Injury to the Spinal Cord

Overview

Spinal cord injury (SCI) is damage to the spinal cord that results in temporary or permanent changes in its function. The spinal cord is a bundle of nerves that carries messages between the brain and the rest of the body, running from the base of the brain down through the spine. When injured, the ability of the spinal cord to transmit these messages is compromised, leading to loss of mobility, sensation, and autonomic function below the level of injury.

The severity and location of a spinal cord injury determine its impact on an individual's functional abilities. Injuries are classified as complete or incomplete. A complete injury means there is no function below the level of the injury - no sensation and no voluntary movement on both sides of the body. An incomplete injury means that some function remains below the primary level of the injury. A person with an incomplete injury may be able to move one limb more than another, may have more functioning on one side of the body, or may have sensation in parts of the body that cannot be moved.

Approximately 17,000 new spinal cord injuries occur each year in the United States, with about 282,000 people currently living with SCI. The injury profoundly impacts not just physical function but also psychological well-being, independence, and quality of life. However, advances in acute care, rehabilitation, and assistive technology have significantly improved outcomes. Many people with spinal cord injuries lead productive, fulfilling lives, though they face ongoing challenges related to mobility, health maintenance, and accessibility. Understanding SCI is crucial for patients, families, and caregivers to optimize recovery and adaptation to life after injury.

Symptoms

The symptoms of spinal cord injury vary dramatically depending on the severity and location of the injury. Higher injuries generally result in more extensive paralysis and loss of function, while the completeness of injury determines whether any function remains below the injury level.

Level-Specific Symptoms

The location of injury determines which body functions are affected. Cervical (neck) injuries result in quadriplegia/tetraplegia, affecting arms, hands, trunk, legs, and pelvic organs. C1-C4 injuries may affect breathing and require ventilator support. C5 injuries typically preserve shoulder and bicep control but not wrist or hand function. C6 injuries generally allow wrist extension but no hand function. C7-C8 injuries usually permit arm straightening and some hand function. Thoracic (chest level) injuries result in paraplegia, affecting the trunk and legs but preserving arm and hand function. Upper thoracic (T1-T8) injuries affect trunk control and abdominal muscles. Lower thoracic (T9-T12) injuries allow good trunk control and abdominal muscle function. Lumbar and sacral injuries affect the hips and legs with decreasing severity, often preserving some leg movement and potentially allowing walking with aids.

Secondary Complications

Beyond the immediate effects of paralysis and sensory loss, spinal cord injury leads to numerous secondary complications. Respiratory problems including pneumonia and breathing difficulties are common, especially with high injuries. Cardiovascular issues such as blood pressure instability, blood clots, and reduced cardiovascular fitness develop due to immobility. Spasticity causes muscle stiffness and involuntary contractions. Pressure sores result from prolonged pressure on skin without sensation. Chronic pain affects up to 80% of people with SCI. Sexual dysfunction and fertility issues impact quality of life. Osteoporosis and increased fracture risk develop from lack of weight-bearing. Depression and anxiety are common psychological responses. Autonomic dysreflexia in injuries above T6 causes dangerous blood pressure spikes triggered by stimuli below the injury level.

Causes

Spinal cord injuries result from damage to the vertebrae, ligaments, disks of the spinal column, or the spinal cord itself. Understanding the mechanisms of injury helps in prevention efforts and immediate management of suspected spinal trauma.

Traumatic Causes

Traumatic spinal cord injury results from a sudden blow or impact to the spine that fractures, dislocates, crushes, or compresses one or more vertebrae. Motor vehicle accidents account for approximately 38% of spinal cord injuries, remaining the leading cause. These include car, motorcycle, and pedestrian accidents, with risk increased by not wearing seatbelts or helmets. Falls cause about 30% of SCIs, particularly in older adults over 65 where they account for the majority of injuries. Violence, primarily gunshot wounds and knife injuries, causes about 14% of SCIs, with rates varying significantly by geographic location. Sports and recreation injuries account for 9%, including diving into shallow water, football, rugby, gymnastics, and extreme sports. The mechanism of injury often involves hyperextension, hyperflexion, compression, rotation, or penetration of the spine.

Non-Traumatic Causes

Non-traumatic spinal cord injuries develop from various medical conditions rather than external trauma. Tumors, both primary and metastatic, can compress the spinal cord or infiltrate nerve tissue. Infections such as spinal epidural abscess, meningitis, or tuberculosis (Pott's disease) can damage the cord through inflammation and compression. Vascular disorders including spinal cord stroke (infarction), arteriovenous malformations, and bleeding disorders can interrupt blood supply to cord tissue. Inflammatory conditions like transverse myelitis and multiple sclerosis cause demyelination and nerve damage. Degenerative conditions such as severe spinal stenosis, disk herniation, and spondylosis can gradually compress the cord. Congenital conditions including spina bifida and tethered cord syndrome may cause progressive neurological deterioration. Medical procedures, though rare, can result in iatrogenic injury during spinal surgery or epidural injections.

