The Midline Forehead Flap in Nasal Reconstruction




An ancient Indian medical document, the Sushruta Samhita, describes a technique of using a flap from the forehead for nasal reconstruction. The forehead flap remains the workhorse for major nasal resurfacing today. Contemporary nasal reconstruction with forehead flaps uses the well-established concept of facial and nasal subunits, restoring the three-dimensional morphology by replacing missing tissue with like tissue. This article covers the history of forehead flap surgery, current concepts in flap design, surgical steps, potential complications, defect analysis, lining, framework, and cover as a means of restoring the three-dimensional nasal morphology.


History


Nasal reconstruction originated almost 3000 years ago in India, where large cheek flaps were developed to reconstruct noses. Nasal amputation was a common form of social punishment for various crimes, from theft to adultery, thus giving rise to a large group of individuals in need of total or subtotal nasal reconstruction. A seventh century Indian medical document, the Sushruta Samhita, describes a technique of using a flap from the forehead for nasal restoration. In the fifteenth century, Antonio Branca of Italy discovered an Arabic translation of the Sushruta Samhita and is believed to be the first to perform a similar procedure outside India. In Europe, Italian surgeons used a pedicled flap from the medial surface of the upper arm for nasal reconstruction.


In the late eighteenth century, JC Carpue found a description of this Indian technique, giving rise to the modern era of nasal resurfacing with the use of a pedicled forehead flap. Carpue first practiced these techniques on cadavers and later applied them to live patients, eventually publishing his results. His writings soon spread across Europe and to America, revolutionizing nasal reconstruction. Carpue’s basic techniques laid the foundation for modern nasal reconstruction for the next century.


These techniques were modified further and popularized by other surgical giants. Kazanjian advanced the development of the forehead flap by advocating primary closure of the forehead donor site. Millard, in the 1960s and 1970s, used a characteristic gull-wing design with lateral extensions for alar reconstruction and extended the pedicle incisions below the brow to provide greater flap length.


Burget and Menick made further contributions to the design by emphasizing aggressive thinning of the skin paddle, narrowing the pedicle base for easier rotation and length, and modifying defects to follow aesthetic subunits of the nose.




Key principles


The use of the forehead flap in nasal reconstruction poses the challenges of restoring aesthetics in a prominent area on the face while preserving function. A full-thickness defect requires a multilayered reconstruction that addresses each of the 3 separate layers of the nose (ie, cutaneous surface, structural support, internal lining). Once structural grafting is placed, its covering must be durable and of similar thickness and texture to native nasal skin and it must have its own blood supply. Ideally, this is accomplished with minimal donor site morbidity and with reproducible dependability, which is best addressed with the forehead flap.


Facial and Nasal Subunits


At the core of any discussion about reconstruction of nasal defects is the concept of facial aesthetic units as popularized by Burget and Menick. The face is divided into aesthetic units defined by subtle changes in contour and natural creases. These distinct topographic areas are characterized by their skin color, contour, skin thickness, hair density, skin texture, and mobility. The nasal subunits together with the eyes and lips form the central core of the facial aesthetic units. Our eyes tend to focus on this central core and therefore attaining adequate fidelity in our reconstruction ensures a successful result. Scars that traverse the subunit may result in an unfavorable scar. If greater than 50% of the subunit is involved, Burget and Menick recommend completing the excision of the involved subunit before reconstruction. Nevertheless, this concept of aesthetic units has seen its fair share of critiques. Singh and Barlett focused on local characteristics such as color, texture, contour, and actinic change that may override the traditional nasal subunits. Yotsuyanagi and colleagues proposed a different set of nasal subunits for the Oriental face and used these for their reconstructions. Rohrich and colleagues advocated reconstruction of the defect, not the subunit, seeking good contour as the aesthetic end point. Hence, it is important to know that there are limitations to this concept of aesthetic subunits. More recently, Menick emphasized that the subunit principle can be helpful, but is only a single tool in a surgeon’s armamentarium.


A more aggressive application of the subunit principle is used for the tip and alar regions where 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 the nasal dorsum and sidewalls, it is less applicable, because these relatively flat subunits blend indistinctly. The subunit principle is also less applicable when skin grafts are used for resurfacing because grafts do not pincushion.


