A Systematic Review of Local Flaps Utilized for External Auditory Canal Defects

Abstract

Study Design: Systematic review of the literature. Objective: The goal of this study is to review and summarize current literature on local flap reconstruction of external auditory canal (EAC) defects. Methods: PubMed and Ovid databases were queried utilizing search term combinations of “external auditory canal”, “defects”, “flaps”, “local”, and “reconstruction”. References in included articles were subject for review and inclusion. Articles published between 2013 and 2023 were included in the study. Results: A total of 108 articles were screened after duplicates were excluded. Of the 108 articles, 3 were not written or translated to English, 10 were not accessible for review on either database, and 71 were not applicable to our subject of interest. The remaining 24 articles were included in the systematic review. Due to the primary descriptive nature of the surgical techniques and variability of data collection, a formal meta-analysis was not possible. Conclusions: The EAC defect creates a difficult reconstructive dilemma. The armamentarium for repairing these defects can range from healing by secondary intention to free tissue transfer, however, local flap reconstruction proves to be a reliable and versatile option. This article reviews current local flap techniques for EAC defects and compares their advantages and disadvantages. Further, the authors provide a treatment algorithm and indications for choosing each flap in external auditory canal reconstruction.

Introduction

The ear is divided into the external auricle and the external auditory canal (EAC); the EAC is further divided into a lateral (40%) cartilaginous portion and a medial (60%) osseous portion. The EAC is S-shaped, around 2.5 centimeters in length, and contains a thin layer of subcutaneous tissue between skin and the canal [1]. Defects of the EAC can heal by secondary intention or can be repaired using skin grafts, composite grafts, local flaps, regional flaps, or free tissue transfer. Defects left to heal by secondary intention should not have cartilage exposed and should not be larger than one quarter of the EAC to avoid contraction [2]. Skin grafts, composite grafts, and local advancement tissue rearrangement can be used in defects less than half of the EAC circumference. Even these reconstructive options are limited to certain defect locations and sizes [3]. Local flaps can be used in full circumferential defects of the EAC as well as for defects involving other portions of the external auricle.

Regional flaps and free tissue transfer is an option for the most complex reconstruction scenarios including poor local tissue or total auricular defects. Local flaps provide surgeons a great deal of diversity in their armamentarium when reconstructing the EAC. One classification of local flaps organizes them based on blood circulation: an axial pattern vs random pattern [4]. The axial pattern flap runs parallel to a subcutaneous vessel named the direct cutaneous artery while the random pattern flap utilizes a random subcutaneous vascular network for blood supply. The latter tends to be less stable. Another classification of local flaps divides them based on their method of transfer: pivotal, advancement, or hinge. Pivotal flaps have further subcategories: rotation, transposition, interpolated, and island [5]. Pivotal flaps pivot around the base of the pedicle to move towards the defect. Rotational flaps are curvilinear, while transposition (i.e., rhombic, bilobe), and interpolated flaps (i.e., paramedian forehead flaps) are linear. Transposition and interpolated flaps transfer adjacent tissue about their base (pivotal point). However, they differ in a key aspect: in interpolated flaps, the base is not contiguous with the defect and is instead separated by intervening tissue. Island flaps can either be pivotal or advancement flaps and are incised on all borders with a pedicle of subcutaneous tissue (i.e., melolabial flaps). Advancement flaps are linear by design and move as such towards the defect without a pivot (i.e., V-Y flap). Hinge flaps are designed adjacent to the defect and turn over onto the defect like a page in a book (i.e., nasal septal flap) [5,6]. The various local flaps available for EAC reconstruction fall into each of the above categories. Choosing the right reconstructive option is dependent on the status of local tissue, the primary objective for reconstruction, and the patient’s goals and expectations.

The goal of this systematic review is to summarize local flap reconstructive techniques available for external auditory canal defects and to discuss the advantages and disadvantages of each. Further, we hope to present a treatment algorithm as an aid to the reconstructive surgeon.

