Originally published in the August 2015 issue of Veterinary Practice News. Cleft palate surgeries are one of my favorite procedures in dentistry and oral surgery. Maybe it is because the opportunity to see a puppy amidst a predominately geriatric patient population. Perhaps it’s because every cleft palate is just a little bit different than the previous one. The most likely reason is the exhilaration and challenge of repairing a defect that has already had three (or more!) attempts at repair prior to presenting to a specialist. © 2009, John Lewis, University of Pennsylvania. Figure 1A: Bilateral cleft lip in a 7-month-old pit bull. Figure1B: Bilateral clefts of the primary palate in the same dog. Terminology Defects of the primary palate occur from a lack of fusion of the developing incisive bone to the palatine process of the maxilla and/or defects of development of the soft-tissue structures of the upper lip. These defects are often extending from the midline incisive papilla, radiating rostrolaterally, unilaterally or bilaterally (Figure 1A and 1B). Unilateral cleft-lip defects in dogs occur more commonly on the left side, which is also true in people. Defects of the secondary palate involve a cleft of the hard palate behind the incisive papilla and continue caudally to include the soft palate. Repair: Golden Rules Clefts of the lip are mainly a cosmetic concern, and therefore, they may not require repair. Clefts of the rostral hard palate may result in rhinitis. Clefts of the primary palate are unlikely to cause aspiration pneumonia. Clefts of the secondary palate have the potential to cause both rhinitis and aspiration pneumonia. Usually, a cleft of the hard palate at this level, invariably, includes a cleft of the soft palate to its caudal-most extent. There are many golden rules associated with cleft palate repair. The first attempt is often the best chance to get a repair. After the initial surgery, scar tissue formation and changes in blood supply may affect future options. Therefore, it is advisable to have an experienced palate surgeon do the first surgery. Gentle tissue handling is important. Use stay sutures to retract flaps rather than repeatedly grabbing on to the edges of a flap with thumb forceps. Raise large flaps for small defects, and raise really large flaps for large defects. Use double flaps for large defects when possible. Try to avoid having the suture line over a bony defect, especially with large defects. This is not always possible, but an overlapping flap technique is one example of a technique that allows the suture line to be supported by bone. Flap closure needs to be tension-free. This last tenet is far and away the most important aspect of a successful congenital palate repair. Tension can occur due to lack of appropriate undermining of the flap, but it can also occur due to tension placed on a flap by opposing teeth postoperatively. Therefore, it is important to consider what will happen to your flap after the animal is extubated and the mouth is in full closure. The two most common techniques for repair of a congenital midline hard palate defect are the overlapping-flap technique and the medially positioned double-flap technique, sometimes called the von Langenbeck technique. © 2014, John Lewis, NorthStar VETS. Figure 2A: Cleft of the secondary palate in a dog, beginning behind the incisive papilla. The dotted lines indicate the lines of cutting to create an overlapping flap. Figure 2B: The overlapping flap is rotated on its hinged attachment, taking with it the major palatine and accessory palatine arteries. The overlapping flap is tucked into a deep envelope incision on the opposite side of the defect to allow for sutures to be far from the bony defect. The exposed bone of the donor site will granulate and eventually fill with fibrous tissue. The overlapping flap technique utilizes an axial-pattern flap in the form of a large hinge of tissue raised on three sides, with the hinge attached just lateral to the defect. This allows for the tissue to be rotated on its hinge, which is then tucked into an envelope incision on the opposite side of the defect (Figure 2A and 2B). © 2012, Journal of Veterinary Dentistry, reprinted with permission. Figure 3A: Traumatic full-thickness midline defect of the hard and soft palate in a cat with high-rise syndrome. An axial-pattern flap is a flap that is centered over, and takes with it, a specific artery that runs in its long axis. The overlapping-flap technique utilizes the major palatine and accessory palatine arteries to allow for an excellent blood supply. The medially positioned double-flap technique utilizes bilateral releasing incisions just medial to the teeth and complete undermining of the flaps from the palatine process of the maxilla while keeping the major palatine and accessory palatine arteries intact and attached to the underside of the flap. With this technique, the edges of the congenital defect require scarification to allow for healing at the midline. © 2012, Journal of Veterinary Dentistry, reprinted with permission. Figure 3B: Medially positioned double flaps are raised from their periosteal attachments of the bone of the hard palate by careful use of a periosteal elevator. Care is taken to not transect the major palatine artery during elevation to avoid possible problems with blood supply to the medially positioned flaps. Figure 3C: Fresh edges are apposed with 5-0 poliglecaprone in a simple interrupted pattern. This technique is also used for traumatic midline hard-palate defects such as those seen in cats with high-rise syndrome (Figure 3A, 3B and 3C).1 With the medially positioned double flap, the sutures are directly over a bony defect. After the hard-palate defect is repaired, the soft-palate defect is closed by first incising along the defect to separate the dorsal and ventral soft-palate mucosal layers. The soft palate is then closed in two or three layers: dorsal layer of mucosa, ventral layer of mucosa, and plus or minus muscular-layer closure in between these layers. Surgery Timing Regarding timing of the surgery based on age of the patient: we try to allow puppies to grow to a size where soft tissue is more abundant. Repair of a congenital cleft is often done at 12 to 16 weeks of age. Sometimes there may be a benefit to waiting until later in life (after eruption of the permanent teeth) if adult teeth require extraction prior to raising a large-flap lateral to the permanent maxillary teeth.2 Given that adult teeth don’t erupt until 4 to 6 months of age, a staged procedure may require non-traumatic extraction of adult teeth at 6 months of age followed by the definitive repair approximately eight weeks later. References Bonner SE, Reiter AM, Lewis JR. “Orofacial manifestations of high-rise syndrome in cats: a retrospective study of 84 cases.” J Vet Dent. 2012; 29(1): 10-18. Peralta S, Nemec A, Fiani N, Verstraete FJ. “Staged double-layer closure of palatal defects in 6 dogs.” Vet Surg. 2015; 44(4): 423-431.
