Nasal Reconstruction With Paramedian Forehead Flap

Robert D. Wallace

Petros Konofaos

DEFINITION

Nasal defects can be caused by trauma (including burns) and the sequela of skin cancer treatment by excision or radiation. Nasal defects can be partial or through and through involving all the three layers of the nose.
Nasal reconstruction involves the use of autologous tissues to repair nasal defects.
- All of the affected or missing parts must be replaced to achieve both an aesthetic (normal-looking nose) and a functional (easy breathing) reconstruction.
The paramedian forehead flap (PMFF) is an interpolated axial flap based primarily off the supratrochlear neurovascular system and is well suited for reconstructing complex defects of the nose.
- This flap produces an excellent tissue color and texture match for nasal reconstruction.

ANATOMY

Nose

The nose consists of a pair of nasal bones that extend from the frontal bone and caudally fuse with the dorsal septum forming a support structure that extends along the length of the nasal dorsum (FIG 1A).
- The caudal aspect of the nasal bones overlaps the cephalic portion of the upper lateral cartilages for a distance of 2 to 4 mm.
FIG 1 • A-C. Anatomy of the nose.
The upper lateral cartilages constitute the distal nasal sidewalls and extend toward the tip of the nose (FIG 1B).
- At their caudal free edge, they are overlapped by the cephalic portions of the lower lateral cartilages.
- The lower lateral cartilages provide the structural support to the soft tissues of the lower third of the nose.
The nasal septum is composed of three structures: the perpendicular plate of the ethmoid posteriorly and cephalically, the vomer posteriorly and caudally, and the quadrangular septum anteriorly (see FIG 1A).
- The septum functions as a support structure for the midportion of the nose, and it also constitutes the medial component of the internal nasal valve.
The blood supply to the dorsal nose is derived from the dorsal nasal artery and the anterior ethmoidal artery (FIG 1C).
- The lateral nasal artery, branch of the angular artery, supplies the nasal sidewalls and the caudal nasal dorsum and tip. The columellar branches of the superior labial artery with the distal branches of the lateral nasal artery supply the nasal tip from below.
- The blood supply to the septum comes from the anterior and posterior ethmoidal arteries, the sphenopalatine artery, and the posterior septal artery.
The sensory innervation to the nose is derived from the ophthalmic (V1) (upper half of the nose) and the maxillary (V2) (lower half of the nose) divisions of the cranial nerve V. The motor innervation is from the facial nerve (VII).

FIG 1 (Continued)
There are three nasal vaults:
- The bony vault consists of the paired nasal bones and the ascending frontal process of the maxilla.
- The upper cartilaginous vault is outlined by the paired upper lateral cartilages.
- The lower cartilaginous vault is made of the lower lateral cartilages.
The skin envelope of the upper two-thirds of the nose consists of thin, loose, and mobile skin with few sebaceous glands.
- The skin of the lower third of the nose is thick and less mobile, with aberrant sebaceous glands.

Paramedian Forehead Flap

The forehead provides a source of skin with an excellent color and texture match with nasal skin.
The PMFF is an axial pattern interpolated flap that is based on the ipsilateral or contralateral supratrochlear neurovascular system to exit the orbit approximately 1.7 to 2.2 cm lateral to the midline, in a vertical vector, passing under orbicularis oculi and above corrugator supercilii muscles (FIG 2).
- The artery, 1 cm above the brow, runs in the submuscular plane, under the frontalis, to a more superficial, subcutaneous position at the middle of the forehead.
The PMFF consists of frontalis muscle, subcutaneous fat, and skin, except its distal portion, in which the majority of subcutaneous fat and the frontalis are removed.

PATIENT HISTORY AND PHYSICAL FINDINGS

During the process of taking the patient’s medical and surgical history, emphasis should be put on the following:
- Case of the nasal injury, disease remission, or cancer clearance
- Tobacco and alcohol use
- Previous surgeries on the nose, midface, and forehead regions
  
  FIG 2 • Design of paramedian forehead flap. M, medial side of the flap; L, lateral side of the defect; A, ala; S, skin excess.
- History of radiation therapy and/or chemotherapy
- General health status of the patient and more specifically the existence of conditions affecting wound healing and flap viability
- Patient’s ethnicity
- Active drug use
Physical examination
- The skin of the midface and the forehead regions is inspected for scarring and previous incision sites.
- The patency of the nasal airway should be evaluated for constrictions and/or bulky obstructing tissue, for lateral nasal wall collapse, or external nasal valve deficiency.
- Moreover, the nose and the forehead area should be inspected for variations from normal anatomical topography.
- Evaluation of the primary defect includes¹
  - Wound dimensions, shape, and location
  - Identification of nasal and/or facial subunits involved
  - Wound inspection for infection, constrictions, and other deformities
  - Understanding the defect in terms of tissues involved, as complex nasal defects often involve loss of lining, support, and skin cover
- Identification of the location of the supratrochlear artery can be achieved through palpation and/or using a handheld Doppler.
- Preoperative photography is essential to document the defect, allow outcome review and comparison, and educate the patient regarding the indicated surgical treatment.