Materials and Methods

After institutional review board exemption was obtained at the University of Arkansas for Medical Sciences (IRB: 275 778), we performed a systematic literature review on surgical techniques, specifically local flap reconstruction of external auditory canal defects. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Protocol [7,8]. PubMed and Ovid databases were queried between April 1, 2023 and May 1, 2023. Search term combinations included “external auditory canal,” “defects,” “flaps,” “local,” and “reconstruction.” Further, references in included articles were subject for review and inclusion. Inclusion criteria included articles published between 2013 and 2023 and involved the local reconstruction of the external auditory canal. All study types and range of cohort populations were included in the database search. Articles not written or translated to English, not openly accessible articles, and duplicated articles were excluded. Two separate reviewers (A.C.G. and O.S.) independently appraised all studies meeting inclusion and exclusion criteria. All included articles were reviewed by two authors (A.C.G. and O. S.). Disagreements were discussed with an additional author (J.R.B. or R.S.) and consensus reached whenever appropriate.

Results

One hundred forty five articles resulted between the published year 2013 and 2023. Of the 145 articles, 45 were duplicates which left 100 articles. Three articles were not written or translated in English and were therefore excluded. Ten articles were not accessible for review on PubMed or Ovid databases and were also excluded which left 87 articles. Eight additional articles were included through reviewing references of the included articles. A total of 95 articles were reviewed for potential inclusion. Seventy one articles were reviewed and excluded as they were not applicable to our subject of interest. Those excluded were articles that described auricular reconstruction without use of a flap (N = 6) or used free tissue transfer for reconstruction (N = 12), articles that focused on general microtia or congenital auricular anomaly management (N = 8), techniques associated with veterinary medicine (N = 2), and articles that focused on generalized approaches to ear tumors or stenosis management (N = 11). Articles focusing on ear surgeries not pertaining to our review were excluded such as cholesteatoma management (N = 8), standard meatoplasty (N = 2), middle ear surgeries (N = 4), tympanoplasty (N = 2), otomastoiditis (N = 1), temporal bone resection (N = 3), and mastoid reconstruction (N = 4). Further categories of articles excluded were ventral skull base flaps (N = 3), not applicable cadaveric studies (N = 2), condylar dislocation management (N = 2), and a study on generalized flap properties (N = 1). Twenty four articles were included in the systematic review. See Figure 1 for a PRISMA flow diagram [8].

Due to the primary descriptive nature of the surgical techniques and variability of data collection, a formal meta-analysis was not possible. We compiled all surgical techniques that resulted from our inclusion criteria within the last 10 years and describe them below. We also describe advantages and disadvantages of each technique, type of flap, and tissue type and summarize the results in

Table 1. Local EAC Flap Characteristics.

