| Patient Education |
|
Click here for patient education.
|
|
You are in: eMedicine Specialties >
Clinical Procedures > Ophthalmologic Procedures
Lateral Orbital Canthotomy
Article Last Updated: Aug 11, 2008
AUTHOR AND EDITOR INFORMATION
Section 1 of 12  
Author: Linda G Liu, MD, Attending Physician, Department of Emergency Medicine, Rochester General Hospital
Linda G Liu is a member of the following medical societies: Phi Beta Kappa
Coauthor(s):
Tiffany Sunshine Hackett, MD, MBA, Attending Physician, Cedars Sinai Department of Emergency Medicine, Clinical Instructor of Emergency Medicine, Los Angeles County-University of Southern California Department of Emergency Medicine
Editors: Pascal Juang, MD, FAAEM, FACEP, Attending Physician, Emergency Care Unit, Hoag Memorial Hospital Presbyterian, Newport Beach, CA; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine; Luis M Lovato, MD, Associate Clinical Professor, David Geffen School of Medicine at UCLA; Director of Critical Care, Department of Emergency Medicine, Olive View/UCLA Medical Center; Gil Z Shlamovitz, MD, Assistant Professor of Emergency Medicine, University of Connecticut School of Medicine; Attending Physician, Emergency Department, Windham Community Memorial Hospital, Willimantic, CT; Attending Physician, Emergency Department, Hartford Hospital, Hartford, CT; Rick Kulkarni, MD, Medical Director, Assistant Professor of Surgery, Section of Emergency Medicine, Yale-New Haven Hospital
Author and Editor Disclosure
Synonyms and related keywords:
lateral cantholysis, orbital decompression, blindness, retrobulbar hemorrhage, retrobulbar hematoma, orbital hemorrhage, orbital compartment syndrome, orbital trauma, eye trauma, ischemia of the optic nerve, retrobulbar anesthesia, atherosclerosis, intraorbital aneurysm of the ophthalmic artery, hemophilia, leukemia, von Willebrand disease, von Willebrand's disease, hypertension, diplopia, proptosis, ecchymosis, bloody chemosis, intraocular pressure, IOP, severe eye pain, afferent pupillary defect, ophthalmoplegia, cherry-red macula, optic nerve head pallor, Marcus Gunn pupil, lateral canthus, globe injury, vision loss
Retrobulbar hemorrhage is an ocular emergency whose prompt diagnosis and treatment are essential to prevent blindness.1 Because the orbit is a relatively closed compartment, orbital pressure can rise rapidly when hemorrhage occurs. Untreated, orbital compartment syndrome develops with resultant ischemia of the optic nerve. For more information, see Acute Orbital Compartment Syndrome.
Retrobulbar hemorrhage most often results from trauma, recent retrobulbar anesthesia, or eyelid surgery. Spontaneous retrobulbar hemorrhage due to venous anomalies, atherosclerosis, intraorbital aneurysm of the ophthalmic artery, hemophilia, leukemia, von Willebrand disease, and hypertension has also been described.
Patients with increased orbital pressure present with pain, decreased vision, diplopia, limited extraocular movements, proptosis, ecchymosis around the eye, bloody chemosis, increased intraocular pressure (IOP), resistance to retropulsion, and an afferent pupillary defect.
Orbital pressure can be relieved with an emergent lateral canthotomy.2 Without decompression, irreversible vision loss due to increasing orbital pressure may occur in as little as 90-120 minutes.3, 4 Knowledge of this potentially sight-saving procedure is important for physicians, especially those in remote areas where access to ophthalmologists is not readily available.5
For more information, see the Medscape Expert Review on Retrobulbar Hemorrhage.
