Paramedian Forehead Flap

Key points

  • The paramedian forehead flap is a reliable flap for reconstruction of extensive nasal defects.

  • The flap can be completed in 1, 2, or 3 stages depending on the patient’s defect, comorbidities, and patient desires.

  • The flap has very low failure rates, with the most common complications being local infection and distal flap necrosis.

  • The overall patient satisfaction with this flap is very high, with few patients needing multiple refinement procedures.

Introduction

Reconstruction of central facial defects is challenging and the efforts must establish precise outlines and positions to reestablish facial symmetry. Numerous etiologies for nasal skin defects (pathologic, traumatic, congenital, infectious, etc) must be taken into consideration for flap design. Reconstructive goals include restoration of nasal form and function (airflow), incorporating proper nasal dimension, volume, position, and contour. The reconstruction chosen must consider the patient’s nasal deformity (size, depth, and subunits involved), available donor sites, patient’s comorbidities, and the patient’s desired outcome. For the reconstruction of full-thickness, large nasal defects, the interpolated, multilaminar paramedian forehead flap provides excellent results to restore patient’s form and function.

Surgical technique

Preoperative planning

The most important factor regarding successful flap reconstruction is proper planning. This begins with the initial clinical examination with key points highlighted in Table 1 .

Table 1
Clinical examination components and their significance
Clinical Examination Component Significance
History
Etiology and duration of defect
  • Must ensure wound is stable with proper disease control (clear margins, resolved infection, etc).

  • Recent injury can lead to enlarged defects from edema and gravity. Older wound sites can be contracted leading to underestimating defect size.

Patient risk factor—smokers
  • Consider smoking cessation before surgery.

  • May elect for delayed flap transfer (most distal aspect of flap is incised 3 months before flap transfer to develop robust distal vasculature).

  • May limit thinning of distal flap during flap transfer.

Patient risk factor—scar near the donor site
  • Transverse scars overlying the supratrochlear artery are most concerning.

  • Use Doppler imaging to confirm blood supply.

  • Could consider a 3-stage procedure.

Patient risk factor—eyewear
  • Have postoperative plan to ensure patient can maintain activities of daily living and provide self-care if they are not wearing their glasses.

Patient risk factor—history of head and neck radiation
  • Obtain a history of location and consider multistage surgery.

Patient risk factor—inability to tolerate staged procedure
  • Provide patient with previous case photos and consider alternative reconstruction options if necessary.

Physical examination
Is there a nasal lining and/or cartilage defect?
  • Additional staged procedure to include cartilage graft as a staged procedure.

  • If so, this could be repaired before substructure and cover/skin reconstruction for proper nasal function.

Define subunits involved in defect
  • If a defect of a central convex subunit is >50%, plan to resect adjacent normal tissue within the subunit and resurface the entire subunit.

Are the central subunits (lips and eyelids) intact?
  • All have 3-dimensional shape, proportions and outline with distinct symmetry to contralateral side. Outline and contour are more important than skin quality.

  • Reconstruct lip defect before nasal defect to set foundation.

Where is the patient’s hairline?
  • Low hairlines or short foreheads with previous surgery may require tissue expansion before surgery.

Are there any bony defects contributing to the nasal defect?
  • If the cheek and lip are not well supported, the nasal reconstruction will not be predictable. The bony substructure must be addressed before the surface. Consider a computed tomography scan to fully understand the underlying bony support.

Preparation and patient positioning

  • Supine

  • Oral intubation with Mastisol and Tegaderm on the upper lip to seal the oral cavity without distorting lip and cheek position

  • A 20 to 30° reverse Trendelenburg to decrease venous pooling and blood loss

  • Corneal shields with Lacrilube placed

  • 10% Providine preparation

Surgical approach

For the purpose of this article, we assume that nasal lining and substructures are present with a defect not amenable to other local flap reconstruction options owing to the size of the defect and the patient’s desired aesthetic outcomes. The patient elects for a paramedian forehead flap as the reconstructive option owing to its superior color, texture, size, versatility, low morbidity, and aesthetic result. However, the surgeon must determine how many stages are needed for the patient’s best functional and aesthetic outcome. Table 2 summarizes the indications for each type of staging and what each stage entails.

Table 2
Indications for staging
Number of Stages Indications and Staged Plan
One (island flap) Only indicated when the patient has a compromised medical history and cannot have multiple anesthetics or when the patient desires 1 surgery and knows of the aesthetic compromise of a single-stage surgery. A single-stage surgery can lead to excessive bulk, compromised perfusion from overlying tight glabellar skin, and overall poor aesthetic reconstruction.
Two
  • Ideal for small surface defects of the tip, dorsum or ala that do not require complex support grafts, nasal lining or delicate contour recreation.

    • Stage 1—Flap transfer with complete thinning and contouring of distal flap.

    • Stage 2 (3–4 weeks later)—Division and inset of flap without ability to contour distal aspect of flap (tip, ala. and columella). There is a growing amount of literature advocating for stage 2 in 7–10 d after stage 1 with promising results.

Three
  • Ideal for large, full-thickness defects (including columella and ala). Consider 3 stages for smokers or patients with scars in the region of the flap with concern for blood supply.

    • Stage 1—Flap transfer with minimal thinning and contouring of the distal flap.

    • Stage 2 (3 weeks later)—Entire skin flap is elevated with subdermal plexus remaining with skin and the underlying tissue is contoured. Flap inset with quilting sutures to define alar base, tip contour and dorsal lines.

