Brown Séquard Syndrome/Hemi-Cord Syndrome
Spinal cord injuries span the spectrum from the devastating complete paralysis to inconsequential sensory pathology. There are approximately 200,000 to 230,000 people with spinal cord injuries in the United States at any given moment. Motor vehicle accidents account for the vast majority new spinal cord injuries of these producing nearly half of these. The average age of a patient with a new onset spinal cord injury ranges between 28 and 36 years old. On the other hand, the patients that experience a spinal cord injury due to a fall are generally an elderly person with underlying cervical spine pathology such as stenosis.
Cervical Spine Anatomy and Pathophysiology:
The spinal cord has multiple ascending and descending tracts that serve specific functions. The dorsal columns contain both the fasciculus cuneatus (T6 and cephalad) and fasciculus gracilis (T7 and caudal) which serve to transmit ipsilateral two point discrimination, vibration and conscious proprioception to the medulla oblongata of the midbrain.
The corticospinal tract transmits motor axons from the cerebral cortex to the synapses in the spine that control contralateral voluntary motor function. This corticospinal tract is composed of a lateral corticospinal tract and a medial corticospinal tract. About eighty to eight-five percent of the axons cross over in the medulla oblongata and run in the lateral corticospinal tract, while the fibers that do not cross run in the medial corticospinal tract. These axons cross through the anterior commissure to supply motor function to the contralateral side of the body.
Lastly, the anterior and lateral spinothalamic tracts carry ascending fibers to the thalamus for pain, temperature and crude touch. These fibers cross over at the level of the spinal cord via the anterior commissure to ascend on the contralateral side of the spinal cord.
Hence, a classic Hemi-Cord Syndrome, therefore, will produce ipsilateral motor paralysis and ipsilateral loss of proprioception and two point discrimination, with contralateral loss of pain, temperature and crude touch.
Patient History and Physical Exam:
Although there are many causes to Brown Séquard Syndrome, initial examination of a traumatic etiology should include the airway, breathing, circulation, disability and exposure protocol as described by the Advanced Trauma Life Support system. The cervical spine should be immobilized and a thorough history and physical should be completed. Additionally, a rectal exam should be performed and an American Spinal Injury Association (ASIA) score should be obtained.
Although trauma is the most common cause of Brown Séquard Syndrome , other causes exist. Other etiologies include a mass effect from a tumor, an infection, tuberculosis, multiple sclerosis, and iatrogenic causes.
The patient may experience the full gamut of a classic Hemi-Cord Syndrome with ipsilateral motor paralysis and ipsilateral loss of proprioception and two point discrimination, with contralateral loss of pain, temperature and crude touch, or any combination of these signs. The patient may have loss of bowel and bladder function. Additionally, the patient will experience spasticity due to the upper motor neuron lesions.
Imaging and other Diagnostic Studies:
Magnetic resonance imaging (MRI) will show transaction of the spinal cord, a mass effect, necrosis of the spinal cord, or other etiologies causing the Hemi-Cord Syndrome.
Treatment and Outcomes:
Surgical treatment is usually reserved for non traumatic Hemi-Cord Syndrome unless the spine is unstable from the trauma. Other etiologies are addressed accordingly.
Historically, Brown Séquard Syndrome has a good prognosis doing better most incomplete spinal cord injuries. Between 75% to 90% of patients regain motor function with the ability to ambulate.