Rostral Spinal Cord
Rostral spinal cord injuries (C1 to C2 level) are usually traumatic. They produce apnea by interrupting the fibers that conduct the impulses from the ventral and dorsal respiratory groups to the phrenic center and the intercostal alpha motor neurons. It is usually diagnosed by MRI (Figure 31.1). Cervical spine radiography may demonstrate a C1-2 subluxation.

Figure 31.1.— MRI of the brain demonstrating cervico-medullary junction atrophy.

The classic clinical presentation of rostral spinal cord injury consists of absence of movements of the upper and lower extremities in an alert neonate with normal midbrain, pontine, and medullary cranial nerve functions. This classic presentation is not always present because: (1) trauma, the most frequent cause of spinal cord injury, often involves the brain and leads to coma; (2) damage to the fibers of cranial nerve XI as they ascend in the spinal canal produces head tilt; and (3) damage to the hypoglossal motor nuclei or nerve in the lower medulla produces a weak tongue.
Rostral spinal cord injury produces central, obstructive, and mixed apnea. Central apnea occurs because of disconnection of the dorsal and ventral respiratory groups from the phrenic center. Obstructive and mixed apnea may also occur due to hypoglossal motor nuclei and nerve damage, or due to lack of temporal coordination between upper airway muscles and diaphragmatic contractions. The latter occurs as a result of delay in signal transmission from the ventral and dorsal respiratory groups to the phrenic motor center.
The diagnosis of rostral spinal cord injury is established by MRI and radiography. They may show vertebral fracture, C1-C2 subluxation, extraaxial hematoma, parenchymal lesion, or atrophy. Pathological findings may reveal a hemorrhagic discoloration of the rostral cervical cord (Figure 31.2). Treatment of the primary disease may be surgical. Tracheostomy with mechanical ventilation and diaphragmatic pacemaker are usually needed.

Figure 31.2.— Rostral cervical cord showing dark gray-blue discoloration.