Trauma Flashcards
Four articulations of the Zygoma
Frontozygomatic, zygomaticomaxillary, zygomaticotemporal, zygomaticosphenoidal
ZMC Classification
Knight and North. Based on direction of displacement on a Water’s View radiograph
Group 1 - Nondisplaced
Group 2 - Arch fractures
Group 3 - Unrotated
Group 4 - Medially rotated
Group 5 - Lateral rotation outward
Group 6 - Complex fractures
Cardinal fields of orbital exam
Fields of gaze, integrity of rim, ecchymosis, hyphema, shape of pupil, reactivity of pupil, size of pupil, subconjunctival ecchymosis, periorbital edema, chemosis and position of globe
ZMC physical examination
Orbital - check pupillary level
Malar eminence flattening
Depression of preauricular region, Antimongoloid slanting -(disruption of frontozygomatic suture and inferior displacement of Whitnalls tubercle)
Neuro disturbances
Step Deformities
Ecchymosis of maxillary vestibule
Trismus - coronoid impingement
Approaches for isolated Arch fractures
Keen of Gilles
Keen - A 2 cm lateral maxillary vestibular incision (upper gingival buccal incision) is made with a scalpel or a cautery device just at the base of the zygomaticomaxillary buttress. The incision is made through mucosa only. an instrument can easily be placed deep to the fractures to allow elevation of a depressed zygomatic arch
Gilles - temporal incision (2 cm in length), made 2.5 cm superior and anterior to the helix, within the hairline. being careful to avoid superficial temporal artery. dissection continues through the subcutaneous tissue and superficial temporal fascia down to the deep portion of the deep temporal fascia. This fascia is then incised to expose the temporalis muscle. A Rowe zygomatic elevator is inserted just deep to the depressed zygomatic arch and an outward force is applied
ZMC fracture order of repair
Frontozygomatic to restore facial height
ZM buttress to restore facial projection
Orbital rim to define orbital volume
Orbital floor last
Alignment of sphenozygomatic suture is good indicator of three dimensional position of zygoma
Complications of ZMC
Malunion/asymmetry
Enopthalmos - eye moves posteriorly in AP position. (Requires placement of space occupying material like bone graft, prosthetic or custom implant)
Blindness - rare, retrobulbar hematoma
Retrobulbar hemorrhage - managed by lateral canthotomy and cantholysis for decompression
Vertical dystopia - reconstruct floor height with autogenous bone or implant/custom plate
Volume of an Orbit
30 ml, 4 cm horizontal dimension and 3.5 vertical on average
Bones of the Orbit
Orbital roof (frontal and lesser wings of sphenoid)
Lateral wall (greater wing of sphenoid and zygomatic bone
Orbital floor (maxillary bone, zygomatic bone and palatine bone)
Medial wall (frontal process of maxilla, ethmoid, lacrimal and sphenoid bones)
Anatomic Landmarks for Orbit
Inferior orbital fissure gives rise to infraorbital groove about 2.5- 30.0 cm posterior to orbital rim. Exits the infraorbital foramen about 5 mm below the infraorbital rim
Superior orbital fissure: CN III, IV, VI, sensory nerve V1, superior opthalmic vein, recurrent and middle meningeal artery
Inferior orbital fissure: Sensory nerve V2, inferior ophthalmic vein
Optic canal : optic nerve, ophthalmic artery
Whitnalls Tubercle - located 10 mm below the Frontozygomatic suture and 3-4 mm inside the lateral orbital rim. Attached to the lateral canthal tendon
Annulis of Zinn: Tendanous ring of fibrous tissue at the apex of the orbit surrounding the optic nerve that is the origin of the rectus muscles of the eye
Safe dissection: All measurements are from an intact anterior lacrimal crest. Anterior ethmoidal foramen 24 mm, posterior ethmoidal foramen 36 mm, optic foramen 42 mm
Layers of the Eye
Skin, Subcutaneous tissue, orbicularis oclui, septum, tarsal plate, conjunctiva pg 193
Orbital Septum
Forms the anterior boundary of the orbit
Orbicularis Oculi
CN VII. Pretarsal and Preseptal: Reflex eyelid closure. Forceful voluntary eyelid closure
Levator palpebrae superioris
CN III: Main retractor of upper eyelid
Muller’s muscle: superior tarsal
Tone of upper eyelid that gives 2mm of lift
Medial canthal ligament
Anteriorly inserts onto maxillary bone, posteriorly onto posterior lacrimal crest, superiorly onto orbital process of frontal bone.
