Auer Ch 55 Surgery Of The Orbit

Front 1

Components of the orbital rim:

Back 1

frontal bone (dorsal), lacrimal bone (medial), zygomatic bone (ventral), fusion of zygomatic process of frontal bone, frontal process of zygomatic bone, zygomatic process of temporal bone (lateral)

Front 2

Where is the supraorbital foramen located?

Back 2

Dorsolateral orbit in the zygomatic process of the frontal bone

Front 3

What is the lacrimal sac?

Back 3

Dilated origin of the nasolacrimal duct

Front 4

Location of the lacrimal sac and nasolacrimal duct:

Back 4

the lacrimal sac is within the lacrimal fossa, an indentation of the lacrimal bone, and the nasolacrimal duct extends from the sac through the lacrimal canal

Front 5

What forms the medial orbital wall?

Back 5

Lacrimal, sphenoid, palatine bones

Front 6

What forms the orbital floor?

Back 6

Zygomatic arch, periorbital fascia, orbital fat, pterygoid muscle

Front 7

What foramina are in the pterygopalatine fossa of the zygomatic bone?

Back 7

Maxillary foramen (maxillary vessels, nerve), sphenopalatine (sphenopalatine vessels, caudal nasal nerve), caudal palatine foramen(major palatine artery and nerve)

Front 8

What are the foramina of the orbital apex?

Back 8

Ethmoid foramen (dorsal), optic foramen (ventral & caudal to ethmoid foramen), orbital fissure (ventral to optic foramen), rostral alar fissure (caudal and ventral to orbital fissure)

Front 9

Occupants of ethmoid foramen:

Back 9

ethmoid artery, vein, nerve

Front 10

Occupants of optic foramen:

Back 10

optic nerve, internal ophthalmic artery

Front 11

Occupants of orbital fissure:

Back 11

oculomotor (III), trochlear (IV), ophthalmic branch of trigeminal (V), abducens (VI)

Front 12

Occupants of rostral alar foramen:

Back 12

maxillary artery, nerve

Front 13

Function of oculomotor nerve (III):

Back 13

innervation of levator palpebrae superioris; dorsal, medial, ventral rectus; ventral oblique muscles; parasympathetic input of iris sphincter muscle

Front 14

Function of the trochlear nerve (IV):

Back 14

innervation of dorsal oblique muscle

Front 15

Function of ophthalmic branch of trigeminal nerve (V):

Back 15

sensation to cornea, conjunctiva, dorsal eyelid

Front 16

Function of abducens nerve (VI):

Back 16

innervation of retractor bulbi, lateral rectus muscles

Front 17

Major blood supply to the orbit:

Back 17

external ophthalmic artery (branch of maxillary artery)

Front 18

What is the origin of the 4 rectus muscles?

Back 18

Orbital wall medial to orbital fissure

Front 19

Origin and insertion of (dorsal) superior oblique muscle:

Back 19

originates from medial orbital wall, inserts dorsolateral sclera

Front 20

Function of (dorsal) superior oblique muscle:

Back 20

rotates the dorsal globe ventrally and medially

Front 21

Origin and insertion of (ventral) inferior oblique muscle:

Back 21

originates near lacrimal canal, inserts adjacent to the lateral rectus muscle

Front 22

Function of the (ventral) inferior oblique muscle:

Back 22

rotates the globe dorsally and medially

Front 23

Origin and insertion of the retractor bulbi muscle:

Back 23

originates in orbital apex and inserts on the globe equator

Front 24

Components of the orbital fascia:

Back 24

periorbita (cone of fibrous membrane surrounding the eye and its muscles, vessels and nerves) , extraocular muscle fascia, episcleral fascia

Front 25

Contributors to periorbita:

Back 25

periosteum of orbital bones, optic foramen and orbital fissure, contiguous with the dura of the optic nerve; a portion extends to form the orbital septum to merge with tarsal plate at eyelids

Front 26

What is another term for the episcleral fascia?

Back 26

Tenon’s capsule

Front 27

What is the episcleral fascia?

Back 27

Connective tissue layer between bulbar conjunctiva and sclera, adhered to sclera, blends into extraocular muscle fascia

Front 28

Location of the lacrimal gland:

Back 28

between dorsolateral surface of the eye and the zygomatic process

Front 29

What is the relation of the sinus to the orbit?

Back 29

Sphenopalatine sinus (medial, ventral), conchofrontal (medial, dorsal and ventral), maxillary (ventral, axial)

Front 30

Define strabismus:

Back 30

misalignment of the globe position

Front 31

Define exophthalmos:

Back 31

protrusion of the globe from the orbit

Front 32

Define enophthalmos:

Back 32

recession of the globe within the orbit

Front 33

What are the possible locations for orbital disease?

Back 33

Interconal (within the extraocular muscle cone); between the muscle cone and the periorbital sheath; subperiosteal (external to the periorbital sheath)

Front 34

Define buphthalmos:

Back 34

globe enlargement

Front 35

Define corneal globosa:

Back 35

abnormal corneal curvature

Front 36

Define phthisis bulbi:

Back 36

globe shrinkage

Front 37

What is the normal motion of the eye with gentle horizontal head motion?

Back 37

Globe remains central within the palpebral fissures and move in a coordinated fashion

Front 38

What occurs with auriculopalpebral anesthesia?

Back 38

Loss of function (akinesia) of the orbicularis oculi muscle

Front 39

Where can auriculopalpebral nerve block be performed?

