Summer - United States Special Operations Command

Emergency Lateral Canthotomy andCantholysis: A Simple Procedure toPreserve Vision from Sight ThreateningOrbital HemorrhageCPT Steven Roy Ballard, MD; COL Robert W. Enzenauer, MD,MPH; Col (Ret) Thomas O’Donnell, MD; James C. Fleming, MD;COL Gregory Risk, MD, MPH, FACEP; Aaron N. Waite, MDABSTRACTRetrobulbar hemorrhage is an uncommon, but potentially devastating complication associated with facialtrauma. It can rapidly fill the orbit and cause an “orbital compartment syndrome” that subsequently cuts offperfusion to vital ocular structures, leading to permanent visual loss. Treatment must be initiated within a limitedtime in order to prevent these effects; however, specialty consultation is not always available in remote fieldenvironments. This article addresses the mechanism, diagnosis, and treatment of retrobulbar hemorrhage via lateralcanthotomy and cantholysis, and recommends that 18D medical sergeants be properly trained to evaluateand perform this sight-saving procedure in emergent settings where upper echelons of care are not immediatelyavailable.INTRODUCTIONRetrobulbar hemorrhage is a vision-threateningemergency often necessitating immediate lateralcanthotomy for preservation of vision. 1 Prompt recognitionand appropriate treatment of this ocular emergencyis imperative, for timely managementdetermines the ultimate outcome. 2 The medical literaturedescribes multiple causes for true spontaneousorbital hemorrhage; however, head and facial trauma,as well as post-surgical complications, constitute themajority of emergent cases. 3-14 Reports of injuries inOperation Iraqi Freedom document the risk of orbitalhemorrhage and subsequent orbital compartment syndrome(OCS) from penetrating trauma and the potentialvision-threatening consequences. 15Retrospective studies show an incidence of coexistingretrobulbar hemorrhage in patients with orbitalfractures of only 0.45-0.6%. 16 However, inpatients experiencing acute vision loss in the setting oftraumatic retrobulbar hemorrhage, the potential forpermanent blindness is high (44-52%). 17,18 Althoughrare, the potential ophthalmic concern in a war-timeenvironment becomes increasingly real, due to thehigher incidence of facial trauma and delayed presentationto upper echelons where definitive ophthalmiccare can be undertaken.We agree with earlier assessments that theskills to recognize and treat vision-threatening orbitalcompartment syndrome (OCS) due to retrobulbar hemorrhageshould be within the scope of a Special OperationsForces (SOF) medic and concur with therecommendation of Burns and DeLellis that the proceduresof lateral canthotomy and cantholysis could andshould be introduced into the SOF medical training curriculum.19MECHANISMRetrobulbar hemorrhage causes a mass effectwithin the confined space of the orbit, and as it expandsit impinges on sensitive ocular tissues reducing perfusionof the optic nerve. 20 The compartment is restrictedin its ability to expand due to the bony walls. Anteriorexpansion does occur, causing subsequent proptosis,but it is ultimately limited by the orbital septum and thefact that the globe is tethered to the optic nerve. 16,21-24An OCS ultimately develops, increasing orbital pressure,damaging the optic nerve by direct compression,and causing ocular ischemia via decreased perfusionfrom compromised vascular flow, not unlike that seenin other compartment syndromes. 25 If the patient is unconsciousor uncooperative and has periorbital trauma,26Journal of Special Operations Medicine Volume 9, Edition 3 / Summer 09