Proper usage of brain retractors in the interhemispheric fissure based on MRI microanatomy: technical note.

The authors present a method of the surgical dissection of the interhemispheric fissure based on high resolution magnetic resonance images (MRI). The dissection of the interhemispheric space is not easy because the brain surfaces are tightly adherent in the interhemispheric fissure. In other words, in the interhemispheric fissure, the apices of the gyri are touching and are tightly bound together. This microanatomy is clearly revealed using high resolution three-dimensional MRI. The principle of the usage of the brain retractor is to apply them symmetrically in order to give an even tension to both sides. However, in the interhemispheric dissection, this principle should be slightly modified. Namely the brain retractors should be placed on the crest of gyri on both sides to avoid the injury of small arteries located in the sulci by the edge of the brain retractors.