60 Periorbital surgery Flashcards Preview

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Flashcards in 60 Periorbital surgery Deck (31):
1

Name the seven bones that make up the orbit.

Name the seven bones that make up the orbit.

Sphenoid, maxillary, ethmoid, lacrimal, zygoma, palantine, and frontal

2

What are the distances of the anterior ethmoid artery, posterior ethmoid artery, and optic canal from the orbital rim?

What are the distances of the anterior ethmoid artery, posterior ethmoid artery, and optic canal from the orbital rim?

This can be remembered by the mnemonic 24-12-6. The anterior ethmoid is approximately 24 mm from the orbital rim, the posterior ethmoid is another 12 mm posterior to that, and the optic canal is another 6 mm.

3

An object travels through the upper eyelid 12 mm superior to the lid margin. What structures does it travel through?

An object travels through the upper eyelid 12 mm superior to the lid margin. What structures does it travel through?

In the upper eyelid, the tarsus is typically not taller than 10 mm. So at 12 mm, the object will travel above the tarsus. The layers from anterior to posterior are the skin, orbicularis oculi, orbital septum, preaponeurotic fat, levator aponeurosis, Müller’s muscle, and conjunctiva.

4

What are the eyelid lamellae?

What are the eyelid lamellae?

The eyelid is sometimes conceptualized as consisting of an anterior and a posterior lamella. The anterior lamella consists of the skin, and the layer of striated muscle fibers of the orbicularis muscle. The posterior lamella consists of the tarsal plates, a layer of smooth muscle (Müller’s palpebral muscle), and the palpebral conjunctiva. The anterior and posterior lamellae are separated by the orbital septum.

5

What is the difference between dermatochalasis and blepharoptosis?

What is the difference between dermatochalasis and blepharoptosis?

Dermatochalasis refers to excess skin on the upper eyelid. When severe, it can hang down over the upper eyelid lashes and block the superior visual field. Blepharoptosis refers to drooping of the eyelid, often due to levator dysfunction.

6

How is dermatochalasis repaired?

How is dermatochalasis repaired?

By performing a blepharoplasty. In this procedure, excess skin, and occasionally orbicularis muscle, is excised. If there is excessive preaponeurotic or orbital fat, it can be judiciously excised by opening the septum.

7

How is blepharoptosis repaired?

How is blepharoptosis repaired?

The two most common methods to repair blepharoptosis are external levator advancement (ELA) and Müller’s muscle conjunctiva resection (MMCR). ELA involves a skin incision at the lid crease, whereas MMCR is performed on the conjunctival side of the upper lid. When levator function is poor, such as in congenital ptosis, the upper eyelid can be tethered to the frontalis muscle to assist in eyelid elevation. This is known as a frontalis sling.

8

The contralateral eyelid occasionally falls after ipsilateral blepharoptosis repair. Why does this happen?

The contralateral eyelid occasionally falls after ipsilateral blepharoptosis repair. Why does this happen?

Hering’s law of equal innervation postulates that yoke muscles receive equal innervation. More specifically, when one eyelid is ptotic, the brain increases innervation to both levator palpebrae muscles in an attempt to clear the visual axis. The increased innervation to the contralateral eyelid can result in pseudoretraction. After repair of unilateral blepharoptosis, the innervation to the levator palpebrae is decreased and a drop of the contralateral eyelid may occur.

9

What is the best treatment a patient with biopsy-proven basal cell carcinoma of the lower eyelid?

What is the best treatment a patient with biopsy-proven basal cell carcinoma of the lower eyelid?

Complete excision with frozen sections. Alternatively, they can be referred to a Mohs surgeon for excision.

10

What principles should be kept in mind when planning reconstruction of an eyelid defect?

What principles should be kept in mind when planning reconstruction of an eyelid defect?

Important principles include avoiding vertical tension and maintaining a good vascular supply. Minimizing vertical tension avoids eyelid retraction. When a full thickness defect is present, only one lamella can be repaired with a free graft. If both anterior and posterior lamella are replaced with free grafts, the rate of failure is high due to lack of blood supply.

11

What is ectropion? What are the causes?

What is ectropion? What are the causes?

Ectropion is outward turning of the eyelid. Causes can be involutional, paralytic, mechanical, cicatricial, and congenital in nature.

12

What is entropion? What are the causes?

What is entropion? What are the causes?

Entropion is an inward turning of the eyelid. Causes can be involutional, acute spastic, cicatricial, and congenital in nature.

13

How does repair of involutional ectropion and entropion differ?

How does repair of involutional ectropion and entropion differ?

Both involve horizontal shortening of the eyelid. For ectropion, this is usually sufficient. For entropion, the surgeon must also reattach the lower lid retractors to the tarsus to avoid recurrence.

14

If a patient with thyroid eye disease has proptosis, strabismus, and eyelid retraction, what is the order of surgeries to correct their issues?

If a patient with thyroid eye disease has proptosis, strabismus, and eyelid retraction, what is the order of surgeries to correct their issues?

They should first have a decompression, followed by strabismus surgery, then correction of eyelid retraction. This is because decompression can alter strabismus, and strabismus surgery can alter eyelid position.

15

Name five surgical incisions to approach the orbit.

