Managing challenging oral cases in dogs: part I (Proceedings)
The presentation will review the recognition and treatment of both congenital and acquired palatal defects as well as the management of mandibular fractures utilizing interdental splints.
Two basic techniques for the repair of palatal defects are most commonly utilized. The first technique involves removal of the epithelium from the edges of the defect and complete periosteal elevation of the palatine mucosa bilaterally on each side of the cleft. Bilateral releasing incisions are made along the upper dental arcade to permit apposition of the edges of the midline defect. The overlapping flap technique, the second basic technique, is preferred by most surgeons because there is less tension on the suture line, the suture line is not located directly over the defect, and the area of opposing connective tissue is larger which results in a stronger scar. The need for releasing incisions is also unnecessary in most cases with the overlapping flap technique.
The overlapping flap technique is performed by creating two mucoperiosteal flaps. One flap is hinged at the end of the palatal defect and is turned beneath the other flap. Vest-over-pants type sutures of synthetic absorbable suture material are utilized to maintain the connective tissue surfaces of both flaps in apposition. This technique provides a wide area of connective tissue contact without tension.Cleft soft palatal defects are repaired using a double flap technique in which incisions are made along the medial margin of the palatal cleft on each side. A small scissors is utilized to divide the palatal tissue into a dorsal and ventral component. The two dorsal flaps are sutured together using absorbable suture material in a simple interrupted pattern with the knots located intranasally. The two ventral flaps are sutured using a similar material and pattern with the knots located intraorally. The edge of the repaired soft palate should reach the midpoint or caudal end of the tonsils and oppose the tip of the epiglottis when the tongue is in normal position.
Acquired palatal defects that have etiologies other than dental disease are usually located in the hard palate. These acquired palatal defects are caused by various types of trauma including dog bites, blunt head trauma, electrical shock, gunshot wounds, foreign body penetration and pressure necrosis. The acute inflammatory reaction and the overall clinical status of the patient with acute trauma should be managed prior to surgical correction of the palatal defect. Various surgical techniques can be utilized to repair acquired palatal defects including buccal flaps, rotation flaps, advancement flaps, tongue flaps, split palatal U-flaps and island flaps. The technique selected for repair of an acquired palatal defect depends on the location of the defect. In general the technique that will provide the largest flap with no tension is recommended.
Buccal flaps can be utilized to repair defects associated with oronasal fistulas secondary to periodontal disease. The edges of the defect are debrided to remove all of the epithelial margins of the palatal defect and divergent incisions are made mesial and distal to the defect through the gingiva, mucogingival line and alveolar mucosa. The periosteal layer of the flap is incised on the inner layer of the flap to release the tension on the flap prior to closure.
Rotation flaps are recommended for small circular defects especially defects located lateral to the midline. Large caudal defects that cross the midline can be repaired using an advancement flap. The defect is repaired by excising a thin section of mucosa from the perimeter of the defect and then creating a large mucoperiosteal flap caudal to the defect, incising the periosteal layer of the flap caudally, advancing the flap rostrally and suturing the flap over the defect with monofilament absorbable suture material in a simple interrupted pattern.
Tongue flaps may be used to repair large rostral palatal defects. The edges of the dorsal aspect of the tongue are excised and apposed to the debrided edges of the palatal defect. Approximately four weeks later the tongue is separated from the palate leaving enough tongue with the palate to close the defect without tension. Alternative techniques to tongue flaps are recommended whenever possible because of the high incidence of dehiscence associated with tongue flaps.
The split palatal U-flap can be used to repair acquired hard palatal defects located in the caudal hard palate. The edges of the palatal defect are debrided and a large U-shaped flap is created rostral to the defect. The major palatine arteries should be preserved during the creation of the U-flap. The U-flap is divided on the midline. One side of the U-flap is rotated 90 degrees into the defect and sutured in place. The second side of the U-flap is rotated 90 degrees and sutured to the previously rotated flap. The site from which the U-flap is harvested fills with granulation tissue and will be covered with epithelium in 4-8 weeks.