Functional Endoscopic Sinus Surgery for Paranasal Sinusitis Originating From a Peri-implantitis–Triggered Infection in the Augmented Maxilla: A Case Report
The aim of this case report was to report the course of treatment for advanced paranasal sinus infection triggered by peri-implantitis, managed using functional endoscopic sinus surgery (FESS), with outcomes. A nonsmoking male patient received sinus augmentation with implant placement on his left posterior maxilla 15 years ago. Possibly due to noncompliance to maintenance, peri-implantitis developed and progressed into the augmented bone area in the maxilla. Eventually, maxillary sinusitis occurred concomitantly with a spread of the infection to the other paranasal sinuses. Implant removal and intraoral debridement of inflammatory tissue were performed, but there was no resolution. Subsequently, FESS was performed, with removal of nasal polyp and sequestrum. After FESS, the patient's sinusitis resolved. Histologically, the sequestrum was composed of bone substitute particles, necrotic bone, stromal fibrosis, and a very limited cellular component. Two implants were placed on the present site, and no adverse event occurred for up to 1 year after the insertion of the final prosthesis. Peri-implantitis in the posterior maxilla can trigger maxillary sinusitis with concomitant infection to the neighboring paranasal sinuses. FESS should be considered to treat this condition.

Figure 1. Sequential panoramic radiographs. (a) At the time of implant placement 15 years ago. (b) At the time of revisit due to paranasal sinus infection. (c) At 1 year following functional endoscopic sinus surgery, reimplantation, and final prosthesis insertion. Figure 2. Clinical photographs at the time of revisit. (a) After removal of the prosthesis, severe inflammation was observed. (b) The #17 implant was removed, and oroantral communication occurred.

Cone-beam computerized tomographic views before functional endoscopic sinus surgery (FESS) (a–e) and at 1 year following FESS, reimplantation, and final prosthesis insertion (f–h). (a) Severe mucosal edema and a floating mass were observed in the left maxillary sinus. (b) Complete obstruction was observed in the left maxillary sinus (axial view). (c–e) Severe inflammatory change was observed in the maxillary/ethmoid sinuses and middle meatus. A floating radiopaque mass was observed above the #17 implant (sagittal view: between #15 and #17 implant areas). (f) Resolution of the mucosal edema was observed (axial view). (g, h) The enlarged ostium and resolution of the sinus membrane thickening were observed. The bone substitute material grafted in the sinus around the #15 implant was preserved without removal.

Figure 4. Functional endoscopic sinus surgery. (a) Initial nasal endoscopy revealing that the nasal polyp occupied the middle meatus. (b) Following the enlargement of the ostium, purulent matter and sequestrum were removed. (c) One month after functional endoscopic sinus surgery (FESS), mucosal edema was still observed. (d) Six months after FESS, mucosal edema disappeared. Oroantral communication was covered by soft tissue, but the tissue depression remained (white arrow). Figure 5. Histologic observation of the mass removed during FESS. (a) Gross section of the removed mass of approximately 10-mm length. (b) Bone substitute particles were surrounded by necrotic bone tissue (hematoxylin/eosin staining).

Figure 6. Clinical photographs at 6 months following functional endoscopic sinus surgery. (a) No specific findings in the oral mucosa. (b) After flap reflection, the #15 implant was removed using a trephine. A histologic specimen was made from the removed tissue. A new implant was placed leaning against the palatal bony wall. (c) Bone substitute material was grafted on to the surgical site. (d) Primary flap closure was achieved. Figure 7. Histologic observation of the tissue specimen at the time of implant placement. (a) Bone substitute particles grafted 15 years ago were in close contact with vital bone tissue. The periphery of the specimen demonstrating slight fibrosis. (b) Host bone tissue is well interconnected with bone substitute particles (hematoxylin/eosin staining).
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