Oroantral communication and fistula are commonly seen complications in the field of oral and maxillofacial surgery. Oral surgeons must be familiar with the diagnosis and proper management including multiple soft and hard tissue approaches to this surgical dilemma.
Clinical diagnosis of oral antral communication.
Xenografts also make important role in the treatment of chronic oral antral communications.
One of the most encountered complications by oral and maxillofacial surgeons is oroantral communications (OACs). OAC is an unnatural opening between the maxillary sinus and the oral cavity. These complications occur most frequently following odontectomy of maxillary premolars and molars due to the close proximity of the roots within the maxillary sinus. Other common causes include tuberosity fracture following maxillary posterior teeth extractions, implant dislodgement, dehiscence following implant failure, pathologic lesions within the maxillary sinus, maxillary tumor or cyst enucleation, and a Caldwell-Luc procedure complication. Procedures involving the posterior maxilla with a pneumatized maxillary sinus, preexisting acute or chronic sinusitis, and traumatic extractions of teeth with large divergent roots can impose a high risk leading to the development an OAC. Existing literature reported a more frequent occurrence of OAC in male populations than in female populations largely due to a higher frequency of traumatic odontectomy in men.
Maxillary sinuses and maxillary posterior teeth
The maxillary sinus is a quadrangular pyramid with its roof housing the floor of the orbit and floor contributing to the alveolar process of posterior maxilla. The volume can expand from 6 mL at birth up to 15 mL during adulthood, and sinus pneumatization occurs with advancing age. The maxillary sinus is innervated by the anterior superior, middle, and posterior superior alveolar nerves, all of which are the terminal nerves of the maxillary branch from the trigeminal nerve. It receives blood supplies from the anterior, middle, and posterior superior alveolar arteries, all of which are branches of the maxillary artery from the external carotid artery. , The maxillary sinus is lined by a pseudostratified ciliated columnar epithelium of 0.8 mm thickness called the schneiderian membrane. It is the inflammation of this membrane that causes acute or chronic sinusitis, which is a typical pathology that OAC is capable of progressing to.
To better understand the etiology of OAC, it is important to fully grasp the spatial relations of maxillary posterior teeth apices to the maxillary sinus floor. The antral floor communicates with the roots of the maxillary first and second M with an incidence of 40%. The palatal roots of those teeth are 50% closer to the sinus floor than they are to the palate. The apex of the mesiobuccal root of the maxillary second M was the closest to the antral floor with a mean distance of 0.83 mm, whereas the apex of the palatal root of the maxillary first premolar remains the farthest away with a mean distance of 7.05 mm ( Table 1 ). The distance from the root apices from maxillary third molars to the floor of the maxillary sinus is rather difficult to determine due to various patterns of impactions. Hasegawa and colleagues formulated the 5 types of root-to-sinus (RS) classifications ( Fig. 1 ) and reported that the extraction of a mesioangular maxillary third molar with a type 3 RS classification imposes a higher risk of OAC.
|Buccal 1st premolar||6.18||1.60|
|Lingual 1st premolar||7.05||1.92|
|Mesiobuccal 1st molar||2.82||0.59|
|Palatal 1st molar||1.56||0.77|
|Distalbuccal 1st molar||2.79||1.13|
|Mesiobuccal 2nd molar||0.83||0.49|
|Palatal 2nd molar||2.04||1.19|
|Distalbuccal 2nd molar||1.97||1.21|
When an OAC fails to spontaneously close and persists for more than 48 hours, patients are at risk of developing an oroantral fistula (OAF). An OAF occurs as the migration of oral epithelium into the defect, resulting in a permanent epithelialized tract between the maxillary sinus and the oral cavity. The persistent communication allows allergens and bacteria to cause the inflammation of the schneiderian membrane, leading to the obstruction of the maxillary sinus ostia through which the fluid is drained into the middle meatus. The accumulation of stagnant sinus secretions in a hypoxic environment causes acute or chronic sinusitis. Iatrogenic causes account for 55.97% of incidents of odontogenic maxillary sinusitis (OMS), whereas other possible etiologies include periodontitis (40.38%) and odontogenic cysts (6.66%). The leading cause for an iatrogenic OAF is extractions (47.56%), followed by extrusion of endodontic obturation materials (22.27%), dressings or foreign bodies (19.72%), amalgam remains after apicoectomies (5.33%), maxillary sinus lift procedures (4.17%), and poorly positioned dental implants (4.17%).