Pathophysiology of Injury

Understanding how spinal cord damage occurs helps explain treatment approaches and prognosis. Primary injury happens at the moment of trauma through mechanical forces that damage nerve cells and blood vessels. This includes direct compression, shearing forces, and laceration of neural tissue. Secondary injury develops over hours to days after the initial trauma through a cascade of cellular and molecular events. This involves inflammation and swelling that further compresses the cord, loss of blood flow (ischemia) leading to cell death, release of toxic chemicals from damaged cells, formation of free radicals causing oxidative damage, and excessive release of neurotransmitters causing excitotoxicity. The zone of injury typically extends beyond the initial damage site. Understanding this two-phase process has led to treatments aimed at limiting secondary injury through early intervention, including prompt surgical decompression, blood pressure management, and anti-inflammatory medications.

Risk Factors

While spinal cord injury can happen to anyone, certain factors significantly increase the risk. Understanding these risk factors helps in developing targeted prevention strategies and identifying high-risk populations who may benefit from additional safety measures.

Demographic Risk Factors

Age plays a significant role in SCI risk, with a bimodal distribution showing peaks in young adults and the elderly. Young adults aged 16-30 face the highest risk, primarily from motor vehicle accidents and sports injuries. After age 65, fall-related SCIs increase dramatically, now representing the leading cause in this age group. Gender is a major factor, with males accounting for approximately 80% of new spinal cord injuries. This disparity is attributed to higher participation in risky activities, dangerous occupations, and violent encounters. Socioeconomic factors also influence risk, with lower income associated with higher rates of violence-related SCI and reduced access to safety equipment. Geographic location matters, with rural areas showing higher rates of vehicle-related injuries and urban areas having more violence-related SCIs.

Behavioral and Lifestyle Factors

Certain behaviors dramatically increase SCI risk. Alcohol and drug use are involved in approximately 25% of spinal cord injuries, impairing judgment and coordination. Risk-taking behavior, including speeding, not wearing seatbelts or helmets, and participating in extreme sports without proper training increases vulnerability. Occupational hazards affect construction workers, military personnel, law enforcement, and professional athletes who face elevated risk. Diving into unknown water bodies causes 10% of sports-related SCIs, often resulting in devastating cervical injuries. Contact sports, particularly American football and rugby, carry inherent risks despite protective equipment. Poor physical conditioning and inadequate warm-up before activities increase injury susceptibility. Previous neck or back injuries may predispose to future SCI through weakened spinal structures.

Medical Risk Factors

Pre-existing medical conditions can increase vulnerability to spinal cord injury or predispose to non-traumatic SCI. Osteoporosis weakens vertebrae, making them susceptible to compression fractures from minor trauma. Rheumatoid arthritis and ankylosing spondylitis cause spinal instability and increased fracture risk. Cancer patients face risk from metastatic disease and weakened bones from treatment. Genetic conditions like Ehlers-Danlos syndrome cause connective tissue weakness. Vitamin D deficiency contributes to bone weakness. Previous spinal surgery may create areas of vulnerability. Elderly individuals often have multiple risk factors including osteoporosis, balance problems, medication effects, and muscle weakness. Understanding medical risk factors helps identify patients who need extra precautions and may benefit from fall prevention programs, bone density screening, and medication review.

Diagnosis

Prompt and accurate diagnosis of spinal cord injury is critical for determining appropriate treatment and predicting outcomes. The diagnostic process begins at the scene of injury and continues through emergency department evaluation and specialized imaging studies.

Initial Assessment

The diagnostic process begins with trauma scene assessment and stabilization. Emergency responders evaluate mechanism of injury, maintain spinal immobilization, and assess airway, breathing, and circulation. The initial neurological examination includes checking consciousness level and orientation, motor function in all limbs, sensation to light touch and pinprick, reflexes including deep tendon and pathological reflexes, and signs of spinal shock (flaccid paralysis, absent reflexes). The ASIA (American Spinal Injury Association) Impairment Scale provides standardized assessment, classifying injuries from A (complete) to E (normal function). Careful documentation of the neurological level of injury and zone of partial preservation helps track changes over time. Serial examinations are crucial as the initial assessment may be complicated by spinal shock, which can mask the true extent of injury.