Flap name	Type of flap	Tissue type	Advantages	Disadvantages	References
Tragal flap	- Random pattern - Advancement flap	- Cutaneous	- Patent EAC good for cancer surveillance and good audiometric outcomes	- Potential poor cosmesis	[3]
Superficial temporal artery (STA) perforator island flap	- Axial - Island	- Cutaneous	- Single stage procedure - Non hair bearing donor site with good skin match and inconspicuous scars - Patent EAC results	- Limited by depth of defect	[9]
Wessex flap	- Axial - Pivotal - transpositional	- Cutaneous	- Single stage - Non hair bearing	- Limited by depth of defect	[10]
Superficial temporal artery (STA) interpolated flap	- Axial - Interpolated	- Cutaneous	- Reliable for salvage defects without need for skin grafting	- Two staged procedure	[11]
Conchal bowl flap	- Random pattern - Pivotal – transpositional flap	- Cutaneous +/− cartilage	- Good option in post surgical or radiated fields	- Skin graft needed for secondary site - Limited to defects the size of or smaller than the conchal bowl and adjacent to it	[2,12]
Tunneled transposition flap	- Random pattern - Pivotal - interpolated/island	- Fasciocutaneous	- Reliable flap site based off laser Doppler assessment - All incisions closed primarily	- Likely limited to smaller EAC defects based off the pedicle to length ratio and accommodating the tunneled pedicle	[13]
Postauricular island flap	- Axial - Island	- Fasciocutaneous +/− muscle +/− cartilage	- Reliable blood supply - Low morbidity and good cosmetic option for large auricular defects - Patent EAC	- Possible posterior pinning of pinna or prominent ear lobule - Make require skin grafting of the harvest site	[2,14,15,16,17,18,19,20,21]
Anterior pedicled retroauricular flap (APRF)	- Random pattern - Pivotal – interpolated flap	- Cutaneous	- Good aesthetic result - Tension free - Can be used for full-thickness defects involving the helix	- Multistaged	[22,23]
Square screw flap	- Random pattern - Pivotal – transpositional flap	- Cutaneous	- Can be used for full circumferential defects - Fewer incisions - Shorter recovery - Better cosmesis - Decreased FN risk	- Not suitable for larger tumors (>T2), thick subQ fat, strong skin tension	[24]
Laterocervical twisted (snail) flap	- Random pattern - Pivotal – transpositional flap	- Fasciocutaneous	- Patent EAC good for cancer surveillance and good audiometric outcomes - Single stage reconstruction of full circumference EAC, conchal and tragal defects - Cosmetically favorable and reliable donor site	- Potential prolonged stent placement - Not suitable for patients with thick subQ fat, strong skin tension - Theoretically can put the marginal mandibular nerve at risk	[25]
Temporoparietal fascial flap	- Axial - Hinge or pivotal – transpositional flap	- Fascia +/− cutaneous	- Reliable and versatile - Used for large defects	- Potential alopecia - Potential damage to the frontotemporal branch of the facial nerve	[26,27,28]
Superficial temporal artery (STA) turnover fascial flap	- Axial - Hinge flap	- Fascia	- Good for large defects	- Requires skin grafting	[2,29]
Middle temporal artery flap	- Axial - Pivotal - transpositional flap	- Fascia, periosteum +/− muscle	- Thin, pliable, robust flap - Less risk of atrophy - Good for cases at risk of poor wound healing or revision cases	- Requires skin grafting for cutaneous defects	[30]

Abbreviations: EAC, external auditory canal; STA, superficial temporal artery; APRF, anterior pedicled retroauricular flap; SubQ, subcutaneous.

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Figure 2 consists of our treatment algorithm and indications for choosing each flap in external auditory canal reconstruction. We categorize the local flaps into cutaneous vs fascial flaps. The cutaneous flaps are further divided based off circumference of the EAC involved. Within the cutaneous flaps, we note if the flap’s pedicle is based anterior to the EAC, “pre-EAC,” or a pedicle based posterior to the EAC, “posterior-EAC.” We also note which cuta-neous flap is favorable based on the defect location.

Cutaneous Flaps

Non-Circumferential Defects

Pre-EAC Based Flaps

Tragal Flap. The tragus is commonly used in tympanoplasty and middle ear reconstruction [31]. However, the tragal flap can also offer a reconstruction option for external ear defects. The flap offers good coverage of the anterior canal with minimal contracture compared to a lining provided by a skin graft. The tragal skin is incised on its posterior surface and the flap is denuded of its cartilage components. With adequate undermining as well as excising potential Burow’s triangles, superior and inferior to the flap, the flap can be advanced into the anterior canal [3]. Any remaining exposed canal can be lined by a skin graft or by other techniques. One technique by Inbal and colleagues [32] used a lobule remnant wrap flap to fill the remaining defect. Typical to other canal reconstruction, a bolster should be placed for several weeks postoperatively to prevent stenosis. While the tragus offers well vascularized lining for canal defects and a patent neo-canal, this technique does have some limitations. Removing the tragal cartilage can result in poor cosmesis which may be distressing to certain patients. (Figure 3).

