After fixation in a Mayfield clamp, the head is translated upwards, hyperextended and then rotated towards the contralateral side such that the malar eminence is the highest point in the field and the frontal lobe falls away from the anterior fossa floor.

Depending on the patient’s hairline, an arched incision is made from just inferior to the zygomatic root half to one centimeter anterior to the tragus (hidden in a facial crease) and extending to the contralateral midpupillary line. For patients with a receding hairline, a bicoronal incision can be used.

A two-layer dissection of the scalp is performed elevating the scalp and separating it from the temporalis muscle. In this process, the superficial temporal artery should be preserved not only for a possible bypass but also to maintain flap vascularity in case of possible postoperative radiation.

The scalp flap is elevated until the fat pad just posterior to the frontozygomatic process is exposed.

At this point, an incision in the superficial temporalis fascia is made and a sharp subfascial dissection is performed to subperiosteally expose the frontozygomatic process and zygomatic arch/root. The dissected fascia is then retracted anteriorly along with the scalp flap.

The temporalis muscle is then dissected subperiosteally from the temporalis fossa where the direction of dissection proceeds from inferior to superior and posterior to anterior, such that the deep fascia and vascular supply of the musculature is preserved.

The muscle is detached from the frontozygomatic process such that the inferior orbital fissure can be identified extraorbitally ( Figure 18.1 ).

Demonstration of the final extent of soft tissue dissection required for the orbitozygomatic osteotomy. The scalp flap is created such that the orbital ridge, frontozygomatic process and zygoma can be exposed. The temporalis is mobilized such that it is reflected inferiorly. Notice the preservation of the facial nerve within the fad pat after a subfascial dissection. In the two-pieces orbitozygomatic approach a fronto-temporal craniotomy is performed first, followed by the orbitozygomatic osteotomy.

The insertion of the masseter into the inferior aspect of the zygomatic arch is detached. In order to reduce the postoperative incidence of trismus, the masseter can be left attached to the zygoma, which can be reflected inferiorly with the musculature.

The periorbita is then dissected from the orbital walls such that it is free from the inferior orbital fissure (lateral limit) to the supraorbital neurovascular bundle (medial limit) and extending posteriorly as much as possible.

A standard fronto-temporosphenoidal craniotomy is created after a burr hole is placed on the fronto-sphenoidal suture 2 cm posterior to the frontozygomatic process. Note that for lesions in the anterior cranial fossa, the craniotomy can be extended medially as much as needed; the supraorbital neurovascular bundle can be mobilized for such instances.

Ultimately, five osteotomies are created to release the superior orbital roof, lateral orbital wall and zygoma. Either a reciprocating saw, bone scalpel or craniotome (with the longer attachment) can be employed.

Osteotomy No. 1: An angled cut (advanced obliquely superiorly and posteriorly) is made at the zygomatic root such that the temporomandibular joint is preserved.

Osteotomies No. 2 and No. 3: These osteotomies extend from the inferior orbital fissure to the temporal process of the zygoma such that the frontal and temporal processes of the zygoma are released in one piece from the body of the zygoma. During Osteotomy No. 2, a small retractor is utilized intraorbitally to protect the periorbita. In order to ensure good cosmetic reconstruction, these two cuts are done in a V-shape.

Osteotomy No. 4: This osteotomy extends from the orbital ridge posteriorly along the orbital roof towards the superior orbital fissure. This cut typically commences just lateral to the superior orbital notch/foramen. In order to prevent postoperative pulsatile proptosis, the cut must extend at least 3 cm posteriorly. As this cut extends posteriorly it is then directed laterally to the junction of the superior and lateral orbital walls or towards the keyhole if a MacCarty keyhole was used.

Osteotomy No. 5: This osteotomy extends from the inferior orbital fissure (extraorbital, extracranial) towards the completion point of the last cut. This last cut releases the lateral orbital wall.

At this point, the complete orbitozygomatic osteotomy is elevated. Subsequently any remaining components of the sphenoid wing towards the anterior clinoid process can be removed.

Depending on the target lesion, additional bony removal can be performed, including: anterior clinoidectomy, optic canal unroofing, superior orbital fissure unroofing. Where the surgeon’s working space is viewed as a cone and the base of the cone is on the surface of the brain, these additional maneuvers increase access to the apex of the cone.