Introduction
The supraorbital approach gives access to several areas of the anterior and middle cranial fossa, sellar and parasellar region. It is a minimally invasive alternative to larger approaches such as fronto-orbital, pterional and orbitozygomatic approaches. Two minimally invasive incisions, the eyelid and eyebrow incision, can be used to perform the supraorbital cranitomy with optimal cosmetic resuts.
Preoperative Considerations
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The decision to use these techniques is based on the desired anatomic and operative trajectory, patient comorbidities, overall health and size of the lesion to be resected or approached, as well as the size of the frontal sinus.
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A CT scan is recommended to evaluate the size and location of the frontal sinus. If the frontal sinus is large and extends laterally to the supraorbital notch, this approach may be relatively contraindicated.
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Endoscopic-assisted technique can be used for wider visualization of the sellar, parasellar regions, as well as the upper third of the clivus, anterior third ventricle and interpeduncular cistern.
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A combined endonasal approach can be used for pathology that extents to the sellar region.
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Placement of a corneal shield or a temporary tarsorrhaphy to the ipsilateral eye is recommended during this procedure.
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A lumbar drain can be used in selected cases to decrease the intracranial pressure and prevent CSF leaks.
Indications
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Anterior cranial fossa lesions: olfactory groove, planum sphenoidale or sphenoid wing meningiomas in the order of 3 cm or less in the largest diameter.
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Sellar and parasellar lesions: pituitary adenomas, craniopharyngiomas and tuberculum sellae meningiomas.
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Intra-axial lesions in the orbital gyrus, medial orbital gyrus and rectus gyrus, and frontal pole: cavernoma, gliomas.
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Anterior circulation aneurysms: mainly, unruptured aneurysm of the anterior communicating artery (ACoA). Also described for aneurysms in the C7 segment of the internal carotid artery.
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This approach gives access to the ipsilateral and contralateral optic nerve (II), ipsilateral oculomotor nerve (III) and the interpeduncular cistern.
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Opening the proximal sylvian fissure gives access to the medial carotid artery complex and the medial temporal lobe.
Contraindications
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The supraorbital craniotomy is not ideal for lesions with significant middle fossa or cavernous sinus involvement.
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Lesions in the superior and middle gyrus of the frontal lobe and precentral gyrus are difficult to access from this approach.
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These approaches are not recommended for tumors that are significantly attached to vascular structures because of the high risk of bleeding and the lack of proximal vascular control.
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Significant edema and associated hydrocephalus are relative contraindications.
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A large frontal sinus is a relative contraindication due to the increased risk of infection and postoperative mucocele formation. The ability to obtain a vascularized pericranial flap for frontal sinus isolation is limited (although with endoscopic procedures a large vascularized pericranial flap can be obtained if required).
Surgical Procedure
Patient Positioning
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The patient is placed supine with a 3-pin headholder.
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The head is elevated above the chest and extended 20–30° (allowing the frontal lobe to fall away from the floor of the anterior fossa).
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The head is rotated from 15 to 60° to the contralateral side depending the anatomical localization of the lesion:
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15° for ipsilateral sylvian fissure
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20° for lateral suprasellar
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30° for anterior suprasellar
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60° for olfactory groove and cribriform plate region.
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Eyelid Approach
Eyelid Incision
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For optimal cosmetic results it is better to mark the eyelid incision with the patient awake to follow the eyelid crease with precision ( Figure 19.1 ).
Figure 19.1
Eyebrow (1) and eyelid (2) incisions for the supraorbital approach.
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A temporary tarsorrhaphy is done, stitching the upper and lower eyelid together with a 4-0 stitch. This will keep the eye closed to protect it during the surgery.
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Local anesthesia with a vasoconstrictor is injected along the planned incision line. Additional vasoconstrictor may be injected supraperiosteally in the superolateral orbital rim.
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The eyelid incision starts at the inner canthal region 3–6 mm lateral to the medial canthus and following the natural upper eyelid crease.
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The lateral extension of the incision is planned in a natural wrinkle line. This can be extended up to 2.5 cm lateral to the lateral canthus. This area is called the “safe zone” because it is free from branches of the frontal facial nerve. At the most lateral part, the incision is made as horizontal as possible to limit the damage to the supraorbital nerve branches which run horizontally at this point ( Figure 19.2 ).
Figure 19.2A
Incision over the eyelid crease for the eyelid approach.
© A. Quiñones-Hinojosa.
Figure 19.2B
Eyelid incision. The “safety zone” is the zone free of facial nerve branches.
© A. Quiñones-Hinojosa.
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The incision is first performed only through the skin.
Soft Tissue Dissection
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Once the skin incision is done, the next structure exposed is the orbicularis oculi muscle. This is carefully dissected following the direction of the fibers until the orbital septum is visualized. The orbital septum is recognized as a white and strong structure that extends from the inferior edge of the orbital rim to the superior surface of the eyeball ( Figure 19.3A ).
