Intracanalicular lesions involve the roots and the portion of the spinal nerve that is inside the vertebral canal (Figure 263.1).

Figure 262.1.— Schematic representation of a cervical spinal cord segment. [A] Lesions before the trunk require neurotization. [B] Lesions at or after the trunk can be treated by saphenous nerve transfer or [C] neurolysis. SEN. COND: sensory conduction; ABN: abnormality; PARASP: paraspinal; M: muscle; R: rhomboid; SA: serratus anterior; S: syndrome.

Intracanalicular lesions may show evidence of cord injury and pseudomeningocele (Figure 263.2). Paraspinal, rhomboid, and serratus anterior muscle weakness and Horner syndrome may be present. Sensory conduction is normal.

Figure 263.2.— MRI of the cervical spine demonstrating bilateral root avulsion and pseudomeningocele.

Extracanalicular pretruncal lesions may present with paraspinal, rhomboid, and serratus anterior weakness. Horner syndrome may be present. Sensory nerve conduction is abnormal because the site of injury is after the dorsal ganglion. Truncal lesions have normal paraspinal, rhomboid, and serratus anterior function; no Horner syndrome; and abnormal sensory nerve conduction.
Neonates with good initial recovery that later slow down in the rate of improvement or deteriorate are candidates for neurolysis. Neurolysis consists of releasing the scar tissue across the neuroma. When the patient is older, tendon transplantation may improve specific movement.