To repeat or to recreate: a contralateral posterior interhemispheric transfalcine transprecuneus approach for recurrent meningiomas at the trigone of the lateral ventricle.

Surgery in the trigone of the lateral ventricle remains a challenge for neurosurgeons. In recurrent trigonal meningiomas (RTM), the disturbance of normal anatomic structures and adhesion due to previous surgeries, significant oedema, and their malignant properties heighten the difficulties associated with their surgical removal. This report presents two patients with recurrent meningiomas with anaplastic transformation at the trigone of the lateral ventricle who were successfully treated with contralateral posterior interhemispheric transfalcine transprecuneus (CITT) surgeries. The primary tumours were both completely removed through a transparietal approach in previous surgeries, but both patients experienced hemianopsia postoperatively. The second surgeries resulted in the complete resection of the recurrent tumours without any new-onset neurological dysfunction. The CITT approach suits most trigonal lesions with advantages of optic radiation preservation, reduction of retraction, improved exposure, and navigation accuracy, and because it addresses the origin of the trigonal lesion. Although the characteristics of RTM heighten the difficulty associated with their surgical removal, these challenges highlight the advantages of the CITT approach. In conclusion, the CITT approach is a safe and effective procedure for the removal of RTM.