Experience with the pectoralis major myocutaneous flap for head and neck reconstruction in a general surgical unit.S Nagral, M Sankhe, CV Patel
Dept of Surgery, Seth GS Medical College, Parel, Bombay, Maharashtra.
The pectoralis major myocutaneous (PMMC) flap or its modification was used in 19 cases after resectional surgery for malignancy of the oral cavity with minimal morbidity and no mortality. The resection as well as reconstruction was done by the same team consisting only of general surgeons. The final functional and cosmetic results were satisfactory. The pectoralis major myocutaneous flap is a hardy flap and can be performed with relative ease even by those not specialised in plastic surgery. This makes it an important tool for a general surgeon practicing in a country like India with its high incidence of head and neck malignancy.
Keywords: Adult, Female, Head, surgery,Head and Neck Neoplasms, surgery,Human, Male, Middle Age, Neck, surgery,Pectoralis Muscles, Surgery Department, Hospital, Surgical Flaps,
Head and neck malignancy is one of the commonest malignancies seen in our country. Annually, almost 7% of all cancer deaths in males and 4% in females have been reported due to oral cancers. This is basically because of the widespread habit of chewing various irritants. As a result general surgeons are many a time called upon to treat such cases. Surgery still remains the treatment modality of choice for large primary tumours (T3 and T4) as well as tumours with neck node involvement. Majority of our patients present with large primary tumours; defects following resectional surgery cannot be closed primarily and since, they are full thickness, cannot even be grafted. Hence, a flap for reconstruction is required.
The pectoraiis major myocutaneous (PM1VIC) flap, an island myocutaneous flap based on the pectoral branches of the thoraco-acromial artery, is hardy, technically easy and quick to perform; it neither involves any complicated measurements nor requires special instruments making it very useful for a general surgeon to use. We present here the technique and results of its use in our unit where the resection and the reconstruction were done by the same team consisting of general surgeons only.
Between December 1989 and December 1991, 19 patients (15 males and 4 females, age range: 36 yr - 64 yrs) underwent reconstruction with this flap. Fifteen (88%) of these were chronic chewers. Six had associated premalignant lesions (leukoplakia in 4, submucous fibrosis in 2). Three patients had received radiation therapy ranging from 4000 to 6000 rads. The sitewise distribution of the primary tumors along with the TNM (UICC, 1987) status was as follows:
1) Buccal Mucosa (n = 12): T3NO - 11; T3N1 - 2; T4NO 1 ; T3N2(a and b) - 3; T4N2 (a and b) - 1; T3N3 - 2 and T4N3 - 2.
2) Lower alveolus (n = 3) : T4N1 - 2 and T4N2 - 1.
3) Retromolar trigone (n = 2): T2N1 - 1 and T4NO - 1
4) Floor mouth (n = l): T3NO.
5) Tongue (n = l): T3N2.
None of the patients had any distant metastasis (Mo). The resectional surgeries performed were,
1) composite resection (wide excision of primary with segmental mandibulectomy and classical radical neck dissection) - 14 patients;
2) wide excision of primary with segmental mandibulectomy and supra-omohyoid neck dissection - 4 patients;
3) wide excision of primary with bilateral supraomohyoid neck dissection - 1 patient.
The types of PMMC and concomitant flaps used were as follows:
1) Classical single paddled I'MIVIC flap -(11), 2) bipaddled (folded) PM1VIC flap - (4), 3) single paddled PMMC with Estlander's Flap - (2), 4) bipaddled 1PM1VIC with Estlander's Flap - (1) and 5) single paddled PMMC with tongue Flap - (1).
The skin paddle size ranged from 6cm x 4 cm to 12 x 6 cm.
The operative technique used was essentially the same as originally described by Ariyan with a modification of the incision as described by Schuller to preserve the deltopectoral flap area. Following resectional procedure the defect was measured. The skin paddle of appropriate size enough to reach the defect without tension was marked over the chest wall. Its length from the clavicle was measured along the axis of the vessel (i.e along the line joining the acromion to the xiphoid process). The skin incision was taken from the anterior axillary fold to meet the marked skin island superolaterally (See [Figure - 1]).
This leaves the area of the deltopectoral flap untouched for further use. The paddle incision was also taken in continuity with the skin incision. The skin paddle was sutured down to the underlying muscle with catgut sutures to prevent shearing movement between the skin and the muscle. The pectoralis major muscle was then elevated from the chest wall to visualise the flap vessel running on its undersurface. The flap pedicle was fashioned by cutting the muscle on either side of the vessel and elevating it till the clavicle (See [Figure - 2]).
