Oroantral Fistulas - Clinical Tree

Introduction

An oroantral communication occurs when there is an abnormal connection between the maxillary sinus and the oral cavity. The communication may be the result of trauma, osteomyelitis, pathologic lesions, or foreign bodies such as dental implants or endodontic material. However, the most common cause of an oroantral communication is the extraction of a posterior maxillary tooth. The root apices are in close proximity to the floor of the maxillary sinus and, in some cases, are only separated by a thin layer of lamellar bone or sinus mucosa. The teeth most commonly involved in communication are the maxillary molars. If left untreated, this communication can result in unsuccessful healing of the Schneiderian membrane and progress to an epithelial-lined tract known as an oroantral fistula, which will not heal spontaneously.

Closure of the fistula is dependent on the size of the bony defect. Healing may occur spontaneously if the defect is less than 5 mm in diameter. However, primary soft tissue closure at the time of the extraction and the use of a collagen plug stabilized with a figure-of-eight suture can promote clot formation and spontaneous healing of the defect. For defects greater than 5 mm, closure using various intraoral flaps in conjunction with functional endoscopic sinus surgery increases the chance for long-term success.

Key Operative Learning Points

1.
Extraction of a posterior maxillary molar tooth is the most common cause of an oroantral fistula.
2.
Long-term success in healing requires débridement of necrotic bone, soft tissue, and the fistulous tract.
3.
Crossing the buccal vestibule with a flap can obliterate the sulcus and interfere with denture use.
4.
Fabrication of an acrylic splint can protect the flap and palate.

Preoperative Period

History

1.
History of present illness
- a.
  Presence of a communication or fistula can be confirmed by asking the patient if regurgitation of fluid from the nose occurs after drinking liquids.
- b.
  Fetid odor/drainage due to oroantral communication
- c.
  Chronic pain from the defect
2.
Past medical history
- a.
  History of chronic sinusitis
3.
Past surgical history
- a.
  Previous attempts at closure of the oroantral fistula
4.
Medications
- a.
  Antibiotics
- b.
  Antiplatelet agents
- c.
  Anticoagulant therapy
- d.
  Immune suppression
- e.
  Over-the-counter (OTC)/herbal medications
5.
Allergies
6.
Social history
- a.
  Alcohol use/abuse
- b.
  Cigarette smoking
- c.
  Illicit drug use/abuse

Physical Examination

1.
Oral and nasal examination may reveal erythema of the mucosa, intraoral or intranasal infection, oralantral fistula, or a compromised ostiomeatal complex ( Fig. 105.5 ).

Imaging

1.
Panorex ( Fig. 105.1 )
- a.
  First choice of radiograph, especially if the fistula occurred after dental extraction(s)
- b.
  Assess the size of the bony defect adjacent to the fistula.
- c.
  Assists in treatment planning and flap design, since there is no scatter from any existing maxillary dental restorations
2.
Computed tomography (CT) scan (maxillofacial or sinuses; Fig. 105.2 )
- a.
  Not necessary as a first-line choice of imaging
- b.
  Recommended with larger defects (>1 cm) or cases of chronic fistula from repeated failure of fistula closure
- c.
  Assess for mucosal thickening, maxillary opacification, and obstruction of the ostiomeatal complex.
- d.
  Intrasinus injections or oral rinse with water-soluble contrast may further enhance the imaging by providing the surgeon with a better understanding of the oroantral fistula’s path between the oral cavity and antrum.

Indications

1.
Nasal regurgitation of liquids through fistula
2.
Foul odor or chronic purulent drainage from the fistula
3.
Air leakage through the fistula
4.
Chronic pain in the fistulous site

Contraindications

1.
Acute oral infection or acute maxillary sinusitis
2.
Medically unstable for anesthesia or surgery (immune compromised, severely malnourished)
3.
Multiple failures with no further tissue options available to close the defect (patient may require prosthesis/obturator to cover the defect)
4.
Patient is unable to consent or declines surgical repair

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