What is an oroantral fistula?

Oroantral Fistula: Definition and Management

An oroantral fistula (OAF) is a pathological, epithelialized communication between the oral cavity and the maxillary sinus that forms when an oroantral communication fails to heal primarily and becomes epithelialized. 1

Etiology and Pathophysiology

Oroantral fistulas commonly result from:

• Dental extractions of posterior maxillary teeth (most common cause)
• Dental implant surgery complications
• Maxillary sinus floor elevation procedures
• Implant migration into the sinus
• Dental infections extending to the sinus
• Trauma or iatrogenic complications
• Cyst or tumor removal
• Radiation therapy sequelae 2, 1, 3

The risk is highest with maxillary molar extractions due to:

• Proximity of dental roots to the maxillary antrum
• Thinness of the antral floor in the posterior maxilla
• Communications larger than 5mm are less likely to heal spontaneously 3

Clinical Presentation

Patients with OAF typically present with:

• Passage of air and fluids between the oral cavity and maxillary sinus
• Nasal voice quality
• Escape of oral fluids into the nose when drinking
• Persistent or recurrent maxillary sinusitis
• Purulent discharge from the fistula
• Foul taste or odor
• Pain and tenderness in the affected area 2, 4

Diagnostic Approach

1. Clinical examination:

   • Visual inspection of the suspected fistula site
   • Valsalva maneuver (asking patient to blow gently through the nose while occluding nostrils)
   • Probing the area carefully to assess the communication

2. Imaging:

   • Computed tomography (CT) is the gold standard for confirming OAF and evaluating maxillary sinus involvement
   • Dental panoramic tomographs for assessing bony lesions
   • Endoscopic examination may be used to visualize the sinus side of the fistula 2

Complications

If left untreated, OAF can lead to:

• Chronic maxillary sinusitis
• Reactive sinusitis
• Sinus obliteration
• Spread of oral bacteria to the sinus
• Impaired quality of life due to persistent symptoms 2

Management Approach

1. Medical Management (First Priority)

For infected OAF, treatment of infection must precede surgical repair:

• Antibiotic therapy: Amoxicillin/clavulanic acid 1g three times daily with metronidazole 500mg three times daily, or levofloxacin 400mg twice daily for 7-10 days 2, 4
• Nasal decongestants and saline irrigation
• Avoidance of positive pressure activities (nose blowing, sneezing with closed mouth)
• Treatment of any underlying sinusitis 2, 4

2. Surgical Management

Once infection is controlled, surgical closure is indicated:

• Small fistulas (<2mm) may heal spontaneously with conservative management
• Larger fistulas require surgical intervention using various flap techniques:

Common Surgical Techniques:

1. Buccal advancement flap:

   • Advantages: Simple technique, good blood supply
   • Disadvantages: May reduce vestibular depth

2. Buccal fat pad flap:

   • Advantages: Excellent blood supply, high success rate, no effect on vestibular depth
   • Particularly effective when combined with endoscopic middle meatal antrostomy for maxillary sinus drainage 5

3. Palatal rotational flap:

   • Advantages: Excellent blood supply, keratinized tissue
   • Disadvantages: More technically demanding, donor site morbidity

4. Novel approaches:

   • Bone sandwich with resorbable guided tissue regeneration membrane
   • Platelet-rich fibrin techniques
   • Pedicled nasoseptal flap for challenging cases 3, 6

Treatment Algorithm

1. Assess and diagnose:

   • Confirm OAF through clinical examination and imaging
   • Evaluate size, location, and presence of infection

2. Control infection:

   • Prescribe appropriate antibiotics
   • Manage sinusitis if present
   • Consider endoscopic sinus drainage in persistent cases

3. Surgical closure:

   • Select appropriate technique based on:
     • Size of defect
     • Location
     • Available tissue
     • Surgeon expertise
   • Ensure tension-free closure with well-vascularized tissue

4. Follow-up:

   • Monitor for recurrence
   • Assess for persistent sinusitis
   • Evaluate need for further intervention 2, 4, 6

Key Considerations

• Early detection and management are crucial to prevent epithelialization and chronic fistula formation
• A multidisciplinary approach involving oral surgeons and otorhinolaryngologists may be necessary for complex cases
• Successful closure requires both management of sinus pathology and appropriate soft tissue coverage
• Patients with predisposing factors (thin sinus floor, periodontal disease) should be identified before dental procedures to minimize risk 2