Evaluation of metabolism on bone resorption, urinary deoxypyridinoline levels and the correlation of results with temporal bone computed tomography and densitometry data in patients with otosclerosis

Otosclerosis is a disease characterized by progressive hearing loss in one or two ears, diagnosed clinically when hearing loss develops. Potential causes include genetic factors, endocrine factors, immune deficiencies, viral infections and diseases of the connective tissue. It is suggested that in patients without a disease associated with bone resorption or increased bone metabolism (osteoporosis, osteogenesis imperfecta, Paget's disease etc.), supporting the diagnosis of otosclerosis with a non-invasive urine test may contribute to rehabilitation and monitoring of the patient, planning of surgical timing, and may be used as a screening test for other family members. In otosclerosis, a disease believed to be genetic, characterized by bone resorption in the bone metabolism of the otic capsule, high-resolution computerized tomography is widely used today to visualize changes in the otic capsule due to demineralization. There are cases where patients who were thought to have otosclerosis due to detection of conductive or mixed type hearing loss in audiological examinations did not show any otosclerotic focus in bone density measurement by computerized tomography. Deoxypyridinoline, a product of bone breakdown, is a marker which is excreted by urine without metabolization and increases with bone resorption and osteoclastic activity. The urinary deoxypyridinoline level, a product of bone breakdown, is not affected by the degradation of newly synthesized collagen and diet. It has been demonstrated that it has high specificity to bone tissues and virtually all are bone based. It is suggested that urinary deoxypiridine level, a bone resorption marker analyzed non-invasively in urine, may be a diagnostic criterion and may inform about the progress of the disease in patients with otosclerosis. When evaluating data related to the urinal breakdown metabolite, two groups were formed, including a patient group and a control group. 12 patients diagnosed with otosclerosis by surgical and audiological methods constituted the patient group. The patient group was further categorized into bilateral (7) and unilateral (5) involvement subgroups after radiological, audiological and surgical assessment. While examining audiological data, 18 ears, diagnosed with otosclerosis by audiological and/or surgical means, belonging to 12 patients assigned as the patient group and diagnosed with otosclerosis by audiological and surgical means were examined. At our hospital, stapedectomy surgery was applied and appropriate pistons placed unilaterally in 11 ears of 12 patients, and in both ears of 1 patient. Patients were grouped according to positive or negative radiological focus revealed by high resolution CT imaging. It was discovered that the most effective parameter in DPD ratio was otosclerosis involvement. In patients with bilateral involvement, DPD values were seen to be statistically significantly high although no radiological focus was observed. In the normal group, this is supported by the fact that the mean value of urinal DPD ratios of patients with bilateral involvement was higher than that of patients with unilateral involvement. When, in the patient group, the correlation between the first and second urinal DPD ratios and otosclerosis was examined, there was moderate correlation between the mean value of second urine DPD ratios and otosclerosis involvement (R=0,61) which was statistically significant (p=0,03). There was positive correlation between two values as their coefficients were positive. In our study, all patients diagnosed with otosclerosis by addition urine DPD ratios to CT imaging without any missing patient. It was seen that by adding urine DPD ratios to CT, sensitivity of CT evaluation increases from %50 to %100. Due to the low number of patients in our study, unilateral cases, correlation with bone conduction threshold, and cochlear otosclerosis cases could not be evaluated. In otosclerosis, diagnosis needs surgical confirmation and have no another techniques to evaluate the metabolic activity of otosclerotic focus except CT. However, after an average examination of data, it was concluded that urine DPD ratio evaluation gives us an opportunity for supporting the diagnosis of otosclerosis with a non-invasive, low cost and quick resulted urine test may contribute to rehabilitation and monitoring of the patient. It is suggested that urinary deoxypiridine level can be a diagnostic criterion and can inform about the progress of the disease and response to medical treatment in patients with otosclerosis.