Spinal Cord Injury

SCI is a serious medical disorder that frequently results in significant morbidity and permanent impairment. When the axons of neurons that go through the spinal cord are damaged, motor and sensory function is lost below the point of lesion. Major trauma is the most common cause of injury, and primary injury is typically irreparable. These injuries are very costly and disabling because they disproportionately impact patients under the age of 30, cause considerable functional impairment for the rest of the person's life, and put the person at risk for a variety of consequences that raise morbidity and mortality. SCI is expected to have a 2.5-to-4-billion-dollar economic impact over its lifetime.

Spinal Cord Injury Epidemiology

Every year, between 255,000 and 500,000 people worldwide suffer a spinal cord injury. The majority of these cases are the result of preventable factors such as violence and car accidents. Each year, around 17,500 new cases of SCI are diagnosed in the United States, with an estimated 280,000 people living with SCI. The majority of individuals with SCI caused by a sports injury are men. The age ranges from 15 to 30 years old have the greatest risk of SCI.

Spinal Cord Injury by Level

The specific site in the spinal cord where damage has occurred is known as the level of injury. Identifying the nerves from the top of the neck down determines the levels. Cervical, thoracic, lumbar, and sacral nerves are the four categories of spinal cord injury.

One of your cervical nerves (1-7) will be affected if the spinal cord in your neck is harmed. This type of injury is referred to as C1, C2, and so on. If you harm your back's spinal cord, you will either hurt the thoracic nerves (T1-T12) or the lumbar nerves (L1-L5). 

Spinal Cord Injury Pathophysiology

Direct trauma to the spinal cord and compression owing to broken vertebrae or masses such as epidural hematomas or abscesses are the most common causes of spinal cord injury. Impairment of blood flow, inflammatory responses, metabolic abnormalities, or exposure to toxic substances are all less prevalent causes of spinal cord injury.

Primary Injury

SCI is caused by an initial injury to the brain, such as mechanical forces. This is referred to as the primary injury. A direct impact is the most prevalent cause of primary injury, and persistent compression is usually caused by bony fragments in fracture-dislocation injuries. Hyperextension injuries, unlike fracture-dislocation injuries, usually lead to less frequent, impact alone plus temporary compression. Distraction injury, a stretch and tear of the spinal cord in its axial plane, occurs when two neighboring vertebrae are pulled apart. Last but not least, laceration/transection injuries are caused by sharp bone pieces, serious dislocations, and missile injuries.

Secondary Injury

Secondary injury is a set of biological events that start within minutes and progress to self-immolation weeks or months after the primary injury. Vascular damage, ionic imbalances, free-radical production, the early inflammatory response, and neurotransmitter buildup (excitotoxicity) are all part of the acute phase of secondary injury after SCI. The subacute phase follows, which involves surviving axon demyelination, Wallerian degeneration, matrix remodeling, and glial scar production.

Immune Response Spinal Cord Injury

Following SCI, neuroinflammation can be useful or harmful depending on the time-point and the condition of immune cells. Inflammatory processes during the first three days after SCI include the recruitment of blood-borne neutrophils, resident microglia, and astrocytes to the injury site. The second phase, which begins three days after the injury, involves the recruitment of macrophages, B-, and T-lymphocytes to the injured area. Antigen-presenting cells activate CD4+ helper T cells, which produce cytokines that drive B cells to make and release antibodies, exacerbating neuroinflammation and tissue death. In the acute phase of SCI, neuroinflammation is more aggressive.

Inflammation can last for years in the subacute and chronic stages, and even for the rest of a patient's life. The composition and phenotype of inflammatory cells change depending on the stage of inflammation and the signals present in the injury microenvironment. T cells, B cells, and microglia/macrophages have the ability to become pro-inflammatory or anti-inflammatory pro-regenerative.

Motor and sensory functions are lost below the degree of injury when nerve axons passing via spinal cord tracts are disrupted. The severity of the damage and which spinal pathways are impacted determine the pattern of impairment.

