26th June 2023

Central Cord Syndrome

Distribution of motor and sensory loss in central cord syndrome from a large lesion affecting the corticospinal tracts, spinothalamic tracts, and dorsal columns at the level of the cervical spine.

Image Source: Dr D Chang – own work

Central cord syndrome is the most common incomplete spinal cord syndrome and has a varied presentation depending on how large the lesion is, which determines how much cord is involved. It is insidious in onset, affecting first the anterior and lateral spinothalamic tracts, causing loss of pain and temperature with preservation of position, vibration, and touch sensation. Lesions causing central pattern spinal cord syndrome typically arise at the level of the cervical spinal cord. Sensory loss here presents in a vest-like pattern over the shoulders with a spectrum of range and severity with size of lesion. Sacral sensation is usually spared.

Larger lesions can progress posteriorly to include the dorsal columns, affecting vibration and proprioception below the lesion, anteriorly to the anterior horns, and laterally involving the corticospinal tracts, causing a flaccid paralysis with fasciculations, with eventual atrophy at the level of the lesion and spastic paralysis of muscles below the lesion.

The aetiology of a central pattern syndrome is most commonly from a traumatic hyperextension injury involving the cervical cord, which specifically injures the central part of the cord, typically the central corticospinal tracts (as opposed to fractures/trauma causing other complete or incomplete spinal cord syndromes). This can result in quadriplegia with some recovery of lower limb function and a disproportionately greater upper limb weakness, worse distally than proximally. This is more common in people with cervical osteoarthritis and cervical spondylosis, where an existing stenosis, e.g. from osteophytes, increases the vulnerability of the spinal cord to injury. Bladder dysfunction, e.g. urinary retention, priapism and autonomic dysreflexia may occur.

In traumatic central cord syndrome, the prognosis is generally favourable, with patients recovering substantial neurological function after the injury with 90 percent return of motor function by three years, progressing in an ascending order with return of lower limb function, then bladder control and eventually proximal upper limbs and hands. Patients undergoing surgical intervention are more likely to attain pre-injury mobility status.

Atraumatic causes are much rarer and include neoplastic causes such as intramedullary spinal cord tumours and syringomyelia.

Syringomyelia

Figure 65: Distribution of pain and temperature loss in syringomyelia.

Image Source: Dt D Chang – own work

Syringomyelia is the development of a CSF filled syrinx within the spinal cord parenchyma or central canal that can enlarge and compress surrounding tracts, typically at the C8/T1 level. It is typically associated with type 1 Arnold-Chiari malformations in which there is downward displacement of the cerebellar tonsils beneath the foramen magnum into the cervical spinal canal, blocking the normal CSF flow between the spinal canal and intracranial space. Syringomyelia can also be associated with a tethered cord (in which the caudal spinal cord can become fixed to surrounding inelastic tissue) and with spina bifida, tumours, meningitis and arachnoiditis.

Syringomyelia typically presents with bilateral pain and temperature insensitivity in a cape-like distribution over the upper limbs due to the compression of the spinothalamic tract decussation in the anterior white commissure, with preserved touch and vibration sense below the level of the syrinx. Symptoms can be static for years but may worsen in association with Valsalva manoeuvres, e.g. coughing or sneezing/heavy lifting/straining, which can cause enlargement and extension of the syrinx.

Enlargement of the syrinx causes the progression of the central cord syndrome, compressing anterior horn cells and corticospinal tracts, leading to a variable presentation of syringomyelia depending on the size of the syrinx and which structures are being compressed. This can include spasticity or paralysis of the legs, ataxia, or fasciculations.

If the syrinx is higher in the cord, extending into the medulla of the brainstem, this is termed syringobulbia, which can result in cerebellar and lower motor cranial nerve nuclei signs.

Investigation is with MRI and dynamic CSF flow MRI studies, with CT myelograms as an alternative in the event of MRI contraindications.

Treatment is typically with surgical intervention to improve CSF flow and is dependent on the cause, e.g. a Chiari malformation indicating a craniocervical decompression if associated with type 1 Arnold-Chiari malformation, or with decompressive laminectomy, syringosubarachnoid or syringoperitoneal shunts.