Transcortical selective microsurgical amygdalohippocampectomy for medically intractable seizures originating in the mesial temporal lobe

Selective microsurgical amygdalohippocampectomy (SMAH) seizure -free outcomes appear to be comparable to other more conventional resective procedures such as traditional temporal lobectomy, or a more limited anterior temporal lobectomy with removal of the inferior amygdala and pes hippocampus through the ventricle. The evidence that this more limited approach produces superior neuropsychological outcomes is mixed. The approach to removing the mesial temporal lobe varies from center to center, based largely on the history and experience of each center. No level 1 evidenciary study has been conducted to compare these various approaches, and likely this will never be accomplished. We favor the transcortical approach to the ventricle, with resection of the amygdala and hippocampus back to the level of the collicular plate, using image-guided surgery. This approach is relatively straightforward, and produces Engle class outcomes on a par with any other approach. A superior contralateral quadrantanopsia is routinely, although not universally, produced, due to violation of Meyer’s Loop, but this is not debilitating and is rarely noticed by patients. Mesial temporal lobe resection for patients with well-documented seizure onset localized to this region, MRI evidence of mesial temporal sclerosis (MTS) and concordant neuropsychological deficits, can produce outstanding and durable seizure control. In this era of increasingly sophisticated, and technologically complex methods for seizure mitigation, it is wise to remember that given a carefully-selected patient, resective surgery directed to the mesial temporal lobe can produce dramatic and life-changing control of certain seizure types.