Bilobed Pectoralis Major Myocutaneous Flap Reconstruction: a Single Institution Experience of 150 Patients and Methods to Prevent Complications

Abstract

Introduction: Bilobed PMMC flap is done for patients who have diseases that require resection of oral cavity mucosa along with the overlying skin, either because of direct tumor invasion to the skin or for achieving adequate tumor-free base of resection. The versatility of the flap allows it to be used to cover both inner and outer linings for a full-thickness defect.

Materials and methods: This was a single-center, retrospective, observational study carried out in the Department of Head and Neck Oncology at a regional cancer center from January 2019 to December 2019. A minimum follow-up duration for all patients was 6 months. The primary endpoint was to study the results and complications associated with bilobed PMMC flap reconstruction and factors affecting it, as well as their management.

Results: The median age was 45 years [24-71 years]. There were 96(64%) males and 54(36%) females. The most common sites reconstructed were lower gingivobuccal sulcus (39.1%), buccal mucosa (30.2%), and lower alveolus (16.7%). The overall complication rate was 41.3%, with 10(6.6%) patients requiring re-exploration. The average hospital stay was 11 days [5-28 days]. On doing a multivariate analysis, for various factors affecting flap necrosis, none of the factors reached statistical significance (p value > 0.05).

Conclusion: PMMC flap remains the workhorse of head and neck reconstruction. In cases of full-thickness defects in oral cancer patients, in our country, in the setup which lacks the expertise in microvascular anastomosis and with immense caseload in the head and neck cancer department, bilobed PMMC flap remains a safe and favorite alternative method for reconstruction.

Keywords: Advanced resection; Bilobed; Free flaps; Full-thickness defects; Pectoralis major myocutaneous flap.

Fig. 1

Complications: a Complete flap loss. b Partial outer flap necrosis. c Operated central arch with exposed titanium plates. d and e Exposed titanium plates in operated central arch managed with DP flap and after flap cutting. f Large oro-cutaneous fistula after partial necrosis of outer and inner flaps managed with a forehead flap

Fig. 2

Follow-up images after a minimum of 6 months

Fig. 3

Commonly used skin paddle markings. a Vertically placed paddle with a skin crease infra-mammary incision mainly used in female breasts. b Vertically placed skin paddle in a male patient. c A horizontally placed paddle which is commonly used. d Skin paddle placed in an L shape with the medial paddle forming the inner lining and lateral paddle forming the outer lining

Fig. 4

Various lengthening techniques. a PM muscle can be completely detached from the clavicle along its full length. Arrow points to the detached part with pedicle b use zigzag muscle cutting incisions starting from the medial border of the pectoralis major muscle till 1 cm from the pedicle and then again back to the medial border of the muscle. The arrow shows a spacious tunnel through which the flap is brought to the neck (c). The medial incision is placed along the green marking 1 cm away from the pedicle. d The clavicular head can be divided along the axis of the pedicle, and the muscle bulk formed by the clavicular head is eliminated. Blackline is a landmark for pedicle, and the green line is along which muscle is cut

Fig. 5

Picture series depicting the inset of bilobed PMMC flap: a full-thickness defect after resection of the primary tumor with ipsilateral neck dissection, b inset of PMMC flap. The lateral skin paddle forms the inner lining of the buccal mucosa. c and d After the inner inset is completed, the flap is cut till the muscle deep to attain good mobility of the outer paddle. The arrow shows the line along which flap is divided (e), (f) and (g) The medial skin paddle forms the outer lining. h Final postoperative picture after completion of inset and closure