Abstract
Full thickness defects following surgical resection of locally advanced carcinoma buccal mucosa involving oral commissure often require complex microvascular procedures that are technically demanding. We present a novel technique of folded pectoralis major myocutaneous flap for reconstruction of such defects without the need for free flaps or additional sling support.
Introduction
Reconstruction of the oral commissure following full thickness resection of carcinoma buccal mucosa with skin involvement poses a unique challenge requiring simultaneous reconstruction of three subsites (cheek skin, buccal mucosa, lip) along with ensuring functional competence of the oral commissure. From the reconstructive perspective, it is often difficult to strike a balance between post-operative oral commissural incompetence with consequent drooling and microstomia, both causing significant distress to the patients. Several techniques have been described in literature to address this issue, ranging from composite free flaps to concomitant use of fascia lata or palmaris longus slings [1–3]. However, the techniques mainly rely on the pliability as well as need for double free flaps, which is often a limitation in resource-constrained settings. Though radial artery forearm flap (RAFF) with palmaris longus sling remains gold standard for commissure reconstruction, herein, we describe a simple modification where the pectoralis major myocutaneous flap (PMMF) can itself be utilized for reconstructing multiple subunits as well as provide oral competence at the commissure.
Case Series
We have reported a retrospective series of prospectively collected data of 4 patients who underwent oncological resection followed by reconstruction with folded pectoralis major myocutaneous flap. Pre-operatively, the patients with locally advanced carcinoma buccal mucosa with oral commissure involvement were subjected to detailed history, clinical examination, radiological and routine pre-operative investigations. The patients were staged according to the AJCC 8th edition staging and operative plan of full thickness wide local excision of buccal mucosa with comprehensive neck dissection and pectoralis major myocutaneous flap was made. All the patients had an intact mandible after ensuring adequate oncological margin. The pre-operative clinical details have been summarized in Table 1.
Table 1.
Operative details and long-term follow-up
| SL. NO | AGE | SEX | DIAGNOSIS | STATUS OF MANDIBLE | EXTENT OF SKIN INVOLVEMENT | EXTENT OF MUCOSAL INVOLVEMENT | EXTENT OF LIP INVOLVEMENT | POST-RESECTION CUTANEOUS DEFECT | POST-RESECTION MUCOSAL DEFECT | DIMENSIONS OF PMMC SKIN PADDLE | FAT THICKNESS AT THE LEVEL OF SKIN PADDLE | FLAP SURVIVAL | MOUTH OPENING (INTER-INCISOR DISTANCE) | ORAL COMPETENCE |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 64 | M | Ca buccal mucosa cT4aN3b | Intact | 4.5 × 4 cm | 4.8 × 3.7 cm | Lateral 1/3 upper and lower lip with oral commissure | 6 × 5.5 cm | 7 × 5.2 cm | 12.5 × 9 cm | 2.2 cm | Healthy | 3.6 cm | No drooling |
| 2 | 56 | M | Ca buccal mucosa cT4aN0 | Intact | 4.1 × 3 cm | 5.4 × 3.8 cm | Lateral 1/3 upper and lower lip with oral commissure | 5 × 4 cm | 7 × 5 cm | 12.5 × 8.5 cm | 2.8 cm | Healthy | 4.3 cm | Drooling + |
| 3 | 46 | M | Ca buccal mucosa cT4aN0 | Intact | 4 × 3 cm | 4.3 × 3.5 cm | Lateral 1/3 lower lip and lateral ¼ upper lip with oral commissure | 7 × 6 cm | 6 × 5 cm | 9 × 8 cm | 1.5 cm | Healthy | 3.5 cm | No drooling |
| 4 | 69 | M | Ca buccal mucosa cT4aN0 | Intact | 3.8 × 3.6 cm | 4.5 × 3 cm | Lateral 1/3 lower lip and lateral ¼ upper lip with oral commissure | 5 × 4.8 cm | 6.5 × 5.5 cm | 12 × 6.5 cm | 0.8 cm | Healthy | 3.2 cm | No drooling |
The patients underwent full thickness wide local excision of the lesion via circumferential incision taking 1.5 cm margins all around, with a vertical dropdown onto neck for neck dissection. For neck dissection, routine steps were followed. Following excision of the primary, both cutaneous and mucosal defects were measured. Ipsilateral pectoralis major myocutaneous flap, based on thoraco-acromial artery, was planned with dimensions encompassing both inner and outer lining of the post-resection defect. The flap was fashioned around fourth intercostal perforator. The nipple-areolar complex was included in the flap in all cases. Flap harvest was done following the conventional steps. The flap dimensions and corresponding fat thickness have been summarized in Table 1. The flap was tunnelled into neck and delivered into the defect site. The flap was folded on itself to create the inner and outer lining of the defect, with the folded edge of the flap forming the missing commissure. The margins of the inner fold of the flap were sutured to remnant buccal mucosa and mandibular periosteum with interdental sutures (intact mandible) using 2 − 0 vicryl sutures. The outer fold of the flap was secured in two layers to the remnant cheek defect. Triangular shaped wedge of the outer lining of the flap at its superior and inferior margins, corresponding to the level of upper and lower lips were de-epithelized so as to match the resected edges of the lips. The disposition of the lower lip was kept at a slightly higher level to ensure optimal apposition of the upper and lower lips for oral competence. Routine post-operative care was undertaken.