Superficial Temporal Artery Perforator Island Flap. The superficial temporal artery perforator island flap is a capillary perforator based flap off of a superficial temporal artery (STA) pedicle as described by Binhimd and colleagues [9]. This flap can be used to reconstruct combined defects of the conchal bowl extending into the EAC. Their study included 3 defects that extended into the cartilaginous EAC (N = 2) and even into the osseous EAC (N = 1). Two of the EAC defects involved half of the circumference of the EAC and one involved three-fourths circumference. The STA perforator island flap is designed in a non hair bearing preauricular skin area and is determined by defect size and local tissue redundancy/laxity. Perforators are located and gentle blunt dissection is used to dissect retrograde to the STAwith careful consideration of the facial nerve. An island flap is ideally created off of 2 perforators. Mobilization of the island flap to the defect is accomplished through an inter tragal notch tunnel (N = 1) or with recreation of a tragal ridge (N = 2). In 2 cases, the distal perforator was sacrificed in order to improve mobilization. The distal part of the flap extended into the ear canal and was sutured to remaining skin. The proximal flap was folded upon itself in order to cover the entire surface of the concha. The donor site is closed primarily. An Otowick mold is placed into the EAC immediately postoperatively and is replaced by a custom made silicone conformer for 6 weeks. Mean operative time was 90 minutes. No total or partial flap failure or healing disruptions were observed. The EAC was patent in all cases and no secondary debulking surgeries were necessary. Texture and skin color were an adequate match and the donor site scar was disguised in the pre auricular crease which became inconspicuous after a year.

Wessex Flap. The Wessex flap is a single stage procedure using a perforator of the STA as described by Chessman and colleagues [10]. The flap is designed in the non hair bearing preauricular skin with a superior or inferiorly based pedicle adjacent to the defect. Adequate length should be measured in order to cover the entire EAC defect, however, maximum length should not be more than 4 times its width. The distal flap is tapered in order to assist with primary closure of the donor site. Tragus or adjacent cartilage may need to be excised to ensure adequate tension free rotation of the flap. The flap is sutured in place. The patient had no evidence of stenosis at a 3 year follow up.

Superficial Temporal Artery Interpolated Flap. Oliver et al describes the use of a STA interpolated flap in the setting of a microtia repair complication and cartilage exposure [11]. An 8 year old patient presented with anterior skin dehiscence (5 mm) and exposed cartilage framework of the antihelix following microtia reconstruction with costochondral graft reconstruction. Salvage surgery was performed with a multi staged preauricular cutaneous perforator flap. The flap was designed along the preauricular sulcus and rotated posteriorly to cover the defect. The undersurface of the flap was covered with an Integra acellular dermal regeneration template. The second stage of the procedure was completed after 3 weeks which included division of the base, removal of the Integra template and inset of the flap. No complications were noted.

Posterior-EAC Based Flaps

Conchal Bowl Flap. One reconstructive method we are terming “the conchal bowl flap” was described in a letter and viewpoint in 2006 by Botting and colleagues [12]. In the case report, the patient had extensive post surgical and radiation changes which limited his reconstructive options. The authors decided to reconstruct the patient’s EAC defect with a cutaneous flap harvested from the conchal bowl. The flap pivoted 180° on a small cymba conchal pedicle to fill the anterior EAC defect with good results. A skin graft was used to cover the donor site. This flap has the option of harvesting native ear cartilage with the flap creating a chondrocutaneous flap. These flaps are limited to defects less than half of the EAC diameter and more lateral defects [2].

Tunneled Transposition Flap. Random flaps are commonly used to cover EAC defects. Kato and colleagues sought to evaluate the blood flow surrounding the external ear using a laser Doppler system in their article published in 2014 [13]. They found that the posterior ear had a greater blood supply than the back but that the face had the highest perfusion unit of the 3 sites. From their results, they concluded a viable random facial flap could safely accommodate a pedicle to length ratio of 1:3 and a random post-auricular flap could accommodate a ratio of 1:2. The authors applied the latter ratio to a tunneled transposition flap technique. Using this flap, a semilunar post-auricular incision is utilized to access and resect the EAC disease. A flap is then procured based on a mastoid pedicle extending superficially along the sternocleidomastoid. The superficial cervical fascia serves as the deep plane of dissection in this flap. The tunneled portion of the flap’s epithelium is denuded and the flap is inserted into the canal defect. The flap is secured into place using suture, topical fibrin spray, and a gelatinous sponge. All incisions are closed primarily.

