High spinal cord injuries (SCI) can have a profound impact on respiratory function, leaving people vulnerable to breathing problems and recurrent chest infections and pneumonia. Some people with high SCI are dependent on mechanical ventilation to help them breathe for all or part of their daily lives.
The higher a spinal cord injury, the more impact it has on the life and ability of the affected person. The spinal cord is a long bundle of nerves which run continuously through a canal within the vertebrae – the bones of the spine. Pairs of nerves branch off from the spinal cord, extending to the left and right of each vertebra and branching off further to form a network nervous system throughout the body.
Each of these pairs of nerves supplies nerve function – impulses that control movement and sensation – to specific areas of the body depending on the level of the nerve. This means that an injury high up the spinal cord will affect more of the body, as there will be dysfunction of the nerves below that point.
The completeness of an SCI also predicts the impact on function – an injury with total or near-total destruction of the nerve pathways will have a more profound effect on a person’s body and life than one which affects, for example, one side of the spinal cord or a specific portion of the bundle of nerves.[i]
What is a C-spine injury?
The C-spine is the cervical spine, roughly the portion of the spinal column that makes up the neck. The cervical spine comprises the top seven vertebrae, labelled from the top (closest to the skull) downwards: C-1 to C-7. These correspond to 8 spinal cord segments, each of which describes a single pair of nerves, with the C8 nerves diverging from the spinal cord just under the C7 vertebra.[ii]
Film x-ray c-spine (Lateral view): Cervical level spine
A spinal injury high in the neck – the cervical spine or C-spine – might affect all four limbs and body functions including movement and sensation, respiratory health, digestive health and continence, sexual function and more. A lower injury, in the lumbar or thoracic spine, might only affect the lower limbs and aspects of continence and sexual function, leaving respiratory function and arm and hand control intact. Spinal injuries can be acute, such as in a traumatic accident like a car crash, or can be a result of chronic conditions, infections, degenerative changes, congenital and genetic conditions, and more.[iii]
How does a C-spine injury affect breathing?
Respiratory dysfunction is the most common cause of serious illness and mortality in people with spinal cord injuries, and higher spinal cord injuries can have a profound impact on respiratory function.[iv]
When the nerves that convey impulses to and from the brain to the body are damaged, a person can lose some or all sensation and conscious control over the parts of their body that rely on those nerves and related muscles. Some unconscious functions can also be affected, meaning that some of the body’s innate actions are disrupted. Sleep-disordered breathing and autonomic dysfunction contribute to breathing problems in people with spinal cord injury.[v]
The muscles responsible for breathing control include the diaphragm – the flat muscle directly beneath the lungs; the abdominal muscles; and the intercostal muscles – the muscles between each rib. With reduced control over these muscles, breathing is affected. The impact of this loss of muscle control can range from a person being completely unable to make useful respiratory effort and becoming dependent on mechanical ventilation to being unable to cough strongly enough to clear secretions from the throat, through to having a reduced vital lung capacity or weakened cough.[vi][vii]
People who are unable to clear fluid from the back of the throat can become very prone to chest infections, and mechanical devices are available to help clear the lungs, including mechanical cough assist devices, and suction for upper airways secretions.
Having an impaired swallow also poses a significant risk to the lungs, as any food or fluid that enters the lungs instead of the stomach can cause very severe aspiration pneumonia.[viii] Aspiration pneumonia most commonly begins in the right lower lobe of the lungs, as the anatomy of the airways mean that any aspirated fluids have a more direct route to the right lung.
Some people with a reduced swallow after a spinal cord injury will need alternative ways of maintaining their nutritional and hydration needs in the short- or long-term. This could be through an NG or nasogastric tube – a tube passed through a nostril directly into the stomach, or through a PEG (percutaneous endoscopic gastrostomy) – a tube fitted to the stomach through the abdominal wall. Either of these routes can be used to administer a special liquid food mix and fluids directly into the stomach. A PEG is particularly likely for people who have tracheostomies.
Levels of spinal cord injury impact on respiratory function
The completeness or incompleteness of a spinal cord injury, and where incomplete, the portion of the spinal cord affected, can mean significant differences in the elements of respiratory function that are preserved on an individual basis.
For the sake of clarity, further discussion of SCI levels assumes a complete or near-complete spinal cord injury. It is also important to remember that the chronic impact of a spinal cord injury isn’t always possible to predict during the acute stages of a spinal cord injury where spinal shock is present.
