Treatment Options for Oronasal Fistulae
Carlos A. Rice, DVM, DAVDC, Center for Animal Referral & Emergency Services, Langhorne, Pennsylvania
Oronasal fistulae can present with varying forms and causes, with chronic end-stage periodontitis being the most common cause (Figure 1). Oronasal fistulae are often associated with a diseased or missing maxillary tooth, but they can result from other congenital, traumatic, or neoplastic conditions affecting the primary and secondary palate.
Related Article: Inapparent Oronasal Fistula
FIGURE 1 The most common cause of oronasal fistula is chronic end-stage periodontitis. Image courtesy of Dr. Jan Bellows
An oronasal fistula may occur secondary to surgical extraction of a maxillary canine tooth. In these cases, excessive force placed on the crown causes medial tooth displacement, perforating the nasal surface of the alveolar bone (Figure 2). An oronasal fistula can also result from extraction of a diseased or missing incisor, premolar, or molar (Figure 3).
FIGURE 2 Surgically extracted maxillary canine tooth (note the small remaining piece of nasal alveolar bone [arrows])
FIGURE 3 Palatal defect associated with a previously extracted right maxillary third premolar (#107)
Image courtesy of Dr. Slava Eroshin
Affected patients often have a history of chronic rhinitis and present with ipsilateral mucopurulent or serohemorrhagic nasal discharge. Clinical signs often correlate positively with the defect’s size and location; larger and caudally located defects are typically most clinical.
Regardless of the cause, treatment often involves surgical intervention.
Related Article: Recurrent Nasal Infections in a Dachshund
Surgical Treatment
Before surgery, a complete oral examination (eg, tooth-by-tooth assessment with periodontal probe, full-mouth intraoral radiography) must be performed while the patient is under general anesthesia. Basic principles of oral surgery must be followed: awareness of surgical anatomy, fundamentals of flap design, creation of tension-free closure, selection of appropriate suture material (Figures 4 and 5).
FIGURE 4 Typical appearance of a chronic nonhealing oronasal fistula following extraction of a right maxillary canine tooth (#104) in a dog. Image courtesy of Dr. Jan Bellows
FIGURE 5 Chronic nonhealing oronasal fistula secondary to extraction of a left maxillary canine tooth (#204, A)
Related Article: Fractured Upper Canine Tooth
Nonsurgical Treatment
If the defect is not amenable to surgical management or previous surgical intervention has failed, a prosthetic palatal obturator can be considered. Palatal obturators can be obtained prefabricated and trimmed to fit the patient or can be custom made chairside with composite or acrylic (Figure 6).
FIGURE 6 A large congenital defect of the caudal hard palate was present in a young golden retriever (A). © Dr. Alexander M. Reiter
When to Refer
Scarring from previous surgery may result in less elastic tissue and compromised blood supply, potentially impairing healing after future surgeries; thus, the first attempt to close a palatal defect is typically the best one.
Because surgical treatment of most palatal defects is technique sensitive, palate surgery can prove challenging. Referral to a board-certified veterinary dentist and oral surgeon (avdc.org) should often be considered.