Spinal cord injury

Spinal cord injury can be traumatic or nontraumatic, Posterior spinal artery syndrome Posterior spinal artery syndrome (PSAS), in which just the dorsal columns of the spinal cord are affected, is usually seen in cases of chronic myelopathy but can also occur with infarction of the posterior spinal artery. This rare syndrome causes the loss of proprioception and sense of vibration below the level of injury while motor function and sensation of pain, temperature, and touch remain intact. Usually posterior cord injuries result from insults like disease or vitamin deficiency rather than trauma. Tabes dorsalis, due to injury to the posterior part of the spinal cord caused by syphilis, results in loss of touch and proprioceptive sensation. Conus medullaris and cauda equina syndromes Conus medullaris syndrome is an injury to the end of the spinal cord the conus medullaris, located at about the T12–L2 vertebrae in adults. This region contains the S4–S5 spinal segments, responsible for bowel, bladder, and some sexual functions, so these can be disrupted in this type of injury. In addition, sensation and the Achilles reflex can be disrupted. Causes include tumors, physical trauma, and ischemia. Cauda equina syndrome may also be caused by central disc prolapse or slipped disc, infections such as epidural abscess, spinal haemorrhages, secondary to medical procedures and birth abnormalities. Cauda equina syndrome (CES) results from a lesion below the level at which the spinal cord ends. Descending nerve roots continue as the cauda equina at levels L2–S5 below the conus medullaris before exiting through intervertebral foraminae. Thus it is not a true spinal cord syndrome since it is nerve roots that are damaged and not the cord itself; however, it is common for several of these nerves to be damaged at the same time due to their proximity. CES can occur by itself or alongside conus medullaris syndrome. It can cause low back pain, weakness or paralysis in the lower limbs, loss of sensation, bowel and bladder dysfunction, and loss of reflexes. There may be bilateral sciatica with central disc prolapse and altered gait. Unlike conus medullaris syndrome, symptoms often occur only on one side of the body. The cause is often compression, e.g. by a ruptured intervertebral disk or tumor. Since the nerves damaged in CES are actually peripheral nerves because they have already branched off from the spinal cord, the injury has better prognosis for recovery of function: the peripheral nervous system has a greater capacity for healing than the central nervous system. ==Signs and symptoms==

Signs (observed by a clinician) and symptoms (experienced by a patient) vary depending on where the spine is injured and the extent of the injury. Dermatome A section of skin innervated through a specific part of the spine is called a dermatome, and injury to that part of the spine can cause pain, numbness, or a loss of sensation in the related areas. Paraesthesia, a tingling or burning sensation in affected areas of the skin, is another symptom. A person with a lowered level of consciousness may show a response to a painful stimulus above a certain point but not below it. Muscle function A group of muscles innervated through a specific part of the spine is called a myotome, and injury to that part of the spinal cord can cause problems with movements that involve those muscles. The muscles may contract uncontrollably (spasticity), become weak, or be completely paralysed. Spinal shock, loss of neural activity including reflexes below the level of injury, occurs shortly after the injury and usually goes away within a day. Priapism, an erection of the penis may be a sign of acute spinal cord injury. The specific parts of the body affected by loss of function are determined by the level of injury. Some signs, such as bowel and bladder dysfunction can occur at any level. Neurogenic bladder involves a compromised ability to empty the bladder and is a common symptom of spinal cord injury. This can lead to high pressures in the bladder that can damage the kidneys. ==Spinal cord injury locations==