Imaging Studies

Modern imaging is essential for visualizing spinal injury and planning treatment. Plain X-rays provide initial screening for obvious fractures and alignment abnormalities but may miss up to 20% of injuries. CT (Computed Tomography) scan is the gold standard for evaluating bony injury, showing fractures, dislocations, and bone fragments with excellent detail. Multidetector CT with reconstructions provides comprehensive spine visualization within minutes. MRI (Magnetic Resonance Imaging) is crucial for evaluating the spinal cord itself, showing cord compression, hemorrhage, edema, and ligamentous injury. MRI helps predict prognosis - presence of cord hemorrhage suggests poorer outcomes. It also identifies disc herniation, epidural hematomas, and ligamentous instability not visible on CT. The timing of MRI remains debated, but most centers perform it within 48 hours of injury. Advanced imaging like DTI (Diffusion Tensor Imaging) shows promise for evaluating white matter tract integrity.

Additional Diagnostic Tests

Beyond structural imaging, several tests help assess function and guide treatment. Electrophysiological studies including somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) can assess pathway integrity when clinical examination is limited. These help distinguish complete from incomplete injuries and may detect subclinical preservation of function. Urodynamic studies evaluate bladder function and guide management strategies. Pulmonary function tests assess respiratory muscle strength in cervical injuries. Blood tests check for complications including electrolyte imbalances, infection markers, and coagulation status. Vascular imaging like CT or MR angiography may be needed if vertebral artery injury is suspected, particularly with cervical fractures. Bone density testing helps assess fracture risk for rehabilitation planning. Psychological assessment screens for depression, anxiety, and adjustment disorders that commonly accompany SCI.

Treatment Options

Treatment of spinal cord injury involves immediate stabilization, acute medical and surgical management, and comprehensive rehabilitation. The goals are to prevent further damage, maximize neurological recovery, and optimize function and quality of life.

Emergency and Acute Care

Immediate treatment focuses on preventing secondary injury and stabilizing vital functions. Pre-hospital care includes spinal immobilization using backboards and cervical collars, airway management with careful intubation if needed, and blood pressure support to maintain spinal cord perfusion. In the emergency department, high-dose methylprednisolone may be considered if started within 8 hours of injury, though its use remains controversial. Blood pressure is maintained with MAP (mean arterial pressure) goals of 85-90 mmHg for 7 days to ensure adequate cord perfusion. Respiratory support ranges from supplemental oxygen to mechanical ventilation for high cervical injuries. DVT prophylaxis begins immediately given the high risk of blood clots. Bladder catheterization prevents retention and autonomic dysreflexia. Temperature regulation is crucial as patients often lose thermoregulation. Early nutrition support prevents catabolism and pressure sores.

Surgical Treatment

Surgery aims to decompress the spinal cord and stabilize the spine. Timing remains debated, but early surgery within 24 hours may improve outcomes in certain cases. Surgical goals include removing bone fragments, herniated disks, or hematomas compressing the cord, realigning the spine, and stabilizing with fusion, instrumentation (rods, screws, plates), or both. Anterior approaches access the front of the spine for cervical injuries, while posterior approaches are used for most thoracic and lumbar injuries. Combined approaches may be necessary for complex injuries. Minimally invasive techniques reduce tissue damage when appropriate. Post-operative care includes monitoring for complications, pain management, and early mobilization when safe. Some patients require staged procedures to address all aspects of their injury. The decision for surgery considers injury pattern, neurological status, overall health, and associated injuries.

Rehabilitation

Rehabilitation begins in the acute care setting and continues for months to years. The comprehensive team includes physiatrists, physical therapists, occupational therapists, nurses, psychologists, social workers, and other specialists. Physical therapy focuses on strengthening preserved muscles, maintaining joint flexibility, learning wheelchair skills, and gait training when appropriate. Occupational therapy addresses activities of daily living, adaptive equipment use, home and vehicle modifications, and vocational planning. Specialized programs address bladder management through intermittent catheterization or indwelling catheters, bowel programs to prevent incontinence and constipation, skin care to prevent pressure sores, sexuality and fertility counseling, and pain management using medications, procedures, and alternative therapies. Assistive technology from wheelchairs to computer interfaces maximizes independence. Psychological support helps adjustment to disability. Peer mentoring connects patients with others living successfully with SCI.

Emerging and Experimental Treatments

Research continues into treatments to restore function after SCI. Stem cell therapy shows promise in early trials, with various cell types being investigated including embryonic, induced pluripotent, and mesenchymal stem cells. Epidural stimulation has enabled some patients with complete injuries to regain voluntary movement when combined with intensive training. Brain-computer interfaces allow direct brain control of assistive devices and show potential for bypassing injury sites. Nerve transfer surgery reroutes functioning nerves to restore specific movements. Drug therapies target various aspects of injury including anti-NOGO antibodies to promote regeneration, chondroitinase to break down scar tissue, and riluzole to protect neurons. Exoskeletons provide powered walking for exercise and mobility. Functional electrical stimulation activates paralyzed muscles for exercise and function. While no treatment currently cures SCI, combining approaches may maximize recovery. Patients should discuss clinical trial opportunities with their physicians.

