SPINAL CORD INJURY

BRIEF OVERVIEW & FUNCTIONAL IMPLICATIONS

DEFINITION

Spinal cord injury (SCI) is an insult to the spinal cord resulting in a change, either temporary or permanent, in the cord’s motor, sensory, or autonomic function.

EPIDEMIOLOGY/PREVALENCE

In a study done in 2018, it was found that the most common mode of injury was fall from height (59.64%) followed by RTA (35.08%). Most common affected age group in this study was 20–39 years followed by 50–59 years age group. Cervical spine injury was the most common (52.63%) followed by thoracic (19.29%) spine. Most common injury found was fracture dislocation of C5-C6 level. Most common associated injury is head trauma (10.52 %) followed by chest injury and 82.45% cases had no associated trauma. Average period of hospital stay was 22.83 days with maximum period of stay was 111 days. The epidemiology of spinal injuries in Sikkim & North Eastern India is different from rest of the India and other developing countries. In present study most common cause of spine injury was fall from height followed by motor vehicle accidents. RTA was the main cause in younger age group and fall from height was more common in elderly group.

As per report of the International Conference, the incidence of spinal injury was estimated at 15 new cases per million per year in India. This translates into 15,000 new cases per year and with a backlog of ten years, the prevalence exceeds 0.15 million.

CLASSIFICATION

According to ASIA, there are certain terms that were coined to classify spinal cord injury & created the international standards for neurological classification of SCI. The terms are:

1. Neurological level - it is defined as the most caudal level of the spinal cord with normal motor & sensory function on both the left & right sides of the body.
2. Motor level- most caudal segment with normal motor function.
3. Sensory level- most caudal segment with normal sensory function.
4. Zones of partial preservation- if an individual has motor or sensory function below neurological level but no function is present at S4 & S5, then the areas of intact motor/sensory function below the neurological level are termed as zones of partial preservation.

ASIA scale

SYNDROMES IN SCI

Central cord syndrome- the central cord syndrome is the most common form of incomplete cord injury and almost always occurs as a consequence of a traumatic injury. It leads to motor deficits that are more pronounced in the upper extremities as compared to the lower extremities, as well as bladder dysfunction with varying sensory deficits below the level of injury. it is a result of hyperextension injury of spine. The upper limbs tracts are medial as compared to the lower extremity while sacral segments being the most lateral, So when compression occurs in cervical cords, the central portion becomes more effected then the outer segments due to the external pressure.

Pain and temperature sensations are typically affected, but also the sensation of light touch can be impaired. The most common sensory deficits are found in a “cape-like” distribution across their upper back and down their posterior upper extremities. Improvement usually occurs in ascending fashion motor leg function appears to comes first, then bladder control and arms. Hand function appears to comes at last.

Anterior cord syndrome- it is an incomplete cord syndrome that predominantly affects the anterior 2/3 of the spinal cord, characteristically resulting in motor paralysis below the level of the lesion as well as the loss of pain and temperature at and below the level of the lesion. The patient presentation typically includes these two findings; however, there is variability depending on the portion of the spinal cord affected. Other findings include back pain, or autonomic dysfunction such as hypotension, neurogenic bowel or bladder, and sexual dysfunction. Preservation of modalities carried by dorsal columns i.e. vibration, proprioception, 2-point discrimination. The severity of motor dysfunction can vary, typically resulting in paraplegia or quadriplegia.

This syndrome is caused by compression of the anterior spinal artery, which results in anterior cord ischemia or direct compression of the anterior cord. It is associated with burst fractures of the spinal column with fragment retropulsion caused by axial compression.

Brown-Sequard syndrome-Brown Sequard syndrome is an incomplete pattern of injury showing a hemi-section of the spinal cord which results in weakness and paralysis on one side of the damage and loss of pain and temperature sensations on the opposite side. This depends on the site of injury which can also involve the cervical or sympathetic thoracic trunk resulting in Horner’s syndrome. It is also known as the hemi-section of the spinal cord.

