Beneficial Impact of “Supercharged” Pectoralis Major Musculocutaneous Flap With Indocyanine Green Angiography on Reconstruction in a Patient at High Risk for Necrosis

The pectoralis major musculocutaneous (PMMC) flap is widely used in patients with tongue cancer for whom reconstruction using free tissue transfer is difficult, including elderly patients and those with a history of cervical irradiation, underlying diabetes, atherosclerosis, or vasospasm.¹ The PMMC flap is advantageous because there is no need for vascular anastomosis, and the surgical duration is short. In contrast, however, the PMMC flap has the disadvantage of unstable blood flow, which can lead to complications including partial necrosis.² Numerous modifications to the PMMC flap have been made.³ In 2013, Makiguchi et al developed the PMMC flap and devised the “supercharged” PMMC in which the lateral thoracic artery is cut and anastomosed to the cervical vessels using microsurgery techniques.³ The supercharged PMMC flap has merits in improving reconstructive procedures for the head and neck.

Real-time visualization of the vasculature during surgery has contributed to the success of the PMMC flap.⁴ Intraoperative indocyanine green (ICG) angiography (ICGA) involves the injection of a fluorescent agent (ie, ICG) into a vessel, thus enabling observation of blood flow to a depth of 1 to 2 cm.^4,5 In the field of reconstructive surgery, ICGA monitoring is frequently used to evaluate the perforator vessel and skin vascularization and to delineate the outline of the flap.^6-8

In this report, the authors created a supercharged PMMC flap with the aid of ICGA for a patient with tongue cancer who was at high risk for necrosis in free tissue transfer. The application of this technique resulted in satisfactory vascularity of the flap without necrosis.

The patient was an 84-year-old Japanese woman who had left tongue cancer (cT2N0M0/pTs squamous cell carcinoma) diagnosed 2 years previously and underwent partial resection of the tongue. Two months later, left cervical lymph node metastasis (rN2b) was found and left cervical dissection was performed. However, recurrence was detected; as such, a third surgical procedure requiring reconstruction was scheduled. The patient also had Alzheimer’s disease and hyperlipidemia.

The patient underwent otolaryngological surgery for subtotal removal of the left side of the tongue and right cervical dissection (Figure 1). Due to her history of multiple cervical surgeries, advanced age, and susceptibility to infection, she had a high risk of necrosis with damage and adhesion in the recipient vessel after surgery. The authors judged that free tissue transfer would not be suitable; accordingly, the PMMC flap was chosen.

A skin island was designed to include the pectoral branch of the thoracoacromial artery branching from the lateral one-third of the clavicle and the fourth intercostal perforating branch 2 cm medial to the nipple (Figure 2A).

The lateral thoracic artery was identified by the descending lateral border of the pectoralis major. The lateral thoracic artery was cut at the branch of the subclavian artery and was preserved in the flap (Figure 2B). An intravenous injection of 2 mL ICG (2.5 mg/mL; Diagnogreen; Daiichi-Sankyo Pharmaceutical) was administered to the patient. Three minutes later, a staining defect was observed on the caudal side of the flap, and a supercharged PMMC flap was used (Figure 2C). The flap was moved into the oral cavity, and the lateral thoracic artery was anastomosed with the superior thyroid artery under microscopic visualization (Figure 3).

 After surgery, the flap was fully adapted. No blood flow failure was noted during the 3 months of postoperative follow-up (Figure 4).

Free tissue transfer is generally the procedure of choice for head and neck reconstructions, and the PMMC flap can be used in cases of failed free tissue transfer, poor cervical vascular status, or skin necrosis after irradiation and in patients in poor general condition.⁹ Despite the wide clinical application of the PMMC flap in oral, head, and neck reconstructions, various PMMC flaps have been found to result in partial distal necrosis and exhibit limited flexibility.^1,2,9 Defects in partial or complete flap necrosis are typically due to unstable blood flow in the flap.

Smoking and diabetes have been shown to be associated with a higher risk for complications. Many risk factors for flap necrosis have frequently been found in patients older than 70 years of age, in individuals who are overweight, and among women.⁹ In particular, because the thick breast tissue in the flap is located between the skin and muscle in women, the placement can make blood flow unstable.¹⁰ The patient described in the present case was at high risk for incidence of these complications listed, in addition to a tissue deficit in her tongue from a previous surgery.

