Ver el código de «Canthotomy»

==Background==
[[File:Schematic diagram of the human eye en.png|thumb|Eye anatomy.]]
*Acute [[Ocular compartment syndrome|orbital compartment syndrome]] (OCS) is a clinical diagnosis
*Vision loss can be permanent after 60-100 min of ischemia<ref name="JEM" /> - do not delay procedure for imaging<ref>Mohammadi F, Rashan A, Psaltis A, et al. Intraocular Pressure Changes in Emergent Surgical Decompression of Orbital Compartment Syndrome. JAMA Otolaryngol Head Neck Surg. 2015 Jun 1;141(6):562-5.</ref>

===Causes===
*Trauma ([[retrobulbar hematoma]]) - most common cause<ref name="JEM">Rowh AD, Ufberg JW, Chan TC, et al. Lateral canthotomy and cantholysis: emergency management of orbital compartment syndrome. J Emerg Med. 2015 Mar;48(3):325-30.</ref>
*Spontaneous bleed
*Tumor
*[[Orbital cellulitis]]/abscess
*Prolonged [[hypoxemia]]

==Indications==
*Suspected acute orbital compartment syndrome (OCS), plus one or more of the following:<ref name="CJEM">McInnes G, Howes DW. Lateral canthotomy and cantholysis: a simple, vision-saving procedure. CJEM. 2002 Jan;4(1):49-52.</ref>
**Decreased visual acuity
**IOP >40 '''or''' marked difference in globe compressibility by palpation
**Proptosis

*Secondary indications (subjective and nonspecific) - if only secondary indications are present, get emergent ophthalmology consult prior to performing canthotomy.
**Afferent pupillary defect
**Cherry red macula
**Ophthalmoplegia
**Nerve head pallor
**Significant eye pain

==Contraindications==
*[[Globe rupture]]

==Equipment==
*Betadine prep
*Sterile drape or towels
*[[Lidocaine]] with epi
**Syringe with 27-30ga needle
*Normal saline for irrigation
*Straight hemostat or needle driver
*Iris or suture scissors
*Forceps

==Procedure==
''Consider sedating patient for procedure, if time allows''<ref name="JEM" /><ref name="CJEM" /><ref name="Spec Ops">Ballard SR, Enzenauer RW, O'Donnell T, et al. Emergency lateral canthotomy and cantholysis: a simple procedure to preserve vision from sight threatening orbital hemorrhage. J Spec Oper Med. 2009 Summer;9(3):26-32.</ref>
*Prep and drape the area (Irrigation with normal saline is acceptable prep given emergent nature of procedure)
*Inject lidocaine with epinephrine into the lateral canthus directing the needle tip toward the lateral orbital rim (away from the globe)
*Apply hemostat to the lateral canthus from the angle of the eye to the orbital rim and clamp shut for ~1 min. (provides relative devascularization as well as a landmark for the canthotomy)
*Using scissors, incise the lateral canthus from the angle of the eyelid to the orbital rim (~1cm).
*Retract the inferior lid and bluntly dissect tissue until the canthal tendon is identified.
*Perform inferior cantholysis - cut the inferior crus of the lateral canthus tendon (point scissors infero-posteriorally toward the lateral orbital rim, avoiding the globe)
*Recheck IOP → if still elevated, perform superior cantholysis - cut the superior crus of the canthal tendon (some experts recommend performing both inferior and superior cantholysis at the same time, prior to re-evaluating IOP)

===Signs of successful procedure===
*improved visual acuity
*resolution of afferent pupillary defect
*decrease in IOP to <40 mm Hg<ref>Scofi J. Lateral canthotomy. In: Shah K, Mason C, eds. Essential Emergency Procedures. 2nd ed. Philadelphia, PA: Wolters Kluwer; 2015:(Ch) 17.</ref>

==Complications==
*Incomplete cantholysis
*Iatrogenic globe or surrounding structure injury (rare)
*Loss of adequate lower lid suspension
*Bleeding
*Infection

==See Also==
*[[Orbital Hematoma]]
*[[Vertical lid split procedure]]

==External Links==
*EMRAP procedure video- https://www.youtube.com/watch?v=tgQaKVGynFA
*Review article by Murali et al: Orbital compartment syndrome: Pearls and pitfalls for the emergency physician. JACEP Open. 2021; 2:e12372. https://doi.org/10.1002/emp2.12372

==References==
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[[Category:Procedures]]
[[Category:Ophthalmology]]