Case

A 75-year-old-female with a past medical history of dementia, diaphragm dysfunction, OSA on CPAP, presents to the Emergency Department for a fall.  She is not on any blood thinning medications. Patient was found in the basement by her husband who believes she tripped over her oxygen tubing.

On physical examination, the patient was found to have right sided periorbital ecchymosis, with pupils 3mm equal and reactive to light bilaterally with intact extraocular movements, and no evidence of afferent pupillary deficit, and grossly intact vision. Patient did not have proptosis and she did not complain of severe eye pain. While awaiting CT scan, bedside ultrasound was performed which revealed an anechoic structure posterior to the globe concerning for retrobulbar hematoma (Figure 1). Intraocular pressures (IOP) were measured, and the right IOP was 14 mmHg and left IOP was 9 mmHg, as measured by tonopen. Visual acuity was 20/40 bilaterally by Snellen chart. Her CT scan revealed minimally displaced right medial orbit wall fracture and right periorbital hematoma with a small amount of intraconal hemorrhage predominantly along the medial aspect of the globe (figure 3), in addition to a subarachnoid hemorrhage. Ophthalmology was consulted who performed a bedside examination and did not find further evidence of orbital compartment syndrome and recommended revaluation of IOP in 6 hours and facial fracture precautions.

IOP remained stable and the patient was ultimately admitted to the Neurological Critical Care service for worsening subarachnoid hemorrhage and a new developing subdural hemorrhage on her repeat CT scan. Lateral canthotomy (LC) was not indicated in our patient.

Patient was ultimately medically managed and discharged to a skilled nursing facility on hospital day 6 with outpatient follow up.

Case discussion

Retrobulbar hematoma is typically a complication of facial trauma, especially in the setting of orbital floor fractures, however, they can be rare complications of facial surgery, or rarely spontaneous in the setting of valsalva maneuvers combined with anticoagulation [1 ].

Incidence of retrobulbar hematoma in patients with facial trauma is estimated to be 3.6% with an incidence of blindness of 0.14% in one study in a tertiary care trauma center [2 ].

Orbital compartment syndrome occurs when a collection of blood develops in the retrobulbar space and as blood accumulates, intraorbital pressure rises causing increased venous pooling, decreased arterial flow and a rise in intraocular pressure [1].  To prevent  retinal ischemia, LC may be indicated.

Indications

Indications for LC include a concern for acute orbital compartment syndrome in addition to one or more of the following: decreased visual acuity, IOP > 40 mmHg or proptosis [3]. If tonometry is unavailable, but marked difference in globe compressibility by palpation exists in the setting of marked proptosis or presence of secondary indications, LC should not be delayed.

Secondary indications include afferent pupillary deficit, cherry red macula, ophthalmoplegia, nerve head pallor, and significant eye pain [3]. If no primary indications are present, it is preferable for emergent ophthalmology consultation. Note, in the unconscious patient IOP > 40 mmgHg is sufficient to indicate LC [3]. The only true contraindication to a LC is an open globe [3]. Note this procedure must be performed without delay as elevated IOP lasting 60 to 100 minutes may result in permanent vision loss [1].

Procedure

Rapid release of pressure through LC to allow for adequate retinal artery blood flow is the main goal when performing this procedure [4]. The decision to provide adequate analgesia and antiemetics for patient comfort as well as proper sterile technique must be weighed against potential delay [4]. If possible it is preferable to provide anesthesia and antiemetics for patient comfort and to prevent Valsalva maneuvers such as vomiting [1].

A simple saline cleanse may be preferred over sterile technique in the setting of the emergent nature of the procedure to prevent further vision loss and not delay care [1].

Equipment required [3,4]:  

1.     Lidocaine with epinephrine

2.     Syringe with 25-gauge needle

3.     Hemostat or needle driver

4.     Iris or suture scissors

5.     Forceps

The steps are as follows [3,4]:   

1.     Cleanse the area (if possible) and identify relevant anatomy

2.     Anesthetize the lateral canthus with 1% or 2% lidocaine with epinephrine

3.     Crush the lateral canthus with hemostat or needle drive for 1-2 minutes to reduce bleeding

4.     Incise the lateral canthus with scissors from the lateral canthus to the orbital rim with caution to prevent globe injury

5.     Locate the superior and inferior crura of the lateral canthal tendon

6.     Release the inferior crus of the lateral canthal ligament with scissors, taking caution to prevent globe injury

7.     If IOP remain elevated after inferior lysis, release superior crus of lateral canthal ligament with scissors

After completion, measurement of IOP, visual acuity, pupillary function, as well as emergent ophthalmological consultation should be repeated as the patient may require adjuvant therapy [1].

Prognosis and complications

Complications from lateral canthotomy are generally damage to nearby structures, open globe, infection, bleeding, and eyelid malpositioning [1]

Take-AWAYS

• Indications for Canthotomy: concern for acute orbital compartment syndrome in addition to one or more of the following: decreased visual acuity, IOP > 40 mmHg or proptosis [3]

• If tonometry is unavailable, but a marked difference in globe compressibility by palpation exists in the setting of marked proptosis or presence of secondary indications, LC should not be delayed

• Secondary indications for LC include: afferent pupillary deficit, cherry red macula, ophthalmoplegia, nerve head pallor, or significant eye pain [3]

• Tools required are lidocaine with epinephrine, syringe, 25-gauge needle, hemostat/needle driver, scissors, and forceps [3,4]

• Do not hesitate, as elevated IOP lasting 60 to 100 minutes may result in permanent vision loss [1]

Author: Gabriel Lowenhaar is a current second year emergency medicine resident at Brown Emergency Medicine Residency

Faculty Reviewer: Dr. Kristin Dwyer is a clinician educator at Brown Emergency Medicine Residency.

 References

1.     Kumar S, Blace N. Retrobulbar Hematoma. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK576417/

2.     Fattahi T, Brewer K, Retana A, Ogledzki M. Incidence of retrobulbar hemorrhage in the emergency department. In: J Oral Maxillofac Surg. 2014 Dec;72(12):2500-2.

3.     McInnes G, Howes DW. Lateral canthotomy and cantholysis: A simple, vision-saving procedure. In CJEM. 2002;4(01):49-52.

4.     Roberts, James R., Catherine B. Custalow, and Todd W. Thomsen. In Roberts and Hedges’ Clinical Procedures in Emergency Medicine and Acute Care. Seventh edition. Philadelphia, PA: Elsevier, 2018. Print.