Supraorbital

The supraorbital keyhole approach applies the principle that a small opening can give a wide view deep in the skull when it is placed precisely, because the corridor widens with depth. Reisch and Perneczky reported ten years of experience with the supraorbital subfrontal approach through an eyebrow incision, showing that it could be used for aneurysms, tumours and other lesions of the anterior skull base and suprasellar region with low morbidity and good cosmetic results^[1]. The endoscope is often used to look around corners.

• Anterior communicating, ophthalmic and selected internal carotid artery aneurysms.
• Olfactory-groove, planum and tuberculum sellae meningiomas of small to moderate size.
• Craniopharyngiomas and pituitary tumours with suprasellar extension, and Rathke cleft cysts.
• Suprasellar arachnoid cysts and lesions of the orbital roof and frontal lobe base.

• Supine, head extended about 15° and rotated 10–60° toward the opposite side depending on the target, so that the frontal lobe falls away from the orbital roof.
• Incision within the eyebrow lateral to the supraorbital notch to protect the supraorbital nerve.
• Reflect the frontalis and part of the temporalis muscle; make a single burr hole behind the temporal line.
• Cut a small craniotomy just above the orbital rim and drill the inner rim and roof ridges flat.
• Open the dura in a curve based on the orbit; release CSF from the opticocarotid and chiasmatic cisterns to relax the brain.
• Work along the orbital roof, using the microscope and, where needed, an endoscope.

The small corridor limits manoeuvrability, so the approach requires a relaxed brain and careful case selection. Large tumours, lesions with high third-ventricular extension, and aneurysms needing proximal control in the neck or complex reconstruction are usually better served by larger craniotomies. A large frontal sinus extending laterally may prevent a safe opening.

• Frontal sinus opening with CSF leak: study the CT and place the craniotomy lateral to the sinus; seal any opening.
• Forehead numbness from supraorbital nerve injury.
• Frontalis weakness from injury to the frontal branch of the facial nerve in the lateral part of the incision.
• Olfactory loss from frontal-lobe elevation.