Transsylvian and trans-Heschl’s gyrus approach for a left posterior insular lesion and functional analyses of the left Heschl’s gyrus: illustrative case

BACKGROUND: A common surgical approach for dominant insular lesions is to make a surgical corridor in asymptomatic cortices based on functional mapping. However, the surgical approach is difficult for posterior insular lesions in a dominant hemisphere because the posterior parts of the perisylvian cortices usually have verbal functions. OBSERVATIONS: We present the case of a 40-year-old male whose magnetic resonance images revealed the presence of contrast-enhancing lesions in the left posterior insula. Our surgical approach was to split the sylvian fissure as widely as possible, and partially resect Heschl’s gyrus if the cortical mapping was negative for language tests. Because Heschl’s gyrus did not have verbal functions, the gyrus was used as a surgical corridor. It was wide enough for the removal of the lesion; however, because intraoperative pathological diagnosis eliminated the possibility of brain tumors, further resection was discontinued. The tissues were histologically diagnosed as tuberculomas. Antituberculosis drugs were administered, and the residual lesions finally disappeared. According to the neurophysiological tests, the patient showed temporary impairment of auditory detection, but the low scores of these tests improved. LESSONS: The transsylvian and trans-Heschl’s gyrus approach can be a novel surgical option for excising dominant posterior insular lesions.