Traumatic injuries are far more common. Gunshot wounds, stabbings, motor vehicle accidents, blunt trauma or a fractured vertebra from a fall could be among the causes. To a lesser extent, Brown-Séquard Syndrome can result from a vast variety of non-traumatic causes including vertebral disc herniation, cysts, cervical spondylosis, tumors, multiple sclerosis, and cystic disease, radiation, decompression sickness.

Posterior cord syndrome- it can occur as a result of posterior spinal artery injury resulting in posterior cord ischemia or infarction. Proprioception and vibration sensation loss occur(below injury level). Motor Strength as well as pain and Temperature sensation are spared.

Cauda equina syndrome- The British Association of Spinal Surgeons (BASS) present a definition that is useful;

‘A patient presenting with acute back pain and/or leg pain…… with a suggestion of a disturbance of their bladder or bowel function and/or saddle sensory disturbance should be suspected of having a CES. Most of these patients will not have critical compression of the cauda equina. However, in the absence of reliably predictive symptoms and signs, there should be a low threshold for investigation with an emergency scan.

Cauda equina syndrome results from compression of the spinal cord and nerves/nerve roots arising from L1-L5 levels. The most common cause of compression in 45% of CES is a herniated lumbar intervertebral disc. Weakness, tingling, or numbness in the legs, and/or feet on one or both sides of the body is a common symptom. Lower body weakness or numbness may make it difficult to walk or stand. it is a LMN disorder & asymmetrical.

Altered sensation in the “saddle region,” or saddle anesthesia. The saddle region is the area of the body that would be in contact with a saddle when sitting on a horse. This region includes the groin, the buttocks and genitals, and the upper inner thighs. With cauda equina syndrome, all or parts of this region may have neurological symptoms of numbness, tingling, and/or weakness.

conus medullaris syndrome- The conus medullaris is the terminal end of the spinal cord, which typically occurs at the L1 vertebral level in the average adult. Conus medullaris syndrome (CMS) results when there is compressive damage to the spinal cord. It typically causes back pain and bowel and bladder dysfunction & saddle anaesthesia, spastic below the level of lesion flaccid weakness at the level of the lesion, and bilateral sensory loss. it has symmetrical involvement.

SPINAL SHOCK- what is it & phases

Spinal shock refers to a clinical syndrome characterized by the loss of reflex, motor and sensory function below the level of injury.

Phases:-

1. Areflexia(0–1 day)- The first phase of spinal shock occurs from 0 to 24h postinjury. Caudal to complete SCI, DTRs such as the Ankle jerk and the Knee jerk are initially absent, and muscles are flaccid. During this time, poly synaptic reflexes such as the Bulbocavernous, the Anal wink, and the Cremasteric reflex begin to recover. Thus, the absence of all reflexes is uncommonly observed during the initial 24 h. Delayed plantar response is also one of the first reflexes to recover.
2. Initial reflex return- This phase of spinal shock lasts for 1 – 3 days post-injury. Cutaneous reflexes become stronger during this time. DTR’s still remain absent. Some studies have found that in older individuals, DTR’s & babinski sign can occur during this phase due to pre-existing myelopathy.
3. Early Hyperreflexia- this phase lasts 4–30 days, DTR’s begin to emerge with ankle jerk appearing before knee jerk. Babinski sign also recovers during this time. Patients with higher cord injuries may also start experiencing autonomic dysreflexia below the level of injury. Timing for reflex return is variable. Delayed plantar response starts decreasing or fading away.
4. Spasticity/Hyperreflexia – this phase lasts from 1 month – 12 months. The DPR has disappeared mostly. Cutaneous reflexes, DTRs, and the Babinski sign become hyperactive and respond to minimal stimuli. This phase also sees emergence of reflex neurogenic bladder, extensor spasms, orthostatic hypotension & autonomic dysreflexia.

Functional implications according to level of spinal cord injury

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