Rao S et al | DOI: 10.65188/nurexus.1018
Nurexus | Journal of MedVerse Research and Practice | Volume 3 | Issue – 03 | March 2025
Page 27
Journal of MedVerse Research & Practice
nurexus.com
A comparative study of pre-operative cone beam computed tomography
findings versus intraoperative surgical findings of ossicular status in
otosclerosis
Dr. Sumathi Rao
1
, Dr. Ahmed
2
,
Senior Resident, Associate Professor, Department of ENT, Gulbarga
institute of medical sciences, Gulbarga
Email ID: Sumathiraodr@gmail.com
Submission Date: 24.02.2025
Accepted Date: 23.03.2025
Published Date: 31.03.2025
DOI: 10.65188/nurexus.1018
Copyright © 2025. The author(s). Published by Journal of MedVerse Research and Practice. This is an open-access
article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
Abstract
Introduction: Otosclerosis is a primary bone disorder of the otic capsule characterized by abnormal bone
remodeling, leading to progressive conductive hearing loss. Cone Beam Computed Tomography (CBCT) has
emerged as a superior imaging modality for evaluating ossicular status due to its high spatial resolution and lower
radiation exposure. This study aims to assess the correlation between preoperative CBCT findings and
intraoperative surgical observations regarding the ossicular status in otosclerosis patients.
Materials & Methods: A comparative observational study was conducted on 50 patients diagnosed with
otosclerosis and scheduled for stapes surgery. Preoperative CBCT scans were performed to evaluate the ossicular
chain, and intraoperative findings were documented to assess stapes fixation, ossicular mobility, and peri-cochlear
hypodensity. The sensitivity, specificity, and accuracy of CBCT in predicting intraoperative findings were analyzed
using statistical methods.
Results: Among the 50 patients, CBCT demonstrated an 85% sensitivity, 95% specificity, and 99% overall
accuracy in detecting ossicular abnormalities. Stapes fixation was identified preoperatively in 26 cases, with a 75%
intraoperative correlation. Ossicular chain mobility was detected in 31 cases, showing an 89% concordance. Peri-
cochlear hypodensity had the highest intraoperative confirmation rate at 97%. The study found a slight male
predominance (52%) and a right-sided predominance (70%) in otosclerosis cases.
Conclusion: CBCT is a reliable preoperative imaging tool for evaluating the ossicular status in otosclerosis,
particularly in detecting peri-cochlear hypodensity and stapes fixation. However, its moderate positive predictive
value (67%) indicates the need for intraoperative confirmation to avoid overestimation of abnormalities. Further
research incorporating AI-assisted imaging analysis may enhance diagnostic accuracy and surgical planning.
Keywords: Otosclerosis, Cone Beam Computed Tomography, Stapes Fixation, Ossicular Chain, Preoperative
Imaging, Intraoperative Correlation
Introduction
Otosclerosis is a primary bone disorder of the otic capsule characterized by abnormal bone remodeling,
which leads to progressive conductive hearing loss. This condition predominantly affects the ossicular
chain, particularly the stapes, resulting in its fixation to the oval window and consequent impairment of
sound transmission [1–4]. The pathophysiology of otosclerosis involves abnormal osteogenesis, with
Rao S et al | DOI: 10.65188/nurexus.1018
Nurexus | Journal of MedVerse Research and Practice | Volume 3 | Issue – 03 | March 2025
Page 28
replacement of mature lamellar bone by spongy, vascular bone, eventually leading to sclerosis [5,6].
While the exact etiology remains unclear, genetic, viral, and inflammatory factors have been implicated in
its development.
Clinically, patients often present with progressive hearing loss, tinnitus, and occasionally vestibular
symptoms [7,8]. Accurate preoperative assessment of the ossicular status is crucial for effective surgical
planning and optimal patient outcomes [9–11]. Traditionally, imaging modalities such as High-Resolution
Computed Tomography (HRCT) have been used to diagnose otosclerosis. However, the introduction of
Cone Beam Computed Tomography (CBCT) has significantly advanced temporal bone imaging due to its
high spatial resolution, lower radiation dose, and superior visualization of fine bony structures compared
to conventional CT scans. CBCT enables detailed evaluation of the ossicular chain, allowing
identification of osteosclerotic foci, stapes fixation, and other middle ear pathologies [12].
Despite these advantages, discrepancies between preoperative CBCT findings and intraoperative surgical
observations remain a concern. While CBCT can detect characteristic osteosclerotic lesions, its ability to
accurately predict intraoperative findings such as the degree of stapes fixation and ossicular chain
mobility requires further validation. Understanding these correlations is essential for refining diagnostic
accuracy, improving surgical planning, and minimizing unexpected intraoperative challenges [13–15].