The patients were followed up weekly for first two weeks and monthly thereafter. The post-operative functional outcomes at 3months follow-up have been summarized in Table 1. None of the patients had any flap related complications. The mean (± S.D) inter-incisor distance was 3.65 (± 0.4) cm. One patient with a skin paddle dimension of 12.5 × 8.5 cm and fat thickness of 2.8 cm had persistent drooling. All patients reported acceptable cosmesis at the end of 3-months follow-up period.
Discussion
Full thickness defects of the cheek skin including oral commissure following resection of advanced stage carcinoma buccal mucosa poses a significant reconstructive challenge. This mandates replenishment of the lost volume of all the three lost layers, namely, buccal mucosa, commissure and cheek. Smaller defects of the commissure with limited lip resection have been reconstructed with Zisser flap [4]. Larger defects following extensive cheek skin through-and-through defects mandate locoregional or free flaps for reconstruction. Several free flaps alone or in combination have been described in literature to restore competence and functionality following extensive resections, such as RAFF, antero-lateral thigh flap, gracilis and dorsalis pedis flap [5–7]. RAFF, though considered gold standard, require sling support to counteract the floppiness to maintain competence. PMMC is an easy, reliable loco-regional flap widely used for reconstruction of oromandibular defects. Although the sizeable nature of the flap might seem counterproductive, we have utilized the very bulk of the flap for maintenance of oral competence.
Conventionally PMMC is not considered for reconstruction in the oral cavity in the presence of an intact mandibular arch due to the apprehension surrounding pedicle compression of the bulky flap between the mandible and overlying intact skin. Our practice has revealed that in thin patients with subcutaneous fat < 2.5cm2 at the level of skin paddle, the defect can be reconstructed with PMMC interposed between intact skin and mandible. A full thickness defect in the presence of intact mandible allows flaps bulkier than 2.5cm2 to be folded as there is no constriction by the overlying native cheek skin. However, in our series the outer PMMC paddle had to be trimmed after harvest during the process of inset to allow neck skin approximation. In some cases, a small area of neck closure can be closed with split thickness skin graft also, if the primary closure seems too tight.
The ease of harvest, robust vascular supply and a single flap to reconstruct all the layers are some of the major advantages of this flap. The flap is particularly useful in case of elderly patients and vessel depleted necks, precluding microvascular anastomosis [8]. PMMC being a myocutaneous flap, the post-irradiation shrinkage is less compared to fasciocutaneous flaps such as RAFF. Moreover, the function of the additional palmaris longus sling, in case of RAFF, is maintained by the bulk of the PMMC flap itself. The flap inset is straightforward even in case of intact mandible and helps to form a neo-sulcus for retention of saliva. The limitations of this method are excessive bulk and fat thickness in obese patients causing difficulty in inset of flap and resultant cosmesis. The bulkier flaps tend to sag downwards resulting in oral incompetence and drooling as seen in the second patient of our series. The flap design holds promise in appropriately selected patients, especially in resource limited settings.
Conclusion
The folded pectoralis major flap is a reliable reconstructive option for full thickness defects of cheek involving the oral commissure.
Fig. 1.
(A,B) Ulceroproliferative growth involving right oral commissure and lateral thirds of upper and lower lips; (C) Skin incision circumscribing the exophytic component of primary with a vertical dropdown into neck; (D) Post-resection mucosal and skin defect; (E) Planning and dimensions of PMMC flap; (F) Flap delivered into defect site from chest, folded; (G) Triangular wedge of skin corresponding to upper and lower lips marked; (H) De-epithelization; (I) Post-operative day 7; (J) Healed flap with preserved oral competence at 3-months follow-up
Funding
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Declarations
Conflict of Interest
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Footnotes
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References
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