Absolute indications for lateral canthotomy include retrobulbar hemorrhage resulting in acute loss of visual acuity, increased IOP, and proptosis.6 In the unconscious or uncooperative patient, an IOP greater than 40 mm Hg is an indication for lateral canthotomy (normal IOP is 10-21 mm Hg).7
Lateral canthotomy may also be considered in patients with retrobulbar hemorrhage along with any of the following: afferent pupillary defect, ophthalmoplegia, cherry-red macula, optic nerve head pallor, and severe eye pain. However, these findings are subjective, less reliable, and nonspecific. A CT scan of the orbit may help to clarify the diagnosis.8
Suspected globe rupture is a contraindication to lateral orbital canthotomy. Signs of globe rupture include hyphema; a peaked, teardrop-shaped, or otherwise irregularly shaped pupil; exposed uveal tissue, which appears reddish-brown; and extraocular movement restriction that is greatest in the direction of the rupture. Subtle signs of globe rupture include subconjunctival hemorrhage, enophthalmos, or a conjunctival laceration. For more information, see Globe Rupture.
Local anesthesia (lidocaine 1-2% with epinephrine) is injected into the lateral canthus.
Equipment needed for the procedure includes the following:
- Sterile gloves, face shield, gown (if desired)
- Lidocaine 1-2% with epinephrine
- Syringe with 25-gauge needle
- Sterile drapes
- Normal saline for irrigation
- Straight hemostat
- Sterile iris or suture scissors
- Forceps
Although the head should be initially elevated to help decrease IOP, the patient must be moved into the supine position and must be able to fully cooperate during the procedure itself. Unexpected patient head movement can result in iatrogenic injury, including accidental globe puncture. To accomplish this, the patient may need to be restrained, undergo conscious sedation, or even be intubated and paralyzed, depending on the situation.
- Provide adequate anesthesia by injecting 1 mL of lidocaine 1-2% with epinephrine into the lateral canthus. Direct the needle tip toward the lateral orbital rim and begin injecting when the needle touches bone. The combination of lidocaine with epinephrine assists with hemostasis and local anesthesia.
- Confirm the affected eye and perform a repeat inspection, noting the typical findings of unilateral proptosis, an afferent pupillary defect, decreased visual acuity, and an intraocular pressure (IOP) of 40 mm Hg or higher.
- Irrigate the eye with normal saline to clear away debris that may enter the eye or interfere with the procedure.
- Use a straight hemostat to crimp the skin at the lateral corner of the patient’s eye. Crimp the skin all the way down to the orbital rim. This crimp functions to achieve hemostasis and to mark the location where the incision is to be made.
Crimping the lateral orbital canthus to mark where to cut the skin. - Use forceps to pick up the skin around the lateral orbit.
- Use the scissors to make a 1-2 cm incision beginning at the lateral corner of the eye and extending laterally outward.
Cutting the lateral orbital canthus. - This incision decreases some pressure but is often insufficient alone; therefore, proceed to cantholysis.
- Retract the inferior lid downward to visualize the lateral canthus tendon.
- With the scissors directed along the lateral orbital rim (pointing away from the globe), dissect the inferior crux of the lateral canthus tendon and cut it.
Cutting the inferior canthal ligament. - If this procedure is insufficient (ie, IOP remains >40 mm Hg), cut the superior portion of the lateral tendon by dissecting superiorly before cutting it.
Verifying laxity of the lateral canthus and inferior canthal ligament after cutting.
A few key points to keep in mind include the following:
- Lateral retraction of the tissue by an assistant during manipulation decreases the chance of a globe injury.
- Despite high intraorbital pressures, only a small amount of blood is usually expressed with the release of the hematoma.9
- Tonometry and globe palpation are contraindicated in patients with an open globe injury.
- A successful procedure is marked by improved visual acuity, resolution of a previously detected afferent pupillary defect, and decrease in IOP to below 40 mm Hg.10
- Always seek emergent consultation with an ophthalmologist when this procedure is performed.
