5.3.16\ Hemispherectomy

5.3.16.1\ Discussion

Hemispherectomy is mainly reserved for treating severe intractable seizure and rarely for gliomatosis cerebri. Several hemispherectomy techniques can be performed depending on the location and extent of seizure foci, and they can be total or partial. Techniques that use partial cortical removal and hemisphere disconnection are termed functional hemispherectomy or hemispherotomy (Fig. 5.66). On the other hand, techniques that result in complete cortical removal

a

from the hemisphere are usually termed anatomical hemispherectomy, classical hemispherectomy, hemidecortication, or hemicorticectomy (Fig. 5.67).

On postoperative imaging, the hemispherectomy resection cavity fills with fluid during the first few days after surgery. With functional hemispherectomy, the remaining disconnected portions of the cerebral hemisphere eventually become atrophic. With complete anatomic hemispherectomy, duraplasty material is used to seal the interhemispheric fissure and prevent herniation of the remaining hemisphere.

b

Fig. 5.66  Functional hemispherectomy. The patient has a history of Rasmussen’s encephalitis recently treated with partial right hemispherectomy. Axial FLAIR images

(a and b) show residual portions of the right frontal, temporal, and occipital lobes, which are partially detached from the remainder of the brain

Fig. 5.67  Anatomical hemispherectomy. The patient has a history of intractable seizures related to Sturge-Weber syndrome treated via complete resection of the right cerebral hemisphere several years prior. Axial CT image (a) and coronal T2-weighted MRI (b) show complete absence

of the right cerebral hemisphere. Duraplasty material (arrow) spans the interhemispheric fissure. 3D time-of- flight MRA (c) demonstrates the absence of the right MCA in the mid M1 segment status post ligation