Reconstruction of Full-Thickness Lateral Defect of the Lower Lip and Vermilion with our Modification of a Fan Flap — Technique and Results

Abstract

Successfully restoring lateral lip defects, while ensuring proper mouth opening, oral competence, and the creation of an aesthetically pleasing vermilion, has consistently posed a challenging undertaking. In a prospective study conducted from 2006 to 2022, we employed our modified version of the McGregor fan flap technique to reconstruct post-oncosurgical pure lateral lower lip and complete lower lip defects. The study excluded cases involving a central lip defect or accompanying buccal mucosa involvement. A total of 126 flap procedures were performed on 122 patients, encompassing lower lip defects ranging from 30 to 100% in size. Unilateral flaps were performed on 118 patients, while four patients necessitated bilateral flap procedures. The reconstruction of the vermilion was accomplished using our modified flap technique in 114 patients, tongue flaps in two patients, and six patients, the flap’s skin was folded to mimic the vermilion. Remarkably, no complications such as hematoma, necrosis, flap loss, infection, microstomia, or dribbling were encountered. The labial sulcus was found to be adequately formed. All patients achieved preoperative mouth opening within 3 months following surgery, with a mean oral sphincteric recovery time of 4.2 months. The color match of the reconstructed vermilion was excellent. Our modified fan flap technique stands as a dependable and robust choice for addressing moderate to large full-thickness lateral defects of the lower lip offering effective vermillion reconstruction in a single surgical procedure. The cases involving associated buccal mucosa or submucous fibrosis may necessitate alternative vermilion reconstruction approaches.

Introduction

The lips are a prominent facial feature playing a key role in mastication, deglutition, retention of oral contents, expression, and verbal, and nonverbal communication. Any post-traumatic or post-oncosurgical defect may lead to severe functional, aesthetic, psychological, and social nuisances if not properly reconstructed. All key components of the lip like skin, subcutaneous tissue, mucosa, muscles, and vermilion require appropriate attention to prevent various functional and aesthetic problems. Many flaps have been described in the literature, but the correct selection of the technique and its meticulous execution are important to obtain desirable results.

Material and Methods

The study encompassed a total of 122 patients who had developed lower lip defects due to the removal of squamous cell carcinoma between 2006 and 2022. In our study, male patients outnumbered their female counterparts, with 104 males and 18 females. One patient was under the age of 10 years. Forty patients fell within the 30–50-year age bracket, while the remaining 81 patients were above the age of 50 years.

The study specifically focused on patients with either lateral lower lip defects or total lower lip defects, while those with pure central defects were excluded from the analysis. Four patients presented with T3 lesions (exceeding 4 cm), whereas the remaining patients had T2 lesions ranging between 2 and 4 cm. Excision of the full-thickness lip was necessary for all patients.

Our study did not incorporate cases of lip carcinomas with associated involvement of the buccal mucosa. Additionally, smaller lip defects, comprising less than 30% of the lip, were managed through primary closure and were not considered within the scope of this study.

For the reconstruction of full-thickness lateral lower lip defects exceeding 30%, we employed McGregor’s fan flap with our modifications as the preferred reconstructive technique.

According to McGregor’s method [1], the total length of the rectangular flap required is the sum of the normal lip height and width of the present lip defect. At the same time, the width of the flap is the height of the normal lip.

In a given figure, the height of a normal lip is CD. Therefore, the width of flap RS = Lip Height CD $\therefore$ RS = CD.

At the same time the length of the flap PQ = Width of the defect AB + Height of the lip CD.

$$\therefore \text{PQ}=\text{AB}+\text{CD}.$$

As per our modification, instead of considering CD as the real height of the lip as shown in the figure, we [2] measure the total mucosal requirement from the gingivobuccal sulcus up to the mucocutaneous junction. Therefore, the Width of the flap RST = Lip Height CD + DE.

$$\therefore \text{RST}=\text{CD}+\text{DE}.$$

At the same time the length of the flap PQ = Width of the defect AB + Height of the lip CD.

$$\therefore \text{PQ}=\text{AB}+\text{CD},\mathrm{which}\mathrm{remains}\mathrm{the}\mathrm{same}.$$

Ex. If the height of the lip CD is 2.5 cm and DE is 1 cm, the width of the flap RST should be 3.5 cm.

The flap is marked, and a solution containing 1:200,000 adrenaline is infiltrated into the flap’s margins to aid dissection and minimize blood loss. The flap is cut through and through and includes skin, muscle, and buccal mucosa. The full-thickness flap is incised and rotated to cover the defect. The size of the back cut is customized according to the rotational requirement. To create a full and aesthetically pleasing vermilion, from the regions marked as DS, the epidermis and dermis are excised, and the subcutaneous tissue, fat, and mucosa are preserved, imparting a desirable lip contour. The surplus flap mucosa of this region is then brought out and sutured to the cut skin margin to create the vermilion.

