The buccal fat pad flap

Introduction

Cleft palate repair poses challenges to the reconstructive surgeon that must be overcome to achieve a durable and functional closure. The paucity of available palatal tissue and the inability to recruit additional local tissue frequently demand the surgeon make certain compromises to reliably close the defect. In the hard palate, the lateral gutter(s) that are created from medial movement of the palatal flaps are commonly left open with exposed maxilla, increasing the risk of maxillary growth restriction. In the soft palate, recruitment of tissue to close wide defects may be detrimental to palatal length due to the finite amount of available tissue, which can negatively impact speech. Finally, when a repair fails and a fistula forms, there is less available unscarred tissue to achieve durable closure.

To address these concerns, the buccal fat pad flap technique can be utilized during primary palatoplasty or palatal fistula repair. The buccal fat pad flap is a robust vascularized adipose flap that can reach the majority of the hard and soft palate. It requires limited additional dissection during harvest and results in minimal donor site morbidity. Although it has only been used for cleft palate repair in the last decade, it has rapidly become a valuable adjunct to bolster palate closure, help prevent fistula formation, minimize scar contracture, and the authors believe its use will decrease growth restriction.

History

The buccal fat pad was first identified in 1727 by Dr. Lorenz Heister (1683–1758). Commonly considered the father of modern German surgery, his principal work, Compendium Anatomicum , identified a structure that he named the glandula molaris or molar gland. Later, the French surgeon Marie François Xavier Bichat (1771–1802) expanded upon the work of Heister, correctly identifying the fatty nature of this tissue. In Anatomie Générale appliquée à la Physiologie et à la Médecine , he described a “greasy ball” between the masseter and the buccinator muscles, which he believed played an important role in the prominent shape of the cheeks. This seminal description of the buccal fat pad produced the eponymous name, Boule de Bichat . The pad was also renamed Sangpolster by Ranke in 1884, which means “sucking cushion”. He believed the pad’s large size in infancy prevented collapse of the cheeks during suckling, and it also served as a gliding plane between overlapping muscle layers.

Contemporarily, the buccal fat pad has renewed interest in both reconstructive and aesthetic surgery. The first description of its operative use was in 1977, when Egyedi detailed use of a pedicled buccal fat pad covered with a split-thickness skin graft to close oronasal and oroantral fistulae following oncologic resections. Neder similarly described its use as a free graft for oral defects in 1983. Utility of the flap was expanded once it was determined that a fat pad flap could be left unlined in the oral cavity and would spontaneously mucosalize within 1–4 weeks. Excision of buccal fat lipodystrophy for facial aesthetics was first performed by Dr. Leonard Epstein in 1980. Since that time, anatomic study and techniques for aesthetic buccal fat pad excision have rapidly expanded.

Considering its success in oral and palatal reconstruction, use of the buccal fat pad flap was expanded to oronasal fistula repair in cleft palate patients. More recently, Buchman and colleagues at the University of Michigan have published multiple reports describing the buccal fat pad flap as a valuable tool in primary cleft palate repair. Subsequently, other publications have confirmed similar success using the technique.

Anatomy

The buccal fat pad occupies a complex three-dimensional space in the deep midface, nestled between the lateral maxilla and mandibular ramus ( Fig. 21.5.1 ). It is a “syssarcosis”, meaning a specialized tissue that enhances intermuscular motion in the cheek. Cadaveric studies have described it as having a central body with four extensions: buccal, pterygoid, deep temporal, and superficial temporal. Pessa and Rohrich more recently described the buccal fat as having inferior, middle, and superior lobes. Although it is called buccal fat, these broad extensions beyond the cheek prompted Stuzin and Baker to suggest that the name “buccal fat pad” is a misnomer.

The largest and most superficial lobule is the buccal extension, or inferior lobe. This portion fills the cheek lateral to the molar region and is what is most commonly utilized for a buccal fat pad flap or buccal lipectomy. It is also the largest lobe, occupying 30%–40% of the total weight of the buccal fat. The buccal extension sits just superficial to the buccinator muscle and is bordered anteriorly by the facial vessels. The lateral border is the anterior edge of the masseter muscle. The buccal extension is separated from the central body, or middle lobe, by the parotid duct. The parotid duct runs along the superficial surface of the pad and pierces the buccinator muscle just anterior to the buccal fat to enter the mouth. The main body sits just superior to the buccal extension and fills the space lateral to the maxilla and beneath the zygoma. The pterygoid extension is the deepest lobe of the buccal fat and wraps around the lateral surface of the maxilla and extends to the pterygoid plates. It fills the space between the pterygoid muscles and creates a smooth gliding plane. This space also occupies the deep surface of the mandibular ramus and protects the mandibular neurovascular bundle as it enters the mandibular canal. The deep temporal extension of the fat pad extends cephalad from the central body and passes deep to the zygomatic arch to rest on the temporalis muscle and its tendinous insertion on the coronoid. The fourth extension that was originally described is known as the superficial temporal extension. More recent studies now consider the superficial temporal fat pad anatomically distinct from the buccal fat pad.

The buccal fat pad is an encapsulated structure, covered on both its superficial and deep surfaces by leaflets of fascia. As the parotid–masseteric fascia extends anteriorly beyond the masseter muscle, it splits around the buccal fat pad. The buccal fat pad also is bound to multiple retaining ligaments attaching to the maxilla, posterior zygoma, orbital fissure, temporalis tendon, and superficial musculo-aponeurotic system (SMAS). Vascular supply to the buccal fat pad is from three sources: buccal and deep temporal branches of the maxillary artery, transverse facial branch of the superficial temporal artery, and direct branches of the facial artery. The parotid duct is intimately associated with the buccal fat pad. It courses over the superficial surface of the fat pad between the central body and buccal extension before it enters the mouth just anterior to the fat pad. Finally, multiple buccal and zygomatic branches of the facial nerve course anterior to the buccal fat en route to innervate the facial mimetic muscles on their deep surfaces.

In contrast to early anatomic reports, the buccal fat pad volume stays consistent throughout one’s life. Loukas et al . evaluated the volumetric variation of the buccal fat pad through computed tomography (CT) and magnetic resonance imaging (MRI) of formalin fixed cadaveric heads. The mean volume in males was 10.2 mL (7.8–11.2 mL), while in females the mean volume was 8.9 mL (7.2–10.8 mL). Mean thickness was 6 mm with a mean weight of 9.7 g.