18 Eyebrow Supraorbital Approach for Skull Base Lesions

Hamid Borghei-Ravazi, Krishna C. Joshi, Varun R. Kshettry, and Pablo F. Recinos

Numerous surgical techniques have been described for lesions of the anterior skull base. These include the frontotemporal approach described by Dandy,1 to the addition of microsurgery by Yasargil et al,^{2 ,​ 3} to more minimal approaches including the supraorbital keyhole approach through an eyebrow incision. The first subfrontal approach was described by Francesco Durante in 1887 for an olfactory groove meningioma.⁴ A tailored approach for anterior skull base pathology using a supraorbital craniotomy was first described by Krause in his pioneering work Experiences in Surgery of the Brain and Spine ⁵ published in 1908. Although Krause created a combined flap that included skin, periosteum, and bone to reduce intraoperative blood loss and avoid postoperative wound infection, the patient did not survive due to severe brain swelling secondary to frontal lobe retraction. A modified supraorbital craniotomy was first described by John Jane et al in 1982,⁶ which was then further modified and popularized by Axel Perneczky in 1999.⁷ Historically, larger craniotomies were needed in order to compensate for lack of specialized tools for visualization and localization. With the advent of improved lighting, visualization with microscopy and endoscopy, and navigation, highly precise access can be achieved through smaller approaches. The supraorbital craniotomy has been extensively used to approach a wide variety of pathologies including meningiomas (e.g., olfactory groove, planum sphenoidale, and tuberculum sellae), anterior clinoid with minimal middle fossa extension, craniopharyngiomas, Rathke’s cleft cysts, suprasellar arachnoid cysts, pituitary adenomas (as an adjunct approach to endonasal for tumors with lateral extension), and vascular abnormalities (e.g., aneurysms and cavernomas).^{7 ,​ 8 ,​ 9 ,​ 10 ,​ 11 ,​ 12 ,​ 13 ,​ 14}

18.2 Relevant Surgical Anatomy

The supraorbital craniotomy gives access to select regions of the anterior cranial fossa and parasellar region. An in-depth understanding of the relevant locoregional anatomy is essential to understand the working corridors. The course of the supraorbital neurovascular bundle and frontotemporal branch of the facial nerve must first be delineated to prevent inadvertent injury.

The supraorbital bundle is formed by the supraorbital artery, vein, and nerve. The supraorbital artery is a branch of the ophthalmic artery and exits the anterior cranial fossa through the supraorbital notch. It ascends in the forehead to supply skin, muscle, and pericranium and anastomoses with the superficial arteries of the scalp. In most cases this vessel arises separately from the supratrochlear artery, but rarely can arise as a single trunk.¹⁵ The main trunk of the supraorbital artery enters the corrugator muscle at the level of the rim and divides into superficial branches to the skin and deep branches to the pericranium. The larger venous tributaries from the superficial layers descend over the frontal area and form the main trunk of the supraorbital vein.

The frontal branch is the largest branch of the ophthalmic nerve (V₁) and may be regarded, both in its size and direction, as the continuation of the nerve. It enters the orbit through the superior orbital fissure and runs forward between levator palpebrae superioris and the periosteum. Midway between the apex and anterior rim of the orbit it divides into two branches, the smaller supratrochlear nerve and the larger supraorbital nerve. The supratrochlear nerve runs directly beneath the medial third of the orbital roof and connects with the infratrochlear nerve to supply the medial angle of the eye, the upper eyelid, root of the nose, and small part of the glabellar region. The supraorbital nerve divides either extra- or intraorbitally into a medial and a lateral branch. It leaves the orbit through a notch/groove or occasionally through a closed foramen, which is located approximately 1 to 19 mm above the orbital rim. The supraorbital nerve is usually a single, thick nerve and can be marked on the skin at the supraorbital rim just medial to the midpupillary line.¹⁶ According to Gray’s Anatomy, “the supraorbital bony margin is interrupted at the junction of its lateral sharp two-thirds and rounded medial third by the supraorbital notch (or foramen), which transmits the supraorbital vessels and the nerve.”¹⁷

Surgically, the supraorbital notch is an important landmark in defining the medial extent of the craniotomy. The incision typically is extended further medial to the supraorbital nerve in the eyebrow in order to gain more superior exposure on the frontal bone. The lateral extent of the incision usually ends in the lateral most extent of the eyebrow. It should be kept in mind that any lateral extension beyond this can lead to injury of the frontotemporal branch of the facial nerve. Various techniques have been described for surface marking of this nerve. The most commonly used technique is using the line of Pitanguy,¹⁸ which is a line starting from a point 0.5 cm below the tragus in the direction of the eyebrow, connecting to a point 1.5 cm above the lateral extremity of the eyebrow.¹⁹ The reader should be wary that it is described in relation to a person’s eyebrow, which is highly variable and sometimes absent. The other line, described by Sabini et al,²⁰ is drawn from the tragus to the lateral canthus ( Fig. 18.1a, b). A second line is drawn from the inferior aspect of the ear lobe to the forehead through a point that bisects the first line. This second line closely parallels the path of the frontal branch.

Fig. 18.1 (a) Left supraorbital incision and landmarks marked preoperatively. (b) Left supraorbital nerve bundle exposed and preserved. PL: Pitunguy’s line; SON: supraorbital nerve; STL: superior temporal line.

18.3 Anatomical Limitations and Surgical Applications

The anterior cranial fossa limit of the supraorbital approach using a microscope is the posterior edge of the crista galli, but it slightly varies depending on the frontal sinus anatomy of the patient.21 In the anterior cranial fossa, it is possible to expose the medial two-thirds of the ipsilateral and medial half of the contralateral sphenoid wings (Fig. 18.2). The inferolateral limit is the superior one-third of the lateral wall of the cavernous sinus ( Fig. 18.3a). The endoscope can help to expose a wider area; however, the exact working area depends on surgical instrumentation available. In a previous anatomic study by our group, we described the limitations and surgical application of the supraorbital approach. Specifically, complete extradural anterior clinoidectomy was not feasible using this approach; however, intradural clinoidectomy was feasible depending on the pathology and goal of the surgery²² ( Fig. 18.3b).

Fig. 18.2 Limitation of a left microscopic supraorbital approach. The areas reachable is seen (gray) where the anterior limit of the approach is the posterior edge of the crista galli.

Related posts:

The Microsurgical Transoral Approach Endoscopic Approach to the Craniocervical Junction Microsurgical Anatomy of the Foramen Magnum The Endoscopic Transpterygoid Approach to the Parasellar and Infratemporal Fossa Cranio-Orbit-Zygomatic (COZ) Approach Pretemporal Approach

Stay updated, free articles. Join our Telegram channel

Join