Page 174 - Manual of Equine Field Surgery
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CHAPTER 30
Enucleation-Transconjunctival and Transpalpebral
Laurence E. Galle
INDICATIONS PREPARATION AND POSITIONING
Enucleation is indicated when there is minimal or The patient should be placed in lateral recum-
no chance for maintenance of vision and when bency under general anesthesia with the affected
leaving the globe would result in continued eye up.
patient discomfort or leave the patient at risk of
systemic complications. Common indications
for enucleation include ruptured globes, intraoc- ANATOMY
ular neoplasia, panophthalmitis, and chronic
uveitis or glaucoma.f It is imperative that the Unlike carnivores, the equine globe is positioned
surgeon consider all alternatives that might within a completely enclosed bony orbit (Figure
otherwise retain a comfortable, visual eye prior 30-1). Extraocular muscles, vascular supply, fat,
to performing an enucleation. The trans- fascia, and the optic nerve form the orbital cone
conjunctival approach is preferred for optimal as they converge to the posterior aspect of the
cosmesis and minimal need for hemostasis. The orbit. The orbital cone is completely enclosed
transpalpebral approach, with use of a complete within a connective tissue fascial sheath called
tarsorrhaphy prior to enucleation, is indicated for Tenon's fascia, which merges anteriorly with the
contaminated or infectious ocular disorders sclera adjacent to the limbus. The conjunctiva is
where reducing the potential of contaminating firmly attached to the limbus, becomes more
the orbit with conjunctiva! microbial flora is elastic and loosely attached as it forms the con-
desired.3 junctiva! fornix, and reflects onto the posterior
surface of the eyelids where it again becomes
firmly attached at the eyelid margin. The fibrous
tarsal plate of the eyelids is continuous with dense
connective tissue called the orbital septum that
inserts on the orbital rim. 4•5
EQUIPMENT
PROCEDURE
A general surgical pack is appropriate for an enu-
cleation. Additional instrumentation that may Transconjunctival Enucleation
prove valuable includes suction, electrocautery,
Steven's tenotomy scissors, and Bishop-Harmon A lateral canthotomy is performed with Metzen-
tissue forceps. baum scissors to facilitate exposure of the globe.
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