3D HRCT Analysis of Supratubal Recess Volume in Chronic Otitis Media: A Case-Control Study

Background and Objectives: This study investigated the association of supratubal recess (STR) volume with chronic otitis media (COM), mastoid pneumatization, and age using three-dimensional (3D) high-resolution computed tomography (HRCT). Materials and Methods: A retrospective analysis was performed on 152 adult patients who underwent surgery for COM and 35 control subjects (70 ears) who underwent cochlear implantation. STR dimensions (width, length, and height) were measured on preoperative HRCT, and STR volume was calculated using Horos software (v4.0.0, macOS) through manual segmentation validated by two blinded radiologists. STR volume was analyzed in relation to mastoid pneumatization type (pneumatized, diploic, and sclerotic), age, and disease subgroup (chronic suppurative otitis media [CSOM] vs. chronic non-suppurative otitis media [CNSOM]). Results: STR volume was significantly higher in pneumatized mastoids compared with diploic and sclerotic types (p < 0.001), with sclerotic mastoids showing the greatest reduction. Univariate analysis showed no significant baseline STR volume differences among CSOM, CNSOM, and controls (mean volumes ± SD: 12.46 ± 6.39, 12.51 ± 7.19, and 13.18 ± 4.90 mm³; p = 0.751). However, multivariable regression indicated that both CSOM (β = 0.220, p = 0.002) and CNSOM (β = 0.416, p < 0.001) were positively associated with STR volume compared to controls, while diploic (β = -0.519, p < 0.001) and sclerotic (β = -0.665, p < 0.001) mastoids were associated with significantly lower STR volumes compared to pneumatized mastoids. Age showed a positive trend without reaching statistical significance (p = 0.053), and sex was not a significant predictor (p = 0.385). Reliability analyses demonstrated good intraobserver agreement (ICC = 0.88) and moderate-to-good interobserver consistency. Conclusions: STR volume is strongly influenced by mastoid pneumatization and independently associated with disease type, whereas age-related changes in adulthood and sex are negligible. 3D HRCT volumetry offers a deeper anatomical understanding of the supratubal recess and may facilitate more comprehensive anatomical and radiological evaluations.