The anterior part of the spinal cord contains spinothalamic pathways. The sensory information for pain and temperature is carried by these nerve axons. Damage to these pathways causes a lack of pain and temperature sensibility on the opposite side. The lateral portions of the spinal cord contain corticospinal pathways. The motor function is controlled by the axons of these nerves. Ipsilateral weakness or paralysis results from damage to these tracts. Axons traveling to the upper extremities are adjacent to the center of the spinal cord in the cervical spine.

Axons traveling to the lower extremities, on the other hand, are found on the periphery. The dorsal columns are located in the back of the spinal cord. Tactile (touch), proprioceptive (kinesthetic awareness), and vibratory sensations are all carried by these tracts. Damage to these tracts causes a loss of touch sensation, kinesthetic awareness, and vibratory sensation on the opposite side.

Spinal Cord Injury Causes

Since 2005, the two main causes of spinal cord injury (SCI) have remained the same: motor vehicle accidents and falls, with the latter being most common in individuals aged 45 or older. Interpersonal violence (mainly gunshot wounds), which is the most common cause in various US metropolitan settings, has a proclivity for vertebral fractures from falls with concomitant SCI in older females with osteoporosis. A penetrating injury to the spinal cord was found to be worse than a blunt trauma in patients who had been assaulted; and sports (with diving being the most frequent cause). Traumatic spinal cord injury (SCI) has significant functional, medical, and financial consequences for the injured person, as well as a significant impact on their psychological well-being.

The following are some of the other causes of spinal cord injury:

• Vascular problems
• Tumors
• Infectious diseases
• Spondylosis
• Osteoporosis-related vertebral fractures
• Disorders of development
• Iatrogenic damage, particularly following spinal injections and the installation of an epidural catheter

Bone fractures, unconsciousness, and traumatic brain injury altering emotional/cognitive functioning are all common injuries associated with severe spinal cord injury.

Alcohol intoxication is common among those who have had spinal cord injuries, with 15-50% of them being drunk.

Symptoms of Spinal Cord Injury

Patients usually appear after a major traumatic event, such as a car accident, a fall from a great height, or a bullet wound. Although high cervical injuries might cause hypotension and bradycardia due to a lack of sympathetic tone, vital signs are uncommon to be abnormal. The physical assessment will indicate weakness and sensory impairments that are related to the injury pattern and the affected spinal systems. Several well-known injury patterns are thoroughly documented.

Complete Spinal Cord Injury

• Below the level of injury, these injuries usually show total bilateral loss of motor control, pain feeling, temperature sensation, proprioception, vibratory sensation, and tactile sense.
• Paralysis and lack of sensation in the lower extremities are common symptoms of lumbosacral injuries. Loss of bowel and bladder control, as well as sexual dysfunction, may occur as a result of these injuries.
• Thoracic injuries have the same impairments as lumbosacral injuries, but they can also cause loss of function in the thoracic muscles, making it difficult to maintain proper posture.
• Cervical injuries cause the same impairments as thoracic injuries, but they can also cause loss of upper-extremity function, leading to quadriplegia. Due to the absence of diaphragm innervation, injuries above C5 may cause respiratory impairment.

Complete Spinal Cord Injury

• Central Cord Syndrome

The most prevalent type of incomplete spinal cord injury is central cord syndrome, which accounts for 20-25 percent of all incomplete SCI. It usually develops when the middle area of the spinal cord is damaged as a result of neck hyperextension. Severe trauma from car accidents is a common cause of central cord syndrome, particularly when the force of the accident causes the neck to thrust forward.

More weakness in the arms than in the legs is a hallmark of central cord syndrome. Because neurons controlling arm movements are more centrally positioned than nerves controlling leg movements, which are located closer to the sides, this is the scenario. Losses in sensation are frequently detected in the upper back and back of the arms, despite the fact that sensation deficiencies vary. Alterations in pain and temperature sensations, as well as alterations in light touch sensations, are common.

• Anterior Cord Syndrome

When the anterior two-thirds of the spinal cord are injured, anterior cord syndrome develops. It frequently causes full motor function deficit and altered sensation below the level of injury.

Injury to the anterior spinal artery, which limits blood flow at that level of injury, is a common cause of incomplete spinal cord injury. It can also happen if the spine is displaced forward. In certain cases, the lower half of the spine compresses the anterior side of the spinal cord, leading to anterior cord syndrome.

