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[Comparison of microfissures between the oval and round window niche areas in human temporal bone]
Abstract:
There are numerous reports on microfissures in the round window niche area, but not many reports have appeared on microfissures in the oval window niche area. In addition, few studies have compared microfissures between the oval and round window niche areas in the same subjects. Hence, the present study investigated the prevalence of microfissures in both areas in human temporal bones. The study was conducted on the 637 ears of 333 cases. Specimens were prepared according to the conventional methods: after fixation, decalcification and dehydration, each specimen was embedded in Celloidin, and the temporal bones were sectioned horizontally at 25-micron intervals. Every 10th section was stained with hematoxylin & eosin, and each section was analyzed under a light microscope. The prevalence of microfissures was analyzed in relation to the sex, left/right differences and age of the subjects. Microfissures were seen in the oval window niche area in 66.2%, and in the round window niche area in 92.0%. When a microfissure was seen in the oval window niche area, it was also detected in the round window niche area in every case. There were no sex or left/right differences in the prevalence of microfissures, and microfissures occurred bilaterally in most cases. The youngest subject with a microfissure in the oval window niche area was a 14-year-old, and the prevalence increased with age up to approximately 60 years. On the other hand, microfissures in the round window niche area were seen in a 3-year-old, and were seen in most cases over the age of ten. These findings suggest that microfissures are more likely to occur in the round window niche area as compared to the oval window niche area. However, the prevalence of microfissures in the oval window niche area was not low either, and it is important to pay attention to both the oval and round niche areas when microfissures are involved in the formation of perilymph fistulae. Given that the prevalence of microfissures in the oval window niche area increased up to about 60 years of age, not only growth, but also mastication, may be involved in the occurrence of microfissures.
Insights
Microfissures are common in the round window niche (92.0%) and oval window niche (66.2%) of human temporal bones. Their prevalence increases with age, highlighting the importance of both areas in perilymph fistula formation.
Area of Science:
- Otolaryngology
- Anatomy
- Pathology
Background:
- Limited comparative studies exist on microfissures in the oval versus round window niche areas.
- Understanding microfissure prevalence is crucial for diagnosing and managing conditions like perilymph fistulae.
Observation:
- A study analyzed 637 human temporal bones to compare microfissure prevalence in the oval and round window niches.
- Specimens were sectioned and analyzed microscopically to identify and quantify microfissures.
Findings:
- Microfissures were observed in 66.2% of oval window niches and 92.0% of round window niches.
- Microfissures in the oval niche were always accompanied by those in the round niche.
- Prevalence increased with age, particularly up to 60 years, with no sex or side differences.
Implications:
- The round window niche exhibits a higher prevalence of microfissures than the oval window niche.
- Both niche areas require attention in cases of microfissure-related perilymph fistulae.
- Factors like growth and mastication may contribute to microfissure development in the oval window niche.