The University of Iowa
Department of Ophthalmology and Visual Sciences
The ability to perform a lateral canthotomy and cantholysis is an essential skill for every ophthalmologist and emergency room physician. It can be a vision-saving technique in the setting of decreased perfusion to the optic nerve or globe as a result of increased orbital pressure. In addition, it is a useful step in many common eyelid procedures. This tutorial will highlight the indications, materials, and technique used to perform a lateral canthotomy and cantholysis.
The orbit consists of four bony walls within the skull which angle posteriorly to form a cone:
The orbit is a closed compartment and therefore any expansile process within the orbit will cause increased pressure on the surrounding structures.
An example of this is a retrobulbar hemorrhage. Increased orbital pressure can cause the anterior displacement of the globe which manifests clinically as proptosis. The anterior displacement of the globe is limited by the eyelid complex which is anchored to the orbital rim primarily by the lateral and medial canthal tendons. In some cases, orbital pressure can increase above the perfusion pressure of the optic nerve leading to ischemia of the optic nerve and retina. This is a vision-threatening condition and should be addressed emergently.
Intraorbital pressure can be indirectly assessed by measuring intraocular pressure.
Clinical signs suspicious for decreased perfusion from orbital compartment syndrome include:
Releasing the lateral canthal tendon from the orbital rim by performing a lateral canthotomy and cantholysis allows for more anterior displacement of the globe, leading to a reduction in intraorbital pressure and a return of optic nerve and retinal circulation.
Many common non-emergent eyelid surgeries also require a lateral canthotomy and cantholysis.
The best example is the lateral tarsal strip. In this case the lateral canthal tendon is released and a new, shorter "lateral canthal tendon" is formed by anchoring the tarsus to the periosteum of the orbital rim. This effectively tightens the lower lid and can be an effective treatment for ectropion or entropion caused by increased lid laxity.
The lateral canthotomy and cantholysis can also be utilized in procedures which increase lower lid laxity in order to close full thickness lower lid defects.
Most supplies are readily available for scheduled eyelid procedures. This is intended to be a checklist for supplies needed in the case of an emergent lateral canthotomy and cantholysis