What are the basic important principals of microsurgery? (8)
- use magnification (2-4x loupes, operating microscope)
- sit down
- elbow rest
- pencil grip for instruments
- proper instrumentation
- small suture materials
- gentle tissue handling, don't touch a tissue without doing something with it
What instruments are unique to microsurgery?
- castroviejo locking needle holders
- #64 beaver blades
- martinez corneal dissector
- colibri forceps (for conj and cornea)
- bishop harmon forceps (for conj and skin)
- stevens tenotomy scissors
- wescott tenotomy scissors
- chalazion clamp
- eyelid speculum
- jaeger eyelid plate
- muscle hooks, eyelid retractor
What type of needles are used in microsurgery?
- Cornea: spatula needle with swaged on 7-0 or 9-0 vicryl suture
- Skin/ conj: cutting needles with swaged on 4-6, 6-0 vicryl or nylon suture
Most canine eyelid masses are _______.
Describe the basic principals of eyelid mass resection. (3)
- use chalazion clamp to immobilize mass and provide hemostasis and a cutting surface
- full-thickness, wedge-shaped excision through skin and tarsal plate with #15 blade
- finish excision with tenotomy scissors
How do you close the conj after a wedge resection of an eyelid mass?
- close conj with 4-0 to 6-0 absorbable suture, starting distally and working towards eyelid margin
- continuous horizontal mattress pattern
- reverse direction at eyelid margin, so the loop across the top opposes the margins of the incision
How do you close the skin after a wedge resection of an eyelid mass?
- 4-0 to 6-0 non-absorbable suture
- start with figure of 8 (modified cruciate) stitch at the eyelid margin; symmetry is imperative
- leave long tags and incorporate them into simple interrupted
Describe the temporary tacking sutures used to correct entropion in young animals.
- 2-3 vertical mattress sutures using 4-0 to 6-0 non-absorbable suture
- MUST START 1mm or less from eyelid margin!!!!
What are considerations when planning for entropion repair? (3)
- lower eyelid entropion is more common than upper
- most also have macroblepharon
- most also have lateral canthal laxity/ rolling (notching of eyelid near lateral canthus)
What are indications for permanent lateral canthoplasty? (2)
- lateral canthal rolling/ laxity
Describe permanent lateral canthoplasty procedure.
- full-thickness excision of crescent, including upper and lower eyelid margin
- two-layered closure (same as wedge resection closure)
- AFTER--> modified hotz-celsus procedure should be performed
What is the modified hotz-celsus procedure?
- crescent-shaped wedge of skin removed from lower lateral lid
- start AT MOST 1-2mm from lower eyelid margin
- place middle two sutures first, then close with interrupteds
- everts lower eyelid
What are the characteristics of an indolent corneal ulcer? (4)
- slow to vascularize
- loose epithelium around margins
What is the treatment for an indolent corneal ulcer?
- corneal cytology to rule out infection
- topical anesthetic
- debride epithelium with dry cotton-tipped swabs
- multiple grid keratectomy with 25 gauge needle or diamond burr
What is the follow up for an indolent corneal ulcer? (5)
- terramycin TID, atropine q 48hr, e-collar
- >90% are healed in 14 days
- wait 2-3 weeks before repeated grid keratectomy
What are indications for a superficial keratectomy? (5)
- melting corneal ulcer
- stromal abscess
- corneal sequestrum
- corneal dermoid
- corneal neoplasia?
What instruments are required for a superficial keratectomy?
- #64 beaver blade or corneal dissector
- colibri forcep
How much of a dog's eyelid can you safely remove and still have primary closure? Cats? Horses?
- Dogs: up to 33% of eyelid margin
- Cats, Horses: up to 25%
How much of the cornea can safely be removed by superficial keratectomy?
up to 50% of stromal depth without need for a graft
What are indications for a conj pedicle graft?
- deep (>50% stromal depth), non-perforating corneal ulcer refractory to medical therapy
- [descemetocele, mycotic keratitis, bullous keratopathy, stromal abscess, melting ulcer]
How is a conjunctival autograft achieved?
- debridement of affected cornea by superficial keratectomy
- bulbar conj mobilized using stevens tenotomy scissors
- dissect away tenon's fascia to create a thin flap without tension
- appose conj and corneal epithelium
- severe blood supply >8wks following sx to limit scar formation
How big should the flap be for a pedicle graft?
must be as wide as the defect and long enough to avoid tension or retraction when put in place