12.2.1 Repair Techniques for the Palate

When palatal defects disrupt the separation of the oral and nasal cavities, proper surgical techniques are essential for reconstruction. Surgical sites can be under constant stress due to the relative inelasticity of palatal mucosa and constant movement from both respiratory efforts and constant movement of the tongue. Two goals in flap design include tension‐free flaps and the incorporation of an adequate blood supply. All tissue edges and any intact epithelial surface in the surgical field should be freshly debrided. Any flap design should be at least 1.5–2 times the size or width of the defect to be covered to allow for contracture of tissue, and sutures should not lie directly over the defect.

12.2.2 Congenital Defects

Primary and secondary palatal cleft (with accompanying lesions) are some of the more common defects seen in newborn puppies. Some advocate surgical repair by six to eight weeks of age, with any delay contraindicated as the defect is likely to get larger [5]. Other guidelines recommend supporting the patient with alternate feeding (orogastric tubes) until they reach 8–12 weeks of age [6]. Surgery can interfere with the growth of the palatal and maxillary tissues if performed any time prior to 16 weeks of age [7]. Custom‐made nursing teats have proven successful in research‐based puppies, with removable, flexible prosthetic plugs placed at the time of weaning [8]. In one case, the patient was maintained on dry kibble and a suspended water bottle and surgery was performed finally at 14 months of age, at which time the defect had partially closed spontaneously [6]. Additional craniomaxillofacial abnormalities are often seen in these patients, and the extent of the osseous lesion is often greater than the soft tissue defect and is hidden [9].

A number of defects can also be seen in the soft palate, with or without hard palate involvement [10]. These could include an extension of a secondary cleft to an asymmetric unilateral defect, or bilateral soft palate hypoplasia [11]. With unilateral hypoplasia, two‐ or three‐layer appositional repair with ipsilateral tonsillectomy may be adequate if there is minimal tension at closure. In bilateral hypoplasia, where the small caudal portion on the midline looks like a uvula, repair of one side can be followed with repair of the other side four to six weeks later. However, if there is considerable tension, then a nasopharyngeal mucosal flap may be needed [11]. Sager describes using two buccal mucosal flaps, each based on a palatoglossal arch (harvested rostrally – finger shaped), with the first positioned and sutured so its mucosa faces the nasal cavity and the second rotated for its mucosa to face the oral cavity [12]. In a feline case, one flap from the hard palatal mucosa and two lateral pharyngeal flaps were required [13]. A similar case in a dog with bilateral hypoplasia and no pseudouvula utilized an initial split thickness hinged soft palate flap. When released, the flap expanded the length of the palate caudally. Bilateral U‐shaped rotational flaps from the adjacent buccal mucosa were placed over the opened palatal flap, with less tension than a pharyngeal flap would have caused [14]. If full function cannot be returned, treatment for palatal hypoplasia may be reconsidered [15].

Nasopharyngeal stenosis due to dysplasia of the palatopharyngeal muscles in the Dachshund is not amenable to surgery in most cases [16, 17]. In one case of nasopharyngeal stenosis due to soft palate dysplasia, the caudal portion adhered dorsally to the pharyngeal mucosa, and anti‐inflammatory medication decreased the edema sufficiently to relieve the dyspnea [18]. In a separate feline case, a mucosal flap for correction and release of the laryngeal webbing avoided the complication of recurrence that has been seen in other cases [19].

By far the most common soft palate defect is an extension of a secondary cleft into the hard palate. If the defect is small to moderate in size, and the two edges can be gently apposed without extensive tension, then a simple two‐ or three‐layer closure may be sufficient [10, 20]. Once the edges are excised, the nasal mucosa should be sutured from a caudal to rostral direction in a simple interrupted pattern with the knots facing the nasal cavity. While some elect not to close the muscle layer to minimize suture material, a continuous pattern can provide additional closure. The final oral mucosa layer is then closed, with knots facing the oral cavity. Tension‐releasing incisions may be made laterally and the tissues can be separated from the pterygoid hamulus.

The more complicated bilateral overlapping mucosal single‐pedicle flaps may be performed if simple closure would result in excessive tension [21]. On one side of the defect, a mucosal flap is harvested with an initial incision 5 mm away from the defect edge, for the length of the defect (Figure 12.1a). Two incisions are made to the midline at the caudal and rostral edges of the initial incision. The oral mucosa is undermined to harvest a flap that will be “flipped” on the hinge formed by the edge of the defect on that side. This flap is positioned dorsal to the soft palate on the other side of the defect, with the mucosa facing the nasal cavity (Figure 12.1b). The mucosal flap on the other side is harvested in a similar manner from the nasal aspect of the tissue, and when undermined and opened and flipped, will be placed on the ventral aspect of the two flaps, with the mucosa facing the oral cavity (Figure 12.1c). The initial flap can be sutured to the lateral‐most aspect of the second flap harvest site to secure the mucosa facing the nasal cavity. The second flap is also sutured to secure its edge facing the oral cavity (Figure 12.1d). This technique was successful in a number of cases with suture lines placed away from the defect and tissue closure over the harvest sites [21].

Elongated soft palates are a common finding in brachycephalic breeds, along with a combination of lesions including stenotic nares, everted tonsils, and laryngeal ventricles, known as Brachycephalic Airway Obstruction Syndrome (BAOS) [22–25]. Correction of an elongated soft palate may be accomplished with cold steel (scissors), electrocautery, low‐temperature, high‐frequency radiotherapy [26], carbon dioxide laser, a bipolar sealing device, or harmonic scalpel. In one study, a CO₂ laser and electrocautery had favorable outcomes, with the laser having a shorter surgical time and less bleeding, while diode laser therapy had more complications [27]. The bipolar sealing device provides firm compression and electrothermal energy that is feedback controlled, without the safety precautions necessary for laser devices [28]. The ultrasonic motion of the blades of the harmonic scalpel are purported to cause less post‐operative pain and swelling, and a decrease in bleeding [29].

No matter what method is used, the basic approach is similar: using lateral stay sutures caudal to the level of the tonsils, retracting the tissue carefully, and resecting enough so the new edge will be positioned just caudal to the epiglottis. With scissors, a cut is made a third of the way across at a time, closing the nasopharyngeal and oropharyngeal mucosal layers for each section, but not incorporating the muscle layer [14]. Crushing the tissues may cause excessive edema and improper use of electrocautery can be damaging.