Characteristics and surgical outcomes for medial temporal post-traumatic epilepsy

Abstract

A common post-traumatic location of epileptogenesis is the medial temporal lobe despite evidence of associated diffuse or remote cerebral injury. We undertook a review of post-traumatic medial temporal lobe epilepsy (MTLE) patients as part of an overall post-traumatic epilepsy population to assess the extent of cerebral injury sustained by this subpopulation and to establish whether surgical outcome differed from that of a non-traumatically-induced epilepsy population. A retrospective review of 57 patients operated for post-traumatic epilepsy (PTE) over a 10-year period (1993-2003) was undertaken with particular attention to those undergoing medial temporal resection. Preoperative magnetic resonance imaging (MRI) was assessed for the type and location of abnormalities. Postoperative outcomes were compared with those of patients with MTLE of non-traumatic origin operated by the same surgeon. Of the 57 patients operated, 30 cases underwent medial temporal lobe resection. The most common mechanism of injury was blunt trauma attributable to motor vehicle accidents with imaging abnormalities characterized by medial temporal sclerosis (MTS; 16 cases), T2/FLAIR hyperintensities (nine cases), periventricular gliosis (seven cases), diffuse cerebral atrophy (five cases) and focal encephalomalacia (three cases). Six patients had normal MRI studies. No significant differences in postoperative outcomes were found between post- and non-traumatic MTLE epilepsy groups. The presence of histopathological change in the medial temporal lobe varied greatly and provided no indication of a favourable postoperative outcome. Patients with post-traumatic medial temporal lobe epilepsy respond favourably to surgical treatment. In the case of medial temporal sclerosis, there is substantial variation of histopathological findings which correlate poorly with current imaging applications. The favourable outcomes obtained following surgery in this group attest to a commonality with other risk factors in the genesis of epilepsy in this location.

Traumatic Medial Temporal Lobe Epilepsy Associated with a Subcortical Lesion in the Internal Capsule - A Case Report

“…Many previous studies have found no significant differences in postoperative outcome between traumatic and non-traumatic MTLE patients, despite the high frequency of widespread cerebral hemispheric injury in traumatic MTLE cases [1][2][3][4]. In the present case, findings from preoperative examinations and intraoperative ECoG were consistent with typical MTLE.…”

“…Although dual pathology is common in MTLE, past discussions on dual pathology have emphasized congenital migration disorders or neoplasias and have not focused on traumatic lesion [12]. Previous studies of traumatic MTLE have described the coexistence of neocortical damage and HS [1][2][3][4][5]. Schwartz et al [9] examined 21 traumatic MTLE patients and found that 8 patients had cystic change or encephalomalacia in the ipsilateral neocortex on preoperative MRI.…”

“…The pathophysiological mechanisms of traumatic MTLE are unclear [1,2,4,5,9]. It is generally accepted that direct injury is one of the major factors in the development of posttraumatic epileptogenesis [10].…”

“…Previous studies have demonstrated that hippocampal sclerosis (HS) frequently coexists with traumatic neocortical damage [1][2][3][4][5]. We report a case of MTLE associated with a subcortical lesion in the internal capsule, suspected to be the result of mild diffuse axonal injury.…”

“…Although there is no universally accepted definition, traumatic medial temporal lobe epilepsy (traumatic MTLE) can be generally defined as a type of post-traumatic epilepsy with medial temporal epileptogenicity [1][2][3]. Previous studies have demonstrated that hippocampal sclerosis (HS) frequently coexists with traumatic neocortical damage [1][2][3][4][5].…”