Sphenoid Sinus Osteitis After Endoscopic Transsphenoidal Surgery: A Bone-Centered Postoperative Entity

Purpose Despite advances in endoscopic skull base surgery, postoperative sinonasal inflammation remains poorly characterized. In particular, sphenoid sinus osteitis has received little attention, as complications after endoscopic transsphenoidal surgery (ETS) have largely been assessed in terms of mucosal pathology. This study aims to determine the incidence of sphenoid sinus osteitis after ETS, describe its clinical and radiological features, and identify associated surgical and demographic risk factors. Methods We retrospectively reviewed patients undergoing primary ETS for sellar or parasellar tumors between September 2021 and September 2024. Osteitis was assessed on high-resolution CT using the Lee and Kennedy classification. Clinical symptoms, particularly cacosmia, and surgical approach and reconstruction techniques were analyzed as potential risk factors. Results Among 1,443 patients, sphenoid sinus osteitis was identified in 12 cases (0.83%). All cases occurred in patients who underwent sellar reconstruction, with no osteitis observed in those without reconstruction (p < 0.001). Regarding reconstruction techniques, the nasoseptal flap showed a borderline statistical significance (p = 0,045). Radiologically, osteitis was Grade 1 in 50%, Grade 2 in 25%, and Grade 3 in 25% of cases. Cacosmia was the presenting symptom in 75% of affected patients (p < 0.001). Surgical revision was required in 11 patients (91.7%), while medical treatment alone was sufficient in one case. Conclusion Sphenoid sinus osteitis represents a rare but clinically relevant bone-centered complication following ETS, distinct from conventional rhinonasal morbidity. Its exclusive association with sellar reconstruction highlights the potential role of reconstruction-related bone contact and localized inflammatory responses in its pathogenesis. Recognizing sphenoid sinus osteitis as a distinct postoperative entity may improve diagnostic accuracy and guide more targeted management of postoperative rhinonasal symptoms.