Interpolated Flaps


Article Author:
Michael Ramsey


Article Editor:
Ahmad Al Aboud


Editors In Chief:
Mark Dreyer
Dustin Constant
Melanie Violand


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Frank Smeeks
Kristina Soman-Faulkner
Trevor Nezwek
Radia Jamil
Patrick Le
Sobhan Daneshfar
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Pritesh Sheth
Hassam Zulfiqar
Navid Mahabadi
Steve Bhimji
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Mark Pellegrini
James Hughes
Beata Beatty
Nazia Sadiq
Hajira Basit
Phillip Hynes
Tehmina Warsi


Updated:
5/17/2019 11:07:34 PM

Introduction

An interpolation flap is a 2-stage tissue flap in which the base of the flap is not directly adjacent to the recipient defect. These flaps are used when insufficient tissue or mobility in nearby skin prevents the coverage of a surgical defect with primary closure or an adjacent flap.[1] The use of an interpolation flap results in a bridge of tissue, or pedicle, between the flap base and the surgical defect. It must be removed in a second stage after establishing vascularity between the wound and the flap.

The interpolation flaps most commonly used in dermatologic surgery are:

  • Forehead flap
  • Cheek interpolation flap
  • Postauricular flap

Anatomy

The paramedian forehead flap is an axial flap based on the supratrochlear arterial blood supply, although some authors have reported that with the abundant anastomoses in the forehead, it can be performed as a random flap.[2][3]  The cheek interpolation flap is a random flap, but it receives an ample blood supply from the perforating branches of the angular, nasal, and superior labial arteries. The postauricular interpolation flap is also a random flap with a broad pedicle supplied by branches of the posterior auricular, superficial temporal, and occipital arteries.

Indications

Interpolation flaps are used when insufficient tissue or mobility in nearby skin prevents the coverage of a surgical defect with primary closure or an adjacent flap. The forehead flap is especially useful on larger defects that are deep or full-thickness, and located on the distal nose.[4] Cheek interpolation flaps are useful on the distal third of the nose, especially laterally, in situations in which adjacent tissue transfer or full-thickness grafts are not practical.[5][6][7] The postauricular interpolation flap is utilized in medium-to-large defects on the helix and adjacent antihelix, with or without the loss of small amounts of cartilage, in situations in which single-stage flaps are not adequate for coverage. [8]

Contraindications

The use of interpolation flaps is contraindicated in patients who are unwilling or unable to tolerate multiple-staged surgical procedures. Likewise, these procedures should be avoided in patients who cannot leave their surgical sites undisturbed, or special measures must be taken to protect the sites in these patients. Actively infected skin should not be covered with a flap or used to form a flap. When performing the paramedian forehead flap (PFF) on a patient with a forehead of low vertical height, a variation of the forehead flap or another repair method may be required to avoid transferring hair-bearing skin to the nose.

Smoking is a relative contraindication to the use of staged island pedicle flaps because it increases the risk of flap necrosis. However, procedures with these flaps can usually be performed safely if fat is not thinned excessively from the undersurface of the flap. In addition, avoiding the use of previously radiated skin or a previous surgical site is generally best, unless no better repair options are available. Interpolation flaps should be performed with great care in patients who are receiving anticoagulant therapy or in patients with bleeding disorders. Consultation with the physician who prescribed the medication is prudent before discontinuing any anticoagulant therapy. The author rarely discontinues warfarin or aspirin prior to surgery. Contacting consulting physicians is appropriate before operating on individuals with bleeding dyscrasias.

Equipment

Equipment required for interpolation flaps is generally the same for other dermatologic surgery, with a few possible additions.