- C1-C3: Any spinal cord injury at this level will have a profound impact on breathing. Without a pathway to the nerves controlling the respiratory muscles, a person will have very little control over their breathing, especially those important functions like coughing. With loss of control over the muscles of the abdomen, the diaphragm and the rib cage, breathing will be shallow, with a reduced lung volume for each breath and inability to clear matter from the chest and throat through deep breathing and coughing. People with C1-C3 spinal cord injuries are likely to need mechanical ventilation for some or all of the time. Complex care needs like mechanical ventilation and tracheostomy care can often be met at home; having a comprehensive package of care can support people in living independent lives.
- C4: a C4 injury will mean impaired diaphragm function, reduced ability to fill the lungs to vital capacity, and a reduced cough. People with a C4 injury may need mechanical ventilation overnight and may find that their breathing can be impaired by something as simple as poor positioning. A cough assist device can help clear the lungs of any secretions, food or fluid.
- C5: someone with an injury at C5 may be able to breathe independently but will have a reduced lung capacity with less effective breathing and cough.
- C6-C7: C7 is the lowest of the cervical vertebrae, and someone with an injury at C6 or below is likely to be able to breathe independently. While some respiratory function is preserved, reduced strength and muscle control does mean that someone with a C6-C7 injury may still have a weaker cough and some reduction in lung volume for each breath. Someone with a C6 – C7 injury is likely to still have some impaired diaphragmatic control, using accessory muscles of the back and chest more than someone without SCI.
A number of other predictors for respiratory impact from lower cervical spinal injuries – those at C5 or lower – have been identified, including pre-existing respiratory disease and whether the person has sustained an injury directly affecting the respiratory system.[ix]
Acute traumatic spinal cord injuries have historically been overwhelmingly incurred by younger people, especially men, although this trend is shifting towards an older at-risk demographic.[x] This means that pre-existing respiratory disease is relatively rare. However, lung conditions can develop subsequently and can also be exacerbated by, or precipitated by, spinal cord injuries.
Other spinal conditions that can affect breathing
Any condition that affects a person’s control over their breathing can cause respiratory problems too. This includes other degenerative conditions that affect the cervical spine, such as cervical stenosis and cervical spondylosis. Chronic neurological conditions which involve progressively worsening nerve function can also affect breathing as they reach severe stages.[xi]
Spinal cord function can be affected by a wide range of conditions relating to the spinal column, muscles or nerves, including:
- Cervical spondylosis: a very common condition caused by age-related osteoarthritic-type changes in the vertebrae, severe cervical spondylosis can cause pressure on or restrict the spinal cord. The most common symptom is neck pain, but in extreme cases cervical spondylosis can begin to affect the nerves of the spinal cord, sometimes affecting breathing.[xii]
- Cervical stenosis: a narrowing of the spinal canal can put pressure on the nerves of the spinal cord, affecting control over the muscles of respiration.[xiii]
- Myositis and related muscle-wasting conditions like dermatomyositis: any condition which can affect the tone of the muscles related to breathing can cause breathing problems and increase the tendency for chest infections and other respiratory complications. These kinds of diseases can also affect related functions such as swallowing, contributing to further problems with the lungs.[xiv]
- Poliomyelitis and post-polio syndrome: polio can cause extreme muscle weakness or even paralysis, and while survival rates are good and the acute symptoms resolve, post-polio syndrome can last a lifetime and is typified by muscle weakness and fatigue which affect the breathing, as well as more specific respiratory symptoms like sleep apnoea and a tendency for chest infections as a secondary complication of muscle weakness.[xv]
- MS: the progressive muscle weakness people with MS experience may, in severe cases, cause weakness of the chest muscles which can affect respiratory effort and make a person more likely to develop respiratory problems. [xvi]
Living with respiratory needs after acute or chronic spinal cord injury
The impact of a spinal injury can vary hugely from one person to the next. The physical impact: the completeness of the injury, the level of impact, and whether the problems are caused by chronic neurodegenerative diseases or acute injury can mean that no two spinal cord injuries are quite the same. The individual person affected can also make a difference, and their psychological and social needs when living with a damaged spinal cord inform their care needs as much as any physical challenges.
Methods for managing problematic respiratory function after a spinal cord injury are increasingly sophisticated and improve both the quality and quantity of life for those living with spinal cord injury. Portable mechanical ventilation as well as larger home devices, home oxygen and equipment are more readily available than ever. Nurses and professional carers who are highly trained in specific complex and respiratory care in the home are also changing the lives of people living in the community with complex care needs.
Close up patient doing hand stretching exercise on massage table
Someone with a condition or injury affecting their high cervical spine is likely to need support with lots of their physical needs, including physiotherapy, access to outside activities, meeting nutrition, hydration and continence needs, and any of the usual activities of daily living that can become a challenge after a spinal cord injury.
