The Operation for Cavernous Malformations in Children
Varies: Positioning of the patient depends on the location of the lesion and the surgical approach.
Use of head holder optional: The use of a head frame with pins is optional. If skull pins are used on young children, care should be taken to avoid fracture, penetration, or deformity of the skull.
Shortest route that avoids functionally important structures: The principle of surgical approach is to choose a point where the lesion is closest to the brain surface and to choose the safe entry zone of the brainstem. A two-point method has been described for selection of the appropriate approach to a brainstem lesion (8). A single point is placed at the center of the lesion, and a second point is placed at the margin of the lesion where it comes closest to or abuts the pia or ependymal surface. A line connecting the two points is extended superficially and delineates the best approach to the lesion. The surgical approach that most closely mimics the two-point approximation is used to resect the lesion.
Mapping for functional structures helpful: Intraoperative neurophysiological monitoring is helpful to find the safe entry zone, especially in the floor of the fourth ventricle.
Remove hematoma carefully: The cavernous malformation proper is often mixed and buried inside the old hematoma products. Careful dissection is needed to achieve complete excision of the cavernous malformation.
Look for vascular bundle and coagulate: A vascular bundle is usually present at the deep part of the lesion. This situation should be anticipated, and hemostasis should be secured.
Remove hemosiderin-stained tissue if possible: For epilepsy surgery, if the location allows, i.e., not a critical eloquent area, removal of the hemosiderin-laden gliotic tissue has been recommended for better seizure outcome (27).
Leave DVAs undisturbed: DVAs are frequently associated with deep-seated cavernous malformations. These veins often contribute to the normal venous drainage of the deep brain structures. Most authors recommend sparing these veins to avoid neurological deficit (19).
Routine: The resection cavity should be carefully inspected for complete resection and for hemostasis before closure. The craniotomy is closed in routine fashion.