Central 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 cervical spinal cord is protected and surrounded by many structures including the nucleus propulsus anteriorly, the ligamentum flavum posteriorly, and the facet joints posterior-laterally. With aging, there is a continuum of degeneration that obstructs the normal spinal impulses down and up the spinal cord.
The function of this nucleus propulsus is to transmit and convert the axial load of the head and neck into a tensile strain for the annulus, a type I collagen. With aging, the nucleus propulsus, a type II collagen, loses hydration causing subsequent degeneration and protrusion of the annulus. With continued dehydration of the disk, the nucleus is unable to perform its function of converting this strain effectively; pressure ensues on the annulus causing a decrease space for the spinal cord.
With the nucleus propulsus losing disk height, the facet joints undergo increased and abnormal biomechanics. Osteophyte development ensues causing additional encroachment of the space available for the cord.
Lastly, the ligamentum flavum, which is normally only a few millimeters thick in early adult life, succumbs to these changes of mechanics of the spine. With loss of disk height due to the dehydration, the ligamentum flavum buckles and thickens taking away more space from the cord.
A hyperextension moment will cause additional compromise to the spinal cord causing injury to the center of the spinal cord. With the cross sectional anatomy of the spinal cord containing the fasciculus cuneatus and fasciculus gracilis posteriorly, and the ventral commisure anteriorly, these structures are relatively spared. Additionally, with the sacral rootlets being the most peripheral, these too are spared.
A classic Central Cord Syndrome, therefore, will identify gross motor deficits to all four extremities, with more profound weakness appreciated in the upper extremities than the lower extremities. Sacral sparing will also be evident
Patient History and Physical Exam:
Patients that experience a Central Cord Syndrome are often elderly. They admit to a hyperextension trauma such as hitting ones head while falling or tripping.
Initial examination 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.
Gross motor deficits to all four extremities, with more profound weakness appreciated in the upper extremities than the lower extremities will usually be evident. Sacral sparing will also be evident with gross salvage of the proprioceptive, touch and vibratory pathways.
Imaging and other Diagnostic Studies:
Magnetic resonance imaging (MRI) will show increased signal with T2 imaging and obvious narrowing of the cervical spine.
Treatment and Outcomes:
Surgical decompression and stabilization for an acute Central Cord Syndrome is controversial. More recent literature is showing promising evidence for acute decompression; however more literature is needed to conclusively concur with these studies.
Historically, Central Cord Syndrome has a moderate prognosis doing better than some incomplete spinal cord injuries such as anterior cord syndrome, but not as well as hemi-section syndrome (Brown-Sequard). Recovery occurs in an expected manner, with lower extremity function improving first, followed by bladder function, and lastly with upper extremity motor function.
