Causes of Spinal Cord Injury

Transcription

1 CHAPTER 2 Spinal Cord Injury Causes of Spinal Cord Injury Spinal cord injury (SCI) happens for a wide variety of reasons. Injuries due to trauma are the most common. Figure 2.1 lists the results of a recent study on causes of SCI in Australia. Damage to the spinal cord can occur due to many other reasons. These include infection, stroke, tumour, inflammation, and several congenital causes. Each of these causes will produce a differing pattern of nerve damage, resulting in differing patterns of sensory loss and paralysis. Sports related Water 6% related 7% Other and unspecified causes 7% Motor vehicle occupants 22% High falls Unprotected (1m +) Low falls road users 16% (<1m) 24% 18% Figure 2.1 Incidence of Spinal Cord Injury from traumatic causes by external cause of injury (major groupings), Australia th Edition Dec

2 Injury Types and Classification In order to allow health workers to communicate accurately about their patients, a system has been developed to describe a spinal cord injury. Typically doctors will name the lowest level of the spinal cord with normal neurological function. This is called the Level of the Lesion. For example, if Joe has good Biceps muscle strength (a Cervical-5 or C-5 muscle), but poor wrist extension (a C-6 muscle), Joe has a C-5 spinal cord injury, or C-5 Level of Lesion. If Ann has good hip flexion (a Lumbar-2 or L-2 muscle), but weak knee extension (L-3 muscle), then Ann has an L-2 spinal cord injury or L-2 Level of Lesion. Paraplegia refers to a spinal injury below the T-1 spinal level. Typically these injuries result in some degree of weakness in the trunk, legs and feet. Individuals with paraplegia have injury to their spinal cord from Thoracic-2 (or T-2) on down through Sacral-5 (S-5). Tetraplegia refers to a spinal cord injury at or above the T-1 spinal level. Typically tetraplegia results in weakness or sensory changes of arms (or hands) and legs. In the past doctors referred to this sort of injury as Quadriplegia. Tetraplegia is now the preferred term in the medical community, although Quadriplegia is still commonly used. Just like a multi-lane highway might have lanes used to go to different places, the spinal cord is organised with different nerve tracts going to specific places. Sensory nerves will travel in different regions of the spinal cord from motor nerves. This can lead to specific patterns of sensory and motor loss when the spinal cord is damaged. 8 th Edition Dec

3 Degree of Injury - Incomplete vs. Complete Many people have the mistaken idea that either someone is paralysed, or they are not. Like many aspects of life, paralysis due to spinal cord injury is not a black or white issue, but many shades of grey. The technical definition of incomplete is quite complex and relates to whether someone has sensation around their anus and/or the ability to contract their anal sphincter at will and/or if they have deep sensation inside the rectum (e.g. you know when an enema is inserted, that your bowels are moving etc). This is due to the fact that some nerve signals pass across the damaged segment of the spinal cord. Someone has a complete lesion if they have no movement and no sensation below their injury level and, in particular, have no sensation / movement in the anal area. If you have regained some movement and/or sensation up to 3 levels (see above section) below your original injury you are still complete. Even if you have some movement or sensation in your lower limbs (despite having a cervical, i.e. neck injury), but no sensation or movement in the anal area, technically, you have a complete injury. The classification for someone with a complete injury is ASIA A. ASIA stands for the American Spinal Injury Association and is the internationally accepted scale in use. An incomplete spinal cord injury is classified as an ASIA B, C, D or E: B = sensory sparing (may only be around the anus at first) C = 50% of the muscles below the injury level are NOT working at "anti-gravity" i.e. they are not strong enough for you to use them in a functional way. D = 50% of the muscles below the injury level ARE working at "anti-gravity". 8 th Edition Dec

4 E = normal muscle strength in all muscle groups and a person with this degree of injury probably won't need to be an inpatient in the spinal unit at all (but may have some bladder, bowel or sexual dysfunction and may be seen in the outpatient department by one of the doctors). We add the lesion level as well, e.g. C6 ASIA A, C7 ASIA C, T12 ASIA D - to indicate level of cord lesion and degree of completeness. The cord lesion may improve a bit over a few weeks or months e.g. C5 ASIA A may improve to C6 or even C7 because there can be a bit of recovery in the nervous system. Unfortunately this doesn't always happen. Pattern of Injury If we look within the spinal cord, we find that it has a very specific organisation. Sensory nerves travel with other sensory nerves, motor nerves likewise. Additionally, the nerves to particular body parts also travel bundled together in specific parts of the spinal cord. This means that some injuries to the spinal cord lead to injuries to specific nerve paths producing characteristic patterns of weakness and numbness. We ll review two common patterns of SCI. 1. Central Cord Syndrome The Central Cord Syndrome results from an injury to the central part of the spinal cord in the cervical (neck) region leading to tetraplegia. As the nerves which supply the arms lie more centrally in the cord, the arms tend to be more affected than other areas of the body. 8 th Edition Dec

