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Orbital compartment syndrome (OCS) is caused due to rapidly increasing intra-orbital pressure and can lead to permanent blindness. OCS is a sight-threatening condition. This activity describes orbital compartment syndrome (OCS) and how it can lead to irreversible vision loss, and it explains the role of emergency medicine physicians and the interprofessional team in evaluating and diagnosing OCS and treating the patients with lateral orbital canthotomy to lessen the probability of permanent vision loss. Objectives: Identify the indications for lateral orbital canthotomy. Outline the typical presentation of a patient with orbital compartment syndrome. Describe the importance of lateral orbital canthotomy performed in a timely fashion. Explain the importance of improving care coordination among the interprofessional team to enhance the delivery of care for patients with orbital compartment syndrome. Access free multiple choice questions on this topic.

Orbital compartment syndrome (OCS) is caused due to rapidly increasing intra-orbital pressure and can lead to permanent blindness. OCS is a sight-threatening condition, originally described by Gordan and McRae in 1950 in a case following zygoma fracture repair. OCS is secondary to ischemia of the optic nerve and related retinal function, and a lack of perfusion can lead to irreversible loss of vision. OCS is a type of compartment syndrome, and as with other compartment syndromes, rapidly increasing intra-compartment pressures are related to significant morbidity and permanent damage.[1] OCS occurs as a result of mass effect within the confines of the orbit; any process that can cause an increase in intraorbital pressure can lead to OCS. Intraorbital pressures can increase due to both hemorrhage and non-hemorrhagic processes, such as fluid accumulation. Non-traumatic causes of hemorrhage include iatrogenic procedures such as orbital, eyelid, and lacrimal surgeries. Orbital hemorrhage can also be caused by commonly used anesthetic procedures such as peribulbar or retrobulbar injections of localized anesthetics. Valsalva-related hemorrhage in the setting of sinonasal carcinoma, orbital-lymphatic malformation-related hemorrhages, extraocular tumors causing metastases has also been demonstrated as causes of OCS.[1] Non-hemorrhagic causes of OCS include processes such as prolonged prone surgery (such as spinal surgery), facial and periocular burns, and massive fluid resuscitation for severe burns, all of which can lead to third-spacing of fluid within the orbital compartment. Uncommon causes of OCS include orbital emphysema in the setting of associated paranasal sinus fractures.[1] All emergency physicians must also be wary of orbital cellulitis, regardless of the presence of an associated abscess, as a possible cause of OCS.[1]

Non-hemorrhagic causes of OCS include processes such as prolonged prone surgery (such as spinal surgery), facial and periocular burns, and massive fluid resuscitation for severe burns, all of which can lead to third-spacing of fluid within the orbital compartment. Uncommon causes of OCS include orbital emphysema in the setting of associated paranasal sinus fractures.[1] All emergency physicians must also be wary of orbital cellulitis, regardless of the presence of an associated abscess, as a possible cause of OCS.[1] OCS is a serious ophthalmologic emergency, regardless of etiology, and all emergency physicians should be able to clinically diagnose this condition and have an understanding of lateral orbital canthotomy and cantholysis (LOC) procedure in order help prevent permanent vision loss. OCS can lead to proptosis of the globe, which leads to stretch tension on the optic nerve in addition to the compressive forces of the intra-compartment pressure. The goal of LOC is to free the eyelid from its lateral attachment to the bony orbit, thus releasing the pressure that has accumulated within the closed orbital compartment.[2] While emergent ophthalmologic consultation is ideal for intervention, optic nerve ischemia due to OCS can develop very rapidly. Improved visual outcomes can be achieved if interventions such as LOC are performed promptly (ideally within 2 hours of presentation).[3]

There are five main complications associated with an emergency lateral orbital canthotomy: incomplete cantholysis, iatrogenic globe rupture or surrounding structure injury (rare), loss of adequate lower lid suspension, and subsequent eyelid mispositioning, infection and bleeding.[6] Iatrogenic globe injury and/or rupture from the instruments, such as forceps, scissors, surgical blades, or hemostat, used for the procedure is a possible complication of this injury. Additional complications include ptosis, which can occur due to damage to levator aponeurosis and Müller’s muscle, which are located superiorly in the orbital cavity. Injury to the lacrimal gland and Meibomian glands are possible complications as these are located superiorly in the orbital cavity.[6] Less common complications include bleeding and infection. As with any surgical procedure, there is a risk of infection from accessing parts of the eyes from iatrogenic rupture of the barrier, as well as through instrumentation in that area. Bleeding is another common risk of a surgical procedure. In this case, injury to the lacrimal artery can cause severe bleeding, along with possible incision to other vasculature in the area.[6]

Orbital compartment syndrome (OCS) is a vision-threatening condition, which is best diagnosed clinically, and the definitive treatment is lateral orbital canthotomy (LOC) and cantholysis. Irreversible vision loss can be avoided if LOC is performed within the first two hours of the patient’s presentation.[8] Most often, these procedures are performed by the consulting ophthalmologist, but often the acuity of the patient’s injuries, deteriorating visual acuity, unavailability of the ophthalmologist due to other commitments leads to suboptimal outcomes if the procedure is not performed in a timely fashion. Therefore, widespread training of LOC amongst all the physicians in the healthcare team, especially emergency medicine (EM) physicians, can lead to improved outcomes for patients with OCS. While EM physicians are first to encounter patients with potential OCS, a 2019 prospective cohort study on the management of OCS by non-ophthalmologic EM physicians demonstrated that 82.8% of participating physicians were able to diagnose the ophthalmologic emergency, and an overwhelming 78.7% indicated that they would first perform a diagnostic computed tomography (CT) scan. Only 37.1% reported that they would perform LOC themselves, and 92.2% indicated that they would not perform the procedure themselves is because they believed they needed more training in diagnosing OCS and performing LOC. This demonstrates a need for a healthcare-based approach to the importance of collaboration between ophthalmologists and emergency physicians in training together to lead to better outcomes for the patients.[11] [Level 3] While emergency medicine physicians are not required to be certified in LOC as per American Counsel of Graduate Medical Education’s (ACGME) training curriculum, training for LOC in EM physicians and general surgeons can avoid permanent loss of vision in patients with OCS. A 2019 randomized control study by the Association of Military Surgeons of the United States demonstrated that synthetic models are comparable to swine models for the training for LOC. Synthetic models can be produced and distributed widely, and incorporation of LOC in the training of all EM physicians by ACGME will lead to improved outcomes for patients.[12] [Level 2]