Brown-Séquard syndrome, also known as hemicord syndrome, is the result of damage to, or impairment of, the left or right side of the spinal cord. It is characterised by a characteristic pattern of motor and sensory deficits that are determined by the decussation pattern of various white matter tracts. 

Clinical presentation

Due to some fibres crossing within the cord whilst others cross in the brainstem, the neurology is bilateral, namely ^1,6: 

• ipsilateral loss of proprioception, touch, and vibration sense below the lesion due to damage to the ascending dorsal columns 

• ipsilateral upper motor neurone spastic paralysis below the lesion due to damage to the descending lateral corticospinal tracts

• contralateral loss of pain and temperature sensation 2 to 3 levels below the level of the lesion due to damage to the ascending lateral spinothalamic tract which cross 2 to 3 levels above the level of their respective dorsal root 

• ipsilateral loss of motor and sensory function just at the level of the injured segments due to direct damage to ventral and dorsal grey matter

Pathology

There are many reported causes of damage to one side of the cord, including ^1-7: 

• trauma/compression

  • penetrating injury (e.g. stabbing or gunshot wounds) - most common

  • excessive motion (e.g. chiropractic manipulation ¹, motor vehicle accidents)

  • iatrogenic (e.g. surgery)

  • compression (e.g. disc herniation, extramedullary collection)

  • distortion (e.g. ventral cord herniation)

  • spinal cord tumours

• vascular 

  • endoluminal aortic repair

  • vertebral artery dissection

  • spinal cord haemorrhage secondary to vascular lesions

• radiation therapy ²

• demyelination (e.g. multiple sclerosis ⁷)

Radiographic features

MRI

MRI is the modality of choice for assessing patients with suspected Brown-Séquard syndrome and the features in any one case will naturally depend on the underlying cause, although all will have in common (predominantly) unilateral pathology.

History and etymology

The syndrome was first described by the physiologist Charles-Édouard Brown-Séquard, who studied spinal cord trauma in sugarcane farmers in Mauritius.

See also

• Brown syndrome (orbit)

• Paterson-Brown syndrome