IMAGING

No specific radiographic imaging studies are required.
Facial radiograph, computed tomography, or magnetic resonance imaging is occasionally employed in cancer-related cases with high risk of recurrence or to clarify bony and soft tissue injury of the midface region.

SURGICAL MANAGEMENT

Immediate nasal reconstruction after skin tumor extirpation is safe in selected patients.
- Reconstruction is delayed when the histologic margins are questionable, the tumor histology is aggressive, in case of perineural or deep bony invasion, and when radiotherapy is to be given.
Factors governing the choice of nasal reconstruction include donor-site morbidity, facial scarring, and the complications associated with borderline vascularity.
- Function and appearance were considered of secondary importance. On the other hand, modern nasal reconstruction emphasizes the restoration of a normal appearance and function, not on simply obtaining a healed wound.
Millard envisioned facial landmarks as “units” and suggested to replace them in their entirety with tissue of similar color and texture to avoid a patchlike repair.
Burget and Menick² analyzed the nose as a facial unit with subunits, based on the skin quality, border outline, and 3-D contour of each region (FIG 3).
They also introduced the nasal subunit principle, which holds that, if the defect is greater than 50% of the subunits, it is better to discard adjacent normal tissue within the subunit and resurface the entire subunit rather than merely “patching the hole.” Thus, depending on the extent of the defect, wounds should be altered in size, configuration, and depth to reconstruct an entire unit.
- The subunit principle finds its ideal application for defects of the tip and alar regions because these subunits are convex and can lead to a trapdoor effect following flap inset and healing, thereby augmenting the effect of recreating the convex shape of the subunit.
- For defects of the nasal dorsum and sidewalls, the subunit principle is less applicable, because these relatively flat subunits blend indistinctly.
The principles of ideal nasal reconstruction include
- The exact replacement of missing tissues in dimension, thickness, and outline
- The use of the contralateral subunit as a template for reconstruction
- The establishment of a support framework with primary and delayed primary cartilage and bone grafts
- Flap edges blended to the recipient site
  
  FIG 3 • Aesthetic subunits of the nose.
- Marginal scars braced by cartilage grafts
- Detailed subcutaneous sculpture
It is imperative to educate the patient and outline the necessary steps that will be required to repair the defect. Moreover, the patient’s preferences and needs must be considered by the surgeon at the planning of the indicated reconstruction.

Preoperative Planning

Preoperative planning should be guided by the principles of aesthetic regional unit reconstruction: alter the wound in size, outline, depth, or position, if helpful, to improve the final result. After defining the defect by means of location and missing layers, the reconstruction can be broken down into component parts, with each part addressed in turn.
Successful reconstruction is composed of thin, conforming cover that matches nasal skin in color and texture; thin, vascular, and supple lining that does not stuff the airway; and a hard tissue framework to support, shape, and brace soft tissue against gravity, tension, and scar contraction.
When designing the selected flap, it is important to avoid either distorting adjacent structures or making the flap too small. When substantial amounts of all three layers are lacking, however, the reconstruction becomes more complex and less predictable.
The PMFF is the mainstay of reconstruction for a wide variety of nasal defects.
- For subtotal or total nasal defects, a three-stage full-thickness PMFF (with an extension to supply missing lining or combined with a septal mucosal flap) and septal or ear support grafts are used.
- The two-stage PMFF is best suited to resurface small defects that do not require contour recreation, complex support grafts, or lining replacement. All stages are performed under general anesthesia.
If missing, the nasal midlayer support framework must be replaced, to prevent nose collapse.
- The support grafts can be placed primarily if vascularized lining remains or is restored with intranasal lining flaps.
- Otherwise, the structural grafts are placed during the second stage of reconstruction with PMFF.
- Sources for support graft for cartilage can be septal or ear cartilage and for bone calvarial or rib bone grafts.
- Whereas septal cartilage is especially useful as a single or layered onlay dorsal graft, a tip graft, a sidewall brace, or a columellar strut, the ear remains the workhorse of tip and alar repair.
If deficits of the internal lining cannot be closed primarily, there are several options for reconstituting it.
- If left unrepaired, the area will heal by secondary intention with significant wound contracture, alar distortion, and nasal obstruction.
- Punctate defects can be closed primarily, whereas an independent flap is required to repair larger defects.
- Most commonly used options include the folded PMFF, the ipsilateral septal mucosal flap, and a full-thickness skin graft (in combination with PMFF).
In cases in which ischemic tissue is identified, prior to reconstruction, the wound should be debrided after it demarcates itself.
- A contaminated or infected wound should be debrided and controlled with antibiotics prior to reconstruction.
- Significant edema and wound tension are given time to resolve.
In cases in which the defect extends/includes to the lip and/or cheek units, reconstruction of these areas must be established, prior to nasal reconstruction.
- Options include cheek advancement flap with/without a nasolabial extension to resurface the cheek and/or lip, an Abbe flap (if the full thickness of the upper lip is absent), or a free flap depending on the dimensions and/or depth of the defect.