The PMMC flap was initially scheduled for this patient because she had a history of cervical surgery and was considered to be at high risk for necrosis with free tissue transfer. The patient had a significant lack of tissue due to tissue removal from the previous surgery and required a large mass of pectoral major muscle skin flap for reconstruction. When the flap was elevated, intraoperative ICGA was used to evaluate blood flow in the flap, thus enabling visualization of the part with inadequate blood flow. Because this defect is a predictor of postoperative partial necrosis of the flap, a supercharged PMMC flap involving the lateral thoracic artery was applied. Three months after surgery, normal engraftment of the flap was observed; therefore, the supercharged PMMC flap demonstrated its utility in reconstruction of the tongue in a patient at high risk for free tissue transfer.

With advances in imaging techniques, such as ICGA, incidental operative abnormalities of the artery are no longer perceived as sufficiently harmful to prevent pedicle grafting. The authors demonstrated the importance of intraoperative ICGA monitoring for appropriate selection of the surgical procedure. Similarly, Miyazaki et al⁸ reported that observations of blood perfusion using intraoperative ICGA and preserving the lateral thoracic artery in a PMMC flap application resulted in effective reconstruction compared with conventional flap harvest. Although it has been reported that spasm of blood vessels and angiosomes outside of the choke vessel in the pedicle flap causes unstained regions during intraoperative ICGA,¹¹ the authors recommend that combining a supercharged PMMC flap with ICGA to preserve the lateral thoracic artery is the best choice to reduce the risk to patients. Furthermore, this proposed technique will facilitate the reconstruction for patients with arteriosclerosis and diabetes who are carrying damage in their blood vessels. This technique may be especially useful for patients treated with dialysis or repeated operations, radiation therapy, and chemotherapy, all of which lead to increased risk of flap necrosis.

Vascular variations have been left to modifications in the flap harvesting technique, and various surgical techniques have been reported to compensate for the insufficiency of blood flow in the PMMC flap. More specifically, variable vascularization of the PMMC flap containing a sufficient arc of rotation was divided into the pectoral branch of the thoracic artery, providing the upper site of the PMMC flap, and the lateral thoracic artery and anterior intercostal branches of the artery for the skin region onto the lower site of the flap. Yuen et al reported that preservation of the lateral thoracic artery led to improvement in vascular supply without compromising pedicle length in harvesting the pectoralis myocutaneous flap.² Makiguchi et al proposed that the lateral thoracic artery could be preserved without compromising pedicle length and was directly connected to the other branches of the anterior intercostal perforator and pectoral branch of the thoracoacromial artery supplying the muscle, calling it the “supercharged” PMMC flap.³ Preserving the lateral thoracic artery during PMMC flap harvesting to improve the distal blood supply is reasonable because the lateral thoracic vessels are sectioned and anastomosed to the cervical vessels to create a conventionally prepared PMMC flap nourished by the dominant thoracoacromial vessels. Thereafter, several studies have reported that preservation of the lateral thoracic artery is a promising technique for stabilizing blood flow of the distal and lateral parts of the PMMC flap and skin paddle.^2,3,12 In the current case, the supercharged PMMC flap, in which the lateral thoracic artery was cut and anastomosed to the cervical vessels using a microscope, was confirmed to be advantageous.

There were some limitations, however, that could have influenced the results in this case. It is possible that the successful outcome using a supercharged PMMC flap in a single patient resulted by chance; as such, the authors acknowledge the lack of statistical power. Furthermore, the median follow-up in this study was rather short. Therefore, more information from studies involving larger population-based samples is needed to better comprehend the technique and to verify its efficacy.

The present study demonstrated the possibility of using the “supercharged” PMMC flap technique to preserve the lateral thoracic artery and anastomose it to the cervical vessels, which resulted in successful flap survival without partial necrosis. In addition, real-time visualization of blood flow using intraoperative ICGA at the time of flap elevation was helpful as an indicator of blood flow. Thus, the novel technique of combining a supercharged PMMC flap with ICGA in patients at high risk for complications in free tissue transfer procedures may be useful in future reconstructive surgeries.

Affiliations: ¹Department of Plastic and Reconstructive Surgery, Kansai Medical University, Hirakata, Osaka, Japan; ²Department of Plastic and Reconstructive Surgery, Hikone Municipal Hospital, Hikone, Shiga, Japan

Correspondence: Maako Fujita, MD; fmfm.maako@gmail.com

Ethics: Informed written consent was obtained from the patient for the publication of this report.

Disclosures: The authors report no conflicts of interest.

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