Chapter 60 - Periorbital surgery Flashcards
7 bones make up orbit
sphenoid maxillary ethmoid lacrimal zygoma palatine frontal
A –> P layers of eyelid
skin orb oculi septum preaponeurotic fat levator aponeurosis Muller muscle (sm-m) conjunctiva
distances of anterior ethmoid/posterior ethmoid/optic canal from rim
24 mm (ant ethm)
12mm more posterior (post)
6mm more posterior (canal)
Dermatochalasis vs blepharoptosis
D: excess skin upper eyelid
B: droop eyelid often 2/2 levator dysfunction
3 methods of blepharoptosis repair
External levator advancement
Muller muscle conjunctiva resection
Frontalis sling (tether lid to frontalis if levator fxn poor)
Why contralateral eye may fall after bleph repair
Hering’s law of equal innervation
Brain had increased levator innervation to both eyes when one was ptotic, giving pseudoretraction to other eye
After repair, brain decreases innervation to both, so contralat eye may now drop
Order to repair proptosis, strabismus and eyelid retraction in thyroid eye disease
Decompression then strabismus then eyelid retraction
5 incisions to approach orbit
transconj lateral canthotomy upper lid skin crease transcaruncular vertical lid split
What to preserve in decompression orb floor to minimize dystopia/diplopia
inferomedial orbital strut
How to fill anophthalmic socket
dermis fat graft
silicone, polymethylmathacrylate (PMMA)
hydroxyapetite, porous polyethylene, aluminum oxide (these three allow fibrovascular growth)
How to repair involutional ectropion/entropion
horizontal shortening of eyelid
Sx of orbital compartment syndrome
decreased vision
afferent pupillary defect
increased IOP
Which lacrimal lobe to biopsy
orbital lobe
to not injure outflow apparatus from palpebral lobe
What lies between lower eyelid medial and central fat pads
inferior oblique
Changes to periorbital with age
tissue descent, lose SQ fat, deepen skin wrinkles
rhytids, brow ptosis, dermatochalasis, orbital fat prolapse (weakened septum)
