Prognostic Factors for Adverse Outcomes in Odontogenic Infections Requiring Hospitalization: A Single-Center Retrospective Study in Kraków, Poland

Background/Objectives: Odontogenic infections range from localized abscesses to life-threatening deep neck infections and are a frequent cause of emergency admission. We aimed to identify prognostic factors for postoperative complications after their surgical treatment. Methods: We retrospectively analyzed 194 adults (59.3% male) treated at the Department of Cranio-Maxillofacial Surgery in Cracow between 2020 and 2025. The primary outcome was any postoperative complication, graded by the Clavien–Dindo classification and dichotomized into minor (grade I–II) and major (grade ≥ III). Prolonged hospitalization and prolonged irrigation (>7 days) were secondary outcomes. Pre-specified main factors (advanced age, diffuse phlegmonous spread, diabetes mellitus) and covariates (sex, maxillary location, systemic disease) were tested by uni- and multivariable logistic regression. Results: Comorbidities were present in 69.1%. Complications occurred in 49 patients (25.3%): 19 (9.8%) minor and 30 (15.5%) major, including 12 grade IV intensive-care events and two deaths (grade V). In multivariable analysis, diffuse phlegmonous spread independently predicted any complication (adjusted OR 11.7), major complication (OR 23.4), prolonged hospitalization (OR 5.02) and prolonged irrigation (OR 4.39; all p ≤ 0.004). Advancing age independently predicted major complications (OR 1.03 per year, p = 0.037). Both fatal cases shared phlegmon, maxillary location and diabetes. Conclusions: Diffuse phlegmonous spread was the principal prognostic factor across all adverse outcomes, with advancing age additionally predicting major complications. Because intensive-care admission occurred almost exclusively in phlegmon patients, this association is partly definitional. Early identification of diffuse spread and advanced age may support effective triage.