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Published on: November 26, 2015
Prevalence, size and distribution of microdamage in the human otic capsule
Thomas Frisch1, Sune Land Bloch, Mads Sølvsten Sørensen
1Department of Otolaryngology-Head Neck Surgery , Rigshospitalet, Copenhagen , Denmark.
Conclusions:
Age-dependent microdamage (MDx) accumulates excessively in human perilabyrinthine bone, where the bone turnover is almost absent. This may have pathological implications for bone-specific disorders such as otosclerosis. The role of MDx accumulation is discussed from an osteodynamic perspective.
Objectives:
Bone remodelling is highly inhibited within the otic capsule compared with the rest of the skeleton. Consequently excessive accumulation of age-dependent capsular MDx is expected. This study describes the prevalence, size and topographical distribution of MDx in the human otic capsule.
Methods:
A total of 241 undecalcified human temporal bones were examined. Bulk staining and the cutting-grinding technique were used to separate in vivo MDx from microcrack artefacts induced post mortem by the milling procedure. Quantitative data were obtained by fluorescence microscopy by counting and measuring and by the use of stereology.
Results:
Microcracks accumulated continuously and extensively in the human otic capsule throughout life. Both the number and total length of MDx were higher close to the inner ear space as compared with the capsular periphery. The mean length of the MDx remained constant with age. There was no statistically significant sex difference.
Insights
Age-dependent microdamage accumulates extensively in the human otic capsule due to low bone turnover. This accumulation may impact bone disorders like otosclerosis.
Area of Science:
- Orthopedics
- Otolaryngology
- Bone Biology
Background:
- Bone remodeling is significantly reduced in the otic capsule compared to other skeletal sites.
- This low turnover is expected to lead to excessive accumulation of age-dependent microdamage (MDx).
Purpose of the Study:
- To investigate the prevalence, size, and topographical distribution of microdamage (MDx) in the human otic capsule.
- To understand the implications of MDx accumulation in the context of otic capsule osteodynamics.
Main Methods:
- Examination of 241 undecalcified human temporal bones.
- Utilized bulk staining and cutting-grinding techniques to differentiate in vivo MDx from post-mortem artifacts.
- Employed fluorescence microscopy and stereology for quantitative analysis of MDx.
Main Results:
- Continuous and extensive accumulation of microcracks (MDx) observed throughout life in the human otic capsule.
- Higher density and total length of MDx were found near the inner ear compared to the capsular periphery.
- Mean MDx length remained constant with age, with no significant sex-based differences.
Conclusions:
- Age-dependent microdamage (MDx) accumulates excessively in human perilabyrinthine bone with minimal turnover.
- This finding suggests potential pathological implications for bone disorders such as otosclerosis.
- The study provides insights into MDx accumulation from an osteodynamic perspective in the otic capsule.
