Контралатеральный транскаллозально-субхориоидальный подход для резекции таламусной кавернозной ма...

This video shows a contralateral transcallosal-subchoroidal approach for resection of a thalamic cavernous malformation. The patient presented with a known right anterior thalamic cavernous malformation accompanied by headaches and radiological progression on interval MRI. The patient was otherwise neurologically intact. Gravity retraction was used to aid the dissection through the interhemispheric fissure. The contralateral trajectory takes the approach from the left side into the right lateral ventricle to the superior thalamic surface. Accessing the ipsilateral ventricle requires sweeping the pericallosal artery upward and making the transcallosal incision under and lateral to the pericallosal vessel. The choroid plexus in the ventricular body was visualized and coagulated. The choroidal fissure was opened on the lateral side of the choroid, medial to the thalamus. The choroid was enlisted as a protective buffer between the operative corridor and the fornix. A good separation plane was developed between the gliotic plane of the thalamus and the lesion. A round knife was used to sharply dissect around the lesion, pulling it up and away from the gliotic plane. The lesion was worked toward the midline, separating the adhesions to the lateral aspect of the capsule. The cavernous malformation was resected en bloc and careful inspection of the resection bed showed no residual cavernous malformation. No postoperative complications were noted. Postoperative MRI confirmed a clean resection cavity on T1- and T2-weighted imaging. In conclusion, approaches through the choroidal fissure can be medial (transchoroidal) or lateral (subchoroidal) to the choroid plexus of the lateral ventricular body. Transchoroidal approaches have been popularized to protect the thalamus by dissecting further medially, but these approaches are disadvantaged by close proximity to the fornix, which increases the risk of short-term memory deficit. Subchoroidal approaches protect the fornix by dissecting laterally, allowing the choroid to protect the delicate forniceal structure. Subchoroidal approaches should be considered when there is favorable venous anatomy (the ability to work through the thalamostriate and internal cerebral veins) and concern for new memory deficits.