Estimation of Volume of Stria Vascularis and the Length of Its Capillaries in the Human Cochlea

BACKGROUND: The stria vascularis (SV) is a vascularized epithelium that secretes endolymph and is located on the lateral wall of the membranous cochlea. The capillaries of SV directly influence the composition of the endolymph and hence the generation of impulses by the hair-cells that are auditory receptors and thus affect hearing. Therefore, the real morphology of the SV would be very important for understanding the hearing system. There are few reliable reports of the morphology of the human SV. AIMS AND OBJECTIVES: In this research, we have estimated the volume of the SV and total length of strial capillaries in the apical, middle and basal turns of the human cochlea by updated stereological techniques. METHODS: The point-counting Cavalieri's method and hemispherical volume probes were applied on stained, 40 μm-thick serial sections of five celloidin-embedded, decalcified cochleae. RESULTS: The mean age of persons at the time of death was 51 ± 15.25 years, the mean volume of the SV was 0.56 ± 0.054 mm3 and the mean length of the SV capillaries was 289.08 ± 72.96 mm. We also estimated the same parameters with different stereological parameters, probes and in differently stained sections and checked the relationship and limits of agreement between different methods by paired t-test and Bland-Altman plot. We found agreement in our results. CONCLUSION: We provide reliable baseline data on the real morphology of the human SV.