Common clinical manifestations of maxillary sinusitis include nasal congestion, nasal discharge, midface pressure, pain, and headache. Acute maxillary sinusitis usually resolves within 2 weeks with an initial presentation of fever, malaise, facial swelling, and pain when bending forward. Unlike the typical Streptococcus pneumoniae , Haemophilus influenzae , and Moraxella catarrhalis found in acute sinusitis of nonodontogenic origin, the most common bacterial pathogens in odontogenic acute sinusitis include the aerobic S pneumoniae and Staphylococcus aureus, as well as the anaerobic gram-negative bacilli, Peptostreptococcus spp, and Fusobacterium spp . Chronic maxillary sinusitis usually lasts more than 4 weeks with symptoms of postnasal drainage, halitosis, and diminished sense of taste and smell. The predominant pathogens in odontogenic chronic maxillary sinusitis involve a mixture of aerobic and anaerobic bacteria similar to those found in odontogenic acute sinusitis. When sinusitis is diagnosed following an OAC or OAF, the empiric choice of antibiotics should be Augmentin 875 mg twice daily, Clindamycin 300 mg 4 times daily, or Moxifloxacin 400 mg once daily for at least 10 days, depending on the resistance pattern. Culture and sensitive tests should be performed if purulent discharge is noticed. Patients also should be treated with normal saline irrigation, nasal decongestant, antihistamines, and steroids to improve clinical symptoms. If medical attempts fail, surgical options such as a functional endoscopic sinus surgery or Caldwell-Luc antrostomy should be considered to achieve proper drainage of the maxillary sinuses. Attempting an OAC closure without addressing the chronic maxillary sinusitis is a futile effort.
Clinical diagnosis of OAC is usually based on both subjective and objective findings. Patients with an OAC/OAF can be asymptomatic, but most complain of altered nasal resonance, nasal regurgitation of liquid, foul intraoral smelling, whistling sound while speaking, and symptoms associated with sinusitis. A fistula at posterior maxilla can easily be visualized ( Fig. 2 A). A Valsalva test can be used by instructing the patient to gently expel air against closed nostrils while remaining the mouth open. The passage of air or blood at the postoperative site usually indicates the presence of an OAC/OAF. Fogging of a mouth mirror placed at the orifice can also confirm the clinical diagnosis. The formation of an antral polyp can be visualized through the defect at a later stage. A panoramic radiograph and a computed tomography scan can determine the exact location and size of the defect as well as the degree of sinus involvement ( Fig. 2 B, C). Depending on the location of the communication at the maxillary alveolar ridge, OAF/OAC can be further divided into alveolo-sinusal, palatal-sinusal, and vestibulo-sinusal. ,
Treatment options for an oroantral communication/oroantral fistula
Decisions on how to treat an OAC/OAF are based on the size of the defect, the time of diagnosis, the presence of sinus infection, the amount and condition of tissue available for repair, as well as the future restorative treatment plan at the site of defect. It is suggested in the literature that an OAC should be closed within 24 hours, as the longer the communication persists, the more likely one is to sustain an OMS. Maxillary sinusitis should be treated either medically or surgically first before the communication is repaired to avoid impaired drainage. Most OACs are able to close spontaneously if the diameter is less than 2 mm in patients with healthy maxillary sinuses. When the diameter of the defect is between 2 and 5 mm, a gel foam can be placed and secured with figure-of-8 sutures within the defect. Regular follow-ups are recommended to ensure that the communication does not persist. Surgical repair of OACs/OAFs are indicated when the diameter of opening is more than 5 mm, as a defect of this size does not tend to close spontaneously. Multiple closure techniques have been described throughout the years. According to the classification of Visscher and colleagues, treatment modalities of OAC/OAF have been categorized into autogenous soft tissue grafts, autogenous bone grafts, allogeneic materials, xenografts, synthetic closure, and other techniques ( Figs. 3–10 ). , , An important point to remember based on the opinion from the most senior author (Dr Harry Dym) of this article is to remove all the granulation tissues from the OAC before attempting any definitive closure technique.