Venous-Preserving Sylvian Dissection.

Objective: The Sylvian fissure has been dissected through the frontal side of the superficial Sylvian veins with sacrifice of the tributaries of the frontal superficial Sylvian vein, which may lead to venous infarction. In addition, disturbed venous drainage makes the brain susceptible to brain retraction. Therefore, preservation of the vein is essential in modern neurosurgery to decrease morbidity.

Methods: We describe the technical nuances of Sylvian dissection with an emphasis on preserving the veins.

Results: The arachnoid between the frontal and temporal superficial Sylvian veins is divided as to enter the fissure. After the deep part in the Sylvian fissure is reached, the inside of the fissure is dissected along the "microvascular Sylvian fissure," the temporal side of the frontal vessels or the frontal side of the temporal vessels. The Sylvian fissure is dissected in a deep-to-superficial and posterior-to-anterior fashion ("paperknife technique") up to the skull base. The frontal superficial Sylvian vein usually tethers the brain to the dura, restricting the surgical corridor when approaching deep lesions. Peeling off the arachnoid that wraps this vein ("denude technique") allows the vein to stretch.

Conclusions: Keeping the proper dissection plane ("microvascular Sylvian fissure") is crucial to preserve the veins. The "paperknife technique" makes the division of the frontal and temporal lobe easier. The "denude technique" provides a wider space between the frontal lobe and the skull base. These techniques make it possible to obtain a sufficiently wide surgical corridor to the basal cistern without sacrificing the veins and their tributaries.