Surgery Flashcards
When performing a retrobulbar block, the popping sensation is passage of the needle through what?
Orbital fascia
When injecting during a retrobulbar block, where should the eye move?
Move forward and rotate centrally
What happens to the pupil during a retrobulbar block?
Dilates
Why do you want to leave as much soft tissue as possible in an enucleation?
To help reduce depression of skin into socket
Why should you avoid excessive traction on the extra ocular muscles?
You can get an oculocardiac reflex
What size suture to close the periorbital/deep fascial layers, subcutis, and skin in enucleation?
4-0
What should you warn owners about post-op regarding drainage?
There may be serosanginous ipsilateral nasal discharge for a few days until the nasolacrimal duct is obliterated
What is removed in an enucleation? Exenteration?
Enuc: globe, medial caruncle, conj, third eyelid
Exenteration: same as above, plus periorbital tissue and extra ocular muscles
How far from the eyelid margins do you incise for a transpalpebral enucleation? For an exenteration?
TP enuc: 3 mm
Exenteration: 5mm
What are 2 types of mesh that can be used to reduce sinking of skin post-enucleation?
Dacron or prolene
What are the two most common ocular implants used?
Silicone or methyl methacrylate spheres
What size ocular implant is used in dogs (range)?
12-28 mm
Why is the 1/4 anterior-most aspect of the implant removed?
To prevent rotation of the implant and to improve overall cosmesis (edges should be rounded off)
How should an ocular implant fit?
No undue compression of tissues, but snug in orbit. It should not protrude from orbital rim.
When evisceration is performed, how big should the intrascleral sphere be?
Horizontal diameter of the opposite CORNEA, or 1-2 mm wider
What percentage of dogs that have evisceration performed have complications?
10%
What is the most common complication post-evisceration?
Corneal erosion and septic keratitis
What sort of magnification is recommended for eyelid surgery?
3x - 5x
What is more precise: rounded scape blade pulled towards direction of movement, or straight scape blade pushed towards direction of movement?
Straight, pushed in direction of movement
Why should you be careful with microcautery?
Cautery causes local necrosis
When there is diffuse hemorrhage during lid surgery, what tends to swell first, and what does that do to the lid?
Conj swells the most = pushes lid away from the cornea
What happens if the lid pushes away from the cornea during entropion correction surgery?
It may appear that the surgeon OVER corrected, but this should normalize
How does freezing kill cells?
Expands intracellular water and lyses them
How cold (range) do you want to freeze things to?
At least -25C, but no colder than -30C due to necrosis
How many freeze thaws do you want?
At least 2
What two substances can be used to freeze?
Carbon dioxide
Nitrous oxide
How does electrocautery destroy a hair follicle?
Coagulation
How do you use the Perma Tweez?
Follow the hair to the approx level of the hair follicle (3-5 mm max), rotate tip slightly for at least 15 sec, then remove– hopefully hair will come out with it, if not, hair should easily manually epilate (no resistance)… if that doesn’t work, then need to do another procedure
How well do electrocautery units for hemostasis work for distichiasis?
They are too powerful (will destroy free edge of lid)
How well does a bipolar electrolysis apparatus (used to remove mustache hairs in people) work for distichiasis?
Usually not powerful enough (follicle is too deep)
Where (location) is cryosurgery performed for distichiasis?
Over the conjunctival surface of the follicle 3-4 mm behind the free margin of the lid
What temp do you want to perform cryosurgery to remove distichia/
-25 to destroy follicle, but not greater the -30 (will cause necrosis of eyelid)… probes will be set to -25C
How long do you do freeze/thaw in cryosurgery for distichiasis?
60 sec freeze, short thaw, then 30 sec freeze
What is the immediate side effect of cryotherapy?
Significant swelling over site, sometimes to point where they can’t blink
How do you help avoid/treat swelling associated with cryotherapy for distichiasis?
Pre-op NSAID or post-op topical steroid-ABx
How long does swelling associated with cryotherapy last?
2-4 days
How soon after cryo will you see depigmentation? Re-pigmentation?
72 hrs
Up to 6 months
What complications do you need to warn owners about with cryo? (3)
- Risk of permanent depigmentation
- Risk of scarring
- Risk of distortion
Lid splitting techniques to remove distichia require what of the patient? Why?
Adequately thick lids– if not, it can cause cicatricial distortion
In the lid splitting technique that removes part of the tarsal plate to remove the distichia, what can happen if you remove too much?
Entropion
Why would the Celsus–Hotz procedure be used if there is distichia?
If there are lots of distichia along the entire lid, you may be able to evert them away from the corneal surface
What are the two benefits of the Stades procedure for distichia?
- removes the distichia
2. everts the lid
What is the downside of the Stades procedure?
marked scar formation just outside the lid margin (the Stades procedure works by allowing second intention healing to create a scar)
What are ways to destroy the hair follicle of an ectopic cilia?
Evert lid (such as with a chalazion clamp)
- Remove covering over hair follicle with electric scalpel
- Remove en-bloc with scalpel or biopsy punch
- Cryosurgery
After treating an ectopic cilia, what must you tell the owner?
- The germinal bud may not be destroyed and hair shaft may regrow
- There may be adjacent cilia that are not visible but may grow
When is tacking used for entropion? (breed, age)
Usually puppies <12wks, primarily Chow and Shar Pei
What size suture and how many sutures are placed for tacking sutures?
4-0 to 5-0; 2-4 sutures
How long are the bites for tacking sutures?
5mm
How long are the sutures left after tacking?
Long, to allow for multiple adjustments
How long can tacking sutures be left?
4-6 wks or when they fall out
Why are tacking sutures considered surgical correction?
B/c the scar tissue tunnel that they form can cause a permanent correction
Hotz-Celsus: what did they each do (and when did they live?)
Celsus: 1st century AD– just removed skin
Hotz: also took a piece of orbicularis oculi and anchor sutures in remaining muscle
Where is the incision for the Celsus-Hotz procedure made?
2-2.5mm from margin (where you start getting real hairs)
How far (length) do you make an incision for the Celsus-Hotz?
At least 1mm medial and lateral to the length of the entropion
