Acute Orbital Compartment Syndrome Treatment & Management

Trauma evaluation should proceed as per standards for patients with head trauma/multiple trauma, with assessment for life-threatening injuries and stabilization for transport.

Treatment of pain, agitation, and emesis may be appropriate to avoid further increase in intraocular pressure (IOP). Protective eye shields should be used during transport upon concern for penetrating eye injury or scleral rupture. If intubation is necessary and not otherwise contraindicated, some evidence suggests using rocuronium over succinylcholine, as succinylcholine has been demonstrated to increased intraocular pressure, although clinical significance has never been studied. ^{[16, 17]}

Head imaging should be prioritized to evaluate for possible retrobulbar hematoma. If head imaging is delayed or if the history or physical examination reveals concerning features for AOCS, emergent surgical decompression should be immediately considered. Emergent indications include known retrobulbar hematoma with an afferent pupillary defect (APD), vision loss, or proptosis. Facial trauma with an IOP of more than 40 mm Hg is an additional indication. Less-sensitive signs include isolated APD, ophthalmoplegia, cherry-red macula, optic nerve head pallor, and severe eye pain. Patients not meeting criteria for emergent decompression should undergo medical management with hyperosmotic agents, steroids, and serial visual acuity examinations and IOP assessments.

Possible AOCS with concerning features must prompt immediate decompression of the orbital pressure (< 2 hours from onset).

The emergency procedure of choice for acute loss of visual acuity associated with acute orbital compartment syndrome is dissection of the lateral canthus and disinsertion of at least the inferior crus of the lateral canthal tendon (ie, inferior cantholysis). This procedure allows complete mobility of the lower lid.  

In cadaver laboratories, lateral canthotomy/cantholysis and inferior orbital septum release are equally effective at reducing orbital compartment pressure. Additionally, the data support an additive synergistic reduction in compartment pressure when the procedures are both performed. ^{[18, 19]} However, the ease of the procedure and comfort of the provider should be considered when deciding which to perform. Most nonfacial surgeons should perform a lateral canthotomy and inferior cantholysis. It is technically less complex and can be performed in low–resource settings with just a scalpel and basic medical clamp. ^[20]

Lateral canthotomy alone does not relieve raised intraorbital pressure. The lateral canthal tendon firmly anchors the eyelids to the orbital rim. The subsequently performed cantholysis allows the orbital contents to expand forward, relieving intraorbital pressure. Commonly, inferior cantholysis is then performed, with consideration of an additional superior cantholysis if increased pressures persist. ^{[21, 22]}

Lateral canthotomy  ^{[1, 2, 23]}

Steps of lateral canthotomy are as follows:

1. Clean the area with sterile saline.
2. Inject approximately 1 mL of lidocaine 1% into the lateral canthus.
3. Apply a hemostat/clamp with one side anterior and one side posterior to the lateral canthus and advance approximately 1 cm until the rim of the bony orbit is felt.
4. Clamp for 1 minute.
5. Carefully cut through the crushed, demarcated line to the orbital rim/lateral fornix to avoid traumatizing the orbit.

Inferior cantholysis

The steps of inferior cantholysis are as follows:

1. Grasp the lower eyelid with forceps and retract down and out from the orbit.
2. Place the lateral side of an opened pair of curved scissors against the palpebral conjunctiva of the lateral eyelid.
3. Sweep toward the lateral canthotomy incision.
4. Identify and incise the inferior crus of the lateral canthal ligament.
5. The ligament will impede lateral movement of the scissor blade. This technique is recommended in traumatic AOCS, as traumatic edema can complicate visual identification of the ligament.
6. Verify laxity of the lateral canthus to confirm successful dissection.
7. Recheck the IOP and visual acuity. Consider repeating the procedure to dissect the superior crus if IOP is not immediately improved.

In patients who require lateral canthotomy with inferior cantholysis, IOP normalizes, decreasing by an average of 35 mm Hg. ^[6] If visual acuity fails to improve, an ophthalmologist should be notified immediately for consideration of subperiosteal hematoma, operative orbital decompression, or hematoma evacuation. Reports have described patients requiring interventional neuroradiology for treatment of refractory AOCS because of ongoing bleed. ^[24] Physical examination findings such as proptosis and abnormal extraocular movement may not immediately improve and are less-reliable markers of successful decompression.

Conservative or nonsurgical management of early AOCS is appropriate if the examination findings are reassuring and stable and frequent re-examinations are possible. The goal of pharmacotherapy is to reduce morbidity and to prevent complications. Several medications are used to decrease intraocular pressure (IOP) and reduce inflammation and oxidant effects, including steroids, hyperosmotic agents, and carbonic anhydrase inhibitors. ^[3] Other nonsurgical options for management are not supported by data but are centered on reducing intraorbital pressure via elevation of the head of the bed, calming the patient, and ice. ^[5]

Although the definitive management of AOCS is decompression, some data support routine use of hyperosmotic agents such as mannitol to decrease IOP if surgical decompression is delayed or in preparation for decompression. However, this benefit seems to be inconsequential if surgical decompression is performed in a timely manner. ^[25] In one study, intraocular pressures were reduced by over 25 mm Hg in patients who were first managed medically. ^[6]

Steroids in the treatment of AOCS are considered controversial. Initial recommendations were extrapolated from studies showing benefit in motor function in patients with spinal cord injury. ^[26] More recent data from the CRASH trial have shown increased mortality with administration of steroids in patients with head trauma. Animal models have shown that steroids increase axonal loss after optic nerve trauma.

In general, insufficient studies show medical management to be as effective as surgical management for AOCS. In patients in whom immediate surgical decompression is not indicated or in those in whom surgical decompression has been delayed, it is reasonable to trial conservative management in addition to repeat eye examinations (eg, acuity, IOP). ^{[5, 27]}

Emergent ophthalmologic consultation is required whenever an acute orbital compartment syndrome diagnosis is entertained. If necessary, transfer for specialty consultation and/or further workup (including CT scanning or MRI) is indicated once the patient is stabilized and after elevated IOP is treated.

Emergent oromaxillary facial surgery consultation is required if the etiology is postsurgical. In addition, an oral and maxillofacial surgeon (OMFS) should be consulted when hemorrhage is suspected within the optic canal or optic nerve sheath.

Among inexperienced providers who perform lateral canthotomy with cantholysis, the most common pitfall is incomplete canthal release. This is often a consequence of incompletely exposing the tendon during initial lateral dissection.

Most incisions heal on their own, while some require delayed closure (2-3 days). ^[26] Iatrogenic complications are rare and can be managed less emergently; they include infection, cosmetic deformity, and functional impairment. ^[2] If performed with instruments parallel to the surface of the globe with good retraction, injury to the globe or extraocular muscles is exceptionally uncommon.