Combined Orbito-Zygomatic Approaches

Pietro Mortini, Alfio Spina, Michele Bailo, Anthony J. Caputy, Cristian Gragnaniello, and Filippo Gagliardi

17.1 Introduction

The Fronto-orbito-zygomatic (FOZ) approach represents one of the workhorses of skull base surgery. Through this approach, it is possible to provide a wide exposure and a direct access to different tumoral and cerebrovascular pathology of the anterior and middle cranial fossa, sellar and suprasellar area, and anterior upper brainstem. In addition, the orbitozygomatic osteotomy provides the benefit of the extradural unroofing of the optic canal.

17.2 Indications

• Sellar, suprasellar, presellar and parasellar lesions.

• Lesions of the third ventricle.

• Lesions of the anterior surface of the upper brainstem.

• Aneurisms of circle of Willis.

17.3 Patient Positioning

• Position: The patient is positioned supine with head fixed with a Mayfield head holder.

• Body: The chest should be elevated to facilitate venous return.

• Head: The head is rotated 30° to the contralateral side, and extended about 20°.

• The zygomatic process must represent the highest point of the surgical field.

• Pin holders must be positioned as distant as possible to the planned skin incision.

17.4 Skin Incision

17.4.1 Extended Coronal Skin Incision (Figs. 17.1)

• Starting point: Incision starts less than 1 cm anterior to the tragus on the side of the approach.

• Course: Incision runs toward the midline and to the contralateral side, just behind the hairline.

• Ending point: It ends at the junction between the lateral and middle third of the coronal line.

17.4.2 Critical Structures

• Superficial temporal artery and its distal branches.

• Peripheral branches of the facial nerve.

Fig. 17.1 Bicoronal skin incision.

17.5 Soft Tissue Dissection

• Pericranial layer

◦ The pericranial flap is reflected together with the skin flap, up to the orbital rim.

• Muscle (Figs. 17.2, 17.3)

◦ Interfascial dissection of the temporal muscle is carried out (see Chapters 6 and 8).

◦ The subperiosteal dissection of the temporal muscles is performed to the frontal process of the zygoma; the body of the zygomatic bone and the temporal fossa are exposed.

◦ Temporal muscle is reflected inferiorly.

• Bone exposure (Fig. 17.4)

◦ Zygomatic process of the frontal bone, frontal process of the zygomatic bone, temporal fossa (greater wing of the sphenoid, temporal squama).

Fig. 17.2 Superficial soft tissue dissection.
Abbreviations: CS = coronal suture; E = ear; FB = frontal bone; FP = fat pad; SON = supraorbital nerve; STA = superficial temporal artery; TF = temporal fascia.

Fig. 17.3 Superficial soft tissue dissection: Interfascial dissection.
Abbreviations: CS = coronal suture; E = ear; FB = frontal bone; FP = fat pad; SON = supraorbital nerve; STA = superficial temporal artery; TF = temporal fascia; Z = zygomatic process of the frontal bone.