical spine, including C7, is visualized.
It must also be appreciated that patients with pre-existing cervical spondylosis are less tolerant of acute flexion or hyperextension and the osteophytes may contuse the spinal cord without there necessarily being a vertebral column injury.
Thoracolumbar injuries are usually due to violent hyperextension or vertical compression when a heavy object falls on the shoulders. If the posterior ligaments remain intact, there may only be a crush (compression) fracture of the vertebral body.
At the scene of the incident, great care must be taken to avoid causing further damage, particularly to the spinal cord. In the case of suspected cervical spinal injuries, ideally a hard collar should be applied but if none is available, one person should hold the neck in a neutral position and apply gentle traction by holding the patient around the mandibular angles and pulling gently backwards. The patient must be kept flat and moved in a straight position onto a stretcher, which requires four people.
On arrival in hospital, the same precautions must continue. Plain radiography is performed or in many institutions now multi-slice CT scanning can cover the whole of the spine rapidly. Any suspected unstable cervical spinal injury requires skull traction and this is best done using the Gardner-Wells, which can be applied to the skull above the ears in under 60s, and thereafter a pull of at least 3-5 kg weight. A full neurological examination is required. In the past decade there has been a thrust to give large doses of methylpred-nisolone early in an attempt to diminish some of the spinal cord damage; the evidence for the efficacy of this is limited. Inpatient care involves the following:
• The patient must be given details of his injury and any prognosis; maintaining his morale is of paramount importance;
• Skin care is critical particularly in those patients with sensory loss. The prevention of bedsores is a real challenge to the nursing staff who may be helped by turning beds, such as the Stryker frame, or motorized beds that constantly change position;
• Respiratory care is essential though the intensity depends on the level of the lesion. Upper cervical lesions will require ventilatory support, though all patients require regular chest physiotherapy;
• The bladder requires drainage to prevent back-flow, urinary damage and infection. In the long term for lesions above the conus medullaris, reflex bladder action may return stimulated by manual compression or by implanted electrodes. If there is no reflex bladder action, the bladder can be drained by an indwelling catheter or by teaching the patient self-catheterization. Renal function must be carefully and regularly monitored;
• Joints rapidly deteriorate if not moved passively and gently and the prevention of contractures is vital;
• Blood pressure must be watched since patients with severe high lesions develop orthostatic hypotension. G-suits can be used when attempting to elevate the patient beyond the horizontal;
• Deep venous thrombosis must be carefully looked for since not only is the muscle pump inefficient or non-existent but pain is also diminished or lost and as a result the patient may not complain of calf or thigh pain;
• The gastrointestinal tract may not function normally in the early phases and there may even be a paralytic ileus and thus parenteral nutrition is necessary. Thereafter, nutritional requirements must be carefully assessed;
• Further displacement may occur at the fracture/dislocation site and further plain radiology is essential to monitor this area;
• Sexual and reproductive function may be possible even in patients with quite severe neurological deficits, although details of treatment are for specialists in spinal injuries.
The role of surgery is relatively limited and the indications few; some of the techniques are quite complex. The indications for possible surgery are:
• Further deterioration in an incomplete lesion requires urgent radiography in the form of CT or MR scanning. If there is evidence of cord compression from the impingement of bone or disc fragments or an extradural haematoma, then urgent decompression by the appropriate route is indicated;
• Unstable injuries require fixation after they have been reduced. This is mostly by internal fixation, but in some cases of cervical injury, a skull halo and body fixation may be used. The vertebral column is slow to heal and any external fixation may be required for 3-6 months.
Although all the above management can be carried out in any good general hospital, in the UK it is usual to transfer the patient to a regional spinal injuries unit where there are facilities for acute care, rehabilitation and long-term follow-up.
Was this article helpful?