The Floor‐of‐nose flap for reconstruction of endoscopic maxillectomy defects

An endoscopic approach to sinonasal tumors has significantly reduced the morbidity associated with the treatment of these lesions. Traditionally, extranasal en bloc resection via a lateral rhinotomy was considered the gold standard for both benign and malignant lesions given the high recurrence rates associated with early attempts at endonasal approaches.1 With the refinement of endoscopic techniques, however, a gradual but decisive shift toward endoscopic management has occurred with a correspondingly significant decrease in associated morbidity.2 The endoscopic medial maxillectomy has evolved from partial piecemeal removal of the lateral nasal wall into complete en bloc resection in some situations.3 However, as the extent of endoscopic resection has increased, so too has the degree of exposed bone at the end of the case, with a resultant worsening of postoperative nasal crusting. Such crusting generally requires debridement, is uncomfortable for the patient, can create a foul odor, cause epistaxis, incite granulation tissue formation, and obscure tumor surveillance. Herein we describe the floor-of-nose (FON) flap, a novel mucosal nasal flap that can be employed to cover the edges of a maxillectomy defect, and in doing so substantially reduce crusting after surgery. Once the nasal cavity is appropriately prepared for endonasal medial maxillectomy, the tumor is resected from the nasal cavity proper to expose the lateral nasal wall and middle and inferior turbinates. The middle and inferior turbinates are resected if necessary as per the lesion type and attachments. Prior to beginning the actual medial maxillectomy, the FON flap is elevated. Two parallel mucosal incisions are made along the floor of the nose, perpendicular to the long axis of the nasal passage, with one at the anterior end of the anticipated maxillectomy defect and the other at the posterior end. Each incision is the full width of the nasal floor, from the junction at the septum to as far up the medial extent of the medial maxillary wall as can be assured of being nonlesional tissue. These two incisions are then connected by a third, made on the lateral mucosal surface of the medial maxillary wall, at a region of nonlesional tissue. The resulting medially based random pattern mucosal FON flap is then elevated from lateral to medial, and folded over itself for the remainder of the case (Fig. 1). The length of the flap, and the amount of undermining on the floor of the nose, is done so as to give sufficient flap pliability to extend as far as possible in covering the edges of the anticipated maxillectomy defect. The formal endoscopic maxillectomy is then performed by standard technique, as required by the lesion type. Once tumor resection is deemed complete and hemostasis achieved, reconstruction commences. The exposed bony margins of the medial maxillectomy are smoothed and lowered with a diamond bur to facilitate flap adherence and allow further reach of the flap by removing any elevated bone that might interfere (Fig. 2). The FON flap is then rotated back down, mucosal side up, and transposed onto the exposed bone edge, with all flap mucosa unrolled to cover as much bone as possible (Fig. 3). Generally, at least 50% of the exposed bone can be covered. The FON flap edges are then covered with a thin layer of Tisseel fibrin glue (Baxter Healthcare, Deerfield, IL) to affix it in place. In the postoperative period patients are prescribed 1 week of penicillin-based antibiotics, instructed to irrigate the nose with saline nasal rinses 2 to 3 times per day, and are then reviewed 1 month after surgery. Elevation of floor-of-nose flap. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] Preparation of maxillectomy cavity and flap recipient site. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] Transposition and inlay of floor-of-nose flap. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] Postoperative crusting was assessed using the three-point Lund-Kennedy scale for crusting valuations, with 0 = absent, 1 = mild, 2 = severe. Two surgeons rated crusting severity independently, and values were compared using a Pearson correlation coefficient with significance set at P < .05. The FON flap was used in 20 consecutive cases of intranasal lesions requiring an endoscopic medial maxillectomy (Table I). A mean Lund-Kennedy crusting value of 0.3 was achieved in the series at 1 month postoperatively, with a high inter-rater reliability (Pearson correlation coefficient = 0.89; P <.01). No patients in the series required debridement of maxillectomy crusting in the clinic setting (although some still required other nasal debridement depending on the other portions of the surgery), and in all cases the flap healed seamlessly with the surrounding nasal mucosa. Facility with the development of local endonasal flaps has grown correspondingly with endoscopic techniques. The nasoseptal flap described by Hadad et al. has become a workhorse in the reconstruction of skull base defects.4 Local nasal mucosal flaps are used to cover bone during endoscopic dacryocystorhinostomy.5 Local, random pattern septal flaps have also been successfully described in the repair of septal perforations.6, 7 The widespread adoption of these flaps is primarily related to the benefit of providing vascularized tissue to a defect and covering exposed bone, thereby significantly decreasing healing time and restoring a healthy nasal microenvironment. The extensive crusting from both exposed bone and altered nasal environment after an endoscopic medial maxillectomy is a well-known complication that causes significant patient discomfort.8, 9 By covering exposed bone, the FON flap has proven very useful to the senior author in significantly decreasing the amount of crusting post-medial maxillectomy. In our institution's experience, this flap can be used to cover over 50% of the exposed maxillectomy bone. Postoperative patient comfort has been correspondingly enhanced, and for the 20 consecutive cases in this series no maxillectomy cavity debridement has been required at all. We recognize that the validity of the observations in this article are hampered by a lack of formal control group, but in comparison to subjective patient debridement experience prior to usage of the FON flap, and to the endoscopic maxillectomy literature in general,2, 8, 9 there is a clear demarcation and improvement in patient outcome since beginning use of the flap. In our experience prior to usage of the FON flap, the majority of patients required at least an initial maxillectomy debridement, and many required subsequent cleaning too. The FON flap appears to provide not only a cover for exposed bone (which is typically the nidus of crusting) but also possibly helps in restoring a healthier intranasal mucosal environment. We therefore recommend the FON flap as a viable and easy-to-use method of reconstruction following endoscopic medial maxillectomy procedures.

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