Therefore, reconstruction based on the principle of aesthetic subunits aims to maintain the normal segmentation of the face so that scars at the border of 2 units are inconspicuous to the casual observer. There are, however, certainly more factors involved before a successful nasal reconstruction is attained. Burget and Menick have both stressed that the aesthetic subunit principle should not be overemphasized. Although it is a useful concept in most instances, it should not be dogma and it should not replace the ingenuity and craftsmanship of the surgeon.


Form and Function


Internal lining


The internal lining is mentioned briefly as it is covered by other references. A variety of strategies are available for reconstituting defects of the internal nasal lining. They can broadly be divided into



  • 1.

    Grafts: typically chondrocutaneous grafts


  • 2.

    Mucosal flaps: intranasal mucosal or intraoral mucosal flaps


  • 3.

    Local flaps: nasal turn-in flaps, melolabial flaps


  • 4.

    Free flaps: most frequently described would be the radial forearm flap and auricular ascending helical flap.



Specific to the forehead flap, the distal end may be turned in to provide internal lining over the lower third of the nose.


Framework


Reestablishing a framework in nasal reconstruction is of paramount importance for maintaining both form and function. It is an integral part of the 3-layer repair of any full-thickness defect of the nose. Structural grafts are used liberally and often in nonanatomic locations to prevent sidewall collapse, alar retraction, and maintain nasal projection. The current gold standard is an autogenous cartilage graft, typically harvested from the septum or auricle. Rib and split calvarial bone grafts are occasionally required in subtotal and total nasal reconstruction. Clinical success has also been reported with the use of irradiated homograft rib as well as alloplastic materials although we tend not to favor this approach.


Cartilage grafts in nasal reconstruction serve 3 primary roles :



  • 1.

    To provide rigidity to the sidewall and avoid lateral collapse during inspiration


  • 2.

    To resist cephalic retraction of the alar margin


  • 3.

    To establish nasal contour and projection.



The dimension of the cutaneous defect is not a direct indicator for the need of cartilage grafting. Many smaller defects, especially those involving the alar and supraalar crease may lead to sidewall collapse and hence nasal obstruction.


The auricle is ideally suited as a donor site for cartilaginous grafts to the nose and can be relied on with minimal donor site morbidity. Septal cartilage may be used in some circumstances, but there may be limited availability and the favorable curvature of the conchal bowl is often lost. When subtotal or total rhinectomy defects are encountered or when both septal and conchal cartilage is unavailable, rib grafts are the next material of choice.


Suture can be used to reshape existing cartilages, and their versatility is widely demonstrated in rhinoplasty techniques. Sutures can also be used to influence the position of the upper lateral cartilages and the corresponding internal nasal valve. The flaring suture is a quick and noninvasive means of augmenting the cross-sectional area of the internal nasal valve. These flaring sutures are used even in patients without preexisting narrowing of the internal nasal valve as a prophylactic measure against sidewall collapse.


Cicatricial contracture along the vestibule is best prevented by repairing all linings meticulously and providing strong support to the rim. Secondary repair of this type of narrowing is more challenging.


Covering


Resurfacing of the nasal defect takes into consideration the previously mentioned concept of facial subunits. We use the forehead flap for larger nasal cutaneous defects. Its many virtues include abundant tissue availability, its excellent match in color and skin texture, low donor site morbidity, and its robust vascularity. Currently, we use the midline forehead flap, which harvests a skin paddle from the precise center of the forehead but is based on a narrow unilateral pedicle from the medial brow area. The pedicle can be narrow (1.5 cm) and extend below the level of the brow to facilitate flap rotation with less potential for vascular kinking. The oblique pedicle allows a slightly longer reach compared with the paramedian flap. The resultant scar from the midline forehead flap is in the exact center, which is consistent with the principle of aesthetic units.




