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HRCT Correlation with Round Window Identification during Cochlear Implantation in Children
Sai Kiran Pendem1, Rajeswaran Rangasami1, Ravi Kumar Arunachalam2
1Department of Radiology and Imaging Sciences, Sri Ramachandra University, Chennai, Tamil Nadu, India.
Insights
High Resolution Computer Tomography (HRCT) measurements accurately predict round window niche visualization during cochlear implant surgery. This aids surgeons in planning procedures through posterior tympanotomy, improving outcomes.
Area of Science:
- Otolaryngology
- Medical Imaging
- Surgical Planning
Background:
- Accurate visualization of the round window niche is crucial for successful cochlear implantation.
- Posterior tympanotomy is a common surgical approach, but visualization can be challenging.
- High Resolution Computer Tomography (HRCT) offers detailed anatomical imaging of the temporal bone.
Purpose of the Study:
- To evaluate the predictive accuracy of HRCT temporal bone measurements for round window niche visibility.
- To correlate preoperative HRCT measurements with intraoperative surgical views.
- To assess the utility of HRCT in surgical planning for cochlear implant candidates.
Main Methods:
- Prospective study of 37 pediatric cochlear implant candidates (ages 1-6).
- Preoperative HRCT scans measured distances related to the round window niche.
- Intraoperative visualization of the round window niche via posterior tympanotomy was classified (fully, partially, difficult).
Main Results:
- Statistically significant differences (P < 0.01) in HRCT measurements were observed between visibility types.
- HRCT measurements demonstrated high accuracy: 92.3% sensitivity and 96.2% specificity.
- Preoperative measurements effectively predicted the degree of round window niche visualization.
Conclusions:
- Preoperative HRCT temporal bone measurements are valuable tools for predicting round window niche visualization.
- These measurements can assist surgeons in planning posterior tympanotomy approaches for cochlear implantation.
- HRCT aids in anticipating surgical challenges and optimizing surgical strategy.
Objective:
To determine the accuracy of High Resolution Computer Tomography (HRCT) temporal bone measurements in predicting the actual visualization of round window niche as viewed through posterior tympanotomy (i.e. facial recess).
Materials And Methods:
This is a prospective study of 37 cochlear implant candidates, aged between 1and 6 years, who were referred for HRCT temporal bone during the period December 2013 to July 2014. Cochlear implantation was done in 37 children (25 in the right ear and 12 in the left ear). The distance between the short process of incus and the round window niche and the distance between the oval window and the round window niche were measured preoperatively on sub-millimeter (0.7 mm) HRCT images. We classified the visibility of round window niche based on the surgical view (i.e. through posterior tympanotomy) during surgery into three types: 1) Type 1- fully visible, 2) Type 2- partially visible, and 3) Type 3- difficult to visualize. The preoperative HRCT measurements were used to predict the type of visualization of round window niche before surgery and correlated with the findings during surgery.
Results:
The mean and standard deviation for the distance between the short process of incus and the round window niche and for the distance between the oval window and the round window niche for Types 1, 2, and 3 were 8.5 ± 0.2 mm and 3.2 ± 0.2 mm, 8.0 ± 0.4 mm and 3.8 ± 0.2 mm, 7.5 ± 0.2 mm and 4.4 ± 0.2 mm respectively, and showed statistically significant difference (P < 0.01) between them. The preoperative HRCT measurements had a sensitivity and specificity of 92.3% and 96.2%, respectively, in determining the actual visualization of round window niche.
Conclusion:
This study shows preoperative HRCT temporal bone measurements are useful in predicting the actual visualization of round window niche as viewed through posterior tympanotomy.