Name five surgical incisions to approach the orbit.

Transconjunctival, lateral canthotomy, upper lid skin crease, transcaruncular, vertical lid split.

16

During decompression of the orbital floor, what should be preserved to minimize dystopia and diplopia?

During decompression of the orbital floor, what should be preserved to minimize dystopia and diplopia?

The inferomedial orbital strut.

17

What choices are available to fill an anophthalmic socket after enucleation or evisceration?

What choices are available to fill an anophthalmic socket after enucleation or evisceration?

Orbital implants can be autologous or alloplastic. A dermis fat graft is an example of an autologous implant. Alloplastic implants can be divided into porous and nonporous implants. Porous materials allow fibrovascular ingrowth and include hydroxyapatite (HA), porous polyethylene, and aluminum oxide. Nonporous materials include polymethylmethacrylate (PMMA) and silicone.

18

What are the signs of an orbital compartment syndrome due to retrobulbar hemorrhage? What is the treatment?

What are the signs of an orbital compartment syndrome due to retrobulbar hemorrhage? What is the treatment?

Symptoms can include decreased vision, afferent pupillary defect, and increased intraocular pressure. Diagnosis is clinical, not radiographic. Treatment involves lateral canthotomy and cantholysis to relieve orbital pressure.

19

When biopsy of the lacrimal gland is indicated, what lobe should be biopsied?

When biopsy of the lacrimal gland is indicated, what lobe should be biopsied?

The lacrimal gland is made up of an orbital lobe and a palpebral lobe. The orbital lobe drains into the palpebral lobe, which then drains onto the ocular surface. Biopsy of the palpebral lobe can cause injury to the tear outflow apparatus. Therefore, biopsy should be taken from the orbital lobe.

20

What is a DCR? What approaches are available?

What is a DCR? What approaches are available?

DCR stands for dacryocystorhinostomy. It is a surgery used to treat nasolacrimal duct obstruction. The procedure creates a new passage from the nasolacrimal system into the nasal cavity above the level of obstruction. It can be accomplished by an external approach through the skin or by an internal approach through the nose.

21

What are the most common reasons for DCR failure?

What are the most common reasons for DCR failure?

Common canalicular obstruction and closure of the osteotomy secondary to fibrosis or scarring.

22

What lies between the lower eyelid medial and central fat pads?

What lies between the lower eyelid medial and central fat pads?

The inferior oblique muscle.

23

What factors contribute to periorbital aging?

What factors contribute to periorbital aging?

Involutional changes in the upper face include descent of tissues, loss of subcutaneous fat, and deepening of skin wrinkles. Specific findings include static rhytids, dynamic rhytids, brow ptosis, upper eyelid dermatochalasis, and orbital fat prolapse secondary to weakening of the orbital septum.

24

Name some nonsurgical treatments for periorbital aging.

Name some nonsurgical treatments for periorbital aging.

Botulinum toxin injections, dermal fillers, laser resurfacing, and chemical peels.

25

What is the lethal dose of botulinum toxin in an average sized adult?

What is the lethal dose of botulinum toxin in an average sized adult?

Approximately 3000 units.

26

Name some of the common filler materials used in the face?

Name some of the common filler materials used in the face?

  • Autologous fat
  • Collagen materials
  • Hyaluronic acid: Juvederm (Allergan) Restylane, Perlane (Medicis Aesthetics)
  • Poly-L-lactic acid (PLLA): Sculptra (Valeant Aesthetics)
  • Calcium hydroxylapatite: Radiesse (Merz)
  • Polymethylmethacrylate (PMMA): Artefill (Suneva Medical)

27

What is the advantage of using hyaluronic acid fillers?

What is the advantage of using hyaluronic acid fillers?

Hyaluronic acid has represented the largest market share for dermal filling products. This is partly because these fillers are reversible with the application of hyaluronidase.

28

List some of the complications of filler injection.

List some of the complications of filler injection.

The most serious reported complications of dermal filler injection include infection, tissue necrosis, and blindness from direct intravascular injection. Other complications include migration of filler, erythema, bruising, pain, and visible nodules due to injection technique or granulomatous inflammation.

29

List the major and minor complications of blepharoplasty.

List the major and minor complications of blepharoplasty.

Major complications include retrobulbar hemorrhage, globe perforation, diplopia, and severe dry eyes. Minor complications include eyelid malposition, eyelid hematoma, wound dehiscence, milia, and chemosis.

30

Name the different techniques to lift the brow.

Name the different techniques to lift the brow.

Transblepharoplasty, direct, midforehead, temporal, pretrichial, coronal, and endoscopic brow lifts have all been described. These approaches vary with respect to incision site, dissection plane, and fixation method.

31

How is the Asian eyelid different from the western eyelid?

How is the Asian eyelid different from the western eyelid?

The insertion point of the septum into the levator aponeurosis is lower in Asians.  As a result, the fat behind the septum can move lower on the eyelid. This causes the eyelid crease to be lower on nonexistent, and gives the appearance of a fuller lid. If a crease is present, it usually runs parallel to the lid margin, as oppose to the semilunar shape of the western lid. Asian eyelids are also more likely to have an epicanthal fold.

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