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It is caused by damage to the brain or to the spinal cord at a high level - in particular spinal cord injuries secondary to an injury to the cervical spine. The injury causes victims to lose partial or total mobility of all four limbs, meaning the arms and the legs. Severity depends on which cervical vertebra is injured and the extent of the injury. An individual with an injury to C1 (the highest cervical vertebra) will likely be paralyzed and lose function from the neck down and be ventilator dependent. An individual with a C7 injury will likely be paralyzed and lose function from the chest down but still retain use of the arms and much of their hands. The extent of the injury is also important. A complete severing of the spine will result in complete loss of function from that vertebra down. A partial severing of the spinal cord results in varying degrees of mixed function and paralysis. For example, there are quadriplegics who have impairment in all four limbs but can still walk and use their hands due to the relatively minor extent of their injury.
The condition is also termed tetraplegia. Both terms mean "paralysis of four limbs"; however, tetraplegia is becoming the more commonly accepted term for this condition.[How to reference and link to summary or text]
"Tetra", like "plegia", has a Greek root, whereas "quadra" has a Latin root.
Spinal cord injuries are classified as complete and incomplete by the American Spinal Injury Association (ASIA) classification. The ASIA scale grades patients based on their functional impairment as a result of the injury, grading a patient from A to D. (see table 1 for criteria) This has considerable consequences for surgical planning and therapy.
Table 1: ASIA impairment scale
|A||Complete||no motor or sensory function is preserved in the sacral segments S4-S5.|
|B||Incomplete||sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5.|
|C||Incomplete||Incomplete: motor function is preserved below the neurological level, and more than half of key muscles below the neurological level have a muscle grade less than 3.|
|D||Incomplete||Incomplete: motor function is preserved below the neurological level, and at least half of key muscles below the neurological level have a muscle grade of 3 or more.|
|E||Normal||motor and sensory function are normal.|
Complete spinal-cord lesions
Pathophysiologically, the spinal cord of the tetraplegic patient can be divided into three segments which can be useful for classifying the injury.
First there is an injured functional medullary segment. This segment has unparalysed, functional muscles; the action of these muscles is voluntary, not permanent and strength can be evaluated by the British Medical Research Council (BMRC) scale. This scale is used when upper limb surgery is planned, as referred to in the 'International Classification for hand surgery in tetraplegic patients' (see table 2).
A lesional segment (or an injured metamere) consists of denervated corresponding muscles. The lower motor neuron (LMN) of these muscles is damaged. These muscles are hypotonic, atrophic and have no spontaneous contraction. The existence of joint contractures should be monitored.
Below the level of the injured metamere there is an injured sublesional segment with intact lower motor neuron. Which means that medullary reflexes are present, but the upper cortical control is lost. These muscles show some increase in tone when elongated and sometimes spasticity, the trophicity is good.
Incomplete spinal-cord lesions
Incomplete spinal cord injuries result in varied post injury presentations. There are three main syndromes described, depending on the exact site and extent of the lesion.
The central cord syndrome: most of the cord lesion is in the gray matter of the spinal cord, sometimes the lesion continues in the white matter.
The Brown-Sequard syndrome: hemi section of the spinal cord.
The anterior cord syndrome: a lesion of the anterior horns and the anterolateral tracts, with a possible division of the anterior spinal artery.
For most patients with ASIA A (complete) tetraplegia, ASIA B (incomplete) tetraplegia and ASIA C (incomplete) tetraplegia, the International Classification level of the patient can be established without great difficulty. The surgical procedures according to the International Classification level can be performed. In contrast, for patients with ASIA D (incomplete) tetraplegia it is difficult to assign an International Classification other than International Classification level X (others). Therefore it is more difficult to decide which surgical procedures should be performed. A far more personalized approach is needed for these patients. Decisions must be based more on experience than on texts or journals.
The results of tendon transfers for patients with complete injuries are predictable. On the other hand, it is well known that muscles lacking normal excitation perform unreliably after surgical tendon transfers. Despite the unpredictable aspect in incomplete lesions tendon transfers may be useful. The surgeon should be confident that the muscle to be transferred has enough power and is under good voluntary control. Pre-operative assessment is more difficult to assess in incomplete lesions. Patients with an incomplete lesion also often need therapy or surgery before the procedure to restore function to correct the consequences of the injury. These consequences are hypertonicity/spasticity, contractures, painful hyperesthesias and paralyzed proximal upper limb muscles with distal muscle sparing. Spasticity is a frequent consequence of incomplete injuries. Spasticity often decreases function, but sometimes a patient can control the spasticity in a way that it is useful to their function. The location and the effect of the spasticity should be analyzed carefully before treatment is planned. An injection of Botulinum toxin (Botox) into spastic muscles is a treatment to reduce spasticity. This can be used to prevent muscle shorting and early contractures.
Over the last ten years an increase in traumatic incomplete lesions is seen, due to the better protection in traffic.
There are about 5000 cervical spinal cord injuries per year in the United States and about 1000 per year in the UK. In 1988, it was estimated that lifetime care of a 27-year-old rendered tetraplegic was about US $1 million and that the total national costs were US $5.6 billion per year.
Delayed diagnosis of cervical spine injury has grave consequences for the victim. About one in twenty cervical fractures are missed, and about two-thirds of these patients have further spinal cord damage as a result. About 30% of cases of delayed diagnosis of cervical spine injury develop permanent neurological deficits. In high cervical injuries total paralysis from the neck down is the result. Patients will need constant care and assistance in things such as getting dressed, eating, and bowel and bladder help. High quadriplegics will usually use catheters or wear diapers because they are unable to use their arms. Low quadriplegics (C6-C7) can usually live independently.
However people with high level tetraplegia, who are dependent on a ventilator are more likely to request euthanasia through termination of life support than individuals with lower levels of spinal cord injury.
They are also more likey to suffer from a risk anoxia and its attendant cognitive deficits. This may be severe enough to impair their judgement and neuropsychological evaluation should monitor this where necessary.
- Parks, Jennifer (Thursday June 28 2007), "Enjoying the ride", Ottawa 24 hours 1 (155): 11, http://24hrs.ca
- American Spinal Injury Association (ASIA).
- Coulet B, Allieu Y, Chammas M (August 2002). Injured metamere and functional surgery of the tetraplegic upper limb. Hand Clin 18 (3): 399–412, vi.
- Hentz VR, Leclercq C (May 2008). The management of the upper limb in incomplete lesions of the cervical spinal cord. Hand Clin 24 (2): 175–84, vi.
- Elliot, T.R. & Rivera, P (2003). Spinal cord Injury. In Weiner, I.B. (ed) Handbook of Psychology. Volume 9: Health Psychology. Hoboken, N.J.: Wiley & Sons p.423
- Back-Up Trust
- Spinal Cord Injury Peer Support
- CareCure Community
- European Multicenter Study about Spinal Cord Injury
- United Spinal Association 
- Central nervous system disorders
- Clearing the cervical spine
- Musculoskeletal disorders
- Spinal cord injuries
Cerebral palsy and other paralytic syndromes (G80-G83, 342-344)
|Paresis and plegia NOS
|Flaccid vs. spastic|
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