Recovery process of bilaterally injured corticoreticulospinal tracts in a patient with subarachnoid hemorrhage

Abstract

Rationale:A few studies using diffusion tensor tractography (DTT) have demonstrated recovery of injured corticoreticulospinal tract (CRT) in patients with intracerebral hemorrhage and infarct. However, no study reported on a patient who showed peri-infarct reorganization of an injured CRT following a middle cerebral artery territory infarct.Patient concerns:A 56-year-old right-handed male patient was diagnosed as spontaneous subarachnoid hemorrhage (SAH) and intraventricular hemorrhage (IVH) and underwent clipping for a ruptured anterior communicating artery aneurysm and right frontal extraventricular drainage for IVH at the department of neurosurgery of a university hospital. After onset, he presented with complete weakness of both legs.Diagnoses:The patient was diagnosed as spontaneous SAH and IVH.Interventions:Clinical assessment and DTT were performed at 1, 3, 6, and 20 months after onset.Outcomes:The weakness of both legs showed slow recovery for 10 months until 11 months after onset (medical research council: 6 months; 3/3 and 11 months; 4/4). As a result, he was able to walk independently on an even floor at 6 months and on stairs at 11 months after onset. The discontinued both CRTs on 1-month DTT were restored to the cerebral cortex on 3-month DTT, and then thickened consecutively on 6-month and 20-month DTTs.Lessons:The recovery process of injured CRTs concurrent with recovery of leg weakness was demonstrated in a patient with SAH using DTT. This study has important implications in terms of regaining gait function by the recovery of bilaterally injured CRTs which was facilitated by the long-term rehabilitation.

Corticoreticular Tract in the Human Brain: A Mini Review

“…However, further studies that clearly rule out the motor function effects of other neural tracts are needed to clarify accurately the portion of the total motor function for which the CRT is responsible (6, 42). With regard to the potential recovery mechanisms for injured CRTs, thus far, three recovery mechanisms have been suggested in previous DTT studies: recovery of the injured CRT along its original pathway, recovery via perilesional reorganization, and recovery along the transcallosal pathway (21–24, 49, 50). However, these studies are all case reports on a total of six patients; therefore, further original studies involving a larger number of patients are warranted.…”

“…Three different recovery mechanisms of injured CRT in patients with brain injury have been suggested in several studies using DTT of the CRT (21–24, 49, 50). These mechanisms include the recovery of a CRT injury along the original pathway, recovery through perilesional reorganization, and recovery along the transcallosal pathway (21–24, 49, 50). However, this list may be incomplete as these studies were all single-case reports.…”

“…However, this list may be incomplete as these studies were all single-case reports. In addition, these studies except for one study did not describe the CST state, which is a major neural tract for motor function (21–24, 49, 50).…”

“…However, the authors did not describe the CST state. Recently, Jang et al (50) demonstrated recovery of injured CRTs along with recovery of leg weakness in a patient with spontaneous subarachnoid hemorrhage and intraventricular hemorrhage without description on the CST state. After onset, the patient presented with complete weakness of both legs (MRC score: 0/0).…”

Diffusion Tensor Imaging Studies on Spontaneous Subarachnoid Hemorrhage-Related Brain Injury: A Mini-Review

“…This review was limited to studies of human subjects with spontaneous SAH. In addition, we excluded studies that did not demonstrate a definite brain injury due to the lack of normal control data (38)(39)(40)(41)(42)(43)(44). We selected relevant studies based on the flow diagram shown in Figure 1.…”