More orbital lesions are found in the superoanterior part of the orbit than in any other location. Lesions in this area can usually be accessed through a transcutaneous incision. When this approach is used, care must be taken to avoid damaging the levator muscle, superior oblique muscle, trochlea, lacrimal gland, and sensory nerves and vessels entering or exiting the orbit along the superior orbital rim.
A well-hidden incision in the upper eyelid crease provides access to the superior orbital space (Fig 7-3) and offers better cosmesis than an incision placed directly over the superior orbital rim. Both the subperiosteal space and the extraconal space may be approached through this incision. To reach the subperiosteal space, dissection is performed superiorly toward the orbital rim in a plane between the orbicularis oculi muscle and the orbital septum. An incision is then made at the arcus marginalis where the periosteum of the frontal bone reflects to become the orbital septum, thus entering the subperiosteal space. To access the superior extraconal space, the dissection is instead carried posteriorly through the orbital septum after the skin incision.
Figure 7-3 Transcutaneous upper eyelid incision for superior and lateral approach. The upper eyelid crease incision allows access to the superior and lateral orbit and anterior temporalis fossa, as demonstrated in this surgical excision of a dumbbell dermoid involving the lateral orbital wall (asterisk) and anterior temporal fossa (arrow) on the left side.
(Courtesy of Morris E. Hartstein, MD.)
The upper eyelid crease incision may also be used for entry into the medial intraconal space. After opening the orbital septum, the surgeon identifies the medial edge of the levator muscle. Dissection is kept medial to this landmark and proceeds between the medial and central fat pads through the intermuscular septum that extends from the superior rectus muscle to the medial rectus muscle. This approach may be used for biopsy of the optic nerve, for optic nerve sheath fenestration in cases of idiopathic intracranial hypertension, or for accessing intraconal lesions medial to the optic nerve.
The coronal approach to the superior orbit is most often used for trauma or craniofacial surgery. This approach is also used for transcranial orbitotomies to provide better access to apical-based tumors, orbital tumors with intracranial extension, and skull-based tumors with orbital involvement.
Incisions in the superior conjunctiva can be used to reach the superomedial, sub-Tenon, intraconal, or extraconal surgical spaces. Dissection must be performed medial to the levator muscle to prevent postoperative blepharoptosis. Care should also be taken in the superolateral fornix to avoid damage to the lacrimal ductules.
Vertical eyelid splitting
Vertical splitting of the upper eyelid via a full thickness incision allows an extended transconjunctival exposure for the removal of superomedial intraconal tumors. Careful realignment of the tarsal plate and levator aponeurosis prevents postoperative blepharoptosis, eyelid notching, and eyelid retraction.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.