Postauricular Island Flap (PIF). The postauricular island flap (PIF) has various names including the revolving door flap, trap door flap and the flip-flop flap. (Figure 4) This myocutaneous +/— cartilage axial flap has been widely utilized for conchal bowl defects since its first description by Masson in 1972 [33]. However, this flap has been shown to be a reliable option for even larger auricular defects that lack perichondrium including those that involve the helix, antihelix and scapha [14]. One study analyzed the angiosome of the posterior auricular artery (PAA) and found that in a sample of 10 cadaveric specimens, the PAA irrigated an area of retroauricular skin and fascia measuring 10.7 cm in length and 7.07 cm in width [15]. The flap is marked on the postauricular area along the auriculocephalic sulcus. The flap should measure the same dimensions of the defect. The skin is incised along the marked area, creating the island, and using sharp dissection, a tunnel is created to allow transposition of the flap. The most anterior aspect of the PIF will orient to the medial most aspect of the defect. All incisions are closed primarily [16]. This flap offers good cosmetic outcomes as a single stage reconstruction option. In a study of 45 patients, 1 patient had a postoperative hematoma, and no patients had flap loss or EAC stenosis [16]. One potential downfall of this technique includes posterior pinning of the pinna. Further the larger the flap procured, the more prominent the resulting ear lobule. Iljin et al [17]. typically use this flap in patients with T1 or T2 tumors with <1 cm involvement of the EAC. One adaptation of the PIF used the PAA to fashion a folded myocutaneous flap to cover a full thickness defect of the concha with good results. The authors did not use cartilage augmentation for the reconstruction and did not note a resulting lop ear deformity; however, they do note cartilage grafting is an option [18]. If harvesting cartilage with the flap, the postauricular harvest site may require a skin graft [2].

Anterior Pedicled Retroauricular Flap (APRF). The anterior pedicled retroauricular flap (APRF), also called the reversed retroauricular flap (RRF), is a multi-staged option for full thickness defects of the central auricle, concha, or helix [22]. The surgical technique begins by marking the flap along the posterior auricular skin double the size of the defect. The posterior half of the flap is noted as area I and the anterior half is II. The flap is raised in a subcutaneous plane in an anterograde fashion leaving an anterior based pedicle. The flap tip of area I is sutured to the medial most aspect of the dorsal defect and the rest of area I fills the dorsal defect respectively. The repair is allowed to heal for 2 weeks with the attached pedicle. The second stage begins by incising the base of the pedicle creating a flap tip of area II. The flap is folded on itself anteriorly and the flap tip of area II is sutured to the medial most aspect of the ventral/conchal defect. All incisions are closed primarily. After another 2 weeks, the authors recommend a third stage for dividing the transitional part (area I from area II) and debulking the flap. The authors recommend this flap for full-thickness defects measuring between one-forth and three-forths of the vertical auricular size [22]. If further structural support is needed, cartilage grafting can be placed during stage 2 [23]. Although this technique is multi-staged and spans across 6 or so weeks, the authors note good aesthetic results and high patient satisfaction. In a cohort of 11 patients, none of the cases had a hematoma, flap necrosis or infection despite the open wounds between stage 1 and 2. The authors report tension free closure compared with the PIF.

