Isolated lower extremity monoplegia due to a traumatic intraparenchymal contusion: Report of two cases

Abstract

Background: Isolated lower extremity monoparesis/monoplegia (MP) due to epidural or subdural haematomas near the vertex have not been reported due to traumatic intraparenchymal contusions. Due to the limitations of conventional axial computed tomographic (CT) imaging, the evidence of a vertex contusion may be under-appreciated if an overlying skull fracture is absent.Case description: Two cases of isolated MP due to vertex contusions are described and the physical forces involved in the head trauma are described to explain the location of the contusions. Vertex intraparenchymal contusions are rare because of the way the brain deforms in response to the accelerational forces acting on it during head trauma. This study analyses patients’ injuries and addresses the importance of considering the forces acting on the brain when evaluating a victim of head trauma.Conclusion: Isolated lower extremity MP following head trauma is rare because haematomas in the fronto-parietal cortex near the midline that could produce such a deficit are rare. The limitations of typical axial CT imaging can be overcome with coronal reconstructions. Practitioners who evaluate patients with isolated MP after head injury should be aware of the possibility of an intraparenchymal lesion near the vertex as the cause of this deficit.