Damage to the spinothalamic tracts typically affects sensory systems that carry data about pain and temperature.

• Posterior Cord Syndrome

When the posterior part of the spinal cord is damaged, a condition known as posterior cord syndrome develops. It usually results in a loss of proprioception (your sense of where you are and how you move), difficulties distinguishing between two points of skin contact, and a loss of capacity to feel deep touch below the level of the lesion.

Power and your ability to analyze pain, temperature, and mild touch sensations, on the other hand, are usually unaffected.

• Brown-Sequard Syndrome

Brown-Sequard syndrome is an uncommon kind of incomplete spinal cord injury that affects 3-4 percent of all spinal cord injuries. It occurs when one side of the spinal cord (left or right) is injured.

The loss of movement on the same side of the injury, as well as diminished proprioception and vibration sensation, are common symptoms of this form of incomplete spinal cord injury. Pain and temperature perceptions on the opposite side of the injury are frequently affected because the spinothalamic tracts cross in the center of the spinal cord.

Conus Medullaris Syndrome

• Injury to the terminal portion of the spinal cord, just proximal to the cauda equina, causes this syndrome.
• It usually manifests as a lack of sacral nerve root functioning. It's possible to notice a loss of Achilles tendon reflexes, bowel and bladder malfunction, and sexual dysfunction.

Neurogenic Shock

• It is caused by severe cervical traumas that impair the cervical ganglia, resulting in a lack of sympathetic tone.
• A shock state is characterized by hypotension and bradycardia when the sympathetic tone is lost.

Spinal Cord Injury Differential Diagnosis

Based on the patient's presentation, which will almost certainly occur after a significant traumatic event, the diagnosis of spinal cord injury will be relatively accurate. When the onset time and previous events are unclear, however, a wider differential for motor and sensory abnormalities should be evaluated.

• Cerebrovascular accident (CVA)
• Postictal (Todd) paralysis
• Hemiplegic migraine
• Multiple sclerosis
• Guillain-Barré syndrome
• Transverse myelitis
• Tick paralysis
• Myasthenia gravis
• Organophosphate toxicity
• Botulism
• Hypoglycemia
• Hypokalemic periodic paralysis
• Hypocalcemia
• Diabetic neuropathy
• Conversion disorder

Spinal Cord Injury Diagnosis

Specialists will question you about what happened and do a thorough assessment after a trauma. Specialists may evaluate patients' capacity to move different parts of their body and their capacity to feel strong or light sensations in separate segments of their body if they are conscious. These tests are used to see if the injury has impaired movement and sensation. Specialists will inquire about any neck or back problems.

Patients will need imaging tests such as an X-ray, CT scan, or MRI if specialists cannot rule out a spinal cord injury.

• X-ray (plain films).  A test that produces images of bones using unseen electromagnetic energy beams (X-rays). On X-rays, soft tissue structures such as the spinal cord, spinal nerves, the disc, and ligaments, as well as most cancers, vascular diseases, and cysts, are usually not visible. X-rays are used to determine the overall structure of the bones, as well as the curvature and orientation of the vertebral column. X-rays can be used to assess spinal dislocation or slippage (also known as spondylolisthesis), kyphosis, scoliosis, as well as local and overall spinal balance. Plain film X-rays can also detect specific skeletal abnormalities such as bone spurs, disc space constriction, vertebral body fracture, collapse, or erosion. Dynamic, or flexion/extension X-rays (X-rays that show the spine with movement) may be taken to evaluate whether there is any abnormal or excessive movement or instability in the injured levels of the spine.
• CT scan. It is a diagnostic process that employs a mix of X-rays and computer technology to create detailed images of any region of the body, including the bones, muscles, fat, and organs. CT scans provide more information than standard X-rays.
• Magnetic resonance imaging (MRI). It is a diagnostic process that produces comprehensive images of organs and structures within the body using a combination of powerful magnets, radio-frequencies, and a computer. The most useful scan for imaging the spinal cord is an MRI.

