Chapter 125 Emergency Ophtho Surgery Flashcards
(39 cards)
Look at this diagram and learn the muscles…
What are the four layers of the eyelid
How are lacerations closed?
Skin, muscular, fibrous, conjunctiva
2 layer closure
What is best predictor of perfect post-op eyelid function following laceration?
Meticulous marginal apposition
When doing a figure of 8 suture to align eyelid margins, what should be used to determine appropriate eyelid margin exit point
Opening of meibomian glands
When shoudl figure of 8 clusure not be used for eyelid apposition
At lateral (or presumably medial) canthus Just do simple interrupted and tie suture ends into mosre lateral sutures so they dont poke into the eye
How is severed NL duct treated
Thread 2/0 Monofilament along duct and affix end away from eye and nose.
Repair any other damage
Leave suture inplace for 2-4 months!
List 3 broad surgical techniques for management of corneal ulcer (and subcategories where necessary)
-
Autografts
- Bulbar conjunctival graft aka Gunderson’s graft
- Corneoconjunctival transposition
-
Corneal allografts
- Penetrating keratoplasty (full thickness)
- Lamellar keratoplasty (partial thickness)
-
Extracellular matrix grafts
- Porcine SIS
- Porcine urinary bladder
List 4 variations of a conjuntival graft
A, Pedicle graft.
B, Bridge graft.
C and D, Island graft.
E, 360-degree graft.
What is a key step in harvesting conjunctival graft and why
Removal of Tenon’s capsule
To reduce tension on graft and reduce post op contracture by Tenon’s fibroblasts (both risk factors for graft dehisence)
What non-sx steps shoudl be performed before conjunctival graft
Ulcer sampling for cytology and culture + susceptibility
What is size of pedicle graft relative to ulcer?
3mm wider
Describe condition
Axially located descemetocele in a dog. Notice the deep stromal walls that stain positively with fluorescein and the lucent, glistening Descemet’s membrane that does not stain positively.
Where is conjunctival graft harvest started, relative to limbus
1mm lateral
What step is performed prior to conjunctival graft suturing
Prep of ulcer bed
- bed swabbed with cellulose or edge of beaver blader to remove any epithelail cells (want graft to heal TO epithelium, not epithelium healing under graft)
If edges melting resect cornea back to healther tossie to allow suture holding
What suture is used to suture corneal graft
8/0 Vicryl (polyglactin 910)
What steps are performed afer cinjunctival graft suturing
Suture scleral donor site and consider temprrary tarsorrhaphy
How long is conjunctival graft left in place
How is remaing scar minimised
6-8 weeks
Short course topical roids
What is rule of thumb re conjunctival pedical graft arm angle
Shouldnt exceed 45º from vertical to minimise shear stress form blinking (risk for dehisence)
List 3 rosk factors for conjunctival graft dehisence
- Tenons capsuel tension
- Fibrosis from tenons capsule fibroblasts
- Angle >45º from vertical –> shear forces from blinking
What procedure has been performed
Corneoconjunctival transposition immediately after surgery. Notice that the limbus has been shifted toward the corneal axis in the area of the graft.
What is benefit of corneoconjunctival transposition over conjunctival graft
Allows for clear corneal axis
What is sixelimitation for performing conrenoconjunctival transposition
5mm and must be axial
At what stromal level is conrneoconjunctival transposition performed/
Half stomal
What corneal lesions are particularly suited to corneal allograft?
>6mm
or
Already perforated
N.B. corneal allografts and biosynthetic grafts can be covered with a conjunctival graft after if necessary, just NB