Pre-operatively

  • Alcohol (clean and degrease skin prior to marking planned flap)
  • Surgical marker
  • Template material (non-stick dressing material, surgical cottonoid, foil suture wrapper, or other material that allows creation of a template or pattern for the flap)
  • Local anesthetic (author prefers lidocaine 0.5% with epinephrine 1:200,000, buffered with sodium bicarbonate)
  • Surgical scrub solution

Intra-operatively

  • Scalpel with #15 blade
  • Toothed forceps
  • Curved iris scissors, preferably serrated (to thin fat from flap if indicated)
  • Shea or other fine dissecting scissors
  • Skin hooks
  • Suture (4-0 or 5-0 absorbable sutures and 5-0 or 6-0 non-absorbable suture)
  • Gauze
  • Electrocoagulation device

Post-operatively

  • Non-adherent petrolatum-soaked gauze ribbon dressing (to place around pedicle)
  • Fluffed gauze or other absorbent material for post-op bulky dressing
  • Adhesive dressing material or tape with elasticity

Personnel

Interpolation flaps can generally be performed with one surgical assistant, primarily to help manage bleeding and cut suture.

Preparation

We find that it is very helpful to show patients (and their families) illustrations when discussing interpolation flaps prior to surgery. Otherwise, it can be difficult for patients to understand what is about to happen in the surgery and in its aftermath. Serial postoperative photographs can help allay concerns and help patients understand that the final result will take time. It is also essential to explain that minor revisions ("fine tuning") may be indicated in the weeks or months after the initial procedure to obtain optimal results.

Technique

Forehead Flap (Paramedian Forehead Flap, PFF)

The PFF technique first was used in India as early as 700 BC. For many years, a broad midline flap was popular. In the 1960s Menick introduced the PFF, which had a much more narrow and mobile pedicle based on the supratrochlear artery. The PFF uses tissue from the forehead to repair larger, deeper defects on the distal nose (fig. 1a), and sometimes provide nasal lining.[4][3][4] In more extensive defects, the forehead flap can be used in combination with other techniques such as microvascular flaps, cartilage or bone grafts, and mucosal flaps. The PFF is an axial flap based on the supratrochlear artery (fig. 1b). The supratrochlear artery exits the orbit 1.7-2.2 cm from the midline, passing deep to the orbicularis oculi muscle and ascending superficially to the corrugator supercilii muscle. It then passes medial to the eyebrow and through the frontalis muscle ascending superiorly in the subcutaneous tissue and 1.5 to 2 cm from the midline.

The distal nasal defect is examined prior to designing the PFF. A template of the final defect is made, and the location and course of the supratrochlear artery can be identified by using Doppler ultrasonography or anatomic landmarks. The supratrochlear artery runs toward the scalp within 3 mm of a line drawn up from the medial canthus. Other authors have demonstrated the safety of simply taking a pedicle from the glabellar midline to 1.2 cm lateral to the midline.[2] If more than 50% of an anatomic subunit is involved in the surgical defect, it is often preferable to remove the remainder of the subunit to obtain a better aesthetic result.[5] A template of the defect is made, and then tubed gauze or another flexible material is used to measure the needed length for the flap to rotate and reach the defect from the pedicle base. The tube gauze is rotated to the forehead and the inverted template pattern is marked at the uppermost aspect of the pedicle. From that area, a 1 to 1.5 cm pedicle is drawn down to the planned pedicle base. The flap is then mobilized with its base situated at the inferior aspect of the forehead and often around the orbital rim (fig.1c). The forehead donor site is closed primarily and if the wider portion of that defect will not close completely, it is preferable to allow it to heal secondarily rather than to apply a skin graft (fig.1d). The flap is then thinned distally and secured in the nasal defect with simple interrupted sutures. Within 1 to 3 weeks, usually about 2 weeks, the pedicle trunk is excised, and its base defect is best closed primarily. The incised portion of the nasal flap is then thinned and inset into the defect. Minor revision procedures may be indicated during the coming weeks, and it is best to discuss this with the patient prior to starting this flap.

