Page 175 - Manual of Equine Field Surgery
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Enucleation-Transconjunctival and Transpalpebral 171
Zygomatic process of
lnfratrochlear notch frontal bone Zygomatic process of
temporal bone
--- -·-··-··- --
Caudal lacrimal process ....... ~ -- ---........ ·- ---
..
Fossa of lacrimal sac
-
i
..
'
I
Caudal alar foramen
•
Temporal process
of zygomatic bone
Figure 30-1 Schematic demonstrating the horse's bony orbit.
Using delicate toothed forceps, such as Bishop- globe, the optic nerve is isolated and clamped
Harmon tissue forceps, the conjunctiva is gently approximately 4 to 5 mm caudal to the sclera.
grasped adjacent to the limbus and tented, and the Using curved Metzenbaum scissors or enuclea-
conjunctiva is snipped approximately 2 mm from tion scissors, the optic nerve is transected
the limbus with Steven's tenotomy scissors to between the sclera and the clamp to leave approx-
create an incision. A peritomy (360° conjunctiva! imately 2 to 3 mm of optic nerve attached to the
mcision adjacent to the limbus) is performed enucleated globe. The conjunctiva, third eyelid,
using blunt and sharp dissection with Steven's and third eyelid gland are removed using Met-
tenotomy scissors, leaving approximately 2 mm of zenbaum scissors. The eyelid margins are excised
conjunctiva attached to the Iimbus for grasping from the eyelids approximately 4 mm from the
with forceps for globe manipulation (Figure 30-2, eyelid margin using Mayo scissors. Hemostasis
A and B). The dense fibrous connective tissue during removal of the conjunctiva and eyelid
attachment of Tenon's fascia is grasped and margins is provided with hemostatic clamps
incised with tenotomy scissors. Tenon's capsule is or electrocautery. The surgical site is closed in
incised near its insertion over its circumference, three layers. A simple continuous pattern of No.
and the extraocular muscles and fascial attach- 3-0 absorbable suture is used to close the fascia
ments are transected at their insertions using and connective tissue attached to the orbital rim
curved Metzenbaum scissors or curved Steven's in a manner to create a diaphragm to minimize
I tenotomy scissors. Avoiding rostral traction of the concavity postoperatively. A simple continuous
