Describe the injuries of the spine and their medicolegal importance.

Mechanism and Types

• Mechanisms of spinal injury — hyperflexion (the commonest, from a blow to the back of the head or a fall on the flexed neck), producing anterior wedge compression and posterior ligament rupture; hyperextension (a blow to the face or forehead, or a rear-end collision), producing anterior ligament rupture and, in the elderly with cervical spondylosis, central cord injury without any fracture; axial compression (a fall on the head, feet or buttocks, or diving into shallow water), producing burst fractures; rotation, producing unstable fracture-dislocation; and distraction, as in judicial hanging
• The cord may be injured without any radiological fracture — sciwora (spinal cord injury without radiographic abnormality), particularly in children, whose elastic spine allows the cord to be stretched and released without bony injury; and in the elderly with a stenotic canal

Whiplash and Special Injuries

• Whiplash injury — sudden hyperextension followed by hyperflexion of the neck, characteristically in a rear-end collision. It injures the cervical soft tissues, muscles and ligaments, producing pain and stiffness developing over hours; and in severe cases the cervical cord and brain stem, which may cause death with minimal external injury. It is a very common subject of compensation claims, and the difficulty is that the injury is largely subjective and imaging is often normal
• Injury from shaking an infant, in which the same mechanism damages the cervicomedullary junction
• Judicial hanging — the drop produces fracture-dislocation of the upper cervical spine with transection of the cord ("hangman's fracture" of the pars interarticularis of C2), causing immediate death
• Diving into shallow water — axial compression producing a burst fracture of the mid-cervical spine, a classical accidental mechanism
• Movement of an injured spine may convert a stable injury into a cord transection, which is why immobilisation precedes everything else and why careless handling at the scene is itself a cause of paralysis

Medicolegal Aspects and Applied Aspects

• Spinal injury is almost always grievous hurt — under the eighth clause as endangering life or disabling the person for twenty days, and usually under the fifth as permanently impairing the powers of a member
• The questions asked — the mechanism, and whether it fits the account given; whether the injury was accidental, suicidal or homicidal; the extent of permanent disability for compensation; and whether the handling after the injury contributed, which raises a question of negligence
• Immobilise the spine at the scene in any suspected injury, and do not move the patient without it; converting an incomplete injury into a complete one by careless movement is a real and recurring cause of avoidable paralysis
• Suspect a cervical injury in every unconscious trauma patient and in anyone with head or facial injury; the patient cannot complain of neck pain and the injury is missed
• Remember sciwora in children; a normal radiograph does not exclude cord injury, and magnetic resonance imaging is required where the signs are present
• Recognise neurogenic shock by the bradycardia and treat it with vasopressors rather than unlimited fluid, while excluding concurrent haemorrhage
• Examine the spinal cord at autopsy where the mechanism suggests it; the cord is not removed routinely, and a cervical injury may be entirely missed if the posterior approach is not used
• Document disability carefully for compensation — the level, the completeness, the sphincter function and the prognosis — since the award depends on it and the assessment may be revisited years later