The esthetic and functional demands of maxillofacial reconstruction have driven the evolution of an array of options. The palatal flap offers a technically simple and predictable option for intraoral reconstruction. Moreover, the palatal island flap is the only available flap that can provide keratinized mucosa for defect reconstruction. Patients usually encounter minimal postoperative morbidity, and should expect a rapid return to a normal diet. Although the palatal flap cannot serve as a panacea for most intraoral reconstruction, it provides the reconstructive surgeon with a great armamentarium.

Keywords

Palatal rotation-advancement flap

Palatal island flap

Reconstruction

Treatment

Defect

Key points

Introduction

The esthetic and functional demands of maxillofacial reconstruction have driven the evolution of an array of options. Among the various options, it is important that selection takes into account what is most reliable and safest for the patient. Maxillofacial reconstruction can involve local tissue rearrangement and regional flaps. The closer the flap donor site is to the defect, the less morbidity is associated with the reconstructive surgery. Flaps from local tissue also carry the advantages of having similar color and texture. Therefore, the palatal island flap remains popular in reconstructing intraoral defects; moreover, the palatal island flap is the only available flap that can provide keratinized mucosa for defect reconstruction.

The palatal flap was initially described in 1922 by Victor Veau1 to address oronasal fistulas associated with cleft repair. It was later popularized by Millard2 for palatal lengthening during cleft repair in the 1960s; however, it was Gullane and Arena3 who used the flap for postablative defects. The versatility of the palatal island flap led to its widespread use in the 1970s and 1980s; several modifications have been proposed to expand its indications and improve donor site morbidity. Early publications have focused on its use in cleft repair and the closure of oroantral fistulas. Recent publications have shifted the focus to postablative reconstruction, either by itself or together with other flaps.4

Anatomy

The palatal mucosa is strongly adhered to the underlying periosteum, which is subsequently attached to the bone via fibrous tissue pegs known as Sharpey fibers. The osteology of the hard palate is comprised of the palatine process of the maxilla, separated from the horizontal palatal lamina of the palatine bones by a transverse suture. A longitudinal suture separates the maxilla in the midline; the palatal aponeurosis attaches to the posterior margin of the hard palate and is continuous with the tensor veli palatini laterally. The tensor veli palatine muscle arises from the lateral wall of the eustachian tube cartilage, and between the sphenoid spine/scaphoid fossa, before coursing at a right angle anterior to the hamulus to attach to the aponeurosis. The levator veli palatine muscle also meets in the midline, with fibers inserting into the palatine aponeurosis.

The blood supply arises from the greater palatine foramen adjacent to the maxillary second molar, where the transverse suture divides the maxillary and palatal shelves. The descending palatal artery emerges as the greater palatine artery after its exit from the foramen. It eventually anastomoses anteriorly with the nasopalatine branch of the sphenopalatine artery. A rich anastomotic network exists between the right and left greater palatine arteries, exiting across the midline longitudinal raphe. This network, which courses within the mucosa, submucosa, and periosteum, is referred to as a “trilaminar macronet.”5 As a result of this dense network, the entire hard palate mucosa can be elevated on a single neurovascular pedicle. Posteriorly, greater palatine artery also demonstrates a great vascular network with the ascending pharyngeal artery in the soft palate.6 This rich vascular network allows the flap to be raised as a random flap even in the case of greater palatine artery ligation.7 With regard to drainage, the veins empty into the pterygoid or pharyngeal venous plexus.

Indications and contraindications

The defect location and size determine the available reconstructive options. As an axial flap, the palatal flap is limited in the extent of its range; however, it has been applied to oropharyngeal defects, which include the retromolar trigone,8 soft palate,9,10 tonsillar fossa,11 cheek,12,13 posterior one-third of the floor of the mouth,14,15 and oronasal and oroantral fistula closures.16–21 With regard to defect size, up to 75% of the palatal mucosa may be used, allowing defects of up to 16 cm2 to be closed.22 However, when harvested as a random flap, the palatal flap is more suitable for oral-antral/nasal communication. Because of the less reliable vascular blood supply, a palatal flap harvested in a random pattern should not cross the midline and maintain the length/width ratio at less than 2.4:1.7

The flap is contraindicated whenever there is concern for a compromised blood supply. This may result from a history of ipsilateral internal carotid artery ligation, surgeries with adjacent incisions, or radiation therapy, which have been shown to increase the risk of flap failure.3 Although prior histories of vessel ligation or palatal surgery are uncommon, radiation to the palate is commonly encountered in patients with oropharyngeal cancer. Additionally, in children less than 5 years of age, concerns regarding iatrogenic midface growth restriction limit its use.4

Technique

The patient is prepared and draped in regular oral and maxillofacial surgical fashion. Oral intubation with the placement of a Dingmen retractor is usually recommended to facilitate the surgery. Important flap landmarks include (1) palatal gingival crest, (2) greater palatal foremen (palatal to the maxillary second molar), (3) boundary between hard and soft palate, and (4) hamular notch.

The flap design begins after confirming the dimensions of the defect. The anterior region of the flap should be slightly wider than the defect, and the length should allow for a tension-free closure. A template can be trimmed to the dimensions of the defect to help with flap design, whereas the lateral incision is made approximately 5 mm from the gingival margins of the teeth, if present (Figs. 1 and 2). After full-thickness incisions are made through the mucoperiosteum, flap dissection proceeds from anterior to posterior, working toward the neurovascular bundle ipsilateral side, and requires ligation of the contralateral neurovascular bundle in addition to the incisal canal (Fig. 3). After raising the flap, the neurovascular bundle is dissected carefully from the undersurface of the proximal portion of the flap. The dissection continues until the distal portion of the flap being used for the defect is encountered. Finally, the mucosa is transected above the bundle, allowing for and leaving the remaining distal end of the mucosa attached to the bundle. The bundle may be tunneled under adjacent mucosa before reaching the intended defect; however, care must be taken to ensure there is no compression (Fig. 4). Alternatively, the pedicle can cross over the normal palatal tissue before reaching the reconstruction site. This alternative requires second-stage surgery, which can be undertaken approximately 3 weeks later.13