After achieving haemostasis on the cut muscle on the flap side by catgut ligatures, the flap was flipped over the clavicle, tunnelled through the neck and inserted into the defect with 3-0 silk. No flap twisting was required for a mucosal defect in the oral cavity, but if used for a skin defect, a twist in the pedicle was required. When required the flap was bipaddled by cutting the skin down to the muscle of the flap and folding the muscle to create two paddles of the desired size. Haemostasis was achieved with a continuous catgut suture on the cut pectoralis major and the donor site was easily closed primarily with a drain. The flap sutures were removed on the 8th-10th post-operative day.
The average time required for the reconstruction was 1 ½ hr. The average blood loss while raising the flap was 500 ml.
Complications encountered were as follows:
1) Orocutaneous fistula developed in 7 (35%) patients. However, in all of them, it was temporary and healed on conservative treatment. The maximum time required for healing was six weeks. Gastrostomy was performed as a temporary procedure in two.
2) Partial flap necrosis was observed in 6 (32%). This was restricted only to the skin of the flap in 5 cases ranging from 10% - 50% of the paddle area and was mainly seen in the part distai most to the vascular pedicle. It epithelialised within a period of 1-3 weeks except in one patient in whom grafting was required. Full thickness loss of the outer paddle was noted in one
3) There was no instance of total flap necrosis. No particular prediposing factor leading to partial flap necrosis could be identified in the above patients.
4) Two patients developed infection of the flap suture line.
5) Donor site infection was noticed in two.
Of the 19 patients, 8 were followed up for more than a year and found to be free of disease. Of the remaining, 2 died of recurrent disease, 2 were detected to have recurrent disease and advised palliative treatment and 7 were lost to follow up. In the follow up, no significant shoulder disability was noticed. None of the patients complained of hair growth on the flap. The functional and cosmetic results of the flap for mucosal defects (See [Figure - 3]) and skin defects (See [Figure - 4] & [Figure - 5]) were satisfactory. In all cases healing of the donor scar was satisfactory (See [Figure - 6]).
The pectoralis major myocutaneous flap first described by Stephen Ariyan in 1979 is now the workhorse of modern head and neck reconstruction largely replacing the forehead and the deltopectoral (Bakamjiaan) flap as the flap of choice. It has been used extensively and many large series have demonstrated its extremely low rate of complications including necrosis. Flap necrosis rates ranging from 0% to 20% have been reported in various series. A majority of these are partial losses of the skin of the flap, as in the above series, which heal with conservative therapy. Total necrosis of the flap is rare (0% 15%). The other advantages besides the ease of technique and low complication rate include versatility and minimal donor site morbidity. The flap can be used for a very wide range of defects in the head and neck area including the oral cavity, neck, maxilla as well as temporo-orbital area. A tubed PMMC flap can also be used to reconstruct the pharynx and the cervical esophagus. Cosmetically, the donor site scar is totally hidden by clothing; the functional loss is negligible.
The muscle pedicle in the neck effectively covers the exposed carotid vessels after a radical neck dissection as well as recreates the sternomastoid prominence giving symmetry. Elevation of the flap does not require any change of position during surgery and can be done quickly adding minimal extra time to the surgery. Its use does not preclude the use of other flaps later; effective combinations with other flaps like the deltopectoral, forehead and, the Estlander flap can be used for large defects. Like other myocutaneous flaps, it involves a single stage reconstructive procedure and does not require flap delay or release. The flap may be employed before or subsequent to the use of chemotherapy or radiotherapy.
Inlerriales the flap poses some problems because of difficulty in elevation in view of the presence of breast tissue as well as scarring of the breast. Other disadvantages of the flap include excessive bulk in obese or muscular individuals and troublesome hair growth in the oral cavity. The blood loss during surgery is marginally more as compared to fasciocutaneous flaps because of division of muscle.
Further modifications of the flap have how been described which include an osteomyocutaneous variety where the flap is raised along with the anterior part of the fifth or sixth rib to reconstruct the mandible and an innervated flap where the nerve supply is maintained in order to make it more dynamic. The basic attraction however, remains its low complication rate as well as the ease of technique, which makes it possible even for general surgeons not specialised in plastic surgery to use it whenever required as demonstrated by us. This advantage is especially relevant to our country where head and neck malignancy is common.
We thank the Dean, King Edward Memorial Hospital for allowing us to use the hospital data for publication.
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6]