    • Stage 3 (3 weeks later)—Division and final inset of flap with ability to contour distal aspect of flap (tip, ala and columella)

Surgical procedure (2-stage paramedian forehead flap)

Stage I

  • Step 1: Marking patient

    • Involved nasal subunits identified and uninvolved normal tissue in affected convex subunits (tip and ala) are included for planned excision to avoid pin cushion defect and allow for improved scar camouflage ( Fig. 1 A, B )

      Fig. 1
      ( A ) Patient presenting with cutaneous squamous cell carcinoma of the nose. Lesion present on nasal tip, right soft tissue triangle, and right ala. ( B ) After excision of the malignancy with negative margins. Defect now affects bilateral nasal sidewalls, nasal dorsum, nasal tip, bilateral nasal soft tissue triangles, and right alar subunits. ( C ) Profile of paramedian flap after inset. ( D ) Frontal view of inset paramedian forehead flap with split-thickness skin graft placed over the superior flap donor site.
    • Central nasal defects can be reconstructed with left- or right-based flap.

    • Lateral nasal defects should be reconstructed with ipsilateral flap, when possible, to decrease the distance from pivot point to distal defect.

  • Step 2: Develop flap template

    • Templates allow determination of the size, shape and dimension/position of the flap.

    • Use the contralateral normal as a guide to template formation. If not present you can use moulage or additional template formed preoperatively. Many make the template with suture packaging foil.

    • Must replace tissue with exact dimension of template.

      • Flap too large→ Tissue displaced laterally with loss of surface detail.

      • Flap too small→ Contracture with collapse of underlying structure.

  • Step 3: Transfer template design to donor site (forehead), locate pedicle and confirm dimensions

    • Mark outline of template with inferior base of planned flap at hairline directly over the supratrochlear artery

      • Locating the arterial pedicle

        • Normally lies approximately 1.7 to 2.2 cm lateral to midsaggital plane, which is usually coincident with the medial border of the brow.

        • The pedicle should be no more than 3 mm medial or lateral to a vertical line extending from the medial canthus. ,

        • Can use Doppler imaging, but 8% of intact supratrochlear arteries cannot be identified by Doppler imaging.

        • The supratrochlear artery is superficial to the orbital rim periosteum at its origin and sandwiched between the corrugator and frontalis muscles. The vessel moves superficially as it travels superiorly entering the subcutaneous tissues 3.5 cm above the orbital rim.

    • Pedicle width should be 1.5 cm with the vessel in the middle of the flap

      • Thinner pedicle width→ risk to pedicle viability

      • Thicker pedicle width→ restricts pivot and can cause kinking

  • Step 4: Confirm planned flap’s arc of rotation before raising the flap

    • Verify the arc of rotation with passive application of gauze or suture measuring from the pivot point below the medial brow to the most distal aspect of the flap on the forehead and then to the most inferior aspect of the recipient site

      • If more length is needed, extend the flap beyond the hairline or extend the pedicle across the brow toward the medial canthus (medial incision is extended and will be discussed later)

  • Step 5: Development of paramedian flap

    • Planned incision is made distally through skin, subcutaneous tissues and frontalis muscle. Dissection is carried inferiorly between the frontalis muscle and the pericranium.

      • 1 cm superior to the orbital rim, the dissection is carried subperiosteally to maintain the pedicle (between corrugator and frontalis)

    • May need to release corrugator muscle to allow for increased arc of rotation.

    • Once dissection has reached the level of the brow, only the medial incision should be carried further to determine the pivot point and it should not be extended deeper than papillary dermis to maintain the pedicle.

  • Step 6: Management of donor site

    • Wide undermining in the subgaleal plane lateral to donor site defect enables attempt for primary closure in a layered fashion

    • Any area not closed primarily and is inferior to the hairline should be dressed with petroleum gauze and allowed to heal secondarily or a split-thickness skin graft can be used ( Fig. 1 D)

  • Step 7: Contouring distal flap

    • The templated region is then debulked with all excess frontalis muscle and subcutaneous tissue removed to enable proper contouring. When given the choice, thin the recipient bed before further thinning of the distal flap.

    • Must keep 2 to 3 mm of subcutaneous tissue on the distal flap to preserve the subdermal plexus. More subcutaneous tissue should be preserved with smokers.

    • Undermine adjacent tissue to defect to avoid trap door defect and establish the nasolabial crease and alar base definition.

  • Step 8: Inset of the flap ( Fig. 1 C, D)

    • Rotate the flap so that the skin is facing the ipsilateral eye limiting the chance of blood draining into the eye

    • Flap is inset to defect site from distal to proximal with a single layer of 5-0 Prolene interrupted sutures

    • If flap blanches, remove sutures in that region and allow to heal secondarily

Stage II (3–4 weeks after flap harvested)

  • Step 1: Marking the patient ( Fig. 2 A )

    • Mark proximal portion of flap with a small inverted “V” to allow for linear closure of the brow

    • Mark the distal portion of flap, which will become the most superior aspect of the flap when inset

    Fig. 2
    Patient presenting 3 weeks after harvest and inset of right paramedian forehead flap. ( A ) Patient’s presentation on the day of division and inset with a well-vascularized flap and healing skin graft region. ( B ) Frontal view of inset paramedian flap. ( C ) Paramedian flap after division and inset with good color match and contour to surrounding skin and subunits. ( D ) Profile view of inset paramedian flap.
  • Step 2: Incise planned distal and proximal portion of flap with primary closure of the proximal site

  • Step 3: Distal flap inset ( Fig. 2 B–D)

    • Debulk only cephalic aspect of the distal flap to remove excess subcutaneous tissues, frontalis muscle and scar to create proper contouring. The flap remains vascularized through the distal inset and should not be elevated!

  • Step 4: Forehead revision, if needed

    • Excision of scar with bilateral advancement flaps

Potential complications

Complications are rare and when treated promptly have a high propensity to resolve. Table 3 lists the most common complications, and their etiology and management.

Mar 10, 2020 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Paramedian Forehead Flap
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