Dr Stephen Gilmartin
Emergency Physician
Editors: Dr Hector Thomson | Dr David McCreary
The Case
A 27-year-old male attends the emergency department with facial injuries following an alleged assault with a blunt instrument. He has swelling to his right periorbital area with difficulty opening his eyelids and his eye feels tense. You manage to just about open his eye and he can only appreciate light but is unable to count fingers, his pupil is sluggish and his Intra-ocular Pressure (IOP) is 52mmhg.
What is the diagnosis and which procedure can you perform to save this patient's vision?
Orbital compartment syndrome, secondary to retrobulbar haemorrhage. The eye socket is a fixed space and retrobulbar blood can cause increased pressure resulting in ischaemia of the optic nerve and retina causing potentially irreversible visual loss.
Orbital decompression via a lateral canthotomy and cantholysis should be performed as soon as possible once the diagnosis is made. The procedure is most successful when performed in under 60-90 minutes. This means that in clinical scenarios where the diagnosis is clear cut as above, lateral canthotomy should be performed before radiological confirmation of the diagnosis.
What are the indications for orbital decompression?
In a patient with blunt trauma to the eye in whom you have diagnosed or strongly suspect a retrobulbar haematoma any of the associated features suggest an orbital compartment syndrome and should prompt immediate lateral canthotomy:
Relative Afferent Pupillary Defect
Decreased Visual Acuity (<6/18)
Increased Intra-ocular Pressure: 40 mmHg and above of pressure requires decompression
Proptosis
Ophthalmoplegia
The only contraindication is suspicion of globe rupture (diagnosis can be difficult but IOP may be <5mmHg).
Should I get a CT first?
Good question. The answer really depends on how readily available your CT scanner is, your index of suspicion for the diagnosis, and how assessable your patient is (the intubated patient can be a challenge).
Orbital compartment syndrome is a clinical and time-critical diagnosis however and decompression is a relatively low-morbidity procedure and as such shouldn't be delayed for CT unless there is a question of the diagnosis.
What if I can't get the eye open?
The eye is often extremely swollen and difficult to examine. Still, it is important to make a good attempt to examine the globe, and pupil and to determine gross visual acuity.
Some techniques which can be effective are:
Getting an assistant to help with eyelid retraction using folded pieces of dry gauze on the upper and lower lids then slowly drawing the skin apart with your fingertips
Examining for proptosis and feeling the firmness of the eye compared to the contralateral side
Using paper clips (appropriately shaped and cleaned with an alcohol wipe) to retract the eyelids, as below:
Images courtesy of tamingthesru.com's: "The Mighty Paperclip"
🤓 Editor's note: Don't have paperclips to hand? Officeworks closed?
I've previously used the end of the plunger from a 10ml syringe to lift the upper eyelid, particularly for giving you some space to perform the decompression.
What if I still can't get the eye open?
POCUS to the rescue! Ultrasound can be used here to examine for:
Afferent pupillary defects
Ophthalmoplegia
Globe rupture
Retinal detachment
The videos below talk you through how you may go about performing an ultrasound examination of the eye:
Do I really have to do it? Can't I just send the patient to my friendly neighbourhood trauma centre to sort it out?
Afraid not! Time is optic nerve. Optic nerve is sight. This is a low-morbidity procedure, often not even requiring repair afterwards and has potential to save the patient's sight.
Performing an Orbital Decompression (Lateral Canthotomy & Cantholysis)
Equipment needed:
Sterile gloves
Sterile saline
Lignocaine with adrenaline
Syringe
25G needle
Straight kelly clamp / Haemostat
Iris or suture scissors
Toothed forceps
Technique
Clean: Clean the area with sterile saline (Pro tip: do not use chlorhex or alcohol containing solutions)
Local: Infiltrate local anaesthetic into the skin at the lateral margin of the eye extending out to the orbital rim
Crush: Approaching from the nasal size, clamp the lateral canthus for 1 minute to reduce bleeding
Canthotomy: Raise the skin of the lateral canthus away from the eye and cut with the scissors, making a 1-2cm incision. This is in order to expose the underlying lateral canthal tendon.
Cantholysis: Using toothed forceps grasp the lower eyelid laterally at the ‘last lash” and pull upwards towards the ceiling. This will place the inferior canthal tendon under tension. With the closed iris scissor gently sweep the tissue between the orbital rim and the toothed forceps holding the eyelid. The tip of the scissors will ‘twang’ this structure like a guitar string. Cut the tendon. (Don’t expect to be able to see the tendon – there is likely to be bleeding).
Check: If successful the lower eyelid should be loose and free to move, there should be substantial release of blood and the globe should now feel softer. Retest IOP, pupillary response and visual acuity.
(Images courtesy of The Procedures Course)
What about the other tendons?
Only cut the inferior lateral tendon. This will allow the eye to move forwards which relieves the compartment syndrome. Cutting the superior tendon is unlikely to allow much more movement, and is more likely to need formal repair in theatre.
Procedure Tips
Don’t pad the eye – you want to keep checking the pupils
Apply chloramphenicol ointment to the skin incision and the conjunctiva post procedure
There is often significant swelling around the eye. This may make identification, clamping and cutting of the lateral canthus difficult. This may mean this part of the process has to be done in stages.
Twang! Rely on the feel of 'twanging' the tendon - this will no longer be felt following successful cantholysis and the lid will become mobile.
Ask an assistant to retract eyelids using methods discussed above
Anaesthetise the eye with local anaesthetic drops and have a low threshold for procedural sedation if safe to do so.
Case Conclusion
You immediately perform a lateral canthotomy. There is a satisfying release of blood and the eye becomes less firm immediately. His IOP is now improving to within normal limits and he can count your fingers, though his vision is still slightly blurred. You organise a CT of his brain and facial bones and ophthalmology is rushing in to perform a detailed assessment of his eye.
Want your first time performing this procedure to be less high-stakes?
Book your spot on The Procedures Course. Our two-day cadaveric course teaching life, limb and sight-saving procedures.
Additional Resources
Have a listen to the Procedures Course Podcast where Dr Mike Noonan (Emergency and Trauma Physician) dives into the nuances of the procedure with ophthalmologist A/Prof Anthony Hall
References
Groombridge C, Maini A, Mathew J, O'Keeffe F, Noonan M, Smit V, Fitzgerald M, Hall A. Orbital decompression. Emerg Med Australas. 2021 Jun;33(3):552-554. doi: 10.1111/1742-6723.13768. Epub 2021 Mar 11. PMID: 33709505.
Dr Stephen Gilmartin
Emergency Physician
Stephen is an emergency medicine doctor from Ireland (who has since returned to the Motherland). He has interests in trauma, ultrasound and medical education. He’s amazed that your brain is active 24/7, 365 days of the year until your death, the only two times it stops is during an exam and when you’re trying to write a funny bio!
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