Quadriplegia Due to Injury of Corticofugal Tracts from Secondary Motor Area in a Patient With Severe Traumatic Brain Injury
Diffusion tensor imaging data was acquired 10 weeks after onset using a six-channel head coil on a 1.5 T. On 10-week diffusion tensor tractography (DTT), the corticospinal tract (CST) showed partial tearing at the subcortical white matter in both hemispheres. The right dPMC (dorsal premotor cortex)–corticofugal tract (CFT) and supplementary motor area (SMA)–CFT showed narrowing, and the left dPMC-CFT and SMA-CFT were not reconstructed (Fig. 1B).
In this study, using DTT, the CST, dPMC-CFT, and SMA-CFT were reconstructed in a patient who developed quadriplegia after severe traumatic brain injury. In the CST, it appeared that mild traumatic axonal injury (partial tearing at the subcortical white matter) had occurred in both hemispheres, and there are severe injuries of both dPMC-CFT and SMA-CFT in both hemispheres (the right hemisphere: narrowing and left hemisphere: non-reconstruction).1,2 Because the whole spine MRI, the electromyography study, and nerve conduction study showed no abnormality, we assumed that quadriplegia in this patient was mainly ascribed to injury of the dPMC-CFT and SMA-CFT in both hemispheres. As a result, it appeared that the main cause of quadriplegia in this patient was a kind of limb-kinetic apraxia.3,4 In conclusion, quadriplegia due to injury of the CFT from the secondary motor area was demonstrated in a patient with severe TBI.