Trauma rehabilitation

Epidemiology of traumatic spinal cord injury in the united states

The incidence of spinal cord injury is estimated to be approximately 40 new cases per million population per year, or roughly 12,000. The estimated prevalence in the United States is 265 million people. SCI primarily affects young adults. The average age at the time of injury has increased to 40.7 years. The percentage of persons older than 60 years at injury has increased from 4.7% in 1980 to 10.9% since 2000. Of the SCI reported to the national database, 80.7% occur in males. Since 2005, motor vehicle crashes have accounted for 40.5% of SCI cases reported. Falls are the next most common cause of SCI, followed by acts of violence and recreational activities. Since 2005, the most frequent neurological category is incomplete tetraplegia (39.5%), followed by complete paraplegia (22.1%), incomplete paraplegia (21.7%) and complete tetraplegia (16.3%).

Neurological classification

Determining the neurological level and the completeness of injury is the most accurate way of prognosticating recovery and functional outcome. Using the International Standards of Neurological and Functional Classification of Spinal Cord Injury, the examiner determines the motor and sensory level on the right and left and ascertains whether the injury is complete or incomplete.

Using standard dermatomes and myotomes defined by the American Spinal Injury Association (ASIA), motor level is defined as the most caudal segment to have a muscle grade of 3 ( Fig. 2 ). Five muscle groups are tested in both the upper and lower extremities. Each muscle group is supplied by two root levels, and each muscle group is graded from 0 to 5. Therefore, if the muscle grade is at least a 3 of 5, the proximal root is believed to be intact. The sensory level is defined as the most caudal dermatome to have normal sensation to pinprick and light touch. Specific testing points are defined by ASIA. In addition to defining the neurological level, the completeness of injury must be determined. Complete SCI results in no motor or sensory function preserved in the sacral segments (ASIA A). There are four incomplete levels of ASIA: B, C, D, and E. Incomplete SCI is defined as sparing of sensory and/or motor function below the neurological level that includes the sacral (S4–5) segments.

There are a number of incomplete spinal cord injury syndromes, including central cord syndrome, Brown-Séquard syndrome, anterior cord syndrome, dorsal column syndrome, cauda equina syndrome, and conus medullaris syndrome. Central cord syndrome occurs in the cervical cord and produces greater weakness in the upper extremities than lower extremities. Brown-Séquard syndrome is a lesion that produces ipsilateral motor and proprioceptive loss and contralateral loss of pain and temperature perception. Anterior cord syndrome causes variable loss of motor function, pain and temperature perception, while sparing proprioception. This is usually seen with injury to the anterior spinal artery in the thoracic level. Dorsal column syndrome is rare and would produce abnormal proprioception but preserved motor function and pain and temperature sensation. In Cauda equina syndrome, the lumbosacral roots are injured, since the spinal cord ends at approximately the L1–L2 level. This causes lower motor neuron symptoms, such as areflexic bladder, bowel incontinence, lower limb weakness, and sensory abnormalities. Conus medullaris syndrome involves injury to the end of the spinal cord. At this level, the lumbar and sacral roots are affected ( Table 1 ).

Acute medical management

A multicenter collaboration of spinal cord centers established the National Acute Spinal Cord Injury Study (NASCIS) to further delineate potential pharmacological options in acute spinal cord injuries. Three randomized controlled trials were conducted focusing on the effects of steroid administration in this patient population. Results of NASCIS 1, 2, and 3 are summarized in Table 2 .

NASCIS 1 randomized 330 patients to high-dose methylprednisolone with standard-dose methylprednisolone boluses followed by a 10-day course. There was no difference in neurological recovery at 6 months after injury. Mortality was increased in the high-dose bolus but was not statistically significant. NASCIS 2 included three arms—methylprednisolone 30 mg/kg bolus followed by infusion at 5.4 mg/kg/hour for 23 hours, naloxone, and placebo. Spinal cord injury patients in the methylprednisolone arm who received the bolus dose within 8 hours of injury had improved motor function and sensation at 6 months. NASCIS 3 randomized patients to receive methylprednisolone bolus and infusion for 24 hours or 48 hours and tirilazad mesylate for 48 hours. The authors concluded that steroids started within 3 hours of injury should be continued for 24 hours and injuries treated between 3 and 8 hours should receive a 48-hour course.

Efficacy postulated in the NASCIS 1, 2, and 3 trials has been questioned by more recent meta-analysis as well as subsequent critical review of the original NASCIS study design and data analysis. The use of steroids in the treatment of acute SCI can no longer be advocated as an evidence-based standard of care.

The degree of respiratory dysfunction after spinal cord injury is related to the neurological level and the completeness of injury. The level of pulmonary dysfunction increases concomitantly with the level of injury.

C1–C3 neurological levels will require ventilator support. The phrenic nerve (supplied by C3–C5 nerve roots) is intact on patients with a C5 neurological level and below. As the level descends from midcervical to lower cervical and then to thoracic, there will be greater innervation to abdominal and intercostal muscles—thereby making the work of breathing easier. The primary objective in early pulmonary management in SCI is to minimize secondary complications, which include hypoxemia, atelectasis, and aspiration. Aggressive pulmonary management to compensate for impaired clearing of secretions is often required.

Spinal shock refers to the temporary loss of all or most spinal reflexes activity below the level of injury. In neurogenic shock sympathetic activity is reduced or absent leading to bradycardia and hypotension. Volume expansion is the hallmark of neurogenic shock treatment followed by vasopressor support in refractory cases. After resuscitation, the use of elastic stockings, abdominal binders, adequate hydration, and gradual upright positioning are used to reduce the effects of orthostatic hypotension.

Bladder management is usually accomplished with an indwelling catheter, as the bladder is often initially areflexic. The goals of team bladder management are to allow the bladder to empty, prevent urinary retention, minimize urinary tract infections, and determine which methods facilitate independent bladder management. Methods may include use of an indwelling Foley catheter or placement of a suprapubic tube. Intermittent catheterization is appropriate for patients with use of their upper extremities.

Male patients who have reflex voiding and detrusor hyperreflexia may require a sphincterotomy procedure or pharmacological agents to reduce outflow resistance and allow the use of an external catheter. Some patients with incomplete spinal cord injuries will be incontinent. Urodynamic studies are useful at some point to help classify the neurogenic bladder in order to select adequate bladder management methods.

A bowel program should be established. Initially, a paralytic ileus is common. Patients may be placed on a stool softener and a daily or every-other-day suppository, with digital stimulation. This routine should be established about the same time each day. The goal is to prevent or minimize incontinence between bowel programs.

Deep venous thromboembolism (DVT) prevention is extremely important, as DVT and pulmonary embolism are major causes of morbidity and mortality in the SCI population. Sequential compression devices should be used, with or without elastic stockings, to improve lower extremity venous return. Such methods are contraindicated in patients with severe arterial insufficiency. Pharmacological prophylaxis should be initiated within the first 72 hours, when not contraindicated. Low-molecular-weight heparin is the current recommendation. Anticoagulation should be continued for 8 weeks in patients with uncomplicated complete motor impairments and for 12 weeks in complete motor injuries with other risk factors (lower limb fractures, history of thrombosis, cancer, heart failure, obesity, and age over 70). Vena cava filter placement is indicated in SCI patients with a contraindication for pharmacological prophylaxis.