Introduction

The temporoparietal fascia flap is one of the most versatile flaps in head and neck reconstruction. Monks described the flap at the end of the nineteenth century for the use of reconstruction of eyelid defects as well to reconstruct auricular defects.¹ The flap was slow to gain popularity until the 1980s and 1990s. Since this time, the flap has gained a solid place in the armamentarium of head and neck reconstructive surgeons.

The slow adoption of the temporoparietal fascia flap (TPF) was likely due to the inherent difficulty in raising this flap. The surgeon raising the TPF flap has to be very familiar with the anatomy of the region. He or she also has to be able to carry out the meticulous dissection needed to ensure that the elevation of the scalp flap remains in the right plane. A misstep in elevation of the scalp flap will lead to violation of the TPF and potentially result in the compromise of the flap.

The main advantages of the TPF flap are the width, length, thickness, and pliability. All of these properties render the TPF a good option for use in lining various defects. The flap is also a first option in the coverage of prosthetic ear implants without the loss of details. This fact is one of the reasons why the TPF is widely used in the reconstruction of auricular defects.

The TPF can be used in several variations. The TPF can be elevated with a portion of the forehead skin or scalp in cases where the eyebrow needs to be reconstructed. Additionally, the fasciocutaneous TPF is often used to reconstruct an upper lip defect in males. Less often, the flap can be raised with bone to transfer a vascularized split calvarium bone.

The disadvantages of the TPF are the difficulty in flap elevation and the associated postoperative alopecia that can be seen in and near the area of the scalp incision site.

Anatomy

The temporoparietal fascia lies immediately deep to the skin and subcutaneous tissue of the scalp overlying the temporal fossa. It is continuous with the superficial musculoaponeurotic system inferior to the zygomatic arch and with the galea aponeurotica above the superior temporal line. It is also continuous with the orbicularis oculi and frontalis muscle anteriorly and the occipitalis muscle posteriorly.² The temporoparietal fascia is approximately 2–3 mm thick over the parietal region.³ An area approximately 10 cm wide and 14 cm long can be safely harvested. It can be harvested as a fascial, fasciocutaneous, or osseofascial flap and is classified according to the Mathes and Nahai classification system as a Type A fasciocutaneous flap.⁴ The dominant blood supply is the superficial temporal artery, a terminal branch of the external carotid artery. The artery ascends behind the ramus of the mandible and becomes superficial, piercing through the substance of the parotid gland 5 mm in front of the tragus.⁵ The artery has a tortuous course and divides into an anterior (frontal) and posterior (parietal) branch 2–4 cm above the zygomatic arch. The mean diameter of the superficial temporal artery is 2 mm.⁶ Prior to its division the middle temporal artery arises and enters the temporalis muscle. The anterior branch anastomoses with the supraorbital and supratrochlear vessels over the forehead, while the posterior branch anastomoses with the posterior auricular and occipital arteries. The superficial temporal vein is found anterior and superficial to the artery within the subdermal fat. It generally runs with the artery but can be found as far as 3 cm away. The sensory innervation arises from the third division of the trigeminal nerve via the auriculotemporal nerve. The frontal branch of the facial nerve is known to course obliquely 1.5 cm lateral to the eyebrow and not more than 2 cm above the brow, therefore limiting the anterior extent of the dissection to avoid inadvertent injury to the facial nerve.⁷

Flap harvest

• The patient is placed in a supine position with the head slightly elevated and rotated to the donor side.
• Alternatively, the head may be placed in a Mayfield headrest and then rotated to the donor side.
• A small strip of hair may be shaven along the intended path of incision (alternatively, the head can be shaven, this allows for ease of prep, dissection, and closure of the defect). Typically the incision begins at the superior aspect of the pre-auricular area and is extended towards the vertex of the head.
• The incision is made just through the dermis with caution so the superficial temporal vessels are not injured as they are in close proximity in the pre-auricular site of incision.
• In the scalp area, a very thin flap is elevated just under the hair follicles. The surgeon should be able to see the follicles on the underside of the scalp flap in order to be assured that the TPF is not being elevated with the scalp reflection.
• The dissection should be done with elevation and tension to facilitate the view of the dissection plane.
• The direction of dissection is continued superiorly towards the vertex of the scalp. In some circumstances, particularly when a large width of flap is needed, the superior incision is converted to a V shape to allow for easier reflection of the anterior scalp flap and therefore visualization of the TPF.
• Once the anterior scalp elevation is completed, the posterior elevation is carried out in a similar fashion. Due to the close proximity to the hair follicles when elevating the scalp flap, electrocautery should be used sparingly.
• The desired length of the flap should be checked using a suture or string from the lap sponge with the fixed point in the pre-auricular area and rotated to the furthest point of the defect. The length is then transferred superiorly to the distal end of the TPF flap, which corresponds to the region of the scalp vertex.
• Once the desired width and length of the flap is measured, the flap may be elevated by first incision the fascia and staying superficial to the temporalis muscle fascia.
• The flap is elevated in a fan-shaped manner with the narrow end being the pre-auricular area in front of the ear. The dissection typically stops in front of the tragus.
• At this point, the rotation and passive reach of the flap to the defect is confirmed.
• A subcutaneous tunnel is developed to transfer the flap to the defect site.
• The tunnel should wide enough to allow for ease of transfer of the flap while at the same time not compressing the pedicle along its path to the defect site.
• The flap is inset into the defect and the path of the pedicle is evaluated to ensure that the vessels are not twisted or kinked.
• The scalp is closed in layers over a suction drain.

Fasciocutaneous flap

• In some cases, the TPF flap can be elevated with a portion of the skin of the forehead or scalp depending on the needs of the defect.
• In these cases, exact reconstruction of the defect is facilitated by the construction of a template.
• The template design is transferred to the scalp or forehead and checked based on the arc of rotation as well as the reach to be sure that the orientation of the flap will be/>
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