CT assessment of bone remodeling in the otic capsule in chronic renal failure: association with hearing loss

Hearing loss (HL) is common in patients with chronic renal failure (CRF), but its cause is controversial. The aim of this study was to determine the effect of CRF on the bone density of the otic capsule using densitometric measurements with MDCT and to evaluate the relationship between changes in the otic capsule density and HL in patients with CRF. The study included 34 patients with nonsyndromic CRF undergoing hemodialysis and 35 healthy control subjects. A CT was obtained, for a variety of reasons, in control subjects who did not have CRF or HL, but patients with trauma and infection were excluded. Control subjects were chosen on the basis of a normal CT and pure tone audiometry findings. Densitometric measurements were made using CT in the region anterior to the oval window and anterior to the internal auditory canal. These measurements were compared between patients and control subjects. Pure tone audiometry was performed to detect HL. The average levels of parathyroid hormone in the previous 6 months and the duration of hemodialysis in patients were documented. The association between the levels of parathyroid hormone, the duration of hemodialysis, and the region-of-interest density values in the patient groups were evaluated using the Pearson correlation coefficient. HL was found in 40 of 68 ears (58.8%) in the patient group. A significant difference in the otic capsule density was found between the ears with and without HL. There was a strong negative correlation between the parathyroid hormone level and the densitometric measurement of the otic capsule. There is osseous remodeling of the otic capsule in CRF with loss of bone density, and this is associated with HL in CRF.