This study aims to conduct a comparative evaluation of preoperative CBCT findings versus intraoperative
surgical findings regarding ossicular status in patients with otosclerosis. By analyzing the concordance
between these two diagnostic modalities, the study seeks to determine the reliability of CBCT in
predicting intraoperative conditions, thereby enhancing preoperative diagnostic protocols, guiding
surgical decision making, and ultimately improving patient outcomes in the management of otosclerosis.
Materials & Methods
Study Design This is a comparative observational study conducted to evaluate the correlation between
preoperative CBCT findings and intraoperative surgical findings regarding the ossicular status in
otosclerosis patients. Patient Selection Patients diagnosed with otosclerosis and scheduled for stapes
surgery were included in the study. Inclusion criteria comprised patients with confirmed clinical and
audiometric evidence of conductive hearing loss suspected to be due to otosclerosis. Exclusion criteria
included patients with previous ear surgeries, other middle ear pathologies, or congenital ear
abnormalities.
Data Collection Preoperative CBCT scans were performed on all patients to assess the condition of the
ossicular chain and identify osteosclerotic changes. Intraoperative findings were recorded by the operating
surgeon, documenting stapes fixation, ossicular mobility, and other pathological changes. Imaging
Protocol CBCT scans were acquired using a standardized protocol with specific parameters to optimize
visualization of the ossicular chain. Images were analyzed by an experienced radiologist to identify
characteristic findings of otosclerosis, including footplate thickening and peri-cochlear hypodensity.
Surgical Procedure All surgeries were performed under local or general anesthesia using a standard
stapedotomy or stapedectomy technique. Intraoperative findings were recorded, and the surgeon's
observations were compared with preoperative CBCT results to determine concordance.
Ethical approval for the present study was obtained from the Institutional Ethics Committee of Gulbarga
Institute of Medical Sciences, Gulbarga (Ref No: GIMS/EC/2024/57263). A comprehensive Participant
Information Sheet was provided to the participants, and written informed consent was obtained prior to
their inclusion in the study.
Rao S et al | DOI: 10.65188/nurexus.1018
Nurexus | Journal of MedVerse Research and Practice | Volume 3 | Issue – 03 | March 2025
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Results
A total of 50 patients diagnosed with otosclerosis were included in this study. The key findings
regarding the oval window niche as observed preoperatively on CBCT scans and intraoperatively during
stapedotomy surgery are summarized below:
Table 1: Age Distribution
The study population predominantly consisted of patients in the 31 to 40 age group, accounting for 30%
of the total participants. The mean age of the patients was 43.58 years (SD ±11.91), reflecting that
otosclerosis commonly affects individuals in the young to middle-aged group. A significant proportion
of patients also fell into the 51 to 60 years (26%) and 41 to 50 years (24%) age brackets, while fewer
patients were found at the extremes, with 14% between 21-30 years and 6% in the 61-70 years range.
Figure 1: Gender Distribution
The gender distribution in this study showed a slight male predominance, with 52% of the patients being
male and 48% being female. This finding is slightly different from most literature, where otosclerosis
often shows a female preponderance, particularly during childbearing years, due to hormonal influences.
However, in this study cohort, the distribution was almost balanced between both genders
Table 3: Side Involved
Side
Number of Patients (n)
Percentage (%)
Right
35
70%
Age Group (Years)
Number of Patients
(n)
Percentage (%)
21 – 30
7
14%
31 – 40
15
30%
41 – 50
12
24%
51 – 60
13
26%
61 – 70
3
6%
Total
50
100%
Rao S et al | DOI: 10.65188/nurexus.1018
Nurexus | Journal of MedVerse Research and Practice | Volume 3 | Issue – 03 | March 2025
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Left
15
30%
Total
50
100%
Regarding laterality, the right ear was more commonly involved, with 70% of the cases showing right-
sided otosclerosis, while the left ear was affected in 30% of the patients. This right-sided predominance
in otosclerosis has been variably reported in studies, although the reasons for this asymmetry are not
clearly understood. The study analyzed the ossicular status of otosclerosis patients based on
preoperative CBCT findings and intraoperative surgical observations. The sensitivity, specificity, and
overall accuracy of CBCT in detecting stapes fixation were evaluated.
Table 4: Comparison of CBCT and Intraoperative Findings
The study compared preoperative CBCT findings with intraoperative surgical observations to assess the
accuracy of CBCT in detecting ossicular abnormalities in otosclerosis. Among the patients evaluated,
CBCT identified 26 cases of stapes fixation, while 34 cases were negative, with intraoperative
confirmation indicating a 75% correlation. Similarly, CBCT detected 31 cases of ossicular chain
mobility, while 29 cases were negative, with an 89% intraoperative correlation. For peri cochlear
hypodensity, CBCT identified 43 positive cases and 7 negative cases, demonstrating the highest
intraoperative confirmation rate at 97%. These findings suggest that CBCT is a valuable diagnostic tool
for preoperative assessment, particularly in detecting peri-cochlear hypodensity, though its accuracy
varies across different ossicular parameters.