Cervical spine Spinal cord injuries at the cervical vertebrae (neck) level result in full or partial tetraplegia, also called quadriplegia. Depending on the specific location and severity of trauma, limited function may be retained. Additional symptoms of cervical injuries include low heart rate, low blood pressure, problems regulating body temperature, and breathing dysfunction. If the injury is high enough in the neck to impair the muscles involved in breathing, the person may not be able to breathe without the help of an endotracheal tube and mechanical ventilator. Lumbosacral The effects of injuries at or above the lumbar or sacral regions of the spinal cord (lower back and pelvis) include decreased control of the legs and hips, genitourinary system, and anus. People injured below level L2 may still have use of their hip flexor and knee extensor muscles. Bowel and bladder function are regulated by the sacral region. It is common to experience sexual dysfunction after injury, as well as dysfunction of the bowel and bladder, including fecal and urinary incontinence. Thoracic In addition to the problems found in lower-level injuries, thorax (chest height) spinal lesions can affect the muscles in the trunk. Injuries at the level of T1 to T8 result in inability to control the abdominal muscles. Trunk stability may be affected; even more so in higher level injuries. The lower the level of injury, the less extensive its effects. Injuries from T9 to T12 result in partial loss of trunk and abdominal muscle control. Thoracic spinal injuries result in paraplegia, but function of the hands, arms, and neck are not affected. Autonomic dysreflexia One condition that occurs typically in lesions above the T6 level is autonomic dysreflexia (AD), in which the blood pressure increases to dangerous levels, high enough to cause potentially deadly stroke. It results from an overreaction of the system to a stimulus such as pain below the level of injury, because inhibitory signals from the brain cannot pass the lesion to dampen the excitatory sympathetic nervous system response. Signs and symptoms of AD include anxiety, headache, nausea, ringing in the ears, blurred vision, flushed skin, and nasal congestion. It can occur shortly after the injury or not until years later. Other autonomic functions may also be disrupted. For example, problems with body temperature regulation mostly occur in injuries at T8 and above. Neurogenic shock Another serious complication that can result from lesions above T6 is neurogenic shock, which results from an interruption in output from the sympathetic nervous system responsible for maintaining muscle tone in the blood vessels. Without the sympathetic input, the vessels relax and dilate. Neurogenic shock presents with dangerously low blood pressure, low heart rate, and blood pooling in the limbs—which results in insufficient blood flow to the spinal cord and potentially further damage to it. == Complications ==

Complications of spinal cord injuries include pulmonary edema, respiratory failure, neurogenic shock, and paralysis below the injury site. Muscle atrophy In the long term, the loss of muscle function can have additional effects from disuse, including muscle atrophy. Immobility also can lead to pressure sores, particularly in bony areas, requiring precautions such as extra cushioning and turning in bed every two hours (in the acute setting) to relieve pressure. In the long term, people in wheelchairs must shift periodically to relieve pressure. Another complication is pain, including nociceptive pain (indication of potential or actual tissue damage) and neuropathic pain, when nerves affected by damage convey erroneous pain signals in the absence of noxious stimuli. Spasticity, the uncontrollable tensing of muscles below the level of injury, occurs in 65–78% of chronic SCI. NHO the most frequent musculoskeletal complications of severe spinal cord injuries with reported incidence varying from 0.5 % to 53% but generally the reported incidence is between 6 and 25%. Recent metanalyses have has reported significant association with severity and completeness of the SCI, spasticity, presence of infections, presence of hip-pelvic trauma. The underlying mechanism by which NHO forms is not fully understood but has been studied in a mouse model of SCI-induced NHO. Neurogenic heterotopic ossficiation is thought to be caused by abnormal muscle repair following trauma. During normal muscle repair, muscle stem cells divide and differentiate to regenerate muscle fibres. This process is controlled by inflammatory cells and support muscle cell growth. A key step during normal muscle repair is the programmed cell death (apoptosis) triggered inflammatory cells to prevent the development of muscle fibrosis. However, following a spinal cord injury, fibro-adipogenic progenitors fail to undergo apoptosis and instead accumulate and differentiate into bone forming osteoblasts. The spinal cord injury stimulates the adrenal glands to release the glucocorticoid corticosterone into the circulation. Excessive corticosterone causes an exaggerated inflammation response in the injured muscle with excessive release of oncostatin M and interleukin-1β. Oncostatin M and interleukin-1 bind to their cognate receptors OSMR and IL1R1 expressed by muscle fibro-adipogenic progenitors which in turn promote their proliferation and osteogenic differentiation. In support of this model, treatment with glucocorticoid receptor antagonists such as mifepristone or relacorilant or conditional deletion of the glucocorticoid receptor gene strongly inhibit the development of NHO after SCI in this mouse model. This mechanism also explains why infections, particularly with gram-negative bacteria, are associated with higher incidence of NHO in victims of traumatic brain and spinal cord injuries. Lipopolysaccharides from gram-negative bacteria worsen NHO by binding to their receptor Toll-like receptor 4 expressed by macrophages and muscle fibro-adipogenic progenitors and further increase oncostatin M and interleukin-1β release by macrophages. ==Causes==