Particular challenges for people with affected respiratory function can include finding ways to get out and about when reliant on mechanical ventilation, preventing and managing chest infections, using cough assist devices, tracheostomy management, and respiratory function and support when asleep.
Family members may be able and willing to help meet some of these needs, but someone with complex care needs can access full-time care packages to cover all physical and support with emotional and social needs too. A good care package supports independence and allows a person to continue to live the kind of life they want, seamlessly making up for self-care deficits and needs.
Mechanical ventilation
Some people with c-spine damage will need to use a mechanical ventilator for some or all of the time to support their respiratory effort and maintain adequate ventilation. Although essential and lifesaving, mechanical ventilation carries its own risks, including an increased risk of chest infections – although this risk is already inherent in anyone who needs respiratory support – and risk of mechanical failure. However, equipment and care is now specialised and sophisticated and with the right support, mechanical ventilation at home can enable, rather than hinder, a desirable lifestyle.
____________________________________________________________________
[i] Anderson, D. K., & Hall, E. D. (1993). Pathophysiology of spinal cord trauma. Annals of emergency medicine, 22(6), 987-992.
[ii] Diaz, E., & Morales, H. (2016, October). Spinal cord anatomy and clinical syndromes. In Seminars in Ultrasound, CT and MRI (Vol. 37, No. 5, pp. 360-371). WB Saunders.
[iii] McDonald, J. W., & Sadowsky, C. (2002). Spinal-cord injury. The Lancet, 359(9304), 417-425.
[iv] Zimmer, M. B., Nantwi, K., & Goshgarian, H. G. (2007). Effect of spinal cord injury on the respiratory system: basic research and current clinical treatment options. The journal of spinal cord medicine, 30(4), 319-330.
[v][v] Berlowitz, D. J., Wadsworth, B., & Ross, J. (2016). Respiratory problems and management in people with spinal cord injury. Breathe (Sheffield, England), 12(4), 328–340. https://doi.org/10.1183/20734735.012616
[vi] Benditt, J. O. (2006). The neuromuscular respiratory system: physiology, pathophysiology, and a respiratory care approach to patients. Respiratory care, 51(8), 829-839.
[vii][vii] Winslow, C., & Rozovsky, J. (2003). Effect of spinal cord injury on the respiratory system. American journal of physical medicine & rehabilitation, 82(10), 803-814.
[viii] Mandell, L. A., & Niederman, M. S. (2019). Aspiration pneumonia. New England Journal of Medicine, 380(7), 651-663.
[ix] Sampol, J., González-Viejo, M. Á., Gómez, A., Martí, S., Pallero, M., Rodríguez, E., … & Ferrer, J. (2020). Predictors of respiratory complications in patients with C5–T5 spinal cord injuries. Spinal cord, 58(12), 1249-1254.
[x] Aarabi, B., Albrecht, J. S., Simard, J. M., Chryssikos, T., Schwartzbauer, G., Sansur, C. A., … & Scarboro, M. (2021). Trends in demographics and markers of injury severity in traumatic cervical spinal cord injury. Journal of neurotrauma, 38(6), 756-764.
[xi] Gilchrist J. M. (2002). Overview of neuromuscular disorders affecting respiratory function. Seminars in respiratory and critical care medicine, 23(3), 191–200. https://doi.org/10.1055/s-2002-33027
[xii] Yu, E., Romero, N., Miles, T., Hsu, S. L., & Kondrashov, D. (2016). Dyspnea as the Presenting Symptom of Cervical Spondylotic Myelopathy. Surgery journal (New York, N.Y.), 2(4), e147–e150. https://doi.org/10.1055/s-0036-1597664
[xiii] Fahad, E. M., Hashm, Z. M., & Nema, I. M. (2020). Cervical spinal stenosis and risk of pulmonary dysfunction. International journal of critical illness and injury science, 10(1), 16–19. https://doi.org/10.4103/IJCIIS.IJCIIS_83_19
[xiv] Rowen, A. J., & Reichel, J. (1983). Dermatomyositis with lung involvement, successfully treated with azathioprine. Respiration, 44(2), 143-146.
[xv] Bach, J. R., & Alba, A. S. (1991). Pulmonary dysfunction and sleep disordered breathing as post-polio sequelae: evaluation and management. Orthopedics, 14(12), 1329-1337.
[xvi] Tantucci, C., Massucci, M., Piperno, R., Betti, L., Grassi, V., & Sorbini, C. A. (1994). Control of breathing and respiratory muscle strength in patients with multiple sclerosis. Chest, 105(4), 1163-1170.