Cheek Interpolation Flap

First used in India in about 600 BC, the medial cheek skin is an excellent color and texture match for defects on the caudal third of the nose (fig. 2a). Based superiorly, the cheek interpolation flap can be based on a cutaneous (fig. 2b) or a subcutaneous pedicle (fig. 2c). The subcutaneous pedicle has greater mobility and vascular supply than the cutaneous pedicle. For small-to-medium alar defects, an inferiorly based flap can also be used to avoid transfer of facial hair. The cheek interpolation flap is a random flap, but it receives an ample blood supply from the perforating branches of the angular, nasal, and superior labial arteries. Small-to-medium, deeper defects on the nasal ala and nasal tip can be repaired by using the cheek interpolation flap.[7][6] Foil or nonabsorbent surgical dressing is used to make a template of the surgical defect to be repaired. Gauze is rolled into a tube, and one end is held in place in the area of the planned flap base, in and lateral to the melolabial crease. While the proximal end is held in place, the remainder of the gauze tube is turned to overlap the wound without tension. The most distal portion covering the wound is marked, and the gauze is swung back into the melolabial crease to mark where the flap should reach.  The template is placed on the cheek with its superior edge placed medially and touching the melolabial crease. The portion of the template representing the lateral wound edge furthest from the flap is placed most inferiorly (or distally) on the cheek, touching the mark previously placed on the cheek. A tapered incision is planned distal to this tissue and parallel to the melolabial crease to allow closure without a dog-ear defect. The flap is mobilized, thinned, trimmed and secured in the recipient wound (fig. 2d). The cheek donor site is sutured and the pedicle is wrapped in non-adherent dressing material. The flap is divided and its remainder is inset in about 3 weeks. The remainder of the donor defect is repaired at that time (fig. 2e).

Postauricular Interpolation Flap

First described by Lewin in 1950, the postauricular interpolation flap provides good coverage and cosmesis in medium-to-large defects on the helix and adjacent antihelix, with or without the loss of small amounts of cartilage (fig. 3a). Branches of the posterior auricular, superficial temporal, and occipital arteries supply the broad pedicle of this flap. Although it is a random flap, it is rarely affected by vascular necrosis. This flap uses skin from the posterior ear and retroauricular sulcus and retroauricular skin to repair defects of the middle third of the auricular helix and adjacent skin.[8] Scars remain well hidden behind the ear. Reconstruction begins by making a template of the helical defect. The template is placed behind the ear with its leading (anterior) edge over the loose portion of the posterior ear and the planned flap is drawn with a surgical marker (fig. 3b). Lines are drawn toward the scalp, gradually tapering outward as they approach the hairline. Burow's triangles can be drawn lateral to the base of the pedicle, but the actual excision of the triangles is often not necessary. Incisions are made through the skin along the planned lines, and the flap is elevated. The surrounding tissue is undermined for a short distance to allow greater tissue mobility, decrease pincushioning, and allow better placement of subcutaneous sutures. The flap is draped over the defect to ensure that coverage of the anterior portion of the defect does not cause excessive tension, and the Burow's triangles can be excised if necessary. Electrocoagulation is used to obtain meticulous hemostasis before the sutures are placed, making every effort to avoid postoperative bleeding. A few interrupted, subcutaneous, absorbable sutures can be used to securely anchor the flap into place, and superficial sutures are placed for fine approximation (fig. 3c). Particularly on the posterior aspect of the ear, it is preferable to use absorbable sutures to avoid the need to manipulate the ear for suture removal. A few basting sutures can be placed through the flap into the cartilage to recreate the helical sulcus if desired. Division and inset are performed at about 3 weeks. The postauricular donor defect may be closed or allowed to heal secondarily.

Complications

Potential complications common to all skin surgery include infection, scarring, bleeding and disfigurement. In addition, pedicle necrosis is possible but infrequent.

Clinical Significance

Interpolation flaps provide a method of repairing surgical defects that otherwise would be difficult, if not impossible, to repair with other reconstructive techniques.

Enhancing Healthcare Team Outcomes

The surgical team should pay particular attention to control and prevention of postoperative bleeding, which is most commonly experienced in the first 24-28 hours after surgery. Salient points are outlined below.

