Difference between canthotomy canthoplasty and cantholysis
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Here is a clear breakdown of the three procedures:
Canthotomy vs. Cantholysis vs. Canthoplasty
These three terms are frequently confused because they often occur together, but they represent distinct surgical steps or procedures with different goals.
1. Canthotomy
What it is: A full-thickness incision through the lateral canthus (the outer corner of the eye), extending approximately 1 cm toward the orbital rim — from conjunctiva to skin.
Purpose: Gains access to the underlying lateral canthal tendon (specifically its inferior and superior crura). It does not by itself provide meaningful orbital decompression.
Key point: Canthotomy alone is inadequate treatment for orbital compartment syndrome (OCS). It is only the first step — the gateway to cantholysis.
"This step simply gains access to the inferior crux of the lateral canthal tendon. It provides little soft tissue decompression." — Wills Eye Manual
2. Cantholysis
What it is: The actual release (lysis) of the lateral canthal tendon's crura (inferior and/or superior) from their periosteal attachment at the orbital rim.
Purpose: This is the decompressive step. By disinserting the eyelid from its bony attachments, it directly reduces intraorbital pressure and restores blood flow. It is performed immediately after canthotomy.
Indication: Orbital compartment syndrome — typically from retrobulbar hemorrhage after trauma, surgery, or spontaneously. The goal is to restore retinal artery perfusion before irreversible infarction (~90 minutes).
Technique: After the canthotomy incision, toothed forceps grasp the lower eyelid; scissors are directed toward the tip of the nose to cut the inferior crus. Success is confirmed when the eyelid falls completely away from the globe and the lid margin retracts medially to the limbus.
"The cantholysis is critical to decompress the orbit and is done exclusively by feel." — Wills Eye Manual
- Inferior cantholysis is done first and is usually sufficient.
- Superior cantholysis (releasing the superior crus) may follow if IOP remains elevated.
3. Canthoplasty
What it is: A reconstructive or aesthetic procedure that involves detaching and repositioning the lateral canthal tendon with the goal of altering eyelid position, tension, or shape.
Purpose: Corrects structural problems — eyelid laxity, ectropion, lower lid malposition, or post-surgical/traumatic deformity. Also used cosmetically to reshape the eye (the "cat-eye" or almond-eye effect).
Key features:
- The lateral canthal tendon is deliberately cut and then re-attached at a new position on the periosteum inside the orbital rim
- Typically includes a tarsal strip procedure — a strip of tarsus (the structural plate of the lid) is fashioned and sutured to bone
- More invasive, requires planned surgical setup (unlike emergency canthotomy/cantholysis)
- Often combined with canthopexy (see below)
Canthopexy vs. Canthoplasty distinction:
| Feature | Canthopexy | Canthoplasty |
|---|---|---|
| Tendon cut? | No | Yes |
| Mechanism | Suture support/tightening of existing tendon | Detach, reposition, and re-anchor tendon |
| Invasiveness | Less | More |
| Use case | Mild laxity, prophylactic support | Significant laxity, ectropion, structural repair |
Summary Comparison
| Canthotomy | Cantholysis | Canthoplasty | |
|---|---|---|---|
| Goal | Access | Decompress orbit | Reconstruct/reposition canthus |
| Tendon cut | No (incises skin/conjunctiva only) | Yes (lyses tendon from bone) | Yes (detach and re-anchor) |
| Setting | Emergency (step 1) | Emergency (step 2, the critical step) | Elective reconstructive/aesthetic |
| Indication | OCS/retrobulbar hemorrhage | OCS/retrobulbar hemorrhage | Ectropion, lid laxity, cosmesis |
| Reversibility | Heals without suture | Requires later repair | Intentional permanent change |
In clinical practice, canthotomy and cantholysis are almost always performed together as "lateral canthotomy and inferior cantholysis" (LCIC) — an emergency bedside procedure for orbital compartment syndrome. Canthoplasty, by contrast, is a planned surgical procedure in the operating room for structural eyelid repair.
Sources: Wills Eye Manual; Roberts and Hedges' Clinical Procedures in Emergency Medicine; Cummings Otolaryngology, p. 3332
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