Surgery through sellckchem an eyebrow incision may not be appropriate for all lesions of the anterior skull base. There is a narrow viewing angle through this approach that may require frequent adjustment of the operating room table and microscope for adequate visualization of a given lesion. The microscope light is often another problem, as there may be some difficulty getting adequate light through such a small opening onto a deep-seated lesion. Microinstruments require almost coaxial control through such narrow anatomic windows [2, 5]. In the setting of vascular lesions, a smaller opening in a blood-filled field can also make it difficult to obtain adequate vascular control without damage to surrounding structures. Use of a rigid rod-lens endoscope in combination with the operative microscope can provide a great benefit with the supraorbital craniotomy and subfrontal approach.

The endoscope can provide a much greater light source at the depths of the exposure, with greater focus and better visualization. Ensuring a large enough size to the craniotomy (no smaller than 1.5�C2cm) is important as well to ensure adequate maneuverability of instruments for a bimanual approach to surgery [2, 5]. Through thoughtful consideration of appropriate lesions and adequate experience with this technique, we believe that safe surgery can be performed on numerous pathologies without brain retraction and with a superb cosmetic result. 2. Surgical Description After general anesthesia, endotracheal intubation, and placement of a Foley catheter, the patient is fixed in a Mayfield three-pin head holder with two pins on the ipsilateral posterior cranium and the one pin site on the contralateral frontal bone.

The torso is slightly elevated at ten degrees, and the head is positioned in a slightly extended position of around 15�C20 degrees to allow gravity retraction of the frontal lobes away from the surgical field. No retractors are used. The head is turned approximately 15�C45 degrees contralaterally to the side of surgery to allow appropriate visualization of midline lesions. The bed can be further rotated as necessary for further adjustments during surgery. Midline lesions, such as olfactory groove lesions, require more rotation, whereas laterally placed lesions require less rotation for appropriate visualization and access.

The most important information in decision making regarding the side of the approach is the structure of the lesion itself and its relationship to surrounding anatomic structures. Certainly, when either side can adequately access the lesion, we typically choose a nondominant approach in order to reduce the risk of damage to the dominant frontal lobe. The skin incision is made Brefeldin_A along the eyebrow without cutting the hair of the eyebrow (Figure 4). Previous studies have shown no increased risk of infection, and leaving the eyebrow intact allows for a better cosmetic result [2, 3, 5, 7, 46].