Lateral canthal ligament
Whitnalls tubercle, 1 cm inferior to the ZF
Nasolacrimal duct
Opens into the inferior meatus of the nasal cavity 10 mm behind the nasal aperture, reflux of tears is prevented by Hasner’s valve
Anisocoria
different sizes of pupils
Diplopia
double vision
Enophthalmos
inward position of globe
Exophthalmos
Outward position of the globe
Hyperglobus
Superior positioning of the globe
Hypoglobus
Inferior positioning of the globe
Hypertropia
misalignment of eyes
Proptosis
Same as exophthalmos
Ptosis
drooping of the eyelid
Orbital physical exam
pupils, extraocular muscle function, visual acuity, ocular pressure, edema, ecchymosis, subconjunctival hemorrhage, proptosis, infraorbital nerve sensation, intercanthal distance
Visual acuity chart
Snellen Chart
Visual fields
Goldman Chart
Afferent pupillary defect
pupils respond differently to light stimuli shone in one eye at a time due to unilateral or asymmetrical disease of the retina or optic nerve
Tonometry
to test for ocular pressures (normal is 10-20 mmHg)
Indication for Orbital fracture repair
Large orbital fractures >50% orbital floor
Enophthalmos >2 mm
Diplopia in primary gaze
Muscle incarceration - entrapped muscles will become ischemic
Signs of oculocardiac reflex - emergent surgery
Surgical approaches to Orbit (Transconjunctival)
Transconjunctival -
-Corneal shield with ophthalmic- grade bacitracin/ocular lubricant placed.
Local with vasoconstrictor injected under the conjunctiva to aid in hemostasis and around the lateral canthus if lateral canthotomy planned.
-15 blade incision made through lateral canthus, iris scissor used to cut through lateral palpebral fissure (lateral extension should not exceed 7 mm for safe distance from temporal branch of facial nerve. Layers are skin, orbicularis oris, orbital septum, lateral canthal tendon, conjunctiva.
-Lateral orbital rim is a stop, inferior cantholysis performed.
- Conjunctiva approached with blunt dissection. Conjunctiva undermined over the orbital septum and extended medially.
-Scissor used to incise conjunctiva below curvature of the tarsal plate. Sutures placed for retracttion and to hold corneal shield in place
- Inferior bony orbit located, dissect down to orbital rim staying lateral to lacrimal sac.
- Elevators used to strip periosteam over orbital rim, anterior surface of maxilla, zygoma and orbital floor
- 4-0 vicryl used to reattach lateral canthal tendon, subcutaneous 6-0 sutures placed along the canthotomy.
Surgical approaches to Orbit (Subciliary)
Corneal shield with ophthalmic bacitracin/ocular lubricant placed on globe.
Skin incision made 2 mm below gray line
Dissection deep to orbicularis oculi muscles includes pretarsal orbicularis muscle in the levated skin muscle flap
Incision through periosteum for entry into the floor of orbit made beneach the infraorbital rim (3mm)
Subperiosteal dissection is accomplished posteriorly exposing orbital walls
Periosteal elevators used to expose orbital floor.
Broad retractor placed to protect the orbit and confine herniating periorbital fat
Orbital repair complications
Infection
Ectropion - shortening of anterior lamellae. May require tarsal strip
Entropion - shorting of posterior lamellae
Persistent enophthalmos
Sympathetic ophthalmia - injury induced antibodies. Enucleation, evisceration, exenteration
Retrobulbar hemorrhage - IV infusion 20% mannitol 2g/kg to shrink vitreous humor and steroids. Manage surgically with lateral canthotomy.
Nasolacrimal duct test
Jones Test
Jones I Test - few drops of fluorescence dye or propofol in the lower conjunctival sac, observe for fluorescein/propofol in the nose. If not, then go to test II
Jones II Test - Irrigate the punctum and inject fluorescein in the SAC puncta/canaliculi. If fluorescen is seen then the blockage is after the lacrimal sac, if not, then the blockage is near the punctum or canaliculus
Repair of nasolacrimal duct
Primary Repair: Dilate with bowman probe, place stent (Crawford or Jackson Tube) through puncta and nasolacrimal duct opening in the nose, suture both ends with 8-0 PDS sutures and leave the stent for 3 months
Secondary Repair: Dacryocystorhinostomy; the goal is to create a bony window between the lacrimal sac and nose. Incision placed 6 mm from medial canthal angle and dissection carried to lacrimal sac. An H incision made in teh nasal soft tissue and lacrimal sac. Posterior flaps sutured together. Puncta intubated with Crawford tube and passed through the openings of the nose. Ends of tube are tied and anterior flaps of the nasal mucosa and lacrimal sac are sutured together. Orbicularis muscle and skin are closed. Stent left in place for 3-6 months
Hyphema treatment
1% ophthalmic drops (Dilates pupil and immobilizes iris to prevent bleeding)
Timolol ophthalmic drops (beta blocker to decrease intraocular pressure
Acetazolamide
Steroids
Horner’s Syndrome
Injury to sympathetic nerves supplying the globe.
Triad of signs: Miosis, ptosis, anhidrosis