This is a technically delicate procedure because the oral commissure is a muscular convergence zone, not just a skin corner. Precision and conservative movement are critical.
Preoperative Planning
? A. Measurement
- Determine desired amount of widening
Mark vertical reference lines from:
- Medial limbus
- Mid-pupil (smile position)
- Avoid going lateral to mid-pupil in most aesthetic cases.
Mark vertical reference lines from:
? B. Symmetry Marking
- Mark new commissure point bilaterally.
- Confirm in:
- Rest
- Natural smile
- Full smile
Mark new commissure point bilaterally.Even 1 mm asymmetry is noticeable.
Anesthesia
- Local infiltration with epinephrine
- Avoid over-distortion of tissues during injection
Mucosal Advancement Technique
Steps:
- Extend incision laterally from existing commissure through skin out to desired width mark
- Excise upper and lower triangular skin segments This leaves a skin defect into which the new mouth corner will move outinto it.
- Excise small wedge of exposed orbicularis muscle to make space for new commissure position
- Release and reposition commissure at skin-muscle ‘defect’
- Layered closure:
Extend incision laterally from existing commissure through skin out to desired width mark
Excise upper and lower triangular skin segments This leaves a skin defect into which the new mouth corner will move outinto it.
Excise small wedge of exposed orbicularis muscle to make space for new commissure position-
- Deep absorbable sutures (muscle approximation)
- Mucosal closure
- Fine skin sutures at vermilion border
Key principle: recreate a natural commissure angle.
Postoperative Management
- Limit very wide mouth opening 10–14 days
- Scar management (silicone gel after epithelialize healing, usually 3 weeks)
?? Most Common Technical Errors
? Over-widening, leads to scar contraction which can pull corners medially and downward
? Failure to create muscle space for new commissure position
? Poor commissure angle recreation by not removing triangles of skin, leads to slit-like widening
Important Reality
This procedure may be technically small but aesthetically high-risk.The visible area is central to facial expression, so precision in execution is important to avoid asymmetries and/or increased scarring.
As a result
- prefer undercorrection
- Carefully counsel about visible scars and the potential need for secondary scar revision
How much widening is typically safe
In cosmetic mouth widening (lateral commissuroplasty), less is more.
? Typical “Safe” Widening Range
- 4–5 mm per side (most common and safest range)
- Rarely 7 mm per side can be done but never more
That means total mouth width increase is usually 10mms or more
? Why It’s Limited
The oral commissure is not just skin — it’s:
- A convergence point of multiple lip muscles
- A high-movement zone
- A tension-prone scar area
If widened too much:
- The corners can look pulled or unnatural
- The mouth may appear flat instead of curved
- Scars become visible when smiling
- Corners can drift downward over time from scar contracture
- “Joker” or “fish-mouth” appearance can occur
Even 1–2 mm makes a visible difference on the face.
? How I Decide the Amount
It’s based on:
- Interpupillary distance (facial proportion reference)
- Existing commissure position relative to the medial limbus of the iris
- Smile dynamics
- Tissue laxity
- Patient ethnicity and lip thickness
As a general aesthetic guideline:
- The commissures ideally align near the mid-pupil or slightly medial at rest. Going lateral to the iris midline usually looks artificial.
- Recognize that the procedure is irreversible…you can always do more if desired
Dr Barry Eppley
Plastic Surgeon