Regional pedicled flap salvage options for large head and neck defects: The old, the new, and the forgotten

Abstract Objectives The objective of this article is to review options for regional pedicled reconstruction for large head and neck defects in a salvage setting. Methods Relevant regional pedicled flaps were identified and reviewed. Expert opinion and supporting literature were used to summarize and describe the available options. Results Specific regional pedicled flap options are presented including the pectoralis major flap, deltopectoral flap, supraclavicular flap, submental flap, latissimus flap, and trapezius flap. Conclusions Regional pedicled flaps are useful options in a salvage setting even for large defects and should be in the armamentarium of any reconstructive head and neck surgeon. Each flap option carries specific characteristics and considerations.


| INTRODUCTION
In the era of modern head and neck reconstruction, microvascular free tissue transfer has become a widely utilized tool for many different types of defects. Before microvascular free flaps were pioneered decades ago, regional pedicled flaps were the primary option for reconstruction of large defects. The pectoralis major muscle flap, for example, became the workhorse flap used for many head and neck defects throughout the 1980s. By the 1990s the superiority of various free flaps for certain large defects had become apparent. This superi- Certain pedicled flaps have unique advantages for certain defects, sometimes rivaling even the best free flap. The potential to provide reliable reconstruction, shorter surgery, and less resource-intensive postoperative care cannot be ignored. Also, specialized operating room equipment, personnel, and postoperative care are usually not required for pedicled flaps. Color and texture match in the head and neck can be superior to free tissue transfer in certain circumstances.
Advanced microvascular fellowship training is also not required for most regional pedicled flaps. Pedicled flaps do still carry some inherent potential drawbacks in general, as with any reconstructive option. Simultaneous flap harvest is not always feasible or practical.
Contouring and placement of the flap can be more challenging in comparison to a free flap. Other controversial and often unspoken variables may also factor in to the willingness to perform pedicled flap reconstruction, from surgeon/facility compensation, to lost microvascular trainee benefit, and hopefully never the desire to have a "high free flap volume" (either as a department or individual) for perceived reputational value or resource allocation purposes.
In the setting of head and neck cancer, the term "salvage" can have a number of different meanings, particularly when talking about reconstruction. In this review, we are referring to salvage as reconstruction in the setting of any previous treatment. In reconstructive surgery, however, salvage typically refers to reconstruction after a previous reconstructive attempt has failed. Reconstruction in a secondary setting carries much higher risk. 1 Despite the popularity of free flaps, numerous different regional pedicled flaps are still used in the modern era. While many different types of pedicled flaps have been described over many decades, some have fallen into disuse, while others have gained significant popularity in recent years. We describe and revisit in this review those common and uncommon regional pedicled flaps that have proven to be invaluable for salvage of large defects in the head and neck. These include: the pectoralis flap, the deltopectoral flap ("the old"), the supraclavicular flap, the submental flap ("the new"), the latissimus flap, and the trapezius flap ("the forgotten"). We describe modern modifications and descriptions for the use of these flaps in current head and neck reconstruction. While various other components of the reconstructive ladder exist to salvage head and neck defects (such as other free flaps, tissue expansion, local flaps, etc.), we focus here on regional pedicled flaps. In addition, while there are many other regional pedicled flaps that have proven to be valuable and need to be included in the armamentarium of the reconstructive surgeon, such as the facial artery musculo-mucosal flap, sternocleidomastoid muscle flap, temporoparietal fascia/temporalis muscle flap, and palatal island flap, we will focus here on options that are particularly useful for large sized or large surface area defects.

