Tailored Extended Bifrontal Craniotomy for Anterior Skull Base Tumors: Anatomic Description of a Modified Surgical Technique and Case Series

BACKGROUND Open transcranial approaches to the anterior skull base remain an integral component of current skull base practice. Evolution of these and other techniques has resulted in revisions of standard, tried-and-true methods in attempts to improve patient outcomes and cosmesis, while still providing the best combination of surgical exposure and ergonomics. OBJECTIVE To describe a modified approach for midline tumors of the anterior skull base. METHODS We describe the anatomy and techniques of a modified extended bifrontal craniotomy for anterior skull base tumors. Case examples and a postoperative 3-dimensional computed tomographic reconstruction of the craniotomy are provided. RESULTS The technique has been employed with success in 3 tuberculum sellae meningiomas where the anterior limit of the tumor is several centimeters back from the inner table of the frontal bone. The mean distance from the tumor to inner table was 2.8 cm (range 1.3-3.8 cm). Mean tumor dimensions were 3.0 cm (transverse), 3.5 cm (anterior-posterior), and 2.2 cm (craniocaudal). Average operative time was 557 min. No cases had new T2/fluid-attenuated inversion recovery magnetic resonance imaging signal of the inferior frontal lobe to indicate retraction injury. CONCLUSION The tailored extended bifrontal craniotomy for anterior skull base tumors provides adequate access to the anterior cranial fossa and has replaced our standard extended bifrontal approach. Keeping the osteotomy cut lines outside of the orbit reduces orbital swelling and mechanical disruption of conjugate eye movements in the early postoperative period, while allowing for minimal frontal lobe retraction and providing sufficient surgical exposure along the anterior skull base.