Hemostasis is achieved to prevent any hematoma. Larger vessels are either ligated or clipped. The corrugated or mini suction drain is placed whenever required. Closure of the buccal mucosa is carried out with great care to avoid any fistula formation. In situations where buccal mucosa closure is challenging, particularly in the retromolar area, the buccal fat pad flap [3] is utilized to bridge the gap and prevent fistula formation.

Re-approximation of the orbicularis oris muscle of the flap and the muscles of the remaining portion of the lip is important in re-establishing the continuity of the oral sphincter. Muscle continuity also decreases tension on the wound edges. Finally, the subcutaneous tissue and skin are closed in layers to complete the procedure. In younger patients, achieving skin closure may occasionally necessitate mobilization of the surrounding skin (Table 1).

Table 1.

Various procedures for lower lip and vermilion reconstruction

Lower lip and vermilion reconstruction	No. of patients
Modified fan flap alone	114
Fan flap with tongue flap for vermillion reconstruction	2
Fan flap with the skin of the flap itself folded for vermillion reconstruction	6
Total	122

Between 2006 and 2022, a total of 126 modified flaps were performed in 122 patients to address lower lip defects. Among these cases, 118 patients underwent a unilateral flap procedure, while four patients with lip defects exceeding 90% required bilateral flaps. For reconstructive purposes, we employed a modified fan flap in 114 patients. However, in two edentulous patients having submucous fibrosis and a scarcity of buccal mucosa, the tongue flap was employed for vermilion reconstruction. Additionally, in six dentulous patients with similar challenges, the flap’s skin itself was folded to replicate the vermilion.

Results

The postoperative recovery progressed without any issues. None of the patients experienced complications such as necrosis, wound infections, dehiscence, or flap loss. There were no instances of microstomia or dribbling observed in any of the cases. All of our patients successfully regained their preoperative mouth opening within 3 months after the surgery. Sphincter function was restored in a range of 2 to 9 months, with an average recovery time of 4.2 months. In all cases, the shade of vermilion was quite pleasing, and the color match met expectations.(Figs. 1, 2, 3, 4).

Fig. 1.

(a) Original McGregor fan flap, (b) Our modification of McGregor fan flap

Fig. 2.

Excision of the tumour, flap rotation, and postoperative results with full sphincteric activity

Fig. 3.

Excision of the tumour, flap rotation, and postoperative results with full sphincteric activity

Fig. 4.

Reconstruction of a near-total lip defect with bilateral flaps

Apart from a minor pin cushioning effect, the functional and aesthetic results were satisfactory. The primary drawbacks observed in cases involving the tongue flap were the thickness of the vermilion and the color mismatch. A similar issue arose when using the flap's skin for vermilion reconstruction. In such situations, patients were advised to consider replacing the skin with a free mucosal graft at a later stage, although most patients expressed satisfaction with the overall results.

Discussion

Recreating a natural-looking lip with the right stoma size, a sufficiently deep sulcus, a suitable color match, and a natural vermilion appearance, and restoring both motor and sensory functions has remained an exciting yet challenging task in the field of lip reconstruction. Numerous techniques have been documented in the medical literature for lip reconstruction. These include methods such as mobilization with primary closure, the Abbe flap [4, 5], the Estlander flap [6], the nasolabial flap [7, 8], the Gilles fan flap [9], and its variations like the McGregor fan flap[1] or Nakajima’s flap[10], as well as the Karapandzic flaps [11], Webster cheek advancement flaps [12], and Gate flaps [13], among others. Additionally, free microvascular flaps like the radial artery forearm flap or anterolateral thigh free flap [14–18] have also been reported as viable options in lip reconstruction.

The drawbacks associated with the Gille’s fan flap and its variants include trap-door deformity, blunting of the commissure, suboptimal oral competence, insufficient tissue volume, a shallow labial sulcus, the introduction of hair into the oral cavity, microstomia, variations in tissue bulk, color mismatch resulting in a pale appearance, inadequate competency leading to drooling, visible scarring, and a lack of vermilion.

Except for the Abbe, Estlander, Karapandzic, and, to some extent, Webster cheek advancement flaps, most other flaps, including the McGregor lip flap, struggle to achieve a natural-looking vermilion restoration. Researchers continue to search for the ideal flap that can fulfil all the necessary reconstructive criteria.

