What is Corticospinal Tract Lesion?
The corticospinal tract is a pathway in the spine that is vital for voluntary movements of the body from the neck to the feet. It begins in a part of the brain called the primary motor cortex, in an area filled with pyramid-shaped nerve cells. The nerve fibers from these cells travel through several areas in the brain before reaching the spinal cord. Here, most of these nerve fibers cross over, making the left side of the brain control the right side of the body, and vice versa. However, a few nerve fibers stay on the same side. These form the anterior corticospinal tract.
The nerve fibers go into the spinal cord where they connect to lower motor neurons, which are cells that send signals to the muscles, causing them to contract. While the anterior corticospinal tract helps with controlling muscles in the middle of the body, the lateral corticospinal tract carries most of the information that lets the body move.
If the lateral corticospinal tract gets damaged, it can lead to several symptoms such as paralysis (inability to move), paresis (decreased muscle strength), and hypertonia (increased muscle tone) in the muscles located below the site of damage. It can get hurt in numerous ways, with the most common injuries being conditions known as central cord syndrome, Brown-Sequard syndrome, and anterior spinal cord syndrome.
What Causes Corticospinal Tract Lesion?
Spinal cord injuries can happen for a variety of reasons, including accidents, blood flow problems, or disease. For instance, Central Cord Syndrome affects the middle part of the spinal cord and typically happens when the neck is over-extended. This typically happens in situations like shaken baby syndrome, car accidents, or high-impact sports like football.
Another condition is Anterior Spinal Cord Syndrome, which happens when the anterior spinal artery is damaged or blocked. This artery brings blood to the front 2/3 of the spinal cord. Damage can be caused by things like blood clots or other blockages. One area that’s particularly prone to injury is the artery of Adamkiewcz, which branches off from the aorta — a major blood vessel in the heart. Due to its location, this artery is also likely to be damaged during certain surgical procedures, so doctors try to identify and protect it during operations. Other causes of Anterior Spinal Cord Syndrome could be diseases that clog arteries, nerve-muscle diseases, multiple sclerosis, or infections like West Nile virus or polio.
Brown-Sequard Syndrome is another type of spinal cord condition, which happens when one side of the spinal cord gets injured. This kind of injury often happens because of trauma like gunshot or stabbing wounds, car accidents, or spine fractures caused by falls. Causes could also include things like slipped discs in the spine, a type of arthritis in the spine called cervical spondylosis, tumors, multiple sclerosis, decompression sickness from diving, cystic diseases, or infections like meningitis, tuberculosis, or shingles.
Risk Factors and Frequency for Corticospinal Tract Lesion
Central cord syndrome primarily affects two age groups: the young and the elderly. It’s seen more often in males and accounts for 9.0% of adult spinal cord injuries and 6.6% of those in children. People with neck narrowing (cervical stenosis) and older people with spinal diseases are especially susceptible. However, it’s also common in younger patients with neck fractures, disk herniations, or if they are victims of the ‘shaken baby’ syndrome.
Anterior spinal cord syndrome is usually seen in adults due to complications after surgery. It’s most commonly observed after surgeries near the back of the abdomen (retroperitoneal surgeries) or after spine surgeries.
- Brown-Sequard syndrome is a rare condition which accounts for about 2 to 4% of spinal cord injuries.
- Each year, about 11,000 new cases are reported in the United States.
- It is most commonly caused by penetrating trauma.
Signs and Symptoms of Corticospinal Tract Lesion
If someone suffers a spinal cord injury, doctors need to figure out how serious the injury is. If the injury is in the neck area, the patient’s head and neck should be kept still during the initial evaluation. This helps to prevent further harm to the spinal cord. The check-up should include an assessment of all the main functions of the spinal cord. These functions include things like movement control, sense of touch, body position awareness, body self-regulation, and the ability to feel pain, temperature, and light touch.
Doctors typically test a patient’s feeling (or sensory function) for touch and pain by touching different parts of the patient’s body with a dull or sharp object. They can also examine how well the brain communicates with the body’s muscles by checking muscle stiffness and involuntary contractions for the arm and leg muscles. They evaluate the patient’s muscle strength and function by asking them to move different muscle groups against resistance.
A few tests like the finger-to-nose test, the rapid alternating movements test, or the Romberg test can be done to evaluate the patient’s body position awareness. If the patient can walk, their gait or the way they walk can give clues about their motor skills and coordination.
An injury at the lower part of the backbone near the waist, can affect the patient’s bladder and bowel control. In such cases, the doctor can check the patient’s rectal muscle tone to understand the level of impact on the body’s automatic functions.
Testing for Corticospinal Tract Lesion
If doctors suspect a spinal cord injury caused by an accident, they may use X-rays to check for any broken bones or dislocations in the spine. Additionally, they may use CT scans or MRI scans. These can help them find any blockages or pressure points, which might show up as an “owl’s eye” shape in the front sections of the spine – this is typical in Brown-Sequard syndrome.
If the doctors think the patient might have anterior spinal syndrome, which affects the front part of the spinal cord, they may use a spinal cord angiogram. This is a procedure that uses X-rays and a special dye to see how blood flows in the spinal cord.