Back 39

Depression at base of ear, between the caudal border of the coronoid process of the mandible and the zygomatic process of the temporal bone; lateral to the highest point on the caudal zygomatic arch, on the dorsal border of the bone; caudal to the bony process of the frontal bone along the zygomatic arch

Front 40

Where is a supraorbital nerve block performed?

Back 40

Over the supraorbital foramen, or inserting 25ga short length needle into the foramen

Front 41

What is anesthetized after supraorbital nerve block?

Back 41

Central 2/3 of the upper eyelid

Front 42

Examples of ophthalmic diagnostic procedures:

Back 42

retrobulbar aspiration, radiography, ultrasonography, CT, and MRI

Front 43

Why is there an increased complication rate associated with anesthesia for ocular surgery?

Back 43

Increased eye movement due to persistence of palpebral and corneal reflexes

Front 44

What procedures can decrease ocular movement under general anesthesia?

Back 44

Administration of neuromuscular blockade, retrobulbar anesthesia, supraorbital and auriculopalpebral anesthesia

Front 45

What are the complications associated with retrobulbar anesthesia?

Back 45

Orbital abscesses, cellulitis, laceration of extraocular muscles, optic nerve, sclera, or ophthalmic artery, oculocardiac reflex

Front 46

How is retrobulbar anesthesia performed?

Back 46

Spinal needle inserted into supraorbital fossa caudal to the dorsal orbital rim, advanced until reaching muscle cone; modified Peterson block by inserting a curved spinal needle from 1 cm lateral to the lateral canthus directed toward the medial canthis; 4 point anesthesia by inserting a spinal needle at each quadrant of the orbit, through skin & conjunctiva, curved toward the extraocular muscles

Front 47

What complications can occur with 4 point retrobulbar anesthesia?

Back 47

Increased pressure on the globe resulting in increased risk of corneal perforation

Front 48

How is the eye prepared for ocular surgery?

Back 48

1:50 dilution of 10% povidone-iodine to the surgical site and flush of the ocular surface

Front 49

Define evisceration:

Back 49

surgical removal of the uveal tract, lens, vitreous, and retina from the cornea and scleral tunic.

Front 50

When is evisceration indicated?

Back 50

Cosmetic procedure for blind or painful eye without evidence of sepsis or neoplasia

Front 51

Describe evisceration:

Back 51

(1) lateral cathotomy (2) conjunctiva incised parallel to and caudal to the limbus (3) expose sclera by undermining conjunctiva (4) full thickness scleral incision of 1.5 cm, 4-5 mm caudal to limbus (5) uvea separated from sclera using evisceration spoon (6) scleral incision extended to 180 degrees (7) remove uvea, retina, vitreous, followed by lens (8) sphere introducer placed (9) silicone implant placed (10) sclera closed in simple interrupted pattern (11) conjunctiva closed in simple continuous pattern (12) lateral canthotomy closed

Front 52

What are the complications associated with evisceration?

Back 52

Corneal ulceration, endophthalmitis, surgical site dehiscence

Front 53

Define enucleation:

Back 53

surgical removal of the palpebral margin, nictitans, conjunctiva, and globe

Front 54

Approaches to enucleation:

Back 54

transpalpebral (+/- intraocular prosthesis) and subconjunctival with intraocular prosthesis

Front 55

Describe transpalpebral enucleation:

Back 55

(1) eyelid sutures closed in continuous pattern (2) elliptical, full thickness skin incision 5 mm from eyelid margin (3) blunt dissection of SQ in caudal direction without penetration of conjunctiva (4) medial and lateral canthotomy (5) transect extraocular muscles at tendinous insertion on globe (6) +/- clamp optic nerve, retractor bulbi muscle with Carmalts or Satinsky clamps (7) transect optic nerve (8) +/- insertion of silicone implant (9) close orbital septum in simple interrupted pattern (10) close SQ with simple continuous pattern (11) close skin with simple continuous or interrupted pattern

Front 56

Describe subconjunctival enucleation:

Back 56

(1) eyelid speculum placed (2) lateral cathotomy (3) conjunctiva incised 5 mm caudal to limbus and undermined 360 degrees around the eye (4) extraocular muscles transected at tendinous insertions on globe (5) transection of optic nerve, retractor bulbi muscle (6) remove 3rd eyelid with its gland and conjunctiva (7) excise 3-5 mm of lid margins and meibomian glands (8) excise remaining conjunctiva (9) place prosthesis (10) close orbital septum simple interrupted pattern (11) close SQ with simple continuous pattern (12) close skin with simple continuous or interrupted pattern

Front 57

What are the complications of enucleation?

Back 57

Intraoperative globe rupture, intra- and post-operative hemorrhage, orbital cyst formation due to incomplete removal of secretory tissue, contralateral blindness

Front 58

Define exenteration:

Back 58

removal of al orbital tissues

Front 59

How does exenteration differ from transpalpebral enucleation?

Back 59

The caudal dissection and trasection of muscles and the optic nerve occurs at the caudal wall of the orbit

Front 60

What are the approaches to orbitotomy?

Back 60

Dorsal (curvilinear incision in dorsal orbit and supraorbital fossa or S shaped incision parallel to the zygomatic process of the frontal bone), lateral (lateral canthus extending caudally)

Front 61

What is the optimal time frame for repair of orbital fractures?

Back 61

As soon as possible, prior to bony callus formation in 10-14 days