The vermilion is the red part of the lip that connects with the oral mucosa of the gingivobuccal sulcus, running the entire length of the oral aperture and serving as the crucial transition zone between the outer skin and the inner mouth’s mucosa. Various methods can be used for vermilion reconstruction, such as advancing the remaining lip or buccal mucosa[19, 20], transposing the buccal mucosa [21], interpolated cross-lip vermilion flap [22], tongue flap [23], and the facial artery musculomucosal flap (FAMM) [24]. These methods, however, come with their own set of disadvantages, including a thinned and retracted appearance, color mismatch, difficulty in restoring vermilion fullness at the mucocutaneous junction, the need for bilateral acrylic molar bite blocks, and the requirement for two operative stages.

Our modified fan flap continues to be the preferred choice for several compelling reasons. The blood supply of the flap is robust. Since the flap’s blood supply relies on contralateral labial vessels, sacrificing the facial artery during neck dissection does not pose any limitation on flap elevation. In bilateral cases, sacrificing both facial arteries enhances flap mobility. We’ve observed robust perfusion of the flaps from branches of the angular, lateral nasal, and infraorbital arteries. Remarkably, we have not experienced any flap loss or marginal necrosis in bilateral flaps.

The flap incorporates all the essential elements required for lip reconstruction. The tissue supply and volume are consistently sufficient to address any lip defect, and even the entire lip can be reconstructed using bilateral flaps whenever required. The creation of the labial sulcus is effectively achieved. It maintains a stable pivot point, minimizing commissure rounding and reducing the need for subsequent revisions. Furthermore, this technique avoids complications such as microstomia and excessive drooling. Over time, we have observed that the remaining lip tissue gradually stretches, reducing the visible size of the reconstructed area, which offers aesthetic advantages. Importantly, there is no introduction of hair into the oral cavity during this procedure. The color match is excellent since the surrounding facial skin is used for the reconstruction. Age is not a barrier to performing this procedure, as we have successfully utilized it in individuals ranging from 8 to 80 years old. The optimal method for reconstructing the vermillion is by utilizing buccal mucosa, which is nearby and offers a superior color match. Our experience indicates that sacrificing 1 cm of skin for vermillion reconstruction does not impede the closure of the skin defect. Preserving depressor anguli ornis and modiolous and subcutaneous tissue in the medial margin contributes to achieving fullness, a natural pout, and full vermilion in the reconstructed lip. This also reduces the need for additional surgical stages.

The Fan flap [25] and the Abbe-Estlander flap are both capable of motor and sensory reinnervation [26], and the motor function typically recovers within a year. Notably, all of our patients recovered sphincter capability within a range of 2 to 9 months, with an average recovery time of 4.2 months, and this outcome was achieved without the need for any nerve or muscle stimulation. The precise underlying cause remains elusive, but there is a presumption that the pedicle, which contains some muscular components, plays a pivotal role in facilitating rapid reinnervation. Besides this, despite cutting the nerves on the side where the flap is harvested, the nerve supply from the opposite side remains unaffected. Consequently, the risk of upper lip atrophy is practically eliminated. Nevertheless, in bilateral cases, initial atrophy may occur, which typically resolves following neurotization.

The inherently mathematical nature of flap design leaves little room for error, rendering it particularly well-suited for addressing lateral defects of the lower lip. While we have successfully applied this flap technique to address sizable lateral defects of the upper lip as well, a comprehensive discussion of these cases falls outside the scope of this paper.

Aside from the inherent post-operative bulging effect seen in all fan flaps, no other drawbacks were observed. It’s worth noting that this bulging effect typically subsides significantly within 6–12 months. There are no contraindications associated with this flap. However, in cases of severe submucous fibrosis, it’s advisable to avoid using this flap, as closing the mucosal defect becomes more challenging. Additionally, this flap is not effective when the adjacent buccal mucosa is affected by the disease. In such scenarios, options like the tongue flap or utilizing hairless skin from the flap itself can be considered as alternatives.

In conclusion, our modified fan flap largely meets the ideal reconstructive criteria for lateral lip defects. Effective planning, careful tissue handling, and precise execution are essential to prevent complications such as flap necrosis, excessive scarring, microstomia, or changes in facial expressions. The consistently positive outcomes in this extensive series underscore the effectiveness of this procedure.

Declarations

Ethics Approval

Informed consent was obtained from all patients to be included in the study.

Additional informed consent was obtained from all individual participants for whom identifying information is included in this article and for the publication of their photographs.

Conflict of Interest

The author declares no competing interests.

The material is original; and it has been neither published elsewhere nor submitted for publication simultaneously. If accepted, the paper will not be published elsewhere in the same or similar form, in English or any other language, without the written consent of the copyright holder.