Key principles


The use of the forehead flap in nasal reconstruction poses the challenges of restoring aesthetics in a prominent area on the face while preserving function. A full-thickness defect requires a multilayered reconstruction that addresses each of the 3 separate layers of the nose (ie, cutaneous surface, structural support, internal lining). Once structural grafting is placed, its covering must be durable and of similar thickness and texture to native nasal skin and it must have its own blood supply. Ideally, this is accomplished with minimal donor site morbidity and with reproducible dependability, which is best addressed with the forehead flap.


Facial and Nasal Subunits


At the core of any discussion about reconstruction of nasal defects is the concept of facial aesthetic units as popularized by Burget and Menick. The face is divided into aesthetic units defined by subtle changes in contour and natural creases. These distinct topographic areas are characterized by their skin color, contour, skin thickness, hair density, skin texture, and mobility. The nasal subunits together with the eyes and lips form the central core of the facial aesthetic units. Our eyes tend to focus on this central core and therefore attaining adequate fidelity in our reconstruction ensures a successful result. Scars that traverse the subunit may result in an unfavorable scar. If greater than 50% of the subunit is involved, Burget and Menick recommend completing the excision of the involved subunit before reconstruction. Nevertheless, this concept of aesthetic units has seen its fair share of critiques. Singh and Barlett focused on local characteristics such as color, texture, contour, and actinic change that may override the traditional nasal subunits. Yotsuyanagi and colleagues proposed a different set of nasal subunits for the Oriental face and used these for their reconstructions. Rohrich and colleagues advocated reconstruction of the defect, not the subunit, seeking good contour as the aesthetic end point. Hence, it is important to know that there are limitations to this concept of aesthetic subunits. More recently, Menick emphasized that the subunit principle can be helpful, but is only a single tool in a surgeon’s armamentarium.


A more aggressive application of the subunit principle is used for the tip and alar regions where 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 the nasal dorsum and sidewalls, it is less applicable, because these relatively flat subunits blend indistinctly. The subunit principle is also less applicable when skin grafts are used for resurfacing because grafts do not pincushion.


Therefore, reconstruction based on the principle of aesthetic subunits aims to maintain the normal segmentation of the face so that scars at the border of 2 units are inconspicuous to the casual observer. There are, however, certainly more factors involved before a successful nasal reconstruction is attained. Burget and Menick have both stressed that the aesthetic subunit principle should not be overemphasized. Although it is a useful concept in most instances, it should not be dogma and it should not replace the ingenuity and craftsmanship of the surgeon.


Form and Function


Internal lining


The internal lining is mentioned briefly as it is covered by other references. A variety of strategies are available for reconstituting defects of the internal nasal lining. They can broadly be divided into



  • 1.

    Grafts: typically chondrocutaneous grafts


  • 2.

    Mucosal flaps: intranasal mucosal or intraoral mucosal flaps


  • 3.

    Local flaps: nasal turn-in flaps, melolabial flaps


  • 4.

    Free flaps: most frequently described would be the radial forearm flap and auricular ascending helical flap.



Specific to the forehead flap, the distal end may be turned in to provide internal lining over the lower third of the nose.


Framework


Reestablishing a framework in nasal reconstruction is of paramount importance for maintaining both form and function. It is an integral part of the 3-layer repair of any full-thickness defect of the nose. Structural grafts are used liberally and often in nonanatomic locations to prevent sidewall collapse, alar retraction, and maintain nasal projection. The current gold standard is an autogenous cartilage graft, typically harvested from the septum or auricle. Rib and split calvarial bone grafts are occasionally required in subtotal and total nasal reconstruction. Clinical success has also been reported with the use of irradiated homograft rib as well as alloplastic materials although we tend not to favor this approach.


Cartilage grafts in nasal reconstruction serve 3 primary roles :



  • 1.

    To provide rigidity to the sidewall and avoid lateral collapse during inspiration


  • 2.

    To resist cephalic retraction of the alar margin


  • 3.

    To establish nasal contour and projection.



The dimension of the cutaneous defect is not a direct indicator for the need of cartilage grafting. Many smaller defects, especially those involving the alar and supraalar crease may lead to sidewall collapse and hence nasal obstruction.