Spinal Cord Injury ASIA

The American Spinal Injury Association Impairment Scale is a standardized neurological assessment that the rehabilitation team uses to measure the sensory and motor levels that have been impacted by the spinal cord injury. There are five levels on the scale, ranging from complete loss of brain function in the affected region to complete normality. The findings aid the team in determining functional objectives based on the neurological level of impairment. According to the National Institutes of Health, the scale includes the following elements:

• Grade A. The impairment is total. Below the level of damage, no motor or sensory function remains.
• Grade B. The impairment is only partially present. Below the neurologic level (the first normal level above the point of injury), the sensory function is preserved but not motor function. Some sensation is retained in the sacral segments S4 and S5.
• Grade C. The impairment is only partially present. Although the motor function is intact below the neurologic level, more than half of the major muscles have a muscle power grade of less than three (i.e., they are not strong enough to move against gravity).
• Grade D. The impairment is only partially present. Below the neurologic level, motor function is intact, and at least half of the major muscles have a muscle grade of three or more (i.e., the joints can be moved against gravity).
• Grade E. The patient's activities are normal and All sensory and motor functions are unaffected.

Spinal Cord Injury Treatments

Treatment begins at the scene of the accident, and paramedics and emergency medical services personnel can help with stabilization before being transported to the hospital. Stabilization can help prevent existing injuries from deteriorating. Address any life threats or concomitant traumatic injuries as soon as possible in the event of serious trauma.

Hypotension and shock will exacerbate the effects of any previous SCI and reduce the chances of neurologic recovery. To sustain respiratory and hemodynamic stability, immediate action is required. If possible, surgical decompression may be necessary to reduce the severity of the injury. This operation aids in the stabilization of the spine, the prevention of discomfort, the reduction of deformity, and the relief of compression caused by a herniated disc, blood clot, or foreign object.

Patients with SCI should be treated in neurological intensive care centers that specialize in such cases. To transfer and care for these patients, specialized trauma centers must be identified and established.

Rehabilitation is an important component of the healing process, and these patients benefit from intensive rehabilitation under the supervision of physiatrists, physiotherapists, and occupational therapists. Once the patient is ready to go home from the inpatient rehabilitation unit, rehabilitation will be maintained on an outpatient basis.

Several drugs have been tested to see whether they can help with SCI outcomes, however, the results haven't demonstrated any substantial improvements. The effects of nimodipine, gacyclidine, thyrotropin-releasing hormone, riluzole, gangliosides, minocycline, magnesium, and the acidic fibroblast growth factor have all been examined in trials. For the recent time, more study into these medications is needed, and high-dose steroids are the cornerstone of acute SCI treatment.

Spinal Cord Injury Complications

Urinary tract infections, pressure sores, deep vein thrombosis, autonomic dysreflexia, and chronic pain are all common sequelae of spinal cord injury.

Individuals with SCI at or above thoracic spinal level 6 (T6) experience autonomic dysreflexia. Orthostatic hypotension is a frequent problem of this condition. Orthostatic hypotension symptoms are typically difficult to treat. Abdominal binder, elastic stocking, peripheral vasoconstrictive drugs such as midodrine, and mineralocorticoids such as fludrocortisone can all help with symptoms. Increased salt consumption can also benefit volume expansion and symptom management. Pneumonia and sepsis are the major causes of death. Indirect expenses include reduced mobility, inability to work, and a substantial caregiver load.

Spinal Cord Injury Prognosis

Patients with spinal cord injuries have a bad prognosis. Sadly, there is no curative therapy for SCI. Only about 1.5% of people with SCI regain full function before being discharged from the hospital. Greater-level injuries result in more major impairment and a higher risk of complications, with higher-level injuries leading to more serious disability and higher complication rates. Patients with SCI have a much higher mortality rate in the first year after injury, and those who survive have a shorter life expectancy. Only 14% of those who complete the course go on to work, and less than half of those who complete it marry.

Conclusion

A spinal cord injury can change your life and make it tough to cope. People with spinal cord injuries, on the other hand, can take part in activities they enjoy and live a full and rewarding life with the help of healthcare staff, friends, and family.