Workhorse Flap for Nasal Reconstruction
The bilobed flap is the workhorse for nasal reconstruction following basal cell carcinoma excision, particularly for defects of the nasal tip and lower third of the nose. 1, 2, 3, 4
Anatomic Considerations for Flap Selection
The nose is designated as a high-risk Area H site for basal cell carcinoma, requiring Mohs micrographic surgery before any reconstructive procedure is undertaken. 5 The choice of flap depends critically on the precise location of the defect within the nasal subunit:
Bilobed Flap Indications
- Primary indication: Nasal tip para-medial defects above the lower lateral cartilage convexity 1
- Most common application: Defects of the lower third of the nose, particularly the nasal tip and dorsum 1, 2, 3
- Success rate: High preservation of facial characteristics with good aesthetic outcomes in large series 2, 3
- Technical advantage: Functions as a double transposition flap that redistributes tension across two pivot points, minimizing distortion 2
Nasolabial Flap as Alternative
- Primary indication: Alar defects and lateral nasal wall defects 4
- Frequency of use: Most commonly employed flap in some series (76.9% of cases) 4
- Best application: Larger defects of the alar region where the nasolabial fold provides excellent tissue match 4
Hatchet Flap for Specific Locations
- Primary indication: Defects of the inferior third of the nasal sidewall, above or bordered by the alar crease 1
- Technical note: May be considered as a simpler alternative to the bilobed flap when the defect location permits 1
Critical Pre-Reconstruction Requirements
Definitive reconstruction with flaps or grafts must not be performed until histopathologic confirmation of negative margins. 5 This is a non-negotiable principle because:
- Proceeding with reconstruction on a margin-positive specimen mandates re-excision or Mohs surgery, regardless of the complexity of the prior repair 5
- For aggressive histologic subtypes (infiltrative, morpheaform, micronodular), Mohs surgery should be considered even when initial margins appear clear 5
- If margins are positive after a flap has been placed, immediate re-excision or Mohs surgery is mandatory 5
Algorithmic Approach to Flap Selection
Step 1: Confirm tumor-free margins
- Obtain complete histopathologic confirmation before proceeding with definitive reconstruction 5
- For high-risk nasal location, Mohs surgery is recommended (99% cure rate for primary BCC) 6
Step 2: Assess defect location
- Nasal tip/para-medial defects above lower lateral cartilage → Bilobed flap 1, 2
- Alar region/lateral nasal wall → Nasolabial flap 4
- Inferior third of nasal sidewall above alar crease → Hatchet flap 1
- Nasal dorsum → Bilobed flap or primary closure depending on size 3, 4
Step 3: Consider defect size and depth
- Small to moderate defects (typically <2 cm): Local flaps as above 3
- Larger or full-thickness defects: May require forehead flap or more complex reconstruction 3
Common Pitfalls to Avoid
- Never reconstruct before margin confirmation: This is the most critical error, as it necessitates flap takedown and re-excision if margins are positive 5
- Trap door deformity with bilobed flaps: While this complication can occur, it can be minimized with proper technique and may even be used to advantage in certain cases 1
- Alar rim distortion: Occurs in approximately 14% of bilobed flap cases but is generally minor and acceptable to patients 2
- Ignoring aggressive histology: Infiltrative, morpheaform, and micronodular subtypes require Mohs surgery even with apparently clear margins due to unpredictable subclinical extension 5
Outcomes and Complications
- Complication rates are low: Partial flap dehiscence, minimal rim necrosis, and irregular scarring occur in <2% of cases 3
- Aesthetic satisfaction: High patient and surgeon satisfaction with color match, texture, and nasal contour preservation 3
- Functional preservation: Normal nasal function maintained in the vast majority of cases 2, 3