Spinal cord injuries are most often caused by physical trauma. Forces involved can be hyperflexion (forward movement of the head); hyperextension (backward movement); lateral stress (sideways movement); rotation (twisting of the head); compression (force along the axis of the spine downward from the head or upward from the pelvis); or distraction (pulling apart of the vertebrae). Traumatic SCI can result in contusion, compression, or stretch injury. Pre-existing asymptomatic congenital anomalies can cause major neurological deficits, such as hemiparesis, to result from otherwise minor trauma. In the U.S., motor vehicle accidents are the most common cause of SCIs; second are falls, then violence such as gunshot wounds, then sports injuries. Another study from Asia, found that the most common cause of the SCI is fall (31.70%) from various sites such as fall from roof-tops (9.75%), electric pole (7.31%), fall from tree (7.31%) etc. Whereas road traffic accidents count for 19.51%, firearm injuries (12.19%), slipped foot (7.31%) and sports injuries (4.87%). As a result of injury, 26.82%In some countries falls are more common, even surpassing vehicle crashes as the leading cause of SCI. The rates of violence-related SCI depend heavily on place and time. Of all sports-related SCIs, shallow water dives are the most common cause; winter sports and water sports have been increasing as causes while association football and trampoline injuries have been declining. Hanging can cause injury to the cervical spine, as may occur in attempted suicide. Military conflicts are another cause, and when they occur they are associated with increased rates of SCI. Another potential cause of SCI is iatrogenic injury, caused by an improperly done medical procedure such as an injection into the spinal column. SCI can also be of a nontraumatic origin. The percentage varies by locale, influenced by efforts to prevent trauma. Developed countries have higher percentages of SCI due to degenerative conditions and tumors than developing countries. In developed countries, the most common cause of nontraumatic SCI is degenerative diseases, followed by tumors; in many developing countries the leading cause is infection such as HIV and tuberculosis. SCI may occur in intervertebral disc disease, and spinal cord vascular disease. Spontaneous bleeding can occur within or outside of the protective membranes that line the cord, and intervertebral disks can herniate. Damage can result from dysfunction of the blood vessels, as in arteriovenous malformation, or when a blood clot becomes lodged in a blood vessel and cuts off blood supply to the cord. When systemic blood pressure drops, blood flow to the spinal cord may be reduced, potentially causing a loss of sensation and voluntary movement in the areas supplied by the affected level of the spinal cord. Congenital conditions and tumors that compress the cord can also cause SCI, as can vertebral spondylosis and ischemia. Multiple sclerosis is a disease that can damage the spinal cord, as can infectious or inflammatory conditions such as tuberculosis, herpes zoster or herpes simplex, meningitis, myelitis, and syphilis. ==Prevention==

Vehicle-related spinal cord injury is prevented with measures including societal and individual efforts to reduce driving under the influence of drugs or alcohol, distracted driving, and drowsy driving. Other efforts include increasing road safety (such as marking hazards and adding lighting) and vehicle safety, both to prevent accidents, such as routine maintenance and antilock brakes. There are also approaches mitigate the damage of crashes, such as head restraints, air bags, seat belts, and child safety seats. Falls can be prevented by making changes to the environment, such as nonslip materials and grab bars in bathtubs and showers, railings for stairs, child and safety gates for windows. Gun-related injuries can be prevented with conflict resolution training, gun safety education campaigns, and changes to the technology of guns, including trigger locks to improve their safety. Sports injuries can be prevented with changes to sports rules and equipment to increase safety, and education campaigns to reduce risky practices such as diving into water of unknown depth or head-first tackling in association football. ==Diagnosis==

A person's presentation in context of trauma or non-traumatic background determines suspicion for a spinal cord injury. The features are namely paralysis, sensory loss, or both at any level. Other symptoms may include incontinence. A radiographic evaluation using an X-ray, CT scan, or MRI can determine if there is damage to the spinal column and where it is located. X-rays are commonly available and can detect instability or misalignment of the spinal column, but do not give very detailed images and can miss injuries to the spinal cord or displacement of ligaments or disks that do not have accompanying spinal column damage. Thus when X-ray findings are normal but SCI is still suspected due to pain or SCI symptoms, CT or MRI scans are used. CT gives greater detail than X-rays, but exposes the patient to more radiation, and it still does not give images of the spinal cord or ligaments; MRI shows body structures in the greatest detail. Thus it is the standard for anyone who has neurological deficits found in SCI or is thought to have an unstable spinal column injury. Neurological evaluations to help determine the degree of impairment are performed initially and repeatedly in the early stages of treatment; this determines the rate of improvement or deterioration and informs treatment and prognosis. The ASIA Impairment Scale outlined above is used to determine the level and severity of injury. ==Management==