Circumferential Defects

Square Screw Flap. The square screw flap, as described by Anazawa and colleagues, is considered a random pattern flap that is a modification of the Di Benedetto snail flap technique [24,34] (Figure 5). A preauricular rectangular flap is raised in the dermal plane with a caudally based pedicle. The rectangular flap is then rotated posteroinferiorly into a cylindrical shape to fill the defect with the distal most aspect curling around to meet the anterior residual canal. The flap site is closed primarily and a gelfoam/gauze dressing is placed into the neo–canal for 2 weeks. As described by the authors, this flap offers the advantage of fewer new incisions as the flap is harvested adjacent to the defect. In comparison to the snail flap technique, this flap uses preauricular non-hair bearing skin which may offer benefit in certain patients. Further, the authors theorize the incisions may reduce risk of facial nerve damage and that the postoperative recovery may be shortened in comparison to other techniques. The authors do note that this flap is not optimal in cases of thick subcutaneous fat and strong skin tension to reduce EAC stenosis. There was a conductive hearing loss with a postoperative air-bone gap of 42.5 dB likely due to the thickness of the full circumferential flap. This is a random based pattern flap which has its inherent drawbacks; however, the flap in the case report did withstand up to 50 Gy of adjuvant radiation without delay. This technique is only suitable for up to clinical stage T2 cancers on the Pittsburgh classification [35].

Laterocervical Twisted Flap (Snail Flap). The laterocervical twisted (snail flap) was first described by Di Benedetto and colleagues in 1997 to cover a defect of the lateral two-thirds of the external auditory canal, concha and tragus [34]. Since its original publication, it has been utilized by other surgeons and adapted to reconstruct other bodily orifices [25,36]. The flap is a transpositional flap based on the mastoid region. The flap is harvested in a supra-platysmal plane parallel to and at least 2 cm inferior to the mandibular edge. The triangular flap can be harvested with a 2.5 cm width and up to a 8.0 cm length [25]. The flap is then tubed on itself to create an epithelium lined neo-canal. The apex is sutured to the junction of the middle and distal thirds of its superior border, and the junction of the proximal and middle thirds of its superior border is fixed at the junction of the middle and distal third of the inferior border. The tube is then sutured into the canal defect and the non-tubed proximal portion of the flap can be used to reconstruct conchal and tragal defects. A splint is placed anywhere between 4 to 16 weeks with good patency results. Some notable advantages of this flap include single stage reconstruction with primary closure of a cosmetically favorable donor site. Further, because the donor site is further from the auricle it is not likely involved in the excision and can be a reliable site. The authors report this flap is not suitable for patients with thick subcutaneous fat or with excessive skin turgor.

Fascial Flaps

Temporal anatomy is favorable for flap creation due to its many layers and axial blood supply. The temporal layers include skin, subcutaneous fat, temporoparietal fascia, superficial temporal fascia, loose areolar tissue, deep temporal fascia and temporalis muscle [2]. The temporoparietal fascia is contiguous with the superficial musculoaponeurotic system and platysma while the deep temporal fascia is contiguous with the calvarial periosteum at the conjoint tendon [37]. The superficial temporal fascial system (temporoparietal and superficial temporal fascia) is primarily supplied by the superficial temporal artery that runs between the two layers. The superficial temporal artery gives off the middle temporal artery just below the zygomatic arch which travels along the deep temporal fascia. The middle temporal artery pierces the deep temporal fascia and temporalis to supply the deep layers [38]. Many of the layers have been used for local flap reconstruction of the EAC which are described below.

