Posterior Cord Syndrome
Introduction:
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/posterior 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 Posterior Cord Syndrome will affect the fasciculus cuneatus and fasciculus gracilis collectively known as the dorsal columns. Being that the fibers have not crossed yet, the patient will experience isolated ipsilateral loss of two point discrimination, vibration and conscious proprioception.
Patient History and Physical Exam:
The literature is sparse with case reports on Posterior Cord Syndrome; however, vascular compromise appears to be the most common etiology. The vascular supply to the spinal cord is segmental with predominant anterior and posterior spinal arteries. With occlusion to the posterior spinal artery, a Posterior Cord Syndrome will ensue.
A thorough history and physical should be obtained. A rectal exam should be performed. The patient may experience the full gamut of a classic Posterior Cord Syndrome with ipsilateral loss of two point discrimination, vibration and conscious proprioception.
Imaging and other Diagnostic Studies:
Magnetic resonance imaging (MRI) may show infarction of the dorsal columns.
Treatment and Outcomes:
Treatment for Posterior Cord Syndrome is symptomatic with identification of the source of infarction.