The afferent pupillary defect, or Marcus Gunn pupil, is tested using the swinging flashlight test. The test is positive when the affected pupil dilates in response to light (the other normal pupil also dilates when light is shone in the affected eye). Both pupils constrict when the light is shone in the normal eye. The Marcus Gunn pupil results from injury to the afferent fibers of cranial nerve II of the defective eye, while the efferent signals from cranial nerve III of the normal eye are uninjured.
For more information, see Neuro-ophthalmic Examination or Examining the Eyes of an Older Person.
Complications include iatrogenic globe injury by forceps or scissor tips. Less common complications include bleeding and infection. Irreversible vision loss can occur if retina ischemia time is greater than 90-120 minutes.
| Media file 1:
Crimping the lateral orbital canthus to mark where to cut the skin. |
|  View Full Size Image | |
Media type: Presentation
|
| Media file 4:
Verifying laxity of the lateral canthus and inferior canthal ligament after cutting. |
| View Full Size Image | |
Media type: Presentation
|
- Lee KY, Tow S, Fong KS. Visual recovery following emergent orbital decompression in traumatic retrobulbar haemorrhage. Ann Acad Med Singapore. Nov 2006;35(11):831-2. [Medline].
- Carrim ZI, Anderson IW, Kyle PM. Traumatic orbital compartment syndrome: importance of prompt recognition and management. Eur J Emerg Med. Jun 2007;14(3):174-6. [Medline].
- Larsen M, Wieslander S. Acute orbital compartment syndrome after lateral blow-out fracture effectively relieved by lateral cantholysis. Acta Ophthalmol Scand. Apr 1999;77(2):232-3. [Medline].
- Popat H, Doyle PT, Davies SJ. Blindness following retrobulbar haemorrhage--it can be prevented. Br J Oral Maxillofac Surg. Mar 2007;45(2):163-4. [Medline].
- Winterton JV, Patel K, Mizen KD. Review of management options for a retrobulbar hemorrhage. J Oral Maxillofac Surg. Feb 2007;65(2):296-9. [Medline].
- Goodall KL, Brahma A, Bates A, Leatherbarrow B. Lateral canthotomy and inferior cantholysis: an effective method of urgent orbital decompression for sight threatening acute retrobulbar haemorrhage. Injury. Sep 1999;30(7):485-90. [Medline].
- McInnes G, Howes DW. Lateral canthotomy and cantholysis: a simple, vision saving procedure. Canadian Journal of Emergency Medicine. 2002;4:49-52. [Full Text].
- Long J, Tann T. Orbital trauma. Ophthalmol Clin North Am. Jun 2002;15(2):249-53, viii. [Medline].
- Vassallo S, Hartstein M, Howard D, Stetz J. Traumatic retrobulbar hemorrhage: emergent decompression by lateral canthotomy and cantholysis. J Emerg Med. Apr 2002;22(3):251-6. [Medline].
- Shek KC, Chung KL, Kam CW, Yau HH. Acute retrobulbar haemorrhage: an ophthalmic emergency. Emerg Med Australas. Jun 2006;18(3):299-301. [Medline].
- Crumpton KL, Shockley LW. Ocular trauma: a quick, illustrated guide to treatment, triage, and medicolegal implications. Emerg Med Rep. 1997;18:223-34.
- Knoop K, Trott A. Ophthalmologic procedures in the emergency department--Part I: Immediate sight-saving procedures. Acad Emerg Med. Jul-Aug 1994;1(4):408-12. [Medline].
- Peak DA. Acute Orbital Compartment Syndrome. eMedicine Journal [serial online]. 2005;Available at http://www.emedicine.com/emerg/topic881.htm.
- Roberts JR, Hedges JR, eds. Clinical Procedures in Emergency Medicine. 4th ed. Portland, Ore: WB Saunders Co; 2004:1275.
- Rosen P, Barkin R. Emergency medicine: Concepts and Clinical Practice. St Louis, Mo: Mosby; 2002:910.
Lateral Orbital Canthotomy excerpt Article Last Updated: Aug 11, 2008
Topic originally published: Jan 5, 2006
|