Pre-hospital treatment with use of a long spinal board The first stage in the management of a suspected spinal cord injury is geared toward basic life support and preventing further injury: maintaining airway, breathing, circulation, and restricting further motion of the spine. Spinal motion restriction In the emergency setting, most people who have been subjected to forces strong enough to cause SCI are treated as though they have instability in the spinal column and have spinal motion restricted to prevent damage to the spinal cord. Injuries or fractures in the head, neck, or pelvis as well as penetrating trauma near the spine and falls from heights are assumed to be associated with an unstable spinal column until it is ruled out in the hospital. Modern trauma care includes a step called clearing the cervical spine, ruling out spinal cord injury if the patient is fully conscious and not under the influence of drugs or alcohol, displays no neurological deficits, has no pain in the middle of the neck and no other painful injuries that could distract from neck pain. If these are all absent, no spinal motion restriction is necessary. If an unstable spinal column injury is moved, damage may occur to the spinal cord. The treatment for shock from blood loss is different from that for neurogenic shock, and could harm people with the latter type, so it is necessary to determine why someone is in shock. However it is also possible for both causes to exist at the same time. As there does not appear to be long term benefits and the medication is associated with risks such as gastrointestinal bleeding and infection its use is not recommended as of 2018. Surgery Surgery may be necessary, e.g. to relieve excess pressure on the cord, to stabilize the spine, or to put vertebrae back in their proper place. This type of surgery is often referred to as "Ultra-Early", coined by Burke et al. at UCSF. Sometimes a patient has too many other injuries to be a surgical candidate this early. However, in cases where a more conservative approach is chosen, bed rest, cervical collars, motion restriction devices, and optionally traction are used. Surgeons may opt to put traction on the spine to remove pressure from the spinal cord by putting dislocated vertebrae back into alignment, but herniation of intervertebral disks may prevent this technique from relieving pressure. Gardner-Wells tongs are one tool used to exert spinal traction to reduce a fracture or dislocation and to reduce motion to the affected areas. For people whose injuries are high enough to interfere with breathing, there is great emphasis on airway clearance during this stage of recovery. In patients with complete paraplegia (ASIA A), this applies to lesion heights between T12 and S5. In patients with incomplete paraplegia (ASIA B-D), orthoses are even suitable for lesion heights above T12. In both cases, however, a detailed muscle function test must be carried out to precisely plan the construction with an orthosis. ==Prognosis==

. Spinal cord injuries generally result in at least some incurable impairment even with the best possible treatment. The best predictor of prognosis is the level and completeness of injury, as measured by the ASIA impairment scale. The neurological score at the initial evaluation done 72 hours after injury is the best predictor of how much function will return. Most people with ASIA scores of A (complete injuries) do not have functional motor recovery, but improvement can occur. Most patients with incomplete injuries recover at least some function. Chances of recovering the ability to walk improve with each AIS grade found at the initial examination; e.g. an ASIA D score confers a better chance of walking than a score of C. The symptoms of incomplete injuries can vary and it is difficult to make an accurate prediction of the outcome. A person with a mild, incomplete injury at the T5 vertebra will have a much better chance of using his or her legs than a person with a severe, complete injury at exactly the same place. Of the incomplete SCI syndromes, Brown-Séquard and central cord syndromes have the best prognosis for recovery and anterior cord syndrome has the worst. People with nontraumatic causes of SCI have been found to be less likely to develop complete injuries and some complications such as pressure sores and deep vein thrombosis, and to have shorter hospital stays. Their scores on functional tests were better than those of people with traumatic SCI upon hospital admission, but when they were tested upon discharge, those with traumatic SCI had improved such that both groups' results were the same. In addition to the completeness and level of the injury, age and concurrent health problems affect the extent to which a person with SCI will be able to live independently and to walk. However, in general people with injuries to L3 or below will likely be able to walk functionally, T10 and below to walk around the house with bracing, and C7 and below to live independently. New therapies are beginning to provide hope for better outcomes in patients with SCI, but most are in the experimental/translational stage. One important predictor of motor recovery in an area is presence of sensation there, particularly pain perception. Most motor recovery occurs in the first year post-injury, but modest improvements can continue for years; sensory recovery is more limited. Recovery is typically quickest during the first six months. Spinal shock, in which reflexes are suppressed, occurs immediately after the injury and resolves largely within three months but continues resolving gradually for another 15. Sexual dysfunction after spinal injury is common. Problems that can occur include erectile dysfunction, loss of ability to ejaculate, insufficient lubrication of the vagina, and reduced sensation and impaired ability to orgasm. Despite this, many people learn ways to adapt their sexual practices so they can lead satisfying sex lives. Although life expectancy has improved with better care options, it is still not as good as the uninjured population. The higher the level of injury, and the more complete the injury, the greater the reduction in life expectancy. Mortality is very elevated within a year of injury. ==Epidemiology==

