General Considerations and Operative Anatomy
Parietal craniotomy is designed to provide an operative exposure of the mid to posterior hemisphere while sparing the highly functional anteriorly located sensorimotor cortices and the posteriorly located visual cortex. The approach can be devised to lateral and mesial parietal lobe lesions as well as to interhemispheric median or paramedian lesions.
The variations of this corridor allow access to lesions through the transcortical route (through the more functionally “silent” superior parietal lobule) or the interhemispheric fissure. The parasagittal veins are often less numerous in the posterior parietal region, therefore providing an opportunity to reach deep lesions through the interhemispheric trajectory.
The right or nondominant parietal lobe (see Wikipedia) is implicated in spatial awareness and navigation. Operative interventions that place the entire right lobe at risk are associated with hemibody neglect. This neglect does significantly improve over time, but some residual disability persists.
The left or dominant parietal lobe (see Wikipedia) is involved in symbolic functions in language and mathematics. Damage to the left lobe results in problems with mathematics, long reading, writing, and understanding symbols. Gerstmann's syndrome is associated with lesions in the dominant inferior parietal lobe, whereas Balint's syndrome (simultanagnosia, oculomotor apraxia, optic ataxia) is associated with bilateral lesions.