See: Paramedian Forehead Flap Case Example

Note: last updated before 2015

GENERAL CONSIDERATIONS

1. Indications
   1. 2 stage reconstruction for facial defects
   2. Often used as an interpolated flap for nasal defect reconstruction
   3. Larger Nasal defects
2. Contraindications
   1. Previous forehead or orbital trauma or surgery with likely interruption of the blood supply of the flap tissues is a contraindication
   2. Previous radiation to the donor site is a relative contraindication
3. Advantages
   1. Large amount of tissue
   2. Reliable Flap
   3. Minimal donor site morbidity
   4. Good tissue match
4. Pertinent Anatomic Considerations
   1. The paramedian forehead flap is based on the supratrochlear artery
      1. The supratrochlear artery is reliably located 1.7-2.2 cm from the midline, corresponding to the medial border of the eyebrow. Usually the notch of the supratrochlear vessels is palpable and that is where the skin pedicle is centered.
      2. The supratrochlear artery and the supraorbital artery, which lies laterally, are terminal branches of the ophthalmic artery (branch of the internal carotid artery), and supplies the anterior pericranium and galea.
      3. The supratrochlear artery divides into superficial and deep branches. The superficial branch enters the frontalis muscle and runs on the surface of the galea until entering the subcutaneous tissue approximately 3.5 cm above the orbital rim. The deep branch runs within the subgaleal fascia (this layer may be considered a component of the pericranium). The deep branches pursue an axial course for approximately 1.5 to 4 cm above the supraorbital rim. There are many penetrating vessels that connect the superficial and deep branches. These vessels are divided if the galea is separated from the underlying pericranium.
   2. Experience suggests that the effective axial blood supply to these tissues may extend farther than is demonstrable in anatomic studies. Even if no Doppler signal is found, a flap with a pedicle based along the midline of the forehead will probably survive.  The pedicle base is perfused by a terminal branch of the angular artery that is actually a major contributor to the flap's arterial supply.
   3. An flap ipsilateral to the defect is commonly used. Considerations in selecting which side to use include:
      1. Increased rotation of an ipsilateral flap has a greater risk of pedicle kinking
      2. A contralateral flap must be longer to reach the defect
   4. Layers of the scalp encountered on raising a paramedian forehead flap
      1. Skin
      2. Subcutaneous fat
      3. Galea- aponeurotic system continuous with the frontalis and occipitalis muscles, the temporoparietal fascia, and the SMAS
      4. Subgaleal fascia- commonly called the loose areolar tissue, this is not a true layer but rather an avascular plane
      5. Pericranium
   5. The flap may be extended into the hair-bearing scalp and/or up to 1.5cm below the orbital rim for additional length

PREOPERATIVE PREPARATION​

1. Evaluation
   1. Smokers
      1. Smoking cessation and consider delayed flap transfer (ie. incise the perimeter first, then complete flap elevation after 3 weeks)
2. Potential Complications
   1. Flap necrosis and failure- dissection in the region of the supraorbital rims should be done carefully so as not to disrupt the blood supply.

NURSING CONSIDERATIONS

1. Room Setup
   1. See Basic Soft Tissue Room Setup
2. Instrumentation and Equipment
   1. Standard
      1. Major Instrument Tray 1, Otolaryngology
      2. Major Instrument Tray 2, Otolaryngology
      3. Bipolar Forceps
3. Medications (specific to nursing)
   1. 1% lidocaine with 1:100,000 epinephrine
   2. Antibiotic ointment
4. Prep and Drape
   1. Standard prep, 10% providone iodine
   2. Drape
      1. Head drape
      2. Towels to square off, leaving the midvertex scalp to the lips exposed
      3. Split sheet
5. Drains and Dressings
   1. Antibiotic ointment to suture line

