New Bone Fluorescence Detection System: Quantitative Analysis of Spectrophotometric Variations Between Necrotic and Vital Bones.

BACKGROUND

Osteonecrosis of the jaw (ONJ) management remains challenging due to the lack of standardized surgical margin criteria. Bone autofluorescence (AF) has shown potential to distinguish necrotic from vital bone tissue intraoperatively.

PURPOSE: The study aimed to measure the association between bone AF intensity and histopathologic diagnosis to explore the potential of a new spectrophotometric method for real-time assessment of bone vitality.

STUDY DESIGN, SETTING, AND SAMPLE: This was a prospective, multicentric, cross-sectional ex vivo study including 40 subjects treated for ONJ at 2 Italian university hospitals between 2023 and 2024. Exclusion criteria were age <18 years and inability to provide informed consent.

PREDICTOR VARIABLE: The predictor variable was bone AF intensity coded as vital (CTRL) or necrotic (ONJ).

OUTCOME VARIABLE: The primary outcome variable was histologic tissue diagnosis coded as vital or necrotic. The secondary outcome was to assess whether systemic or pharmacological variables could influence the spectrophotometric measurements.

COVARIATES: Covariates included clinical history, pharmacologic treatments, and ONJ characteristics.

ANALYSES: Descriptive statistics were computed for all variables. Normality was assessed with the Shapiro-Wilk test, and group differences were analyzed using parametric and nonparametric tests. A mixed-effects modeling framework was applied to account for repeated measures, including a linear mixed-effects model for fluorescence ratios and a mixed-effects logistic regression to assess the association between AF and histology; diagnostic accuracy was derived from model-based probability thresholds.

RESULTS

The sample included 33 females (82.5%) and seven males (17.5%) with a mean age of 68.4 ± 11.9 years. A total of 294 spectral points were analyzed (147 necrotic, 147 vital). The mean photon count at 500 nm for the areas with ONJ was 7,886 ± 4,452, while the mean photon count at 500 nm for the healthy areas was 33,825 ± 10,791. The mean loss of fluorescence intensity (LoFI) ratio was 5.2 ± 2.4. Fluorescence did not differ by oncologic status (P = .8) but was significantly reduced in patients treated with new antiresorptive drugs (P = .004).

CONCLUSIONS AND RELEVANCE: Quantitative bone AF was directly correlated with histopathologic vitality. This objective, real-time method may improve the precision of surgical margin identification in ONJ management.