Correlation Between Pre-Operative Cone Beam CT and Intraoperative Findings of the Footplate Thickness in Otosclerosis

Abstract

Introduction:

Otosclerosis is a progressive disorder of abnormal bone remodeling in the otic capsule, often resulting in stapes footplate fixation and conductive hearing loss. Accurate assessment of footplate morphology is essential for surgical planning, particularly to identify cases with thick or obliterated footplates. Cone Beam Computed Tomography (CBCT) has emerged as a promising imaging modality for detailed visualization of the temporal bone. This study aims to evaluate the correlation between pre-operative CBCT findings and intraoperative observations of footplate thickness in patients undergoing stapedotomy for otosclerosis.

Materials and Methods:

A prospective comparative study was conducted over one year at Bharath Medical College Hospital & Research Institute, Chennai, involving 60 patients diagnosed with otosclerosis. All participants underwent comprehensive clinical and audiological evaluation, followed by CBCT imaging of the temporal bone. During surgery, footplate morphology was assessed using an operating microscope and documented systematically. The pre-operative CBCT findings were then compared with intraoperative observations. Data were statistically analyzed using SPSS Version 26.0, employing chi-square test, Fisher’s exact test, and kappa statistics, with a p-value of <0.05 considered significant.

Results:

CBCT identified thin footplates in 41 patients (68.3%), while intraoperative findings confirmed thin footplates in 43 patients (71.7%). Among the 41 CBCT-predicted thin footplates, 36 were confirmed intraoperatively, yielding a sensitivity of 83.7%, specificity of 70.6%, positive predictive value of 87.8%, negative predictive value of 63.2%, and an overall diagnostic accuracy of 80.0%. The correlation between CBCT and intraoperative findings was statistically significant (p = 0.001), indicating a strong agreement between modalities.

Conclusion:

CBCT demonstrates high diagnostic accuracy in predicting footplate thickness in otosclerosis and serves as a valuable tool for preoperative surgical planning. Its use can help anticipate anatomical variations, minimize intraoperative complications, and guide appropriate surgical technique selection.