Orbital Compartment Syndrome Flashcards
OCS
-background/overview
—general description
—general cause
Rare, treatable complication of incr pressure within orbital space
Mostly secondary to facial trauma or surgical procedure
OCS
-anatomy
Globe and retrobulbar contents are in cone-shaped fascial envelope bound by 7 bony walls
The medial and lateral canthal tendons attach the eyelids to the orbital rim
-limits forward movement of the globe
OCS
- overall pathophysiology
- causes (5)
Incr tissue pressure in an enclosed space -> decr perfusion
-pressure within the orbit exceeds the pressure of the CRA -> ischemia
- Trauma – after large-volume resuscitation, asphysxia syndrome
- Surgery/procedures – extravasated contrast material, complications of spinal surgery in prone position, spontaneous bleeding
- Infection
- Tumor
- Inflammation – Graves
OCS -retrobulbar hematoma pathophysiology —epidemiology and primary cause —hemorrhage emanates from —anatomical concern —condition is causes
Most common cause of OCS
Most commonly occurs as post-op complication
Infraorbital artery/branch
Retrobulbar blood causes large incr in pressure unless decompressive drainage occurs (break/fracture usually better due to pressure release)
Causes AION
- CRA: protection from compression and from incr tissue pressure
- prelaminar caps/peripapillary choroid/posterior ciliaries: do not have same protection -> NAION
OCS -subperiosteal hematoma pathophysiology —anatomy —most common cause —pathophysiology —condition it causes
Hemorrhage within potential space b/w periosteum and bones
Most commonly after trauma
Orbital emphysema from sinus communication causes a 1-way valve -> incr in pressure
Causes AION
OCS
-prognosis
VA loss leads to permanent blindness if emergency decompressive surgery is not initiated immediately
Irreversible vision loss is expected with retinal ischemia that lasts more than 120 minutes
OCS
-history: acute vs chronic
Acute
- incr IOP (>40)
- vision loss
- proptosis
Chronic
- decr VF
- nerve pallor
- cherry red macula
- APD
OCS
-ddx (7)
-Optic nerve decompression for traumatic optic neuropathy
– Graves
– Orbital neoplasm
– Lens dislocation
– Anterior ischemic optic neuropathy
– Globe rupture (never decompress after!)
– Retinal detachment
OCS
-testing (3)
Fundoscopy
IOP (magic # is 40)
CT/MRI
-if truly from acute OCS, then this could delay sight-saving tx
-initiate therapy first, then send for imaging
OCS
-treatment
—options (2)
—contraindication
Lateral canthotomy (opens skin enough to get to crus of ligaments) Inferior cantholysis (cuts ligaments, lets eye come forward)
Suspected globe rupture
OCS
-emergency department care (3)
Osmotic agents and CAIs
High-dose steroids
Consult for emergency decompression surgery
Lateral canthotomy
-procedure (3 steps)
- Lidocaine with epi
- Advance hemostat, clamp to devascularize tissue, hold 30-90sec
- Iris scissors to cut from lateral canthus to outer orbital rim
Inferior cantholysis
-procedure (4 steps)
performed after lateral canthotomy
- Use forceps to reflect lower lid to visualize inferior canthal tendon
- Cut the tendon to decompress globe
- Repeat for upper canthal tendon if IOP is not sufficiently reduced
- Cover with moist gauze and leave tendon open
Canthotomy/cantholysis -post-op IOP mean reductions —canthotomy —cantholysis —combined
Canthotomy = 14.2 mmHg Cantholysis = 19.2 Combined = 30.4
Canthotomy/cantholysis
-post-op pharm (2 categories, 3 drug types)
Decrease AH production
• Beta-blockers (timolol)
• CAIs (acetazolamide)
Decrease corneal edema
• Hyperosmotic (mannitol)