The auricle is ideally suited as a donor site for cartilaginous grafts to the nose and can be relied on with minimal donor site morbidity. Septal cartilage may be used in some circumstances, but there may be limited availability and the favorable curvature of the conchal bowl is often lost. When subtotal or total rhinectomy defects are encountered or when both septal and conchal cartilage is unavailable, rib grafts are the next material of choice.


Suture can be used to reshape existing cartilages, and their versatility is widely demonstrated in rhinoplasty techniques. Sutures can also be used to influence the position of the upper lateral cartilages and the corresponding internal nasal valve. The flaring suture is a quick and noninvasive means of augmenting the cross-sectional area of the internal nasal valve. These flaring sutures are used even in patients without preexisting narrowing of the internal nasal valve as a prophylactic measure against sidewall collapse.


Cicatricial contracture along the vestibule is best prevented by repairing all linings meticulously and providing strong support to the rim. Secondary repair of this type of narrowing is more challenging.


Covering


Resurfacing of the nasal defect takes into consideration the previously mentioned concept of facial subunits. We use the forehead flap for larger nasal cutaneous defects. Its many virtues include abundant tissue availability, its excellent match in color and skin texture, low donor site morbidity, and its robust vascularity. Currently, we use the midline forehead flap, which harvests a skin paddle from the precise center of the forehead but is based on a narrow unilateral pedicle from the medial brow area. The pedicle can be narrow (1.5 cm) and extend below the level of the brow to facilitate flap rotation with less potential for vascular kinking. The oblique pedicle allows a slightly longer reach compared with the paramedian flap. The resultant scar from the midline forehead flap is in the exact center, which is consistent with the principle of aesthetic units.




Anatomy


Forehead flaps are based on the robust vasculature to the forehead via the supraorbital, supratrochlear, and terminal branches of the angular and dorsal nasal vessels. The first anatomic point involves forehead flap terminology.


The median forehead flap is harvested from the mid forehead and has a wide pedicle based in the center of the forehead, which originally captured both supratrochlear vessels.


The paramedian forehead flap is designed around the medial brow area over the superior/medial orbital rim. The skin paddle and pedicle are aligned vertically over the supratrochlear notch. The resultant donor scar is oriented vertically and aligns with the medial brow.


The midline forehead flap is a hybrid of median and paramedian flaps, with the skin paddle harvested from the precise center of the forehead. The associated pedicle runs obliquely and is based on a unilateral supratrochlear vessel and collaterals from the medial brow area. Collateral flow from the angular artery can contribute to significant perfusion pressure at the pedicle base. The body of the midline flap is harvested from the precise center of the forehead, allowing a less conspicuous donor scar that is more consistent with facial aesthetic units. The pedicle may be based on either side, allowing choices between flap length and the arc of pedicle rotation.


The rich anastomosis between the supratrochlear, dorsal nasal, and angular arteries provides a robust perfusion pressure at the medial brow area, thus driving the vascular design of the forehead flap. This zone, which contains the superior orbital plexus, extends 7 mm above the orbital rim as concluded by a study by Reece and colleagues The pedicle base is usually narrow but captures this complex anastomosis at the superior/medial orbital rim. The pedicle can be safely brought down to the medial canthus if additional length is required. A prominent central vein should be incorporated into the pedicle design. The precise anatomic anastomosis between the named major vessels in the medial brow region remains variable. The supratrochlear artery exits at the superior and medial corner of the bony orbit, approximately 1.7 to 2.2 cm from the midline. It passes superficial to the corrugator muscle and deep to the orbicularis, ascending in a paramedian position for approximately 2 cm before piercing the frontalis muscle. A periosteal branch extends beyond 3 cm above the supraorbital rim and sends additional perforators into the flap.


The supratrochlear artery then travels superiorly in the subcutaneous plane, above the galea/frontalis muscle, maintaining numerous anastomoses with the contralateral vessels. The terminal angular artery may ascend the forehead as a distinct vessel or communicate with the ipsilateral supratrochlear artery. The paired dorsal nasal arteries usually merge to form a single central artery of the forehead.

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Feb 8, 2017 | Posted by in General Surgery | Comments Off on The Midline Forehead Flap in Nasal Reconstruction

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