16 Surgical Positioning and Exposures

Orbitozygomatic Osteotomy

1.25 Generally, the orbito-
zygomatic osteotomy supplements the ex-
posures achieved by the pterional, modified
pterional, and subtemporal craniotomies.
In this example, the procedure is used with
the pterional craniotomy. Preparation and
patient positioning for the orbitozygomatic
osteotomy are the same as for the pterional
approach. The orbitozygomatic osteotomy
consists of removal of the superior orbital
rim, orbital roof, and zygoma with inferior
mobilization of the temporalis muscle. This
technique improves the exposure of basilar
aneurysms that originate above the poste-
rior clinoid and most giant aneurysms of the
basilar terminus. The exposure not only
permits a wide opening of the sylvian
fissure by a greater mobility of the temporal
lobe but also reduces brain retraction and
frequently obviates the need to resect the
anterior temporal lobe. Therefore, the or-
bitozygomatic osteotomy yields a wide
field of exposure inferiorly and gives a di-
rect line of view to the undersurface of the
medial frontal lobe.

1.26 The skin incision begins
below the zygoma (1 cm anterior to the
auricle), extends superiorly, and continues
across the midline posterior to the hairline.
The cutaneous flap is elevated from the un-
derlying temporalis fascia, muscle, and
bone; this step exposes the superior and
lateral orbital rim and zygomatic bone. The
temporalis fascia is incised parallel to and 1
cm above the zygomatic process. Next, the
temporalis fat pad, which contains the fron-
talis nerve, is mobilized with the cutaneous
flap. The temporalis muscle and fascia are
incised, leaving a superior cuff of fascia for
closure. The myofascial flap is elevated
from the underlying bone and a pterional
bone flap is elevated.

1.25

Supine: Orbitozygomatic Osteotomy 17

Temporalis
fat pad t

1.26

1.27

1.27 The dura is secured to
the bone edge at multiple sites with absorb-
able sutures. Stainless steel wires are
placed for subsequent stabilization of the
bone flap. The dura is opened near the skull
base. The sphenoid ridge is removed to the
lateral margin of the superior orbital
fissure.

18 Surgical Positioning and Exposures

1.28 Titanium microplates
are positioned at the sites of osteotomy.
Holes are predrilled to ensure that proper
anatomic alignment of the osteotomy flap
will be achieved when it is replaced. Using
a 1-mm pneumatic power drill, the surgeon

makes three osteotomies—across the supe-
rior orbital rim, across the zygoma into the
inferior orbital fissure, and across the zy-
gomatic process (hidden behind the tempo-
ralis muscle).

Supine: Orbitozygomatic Osteotomy 19

Zygomatic
process

Superior

orbital

fissure

Lateral

orbital

rim

Superior

orbital

rim

1.29

1.29 Understanding the anat-
omy of the inferior orbital fissure is critical
to this technique.

1.30 Using an osteotome, the
surgeon continues the osteotomy at the su-
perior orbital rim across both the orbital
roof and the lateral wall of the orbit into the
inferior orbital fissure.

1.30

20 Surgical Positioning and Exposures

1.31 The orbitozygomatic
flap is fractured and removed as a single
piece of bone. The temporalis muscle is
reflected inferiorly.

Supine: Orbitozygomatic Osteotomy 21

1.32 Using a rongeur, the
surgeon removes the temporal bone flush
with the floor of the middle fossa.

1.33 A curvilinear incision is
made in the dura. The flap is reflected infe-
riorly and sutured to the temporalis muscle.

1.33

22 Surgical Positioning and Exposures

1.34

Closure 1.34 The dura is closed with
a continuous absorbable suture. Titanium
microplates and screws secure the orbito-
zygomatic bone flap and cranial bone flap.

Supine: Orbitozygomatic Osteotomy 23

1.35 The temporalis muscle
is replaced beneath the zygomatic process.
Both temporalis muscle and fascia are reap-
proximated and then reattached to the su-
perior fascial cuff on the bone flap. Any
bone defects are replaced with methyl
methacrylate to improve the cosmetic
result.

1.35

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