Worldwide, the number of new cases since 1995 of SCI ranges from 10.4 to 83 people per million per year. This wide range of numbers is probably partly due to differences among regions in whether and how injuries are reported. In North America, about 39 people per every million incur SCI traumatically each year, and in Western Europe, the incidence is 16 per million. In the United States, the incidence of spinal cord injury has been estimated to be about 40 cases per 1 million people per year or around 12,000 cases per year. In China, the incidence is approximately 60,000 per year. The estimated number of people living with SCI in the world ranges from 236 to 4187 per million. Estimates vary widely due to differences in how data are collected and what techniques are used to extrapolate the figures. Little information is available from Asia, and even less from Africa and South America. In Western Europe the estimated prevalence is 300 per million people and in North America it is 853 per million. It is estimated at 440 per million in Iran, 526 per million in Iceland, and 681 per million in Australia. In the United States there are between 225,000 and 296,000 individuals living with spinal cord injuries, and different studies have estimated prevalences from 525 to 906 per million. SCI is present in about 2% of all cases of blunt force trauma. Anyone who has undergone force sufficient to cause a thoracic spinal injury is at high risk for other injuries also. In 44% of SCI cases, other serious injuries are sustained at the same time; 14% of SCI patients also have head trauma or facial trauma. Other commonly associated injuries include chest trauma, abdominal trauma, pelvic fractures, and long bone fractures. Males account for four out of five traumatic spinal cord injuries. Most of these injuries occur in men under 30 years of age. The average age at the time of injury has slowly increased from about 29 years in the 1970s to 41. In Pakistan, spinal cord injury is more common in males (92.68%) as compared to females in the 20–30 years of age group with a median age of 40 years, although people from 12 to 70 years of age suffered from spinal cord injury Rates of injury are at their lowest in children, at their highest in the late teens to early twenties, then get progressively lower in older age groups; however rates may rise in the elderly. In Sweden between 50 and 70% of all cases of SCI occur in people under 30, and 25% occur in those over 50. While SCI rates are highest among people age 15–20, fewer than 3% of SCIs occur in people under 15. Neonatal SCI occurs in one in 60,000 births, e.g. from breech births or injuries by forceps. The difference in rates between the sexes diminishes in injuries at age 3 and younger; the same number of girls are injured as boys, or possibly more. Another cause of pediatric injury is child abuse such as shaken baby syndrome. For children, the most common cause of SCI (56%) is vehicle crashes. High numbers of adolescent injuries are attributable in a large part to traffic accidents and sports injuries. For people over 65, falls are the most common cause of traumatic SCI. The elderly and people with severe arthritis are at high risk for SCI because of defects in the spinal column. In nontraumatic SCI, the gender difference is smaller, the average age of occurrence is greater, and incomplete lesions are more common. ==History==

, who provided the earliest known description of spinal cord injury It was not until the second half of the century that breakthroughs in imaging, surgery, medical care, and rehabilitation medicine contributed to a substantial improvement in SCI care. The relative incidence of incomplete compared to complete injuries has improved since the mid-20th century, due mainly to the emphasis on faster and better initial care and stabilization of spinal cord injury patients. ==Research directions==

s seen under phase contrast microscope at 63-times magnification) Scientists are investigating various avenues for treatment of spinal cord injury. Therapeutic research is focused on two main areas: neuroprotection and neuroregeneration. showing that after 90 days, 2 out of 4 subjects had already improved two motor levels and had thus already achieved its endpoint of 2/5 patients improving two levels within 6–12 months. Six-month data was expected in January 2017. Another type of approach is tissue engineering, using biomaterials to help scaffold and rebuild damaged tissues. and in some cases to enable walking to some degree bypassing the injury. In 2014, Darek Fidyka underwent pioneering spinal surgery that used nerve grafts, from his ankle, to bridge the gap in his severed spinal cord and olfactory ensheathing cells (OECs) to stimulate the spinal cord cells. The surgery was performed in Poland in collaboration with Prof. Geoff Raisman, chair of neural regeneration at University College London's Institute of Neurology, and his research team. The OECs were taken from the patient's olfactory bulbs in his brain and then grown in the lab, these cells were then injected above and below the impaired spinal tissue. In March 2025, researchers reported that a paralyzed man stood for the first time after being injected of neural stem cells to treat his spinal cord injury. The first-of-its-kind study, which is not yet peer-reviewed, is encouraging scientists to consider if reprogrammed stem cells can be used in the future to treat people who are fully paralyzed. Reprogrammed cells are adult cells that are reverted to an embryonic-like state, from which they can be coaxed to develop into other cell types. ==See also==