Temporoparietal Fascial Flap

The temporoparietal flap (TPFF) is a reliable and versatile flap that has been utilized in numerous reconstructive scenarios in head and neck surgery including defects involving the scalp, orbit, face, upper aerodigestive tract and in this case the auricle. A Y or T shaped incision is placed in the preauricular crease and extends cranially. The flap is raised in a subcutaneous plane using sharp dissection to expose the temporoparietal fascia which is incised on this periphery. Care must be taken during this step to not carry the dissection too anterior as this can put the frontotemporal branch of the facial nerve at risk. Further, care must also be taken to not injure the pedicle. The flap can then be tunneled or rotated to reach the defect. The overlying skin can be harvested with the flap or a skin graft can be placed for cutaneous defects [26]. Bae et al [27]. reports a case of a large chondroblastoma (37 mm) with destruction of the temporomandibular joint (TMJ), mandibular condyle, EAC, mandibular fossa of the temporal bone, and facial nerve. Initial resection was obtained through an extended preauricular incision. The tumor destroyed the anterior wall of the right EAC. Reconstruction of the defect included a temporoparietal fascia flap (TPFF) and a free fat graft from the right inguinal region to compensate for volume loss following resection. In addition, Bae et al reviewed 11 craniofacial chondroblastoma cases, 2 of the cases similarly used the temporalis fascia layer. In addition to recreating the EAC, the flap provides a reliable thick tissue option for other needs as well. Van der Woerd et al described a case of a sialocutaneous fistula repair with temporoparietal flap after canaloplasty for congenital auditory canal atresia [28]. The TPFF was rotated to separate the EAC from the parotid to cure gustatory otorrhea. The TPFF can be used in many applications of EAC defects. Some complications unique to the TPFF include alopecia if the subcutaneous dissection injures hair follicles and injury to the frontotemporal branch of the facial nerve if the dissection is carried too anterior. (Figure 6).

Superficial Temporal Artery Turnover Flap. The superficial temporal fascia is a thin fascial layer that has been described for reconstruction in tympanoplasty but can also provide an option in external ear reconstruction with or without harvesting the temporoparietal fascia simultaneously [2]. A superficial temporal fascia flap based on the superficial temporal artery (STA) that can cover large EAC defects was described by Oh and colleagues in 2015 [29]. This flap we are calling the STA turnover flap. In the study, an elderly patient presented with a 5.0 × 5.0 cm defect involving the EAC, concha, and sideburn after undergoing wide local excision of a recurrent cutaneous squamous cell, parotidectomy and neck dissection. The surgeon’s reconstruction options were limited due to the large resection. Further, bony canal and the superficial temporal vessels were partially exposed and needed coverage. The authors describe incising the superficial temporal fascia at the defect’s superior border and elevating an antegrade flap that included the superficial temporal fascia, the subjacent superficial temporal vessels and loose areolar tissue. The EAC was obliterated using fat grafts and the fascial flap was then hinged to cover the bony EAC and the proximally exposed vessels. A split thickness skin graft was placed over the fascia. The patient healed with no complications.

Middle Temporal Artery Flap. The middle temporal artery (MTA) is a branch of the superficial temporal artery that pierces temporalis fascia and runs through or deep to temporalis muscle towards the vertex [39]. This artery serves as the blood supply for an axial transpositional flap that was originally described for mastoid obliteration but has been utilized for EAC defects [40]. The flap consists of periosteum, deep temporal fascia, and has the ability to include temporalis muscle if needed [30]. After incising the temporalis muscle on its posterior aspect and retracting it anteriorly, the flap can be harvested along the MTA. The flap is then rotated into the canal defect followed by a silastic packing that remains for 2-3 weeks. As described by Gluth and colleagues, this flap is a thin, pliable but robust flap that can be used in cases of poor wound healing or revision surgery [30]. The flap is typically harvested to have a width of 3.0 cm and a length of 6.0 cm but can be harvested as long as 10 cm. Because of the thin nature of the flap, the neo-canal has adequate patency allowing for cancer or cholesteatoma surveillance. The periosteum also prevents flap atrophy, a frequent sequelae of flap inset. Skin grafting can then be used to cover any external cutaneous defects.

Conclusion

The external auditory canal (EAC) defect poses a unique dilemma for the reconstructive surgeon. Albeit there are numerous repair options from secondary healing to free tissue transfer, local flap repair offers a diverse and reliable choice. When selecting which local flap to use, several factors are at play including size and location of the EAC defect, circumference of the EAC involved, potential involvement of the adjacent auricle, and the status of local tissue for harvest to name a few. All these factors need to be considered when repairing external auditory canal defects.

Future research should aim at quantifying outcomes of EAC patency, cosmesis and morbidity associated with these different techniques. This systematic review sought to describe and compare the local flaps that are available for EAC defects as well as provide a treatment algorithm for the reconstructive surgeon.