The paramedian forehead flap is especially prone to postoperative bleeding, most commonly from the proximal flap pedicle in the glabella/brow area. This is best managed as follows:

  • Careful, precise electrocoagulation must be performed at the end of the procedure.
  • Apply hemostatic agents such as cellulose gel mesh and/or Monsel's ferric subsulfate solution at the base of the flap.
  • When dressing the surgical site, apply extra gauze or other absorbent materal near the flap base, being careful to not apply excessive pressure (avoiding stangulation of the flap)
  • Have the patient return to the office in 1-2 days for dressing change. If excessive drainage is not present, the next bandage may remain in place until next visit in 5-7 days.

Cheek interpolation flaps are not as prone to heavy bleeding, but do tend to ooze in the early postoperative period.

  • Thorough, but precise electrocoagulation should be administered prior to dressing the surgical site.
  • Postoperative visit in 1-2 days is preferred if possible.
  • Any minor bleeding may be addressed on that visit. If no significant bleeding is noted, a less bulky dressing can be applied at that time.

Postauricular transposition flaps, when they bleed, are particularly challenging due to being located in the tight quarters behind the ear, which is draped with a flap. Prevention is key to success.

  • Meticulous electrocoagulation must be applied at the end of surgery. Once hemostasis has been obtained, it is often a good idea to vigorously rub the wound with gauze to "battle test" one's work. Any additional bleeding can then be treated prior to placement of the flap.
  • The unsutured portion of the pedicle is wrapped with petrolatum-saturated gauze ribbon, followed by application of non-adherent surgical dressing and then fluffed gauze over the entire surgical site. Elastic adhesive bandage is then applied to run in an anterior to posterior direction, thus pulling the ear toward the head. This takes tension off the interpolation flap and also helps apply pressure to minimize risk of bleeding.

  • Image 1575 Not availableImage 1575 Not available
    Contributed by Michael L Ramsey
Attributed To: Contributed by Michael L Ramsey

Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Interpolated Flaps - Questions

Take a quiz of the questions on this article.

Take Quiz
Which of the following features is only seen with an interpolation flap?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Typically, which of the following is not done when performing a postauricular interpolation flap?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is considered an axial flap?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not a contraindication for performing interpolation flaps?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not an interpolation flap used in dermatologic surgery?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Interpolated Flaps - References

References

Outcomes of paramedian forehead and nasolabial interpolation flaps in nasal reconstruction., Paddack AC,Frank RW,Spencer HJ,Key JM,Vural E,, Archives of otolaryngology--head & neck surgery, 2012 Apr     [PubMed]
Paramedian forehead flap: advances, procedural nuances, and variations in technique., Jellinek NJ,Nguyen TH,Albertini JG,, Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.], 2014 Sep     [PubMed]
The forehead flap: the gold standard of nasal soft tissue reconstruction., Correa BJ,Weathers WM,Wolfswinkel EM,Thornton JF,, Seminars in plastic surgery, 2013 May     [PubMed]
Staged cheek-to-nose and auricular interpolation flaps., Nguyen TH,, Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.], 2005 Aug     [PubMed]
The staged cheek-to-nose interpolation flap for reconstruction of the nasal alar rim/lobule., Fader DJ,Baker SR,Johnson TM,, Journal of the American Academy of Dermatology, 1997 Oct     [PubMed]
Interpolation flaps., Mellette JR,Ho DQ,, Dermatologic clinics, 2005 Jan     [PubMed]
The staged retroauricular to auricular direct pedicle (interpolation) flap for helical ear reconstruction., Johnson TM,Fader DJ,, Journal of the American Academy of Dermatology, 1997 Dec     [PubMed]
The Paramidline Forehead Flap: A Clinical and Microanatomic Study., Stigall LE,Bramlette TB,Zitelli JA,Brodland DG,, Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.], 2016 Jun     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Surgery-Podiatry Cert Surgery. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Surgery-Podiatry Cert Surgery, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Surgery-Podiatry Cert Surgery, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Surgery-Podiatry Cert Surgery. When it is time for the Surgery-Podiatry Cert Surgery board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Surgery-Podiatry Cert Surgery.