5 2. Cauda Equina Syndrome The lowest part of the spinal cord ends at the L-2 vertebral level. The nerves continue past this level resembling a horse s tail, or cauda equina in Latin. Injury to this area produces weakness at the knees and/or ankles, plus impairment of bowel and bladder function. Interesting Facts: Your spinal cord is about the same circumference as your little finger Your spinal cord contains roughly 20 million nerve fibres Your spinal cord is roughly 45 cm [18 inches] long Healing and Recovery after SCI With its millions of nerves, the spinal cord is both a delicate and tremendously complicated structure. While a nerve running in the arms or legs can regenerate [regrow] if severed, a nerve in the spinal cord itself has very limited ability to regenerate. In most cases, immediately following spinal cord injury, weakness and sensory loss is at its peak. Some of this loss may be due to permanent injury, and some of the weakness may improve. Unfortunately, both permanent and temporary weakness look the same, so only with time can we tell whether the weakness is permanent or temporary. The time for recovery to occur is variable, depending on the injury. In some cases most recovery occurs within the first 3 months, while with others it can take as long as 18 months. Typically, most recovery occurs in the first few months after SCI. As time goes by, fewer gains are seen. 8 th Edition Dec

6 It is very important to do all you can to help your body to heal. Your medical care helps, certainly. Surgery, if necessary, is typically done to make the bony spinal column stable, reduce compression to the spinal cord, and/or prevent further damage. Medications may be given at certain periods following the SCI to attempt to minimise the nerve damage. Further medical support is given to prevent serious complications, and allow the body maximum health and nutrition for healing. What can you do to help your body s healing process? Eat well Drink adequately: not too much, not too little Take your medications as scheduled Follow the advice of your rehabilitation team Avoid substances that can injure nerves: Alcohol, illicit/recreational drugs Decrease or stop smoking cigarettes Keep a positive mental attitude. Your mental attitude strongly influences your physical health! 8 th Edition Dec

7 Functional Abilities after Spinal Cord Injury Functional abilities vary according to the level and nature of spinal cord injury. There is often variation between individuals who have similar levels of injury for a number of reasons, including severity of injury, associated conditions, age, body build, spasticity and personal goals and priorities. Level of Spinal Cord Lesion FUNCTIONAL ABILITIES (Based on complete injury) C1-3 Assisted breathing (with ventilator). Use of motorised wheelchair with head control. Use of voice-activated computer. Environmental control systems used to operate appliances, eg TV, stereo. C4 C5 C6 C7 Independent breathing. Use of motorised wheelchair with head control. Use of computer and environmental control systems. Use of motorised wheelchair with hand control and manual wheelchair on flat ground surfaces. Independent in most aspects of grooming, eating and drinking, typing, writing and computer use with the aid of splints/devices. Using an overhead strap may assist with rolling in bed. Use of manual wheelchair. Transfer to and from bed with or without slide board, possibly with assistance. Independent bed mobility. Increased independence with personal care, including bladder management, most aspects of showering and dressing and management of bowel care with device. Basic food and drink preparation. May achieve driving using hand-controls. Independent transfers, including in and out of car. Independence with personal care (as noted above) with aids/adaptations. Basic food and drink preparation. Driving using hand-controls, possibly including lifting wheelchair in and out of car. 8 th Edition Dec

8 Level of Spinal Cord Lesion FUNCTIONAL ABILITIES (Based on complete injury) C8 Independent transfers, possibly including floor to wheelchair. Independent personal care, including managing buttons and shoe laces. Management of bowel care with or without use of an aid. Independence with food and drink preparation and some household tasks. Driving, including lifting wheelchair in and out of car. T1-6 Advanced transfers: wheelchair to floor and return. Managing wheelchair up and down curbs, steps, escalators. Therapeutic standing between bars with leg splints. Independent in all aspects of personal care and most household activities. Independent transfers, possibly including floor to wheelchair. T6-L2 Independent transfers, including floor to wheelchair. Improved trunk stability and balance. Advanced wheelchair skills. Therapeutic walking with long leg braces and crutches. L3-S1 Increasing use of legs and therefore, walking with varying amounts of external support. S2-5 Normal gait. Increasing voluntary control over bladder, bowel, and sexual functions. Is there a Cure for SCI? Medicine has come a long way to help save lives of those with a SCI. Up until World War II, victims of SCI were expected to die within days or months following the injury. Since this time, medical science has been able to help restore good health to many people with SCI. As recently as five to ten years ago, many researchers believed that a cure for SCI was impossible. The problem looked insurmountable: the spinal cord is too complex; nerve cells in the spinal cord cannot regenerate. This attitude has changed in the past decade. Researchers have been working on several approaches that show promise in helping heal 8 th Edition Dec

9 the injured spinal cord however we do not know when these treatments will be developed. It is unlikely that any treatment developed in the near future will provide a complete cure for SCI. However, promising developments may lead to treatments that can reduce the effects of SCI and increase the recovery of functional abilities after SCI. Treatments that are developed in the future may not work for all people with SCI. If you would like to know more about this, you are encouraged to attend the Patient Education sessions which will be held during your rehabilitation. The Patient Education session that is presented by the medical staff includes information about current research in SCI and provides an opportunity to ask any questions you may have. For those seeking further information, you might like to visit some of the websites listed in this handbook or ask your doctor about the most up to date developments. It may be tempting to say, Why go to therapy? I ll sit back and wait for a cure. Any future treatment is likely to be most effective for those who have kept their bodies and minds healthy. You may hear about unusual or controversial treatments for paralysis and SCI. Keep in mind that some people might be selling more than they can deliver. It s a good idea to ask your doctor for an opinion about these treatments. 8 th Edition Dec