| THE PECTORALIS FLAP
Ariyan first described the pectoralis major pedicled musculocutaneous flap in 1979 and since then it has been a "workhorse" flap for head and neck reconstruction. 2 Once used for all head and neck defects, the pectoralis major flap lost popularity when selected free flaps were shown to provide better donor tissue match in many defects. It remains, however, an excellent and versatile reconstructive option for some head and neck reconstruction.
The pectoralis major muscle is a large muscle originating from the medial third of the clavicle, sternum, the first six ribs, and the aponeurosis of the external oblique muscle (Figure 1). It inserts onto the greater tubercle of the humerus in the form of a single tendon. The main arterial supply for this flap is the pectoral branch of the thoracoacromial artery, a branch of the second portion of the axillary artery.
Large-sized skin paddles can be reliably harvested over the pectoralis muscle. The pectoralis major flap can usually reach midface and lateral skull base defects, with a superior limit often being stated as the zygoma. The skin paddle can be reliably designed distal to the pectoralis muscle to improve reach by including undisturbed anterior rectus fascia with the random portion of the flap. While normally designed with a skin island directly over the inferior pectoralis muscle, a large elliptical otter tail design can be used to capture a higher number of perforators and maximize the possibility of providing blood supply to skin overlying the rectus fascia via the angiosome concept Flap harvest is quick, easy, and reliable. The donor site can typically be closed primarily after undermining skin flaps over the anterior chest wall. The ability to primarily close the donor site can be quite variable depending on body habitus, donor site tissue quality, and willingness to undermine and distort nearby anatomy such as the nipple or breast. The flap is typically outside of head and neck radiation fields. The reliability of the pectoralis flap is one of its most attractive attributes. Various studies have showed less than 2% total flap failure and 7% to 9% partial flap failure. [6][7][8] The harvest is straightforward and rapid, as meticulous pedicle dissection is not typically required.
The pectoralis major flap possesses a number of characteristics, which can be advantageous or disadvantageous depending on the defect that is being reconstructed. The arc of rotation has a limit ( Figure 2). The reach of the flap to higher head and neck defects can be challenging. The bulk is on the larger side, particularly in patients with large breasts or robust pectoralis muscles. Denervated pectoralis muscle will eventually atrophy, although fat and breast tissue will not.
The large bulk makes the pectoralis flap excellent for situations in which there is a high risk of infection or leak, severely radiated tissues, or need for robust coverage such as in the setting of carotid exposure ( Figure 3). The pectoralis major flap has limited versatility for tissue matching of different defects. Skin, fat, and muscle will all be harvested together unless a muscle-only flap is used. As such, the pectoralis major flap has more utility in the setting of large volume defects and less utility for defects requiring thin lining for tissue match.
The donor site is also a consideration. There can be some cosmetic distortion from the bulk of the pedicle when tunneled through the neck and over the clavicle, although denervation of the flap does help with this. Distortion of the breast is common. Additionally, there is some associated shoulder dysfunction. 9 Positioning and accessibility are usually favorable for most head and neck defects.

| THE DELTOPECTORAL FLAP
The deltopectoral flap was first described by Aymard in 1917 for staged nasal reconstruction. 10   The submental flap has an excellent arc of rotation for most head and neck defects. The reach is sometimes limited for higher facial defects, although it can reach orbital, high facial, and anterior skull base defects in patients with favorable anatomy. 36 The flap can also be "hybridized" by dividing and re-anastomosing the pedicle vein to improve the reach. 37  has been shown to decrease hospital length of stay and also offers a cost reduction. 33,35 The submental flap demands an oncologically sound level I neck dissection during harvest if being employed for oral cavity reconstruction. This oncologically sound approach has been extensively studied in oral cavity malignancy reconstruction demonstrating no difference in locoregional control or recurrence rates. 35,[39][40][41][42][43][44][45] Caution is always advised in cases with level I lymphadenopathy, particularly if there is a concern for extracapsular extension. There is also flexibility in the amount of skin included and it can also be used as a purely musculofascial flap. Vascularized rib can also be included but has limited practical utility.

| THE SUBMENTAL FLAP
The donor site morbidity from latissimus dorsi muscle harvest is generally favorable. 49   can also reach most defects in the neck, lower lateral face, and lateral skull base ( Figure 6). The superior trapezius has limited reach but is also superiorly based, making if favorably located for some defects in the head and neck, particularly lateral and posterior defects. It has the added benefit of not being gravity dependent, which is not the case for most regional pedicled flaps used in head and neck reconstruction.   (Table 1). We stress the importance of having proficiency with these flaps thereby ensuring the surgeon's possession of a full "reconstructive toolbox," particularly for large-sized salvage setting defects.