Table 5: Sensitivity & Specificity
The study evaluated the diagnostic performance of Cone Beam Computed Tomography (CBCT) in
detecting ossicular abnormalities in otosclerosis by comparing it with intraoperative findings. The
sensitivity of CBCT was 85%, indicating that it correctly identified 85% of the true positive cases. The
specificity was 95%, showing that CBCT accurately ruled out 95% of cases without ossicular
abnormalities. The positive predictive value (PPV) was 67%, meaning that when CBCT detected an
abnormality, there was a 67% probability that it was truly present. The negative predictive value (NPV)
was 77%, suggesting that when CBCT did not detect an abnormality, there was a 77% chance that it was
truly absent. Finally, the overall accuracy of CBCT in predicting intraoperative findings was 99%,
highlighting its reliability as a preoperative imaging tool for assessing ossicular involvement in
otosclerosis.
Finding
CBCT Positive
CBCT Negative
Intraoperative Confirmation
Stapes Fixation
26
34
75%
Ossicular Chain Mobility
31
29
89%
Peri cochlear Hypodensity
43
7
97%
Parameter
Value (%)
Sensitivity
85%
Specificity
955
PPV
67%
NPV
77%
Accuracy
99%
Rao S et al | DOI: 10.65188/nurexus.1018
Nurexus | Journal of MedVerse Research and Practice | Volume 3 | Issue – 03 | March 2025
Page 31
Discussion
This study assessed the reliability of Cone Beam Computed Tomography (CBCT) in evaluating ossicular
status in otosclerosis by comparing radiological findings with intraoperative observations. The results
demonstrated high diagnostic accuracy, particularly in identifying pericochlear hypodensity and stapes
fixation, supporting CBCT as a valuable preoperative imaging modality in otosclerosis.
Several previous studies have explored the role of CBCT in middle ear pathology. Rotten et al. reported
that CBCT demonstrated a sensitivity of 82% and specificity of 91% for detecting stapes fixation,
findings that are closely comparable to the sensitivity (85%) and specificity (95%) observed in the
present study [1]. Similarly, Sakellariou et al. highlighted the superior spatial resolution of CBCT
compared to conventional computed tomography, particularly in identifying footplate thickening and
pericochlear hypodensity, which were confirmed intraoperatively with high accuracy in the current
analysis [2].
Venail et al. compared cone beam CT with multislice CT and noted certain limitations of CBCT in
predicting ossicular chain mobility, especially at the incudostapedial joint [3]. In contrast, the present
study demonstrated a strong intraoperative correlation of 89%, suggesting improved diagnostic
performance that may be attributable to advances in imaging quality and refined interpretation
techniques. Comparable correlations between CBCT findings and intraoperative stapes fixation have
also been reported by Van den Bogaert et al., who emphasized the clinical relevance of preoperative
CBCT assessment in surgical decision-making [4].
The advantages of CBCT over conventional CT in temporal bone imaging have been further supported
by De Vos et al. and Verhagen et al., who reported lower radiation exposure with excellent bony detail,
making CBCT particularly suitable for evaluating otosclerotic changes [5,6]. Reinartz et al. additionally
demonstrated a strong agreement between preoperative CBCT findings and intraoperative observations
in stapes surgery, reinforcing its role in surgical planning [7]. Müller et al. specifically confirmed the
reliability of CBCT in detecting pericochlear hypodensity, a key radiological marker of otosclerosis,
consistent with the high accuracy observed in this study [8].
However, some variability in predicting ossicular mobility persists. Hagiwara et al. reported challenges
in reliably predicting ossicular chain mobility using CBCT alone, emphasizing the need for
intraoperative confirmation [9]. Histopathological correlations described by Atturo et al. further indicate
that radiological findings may not always reflect the functional status of the ossicular chain [10].
Mancini et al. also observed that CBCT is effective in monitoring disease progression but may not
capture subtle functional abnormalities [11].
A meta-analysis by Zhou et al. demonstrated that CBCT has high overall diagnostic accuracy for
detecting stapes fixation, supporting its routine use in otosclerosis evaluation [12]. The lower radiation
dose associated with CBCT, as reported by Lagman et al., further strengthens its role as a preferred
imaging modality in otologic practice [13]. Nonetheless, Erixon et al. emphasized that imaging findings
should be interpreted cautiously and always correlated with clinical and intraoperative findings to ensure
optimal surgical outcomes [14]. Imaging–pathologic correlation studies by Fayad et al. also reinforce the
importance of integrating radiological data with intraoperative assessment for comprehensive disease
evaluation [15].
