Thoracoabdominal Flap Closure for Large Post Pectoralis Major Myocutaneous Flap Donor Site in Advanced Oral Cancer: An Innovative Approach in Resource Constraint Setting

Abstract

Oral cancer often presents in advanced stages, requiring complex surgical interventions. The bipedal pectoralis major myocutaneous (PMMC) flap is a commonly used alternative to the gold standard free flaps for reconstruction in resource-constrained settings. However, large donor sites may necessitate split-thickness skin grafting (STSG), leading to aesthetic challenges. This study explores using the thoracoabdominal flap (TA) for a large donor site closure following PMMC flap harvest in advanced oral cancer reconstruction. A retrospective analysis was conducted on twelve patients with advanced oral cancer with extensive skin involvement. The TA flap was utilised to achieve tension-free closure of the donor site. Patient demographics, clinical features, treatment stage, operative details, and postoperative complications were meticulously recorded. All patients had advanced oral cancer, with seven having left-sided disease and five having right-sided disease. The TA flap closure resulted in minimal complications, with two patients developing seromas and one experiencing marginal necrosis during the postoperative period. The innovative TA flap technique is useful in closing extensive donor sites following PMMC flap harvest for advanced oral cancer cases. It offers advantages such as improved cosmetic outcomes and fewer complications than split-thickness skin grafting.

Introduction

Head and neck cancers continue to be a major health problem, especially in countries with high consumption of tobacco and alcohol [1, 2]. The global incidence of lip and oral cavity cancers is estimated to be on an upward trajectory [3]. The standard curative surgical treatment for oral cancer involves a margin-negative three-dimensional resection of the primary tumour along with the address of regional neck nodes [4]. Unfortunately, the majority of the patients present in advanced stages [5]. The potential surgical candidates among them have a large and complex defect arising from resection of advanced disease and require free flaps or multi-staged reconstructions using a combination of pedicled flaps [3, 6]. Bipaddle (pectoralis major myocutaneous (PMMC) flap is a good alternative to the free flaps, which remain the current gold standard for the reconstruction of such defects, especially in low-middle–income countries (LMIC). The donor site is usually closed primarily. However, in certain scenarios where a large flap is harvested, a tension-free primary closure is usually not possible, and split-thickness skin graft (STSG) is the most commonly used option. However, achieving optimal cosmetic outcomes with STSG can be challenging regarding texture discrepancy, colour mismatch, and graft contraction. We explored the role of the thoracoabdominal flap (TA) in such a scenario. TA flap is a composite tissue flap comprising skin and subcutaneous tissue from the thoracic and abdominal regions. The flap has a wide arc of rotation and allows the transfer of a large volume of tissue to reconstruct complex defects resulting from trauma or oncological resections. We present our initial experience with this widely used flap technique in a novel setting.

Methods

A retrospective analysis of the prospective database was conducted to identify patients who underwent thoracoabdominal flap surgery to close the donor site after the PMMC flap harvest. This study included patients treated from May 1, 2021, to August 31, 2023. Institutional ethical committee approval was obtained for the study. Diligent precautions were taken to ensure data anonymity. All the selected patients had biopsy-proven advanced oral cancer (squamous cell carcinoma) with either extensive skin involvement or a frank oro-cutaneous fistula, necessitating large-volume skin resection along with composite bite resection. The demographic profile, clinical features, treatment stage, operative details, and any postoperative complications were meticulously recorded from their medical files.

Surgical Technique

Anatomical Perspective

TA flap is a rotation advancement fasciocutaneous flap (Type-c). It has two bases of pivot points- the medial and the lateral base depending on the two sets of direct perforating segmental arteries. The medially-based flap derives its blood supply from the superior deep epigastric perforating artery. In contrast, the laterally-based flap is based on blood flow from the branches of superficial lumbar, subcostal, intercostal, and thoracic arteries [7]. The medial-based TA flap is colloquially known as the thoraco-epigastric flap.

Pre-operative Planning

Following the harvest of a large PMMC flap the primary closure of the donor site is initially attempted. However, if tension-free closure cannot be attained by initial mobilisation of the surrounding skin and subcutaneous tissue, a plan to proceed with a TA flap is executed.

Patient Positioning

No special positioning is required for a TA flap and the flap harvest can be continued in the usual supine position as is needed for the PMMC flap. Proper padding and support are used to ensure patient comfort and prevent any sores at the pressure points secondary to the prolonged surgeries involving complex resections and reconstructions.

Incision Placement

We employed a laterally-based TA flap for all our cases. This flap receives a robust blood supply from the lumbar and subcostal arteries at the level of the anterior border of the latissimus dorsi muscle. The incision is planned within the limits of the flap, which is midline medially, the anterior axillary line laterally, and a horizontal plane at the level of the anterior superior iliac spine inferiorly. Preferably, a boomerang-shaped incision is planned with the vertical limb starting at the lower limit of the donor site for the PMMC flap. Depending on the arc of rotation needed for the TA flap mobilisation and achieving a tension-free closure, the vertical limb of the incision is extended inferiorly and curved laterally just short of the umbilicus. The horizontal limb of the incision stops just short of the anterior axillary line.

Flap Harvesting and Perforator Preservation

The laterally based TA flap is harvested in a relatively avascular plane deep into the subcutaneous tissue. Dissection continued in a plane superficial to the rectus fascia and aponeurosis of the external oblique muscle. The intercostal perforators of the flap are divided to facilitate the mobilisation of the flap. To avoid any inadvertent damage to the lateral perforators of the flap, the dissection is halted at the lateral limit, i.e. the anterior axillary line.