Prevention

Prevention remains the most effective approach to reducing the devastating impact of spinal cord injuries. Public health initiatives, safety regulations, and individual precautions have successfully reduced SCI incidence in many areas.

Vehicle Safety

Since motor vehicle accidents cause the most SCIs, vehicle safety is paramount. Always wear seatbelts properly positioned across the chest and pelvis - they reduce serious injury risk by 50%. Ensure children use age-appropriate car seats and boosters until they properly fit adult seatbelts. Never drive under the influence of alcohol or drugs, which are factors in 25% of SCI-related crashes. Avoid distracted driving including phone use, eating, or adjusting controls while moving. Follow speed limits and adjust for weather conditions. Maintain vehicles properly, especially brakes, tires, and safety systems. Motorcyclists should always wear DOT-approved helmets and protective gear. Choose vehicles with high safety ratings and features like electronic stability control. Support graduated licensing programs for teen drivers. Advocate for improved road design including barriers, better lighting, and clear signage.

Fall Prevention

Falls cause increasing SCIs, especially in older adults. Home modifications significantly reduce risk: install grab bars in bathrooms, handrails on all stairs, adequate lighting especially on stairs and in hallways, and non-slip surfaces in showers and on steps. Remove tripping hazards like loose rugs, cords, and clutter. Arrange furniture to create clear pathways. Medical management includes regular vision checks and updating prescriptions, reviewing medications that affect balance or cause dizziness, treating conditions affecting balance like inner ear problems or neuropathy, and maintaining bone health through calcium, vitamin D, and exercise. Stay physically active with balance and strength training. Use assistive devices like canes or walkers when needed without pride preventing their use. Wear proper footwear with non-slip soles. Be extra cautious on ladders, using stabilizers and having someone spot you.

Sports and Recreation Safety

Athletic activities require proper precautions to prevent catastrophic injuries. Water safety is crucial - never dive into unknown water or water less than 9 feet deep, check depth and obstacles before diving, and enter water feet first when unsure. Learn proper diving technique from qualified instructors. In contact sports, use proper protective equipment including well-fitted helmets and padding. Learn and practice proper tackling and blocking techniques. Follow return-to-play protocols after any head or neck injury. Ensure qualified medical personnel are present at games and practices. For recreational activities, wear appropriate safety gear including helmets for cycling, skiing, and skateboarding. Take lessons from qualified instructors before attempting new sports. Know your limits and build skills gradually. Warm up properly before activities. Avoid extreme sports when fatigued or under the influence. Support rule changes that improve safety without eliminating reasonable sporting activities.

When to See a Doctor

Recognizing potential spinal cord injury and responding appropriately can mean the difference between recovery and permanent disability. Understanding when to seek emergency care versus routine evaluation helps ensure proper treatment.

Call 911 immediately for: Any trauma with potential spine injury - assume spine injury after falls from height, vehicle accidents, or head trauma until proven otherwise. Signs of acute SCI including inability to move arms or legs, numbness or tingling in extremities, loss of bladder or bowel control, difficulty breathing, severe neck or back pain after trauma, or obvious deformity of the spine. Altered consciousness after trauma as patients may not feel pain with severe injury. Multiple trauma victims as associated injuries are common. Never move someone with suspected spinal injury unless they're in immediate danger (fire, drowning). Stabilize the head and neck while waiting for emergency services.

Seek urgent medical evaluation for: Progressive weakness in arms or legs developing over hours to days, new onset of dropping objects or difficulty walking, loss of bowel or bladder control without trauma, severe back or neck pain with neurological symptoms, or numbness spreading up the body. These may indicate non-traumatic spinal cord compression from tumor, infection, or disk herniation requiring prompt diagnosis and treatment. Band-like pain around the trunk at a specific level suggests cord compression. Sexual dysfunction of sudden onset may indicate spinal pathology.

Schedule prompt evaluation for: Chronic neck or back pain with intermittent numbness or weakness, difficulty with fine motor tasks like buttoning clothes or writing, balance problems or frequent falls, changes in bowel or bladder habits, or persistent pain after minor trauma. These symptoms may indicate developing spinal stenosis, disk disease, or other conditions that could lead to cord injury if untreated. Early intervention may prevent progression to irreversible damage. Bring imaging studies from other facilities to avoid repeat radiation exposure. Document symptom patterns including triggers and relieving factors to aid diagnosis.