ANESTHESIA CONSIDERATIONS

1. General
   1. May be done under MAC with IV sedation, or general anesthesia
   2. The head of the bed is turned 180° from the anesthesiologist, and long anesthesia tubing is required. 20 to 30 degrees of reverse Trendelenburg is useful to reduce venous pooling and blood loss.
   3. Paramedian forehead flaps are associated with post-operative nausea, so consider intraoperative antiemetics (eg. Zofran)
   4. Eyes are protected with Lacrilube and covered with a Tegaderm
2. OPERATIVE PROCEDURE
   1. Flap/defect design
      1. Based on the contralateral normal side of the nose, as skin retraction on the defect can cause distortion
      2. The flap can reach the columella
      3. Reconstruction of a nasal defect
         1. If a defect involves more than 50% of the surface area of a convex nasal subunit (eg ala), consider excising the skin on the remaining parts of the subunit to better camouflage the scar and avoid pin-cushioning. Additional excision of the dorsum and soft tissue triangles is not typically done because the skin is too thin to recreate.
         2. Start by marking the nasal subunits (ala, soft tissue triangles, columella, tip, dorsum, nasal sidewalls), then design the template to cover the missing subunits.
      4. A template of the defect is made using a pliable material such as foil (eg. Suture packaging) or foam sponge.
   2. Pedicle planning
      1. The supratrochlear artery may be identified at the supraorbital rim using landmarks such as the medial brow border, a point 2cm lateral to the midline, or by using a Doppler.
      2. The pedicle is centered over the artery, with a width of 1.5cm. Smaller pedicles risk damage to the supratrochlear artery. Larger pedicles restrict pivotal movement of the flap.
      3. Pedicle length is determined by using a non-stretchable material, such as an unfolded gauze sponge or suture. This is anchored at the superior orbital rim as an approximate pivot point, and the length to the defect is determined.
         1. A small amount of extra length should be included to allow for flap thickness and swelling. This can easily be done by removing superior standing cutaneous deformity of scalp skin with the distal end of the flap and trimming off during inset.
   3. Trace the defect template onto the forehead at the measured pedicle distance
      1. Caution---be certain to orient the template correctly for rotation in the coronal plane
      2. Note that the pedicle can be designed to attach anywhere along the defect paddle (ie. does not have to be in the center)
   4. Raise the flap
      1. Inject local anesthetic circumferentially
         1. Along the pedicle, inject along the borders only to avoid disrupting the supratrochlear artery.
      2. Incise around the marked borders of the flap.
      3. The flap is raised from distal to proximal (ie. superior to inferior)
      4. Layers of the flap
         1. The defect portion of the flap is raised in a subcutaneous plane, leaving the galea/frontalis down. If the donor defect cannot be closed primarily and instead is left to granulate, this decreases the risk of a depression. Also, this decreases the need to thin the flap afterwards.
            1. Other sources describe raising the entire flap in a subgaleal plane because there is less bleeding than in the subcutaneous plane, and because primary closure may require excision of the frontalis anyway.
            2. Inclusion of the frontalis may be useful when bulk is needed to fill a deep defect
         2. The pedicle is raised in a subgaleal plane, leaving periosteum down, until 1 cm superior to the level of the eyebrow. It is then transitioned down to a subperiostial plane to keep the supratrochlear artery protected. 
         3. When the proximal end of the flap is extended across the orbital rim an extra 1.5 cm of length can be obtained. The artery is sandwiched between the corrugator and frontalis muscles in this area
      5. The flap is wrapped in a moist gauze until inset
   5. Close the donor defect
      1. Undermining is done in a subgaleal plane and deep sutures should be placed through galeal layer to ensure adequate strength.
      2. Suture: interrupted 3-0 PDS, 3-0 vicryl, or 3-0 monocryl for subcutaneous tissues, 5-0 black nylon vertical mattress for skin
      3. Gaps that cannot be closed may be left to granulate though secondary healing
      4. The backside of the flap may be covered with thin Alloderm or a split thickness skin graft as a biological dressing and to decrease oozing.
   6. Flap inset
      1. The flap is pivoted clockwise or counterclockwise to reach the defect
         1. Rotation so that the flap skin is facing the ipsilateral eye can decrease ooze from the backend of the flap from reaching the eye
      2. Consider deepening the recipient bed to match the flap depth and/or thinning the distal 1/3-1/2 of the flap
         1. Thinning of the fascia and frontalis muscle and, if necessary, nearly all of the subcutaneous tissue can be done
         2. Undermining of adjacent defect skin to decrease trap door defect
      3. Suture: 5-0 or 6-0 nylon/prolene for skin only. No deep sutures. A minimum of sutures are used so as to minimize risk for flap necrosis

POSTOPERATIVE CARE

1. Immediate post-op
   1. No external dressings as they may compromise flap circulation, wrap exposed pedicle in xeroform gauze.
   2. Open donor defect wounds should be kept moist with antibiotic ointment for the first 3 days, then Vaseline until secondary healing is complete
   3. Consider post-operative antiemetics
   4. Overnight observation may be warranted if there are concerns about severe nausea or for flap monitoring if there are concerns
      1. Flap viability may be improved by removing sutures
2. Sutures are removed 5-7 days post-op
3. Pedicle division is performed in 3 weeks to allow sufficient neovascularization. Consider flap thinning and sculpting, as well as and cartilage grafting at this point or additional stages