Flap Inset

The arc of rotation and advancement of the TA flap is in the cranial direction to permit a tension-free primary closure of the donor site of the PMMC flap. The lax abdominal skin can be adequately mobilised to attain primary closure of the donor site for the TA flap. After ensuring hemostasis, the surgical site is closed in two layers over a closed suction drain (Fig. 1).

Fig. 1.

Intraoperative photographs of thoraco-abdominal flap closure of large PMMC donor site defect

Post-Operative Monitoring

After the flap is inset and closed, close monitoring of the flap’s viability is crucial. Regular clinical assessments evaluate flap colour, capillary refill, and perfusion. Doppler ultrasound or flap monitoring systems are rarely used. Drains are removed when output is less than 30 ml, and suture removal is usually done after two weeks.

Results

During the study period, 168 patients underwent resections for oral cancers, of which surgical defect was reconstructed using PMMC flap in 146 patients. Of these, twelve patients underwent TA flap closure for post-PMMC donor site defect. The median age of the patients was 47 years (range 34 to 82), and all were males. All patients had advanced oral cancer with extensive skin involvement, with four patients having frank oro-cutaneous fistula. Among these patients, seven had the left-sided disease, while five had the right-sided disease. Neoadjuvant chemotherapy (NACT) was administered to six patients because of borderline/unresectable disease. There were no major procedure-related complications observed in this study, except for two patients, one of whom developed seroma, while another patient experienced marginal necrosis during the postoperative period. Table 1 displays the characteristics of the patients.

Table 1.

Characteristics of the patients included in the study

SNO	AGE (years)	Sex	Co-morbidity	Epicentre of the tumor	Laterality	NACT	oro-cutaneous fistula	Pathological stage	TA Flap related complications
1	52	Male	None	Alveobuccal complex	Left	No	Yes	pT4aN3bM0	Seroma
2	49	Male	None	Buccal mucosa	Left	No	No	pT4aN0M0	Marginal necrosis
3	52	Male	Hypertension	Alveobuccal complex	Left	no	No	pT4aN3M0	None
4	82	Male	None	Buccal mucosa	Left	No	No	pT4aN2aM0	None
5	46	Male	Diabetes mellitus	Buccal mucosa	Left	Yes	No	ypT4aN2aM0	None
6	36	Male	None	Buccal mucosa	left	Yes	Yes	ypT4aN2aM0	Marginal necrosis
7	34	Male	None	Alveobuccal complex	Right	Yes	No	ypT1N2aM0	None
8	53	Male	None	Lower alveolus	Right	No	No	pT4aN1M0	None
9	42	Male	None	Buccal mucosa	Right	Yes	No	ypT4aN2bM0	None
10	42	Male	None	Buccal mucosa	Left	Yes	Yes	ypT4aN3bM0	None
11	44	Male	hypertension	Buccal mucosa	Right	Yes	Yes	ypT4aN0bM0	None
12	64	Male	Hypertension	Buccal mucosa	Right	No	No	pT3N2bM0	None

Discussion

The thoracoabdominal flap is a fasciocutaneous rotational-advancement flap. It was first introduced by Brown et al. in 1975 as a soft tissue cover following resections for locally advanced breast cancer (LABC) [8]. Thoracoabdominal flaps are either medially- or laterally-based flaps. Compared with medially-based flaps, laterally-based thoracoabdominal flaps have more stable circulation. A laterally-based thoracoabdominal flap can preserve the lateral intercostal arteries but is less likely to preserve the superior epigastric perforators. In contrast, a medially-based flap can preserve the superior epigastric perforators.

The PMMC flap is a versatile reconstructive technique commonly used in head and neck surgery, particularly for defects in the oral cavity and advanced laryngeal and hypopharyngeal cancers. While the flap offers several advantages, including a robust blood supply and reliable tissue coverage, there are potential complications associated with its use in terms of both the flap necrosis and donor site morbidity, especially when the dimensions of the flap being harvested increase [9]. Harvesting the PMMC flap involves sacrificing a portion of the muscle from the chest wall. This can lead to functional and aesthetic issues at the donor site, including weakness, loss of strength, and contour deformity asymmetry at the chest wall due to removing a portion of the muscle. Most donor site defects can be closed primarily after mobilisation of the remanet skin and subcutaneous tissue over the chest wall. However, in scenarios where large bipedal flaps are harvested, an STSG is commonly used to cover the donor site to avoid a tension-free closure. STSG is prone to complications such as graft loss, graft contraction, infection, or poor cosmetic outcomes in colour and texture match compared to the surrounding recipient skin site. Moreover, poor sensation at the recipient site, high susceptibility to trauma, and prolonged wound care for both the donor and recipient site as compared to primary or a flap closure are other limiting factors. The limitations of our study include its retrospective nature and a relatively small sample size. We also did not objectively assess this flap’s aesthetic and functional outcomes compared to STSG for reconstructing the donor site defect.

Conclusion

The thoracoabdominal flap (TA) effectively closes large donor sites post pectoralis major myo-cutaneous flap removal in advanced oral cancer cases. This overcomes issues associated with split-thickness skin grafting, providing better cosmetic results and minimal complications.

Author Contributions

All authors contributed to the study’s conception and design. All authors were involved in material preparation, data collection and analysis. PK wrote the first draft of the manuscript, and all authors contributed to the final draft. All authors read and approved the final manuscript.

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Declarations

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors. Approval to conduct the study was granted by the Institutional Ethics Committee (reference no. SGRR/IEC/04/23 dated 26th December 2023).

Informed Consent

was obtained from all individual participants included in the study.

Conflict of Interest

All authors declare that they have no conflict of interest.