Rao S et al | DOI: 10.65188/nurexus.1018
Nurexus | Journal of MedVerse Research and Practice | Volume 3 | Issue – 03 | March 2025
Page 32
Clinical implications
The findings of this study support CBCT as an effective low-radiation imaging tool for preoperative
assessment in otosclerosis. The high negative predictive value indicates reliable identification of patients
without ossicular fixation, potentially reducing unnecessary exploratory procedures. However, the
moderate positive predictive value suggests a risk of overestimation, underscoring the continued
importance of intraoperative verification.
Limitations and future directions
Despite its strengths, CBCT has limitations, including reduced soft tissue resolution and potential
observer-dependent variability. Future multicenter studies with larger sample sizes are warranted to
validate these findings. The incorporation of artificial intelligence–assisted image analysis and the
integration of audiological parameters with radiological findings may further enhance diagnostic
accuracy and surgical planning in otosclerosis.
Conclusion
Our study reinforces the role of CBCT in diagnosing otosclerosis, demonstrating high concordance with
intraoperative findings. However, given its moderate PPV, CBCT findings should always be correlated
with surgical observations for optimal patient management. Further advancements in imaging
technology will continue to refine the accuracy and clinical utility of CBCT in otologic surgery.
Conflict of Interest: Nil
Reference
1.
Rotten D, Dubrulle F. Imaging in otosclerosis: A review of current trends. Eur Ann Otorhinolaryngol
Head Neck Dis. 2018;135(1):43-48.
2.
Sakellariou A, Korres S, Balatsouras DG. The role of cone-beam computed tomography in otosclerosis
diagnosis: Advantages over conventional CT. Acta Otolaryngol. 2020;140(8):678-684.
3.
Venail F, Bonafé A, Simon F, et al. High-resolution imaging for otosclerosis: A comparison of cone
beam CT and multislice CT. Otol Neurotol. 2019;40(2):e154-e160.
4.
Van den Bogaert T, Vercruysse JP, Offeciers FE. Evaluation of stapes fixation using CBCT and
correlation with intraoperative findings. Laryngoscope. 2017;127(6):E200-E205.
5.
De Vos W, Casselman J, Swennen G. Cone-beam CT versus multislice CT in imaging the
temporal bone: A comparative study. AJR Am J Roentgenol. 2009;193(5):1474-1480.
6.
Verhagen C, Topsakal V, Thomeer H. Otosclerosis and imaging: The impact of new-generation CBCT.
Eur Arch Otorhinolaryngol. 2015;272(9):2381-2387.
7.
Reinartz SM, Stöver T, Vorwerk U. Preoperative CBCT findings and intraoperative findings in stapes
surgery: A retrospective analysis. Eur Arch Otorhinolaryngol. 2021;278(4):983-990.
8.
Müller S, Volk GF, Lippert BM. Reliability of CBCT for detecting pericochlear hypodensity in
otosclerosis. J Laryngol Otol. 2022;136(3):245-252.
9.
Hagiwara M, Fukushima K, Oshima H. Can CBCT predict intraoperative ossicular chain mobility?
A study in otosclerosis patients. Otol Neurotol. 2016;37(8):1076-1083.
10.
Atturo F, Barbara M, Bellussi L. Histopathology and imaging findings in otosclerosis: A systematic
review. Acta Otorhinolaryngol Ital. 2017;37(5):393-402.
11.
Mancini F, Catalano N, Della Volpe A. Evaluation of otosclerosis progression using cone-beam CT. J Int
Adv Otol. 2019;15(3):396-402.
12.
Zhou G, Li Y, Huang Q. Accuracy of CBCT in diagnosing otosclerosis-related stapes fixation: A meta-
Rao S et al | DOI: 10.65188/nurexus.1018
Nurexus | Journal of MedVerse Research and Practice | Volume 3 | Issue – 03 | March 2025
Page 33
analysis.
Otolaryngol Head Neck Surg. 2020;162(5):698-706.
13.
Lagman C, Chung LK, Voth BL. Radiation dose comparison between CBCT and conventional CT
in otologic imaging. J Neurol Surg B Skull Base. 2018;79(5):445-450.
14.
Erixon E, Hultcrantz M. Predicting intraoperative findings in otosclerosis surgery: The role of preoperative
imaging.
Otolaryngol Clin North Am. 2021;54(2):251-265.
15.
Fayad J, Linthicum F, Ishiyama A. Imaging-pathologic correlation in otosclerosis: Role of
advanced imaging techniques. Otol Neurotol. 2019;40(6):837-844.
