What Is a Unilateral vs Bilateral Cleft Lip?
Understanding the difference between unilateral and bilateral clefts helps you understand treatment. Here is an explanation.
Cleft lip is classified by which side(s) of the lip are affected.
- Unilateral cleft lip:
- Occurs on ONE side of the lip
- More common than bilateral (about 80% of cleft lips)
- The nostril on the affected side is often wider and flattened
- The nasal cartilage on that side is displaced
- The lip tissue on the affected side is shorter
- The cleft may be complete (extending to the nose) or incomplete
- Bilateral cleft lip:
- Occurs on BOTH sides of the lip
- Less common (about 20% of cleft lips)
- The central part of the lip (prolabium) projects forward
- Both nostrils are affected
- The nose is often wide and flat
- The premaxilla (front part of the upper jaw) may protrude
- Usually requires a two-stage repair
Treatment differences:
| Feature | Unilateral | Bilateral |
|---|---|---|
| Surgery timing | 3β6 months | 3β6 months |
| Number of surgeries | Usually one for the lip | May need two stages |
| Lip repair technique | One side repaired | Both sides addressed |
| Nasal correction | Often done at same time | Often staged |
| NAM therapy | May help | Very helpful for protruding premaxilla |
Clinical Guidance
A unilateral cleft lip affects one side of the lip; bilateral affects both sides. Bilateral clefts are less common but more complex to treat. Both are successfully repaired with surgery, often with excellent cosmetic and functional results.