How To: Multilayered Closure of Oronasal and Oroantral Fistula Using Intranasal and Intraoral Flaps

Surgical Technique

Nasoseptal Flap. Initially, the ipsilateral middle turbinate is lateralized, exposing the superior turbinate and posterior septum (Laryngoscope. 2006;116:1882–1886). The natural ostium of the sphenoid sinus is identified posterior to the inferior one-third of the superior turbinate. The flap is harvested using a needle-tip monopolar cautery. The superior cut is made along the posterior septum starting at the level of the sphenoid ostium. Special attention is taken to preserve the olfactory strip superiorly. Depending on the size of the fistula, the flap can be extended anteriorly to the mucocutaneous junction and superiorly to the superior nasal vault. The inferior incision is made immediately above the choana and carried anteriorly to join the previously made anterior incision. Similarly, the flap can be carried laterally off the septum and onto the nasal floor, and even to the inferolateral nasal wall (J Neurol Surg Part B: Skull Base. 2013;74:369–385). Once the perimeter of the flap has been incised, a blunt instrument such as a Freer elevator is utilized to elevate it both off the septum and nasal floor in the submucoperichondrial and submucoperiosteal plane, and stored for later use in the nasopharynx.

Lateral Nasal Wall Flap. An incision is made at the piriform aperture along the ipsilateral mucocutaneous junction and a submucoperiosteal plane elevated along the superior lateral nasal wall, inferior turbinate, and nasal floor, depending on the size of the defect (Int Forum Allergy Rhinol. 2020;10:673–678). The superior incision is along the superior lateral nasal wall and the anterior, posterior, inferior, and lateral incisions over the nasal floor. The flap remains pedicled posteriorly along the posterior aspect of the inferior turbinate. The bone of the inferior turbinate is removed as much as possible and the natural fold of the inferior turbinate is released. The nasolacrimal duct is elevated within the lateral nasal wall mucosa and sharply transected. The exposed bony lateral nasal wall over the flap donor site can then be removed as part of an endoscopic medial maxillectomy anteriorly to the piriform aperture and inferiorly to the nasal floor. The flap may be preserved in the nasopharynx for later use.

Wound Bed Preparation and Flap Insetting. Prior to placement of the flap, on both the oral and nasal sides, the fistula is debrided of diseased mucosa and bone until an adequate margin of healthy tissue surrounds the site. The intranasal flap is then rotated into position to close the fistula from above, and full coverage can be determined from the oral cavity. Angled endoscopes are helpful in evaluating insetting. Intraoral coverage may be performed using a variety of local intraoral flaps, with a palatal island flap used in one of our patients, and a buccal fat pad flap combined with a buccal mucosal advancement flap in the other.