If the physical exam doesn’t show any signs of accidents causing the injury, the doctors will run additional tests to rule out infections as the cause of the symptoms. They may use a skin test (known as a purified protein derivative test) and examine a sample of the patient’s phlegm under a microscope to check for bacteria that cause tuberculosis. They may also perform a chest X-ray to check the lungs for any signs of infection.
Treatment Options for Corticospinal Tract Lesion
The treatment for conditions that affect the body’s main motor pathway, like the corticospinal tract, often includes the use of steroids such as methylprednisolone or corticosteroids. These medications are usually administered within the first 8 hours of the problem occurrence to decrease inflammation and relieve pressure on the spinal cord. However, this type of treatment is not considered suitable for patients with a specific neurological condition known as Brown-Sequard syndrome, mainly because the steroids can increase the patients’ susceptibility to future infections.
In case the injury is located in the upper parts of the spine, such as the high thoracic or cervical areas, those affected may require respiratory support. This could include various treatments provided by a respiratory therapist.
In situations where the damage is due to a traumatic event or a tumor or abscess that’s putting pressure on the spinal cord, decompression surgery might be needed. This procedure creates more space for the spinal cord and relieves pressure.
Once the spine is stable after injury or surgery, physical therapy becomes crucial. Its goal is to help maintain motor activity, strengthen muscles, and retain coordination. It’s common for patients to use aids like wheelchairs, limb supports, and splints to help them move around.
In addition, occupational therapy plays a significant role in enhancing and preserving the function of the patients’ upper limbs, specifically in helping them in performing everyday tasks.
What else can Corticospinal Tract Lesion be?
When doctors are trying to diagnose spinal cord syndromes, there are a number of conditions they consider that could be causing similar symptoms. These include:
- Injuries to both sides of the brachial plexus – the network of nerves that send signals from your spine to your shoulder, arm and hand
- Cysts, which are sac-like structures that can be filled with fluid, air, or other materials
- Dislocations, when the bones of the spine move out of place
- Epidural abscesses or hematomas, which are infections or clotted blood respectively, in the area outside the thin tissue that covers the brain and spinal cord
- Fractures, or broken bones in the spine
- Infections that can affect the spine
- Other conditions and traumas related to the spine
- Strokes – a condition in which part of the brain loses its blood supply
- Trauma of peripheral nerve roots, leading to the forced detachment (avulsion) in both sides of the body
- Tumors, or abnormal growths, in the spine
- Vascular injuries, which are injuries to blood vessels
A correct diagnosis is important so that the most effective course of treatment can be identified and commenced.
What to expect with Corticospinal Tract Lesion
Generally, patients with ‘central cord syndrome’ witness some function recovery. The sooner the treatment is received after the injury, the better the outcomes. Recovery usually occurs in stages, starting with the legs, then bladder/bowel, and eventually the arms and hands. While most patients with this condition have a favorable outlook, factors like old age and the severity of the injury may reduce the chances of recovery.
For ‘Brown-Sequard syndrome’, the prognosis relies on the cause and seriousness of the spinal cord injury. Over half of the patients see a return of motor function, with recovery faster on one side of the body than the other. Moreover, in nine out of ten cases where bowel and bladder functionality was impaired, patients can recover these functions. This recovery process usually takes anywhere between 3 to 6 months and up to two years.
In contrast, patients with ‘anterior spinal cord syndrome’ have the most challenging outlook among spinal cord syndromes. Only 39% of patients see a return of motor control, and half of the individuals diagnosed with this disorder experience no improvement of symptoms over time.
Possible Complications When Diagnosed with Corticospinal Tract Lesion
Problems that can occur due to spinal cord injuries include the disruption of the body’s automatic functions, loss of bladder control, and unending pain. If these conditions are not addressed, more symptoms can arise. These can be a sudden drop in blood pressure, spinal shock which is a temporary period of loss of reflexes, blood clots in the lungs, and infections in the lung or urinary system.
Common Complications:
- Disruption of automatic body functions
- Loss of bladder control
- Chronic pain
- Sudden drop in blood pressure
- Spinal shock
- Blood clots in the lungs
- Lung infection
- Urinary system infection
Recovery from Corticospinal Tract Lesion
For all people with injuries to the corticospinal tract, it’s highly recommended that they undergo physical and occupational therapy. This type of therapy helps individuals recover their movement abilities and adapt to everyday life after their injury. Tools like wheelchairs, limb supports, and splints may be used to help the patient move around. Patients and their families will also need to learn about the specific challenges they face, the therapies they’ll go through, and how to ensure safety at home.
Preventing Corticospinal Tract Lesion
It’s crucial for patients and their families to receive guidance and information on the difficulties, impairments, and potential complications linked to their medical condition. This includes understanding how to manage walking and everyday tasks, as well as dealing with complications like nerve pain, bowel and bladder problems caused by nerve damage, and issues with sexual function. Patients also need to figure out strategies to get back to their daily routine after an injury.
Healthcare professionals should provide the family with specific physical, psychological, and social techniques to help the patient during their recovery process. This educational support is vital in assisting the patient overcome the challenges associated with their condition.