Abstract
Clinical anatomy of the external ear canal (EEC) has a significant role in the diagnosis of Otitis Media (OM) and other auditory system diseases. OM is one of the most common infections and major causes of morbidity in adults if the complications of the OM take place. In the developing and low-income countries, the OM has a direct and indirect role in their life, because it's one of the causes leading to doctors' visits, and the indirect costs may affect the families and economy. EC measurements are needed in daily life, as an example; in the ears plugs manufacturing.
This study was conducted by the Declaration of Helsinki, and approved by the research ethics committee at the Faculty of Medicine, University of Gezira, Sudan, this observational case-control study. Informed consent was obtained from all-volunteer participants enrolled in the study. From January 2015-2018, temporal bone computed tomography (CT) images of volunteer patients and healthy subjects, were collected from Khartoum State. ImageJ software (V 1.52a), used in the measurement of EC; OsiriX image processing application for Mac (OsiriX Lite) to display images for the external ear area of the skull's temporal bone, statistical analysis was performed by Statistical Package for the Social Sciences SPSS V.22, and statistical software suite developed by SAS Institute (The SAS System V.9). The level of significance was set at P-value <0.05. Chi-Square test was used and Receiver Operating Characteristic (ROC) analysis was applied to determine the power of straight length (SL) in predicting patient.
In the cases the total number is 140 (patient 70 and healthy 70), with a range of 18-40 years, 52.9 % (n=74) of the patients were females and 47.1% (n=66) are males. The distribution of quantitative variables shows that the mean of the straight length (SL) is ±34.13, Standard Deviation (SD) ± 5.83, and the minimum and maximum SL are 11.33 and 47.00, respectively. Distribution of quantitative variables by a case in SL, shown that the patients mean ±32.69, SD ±6.58; and the healthy mean ±35.58 SD ±4.66, t ±3.106 and the P-value <0.003. Distribution of SL by Gender shown that in male mean ±34.89, SD ±6.22, female mean ±33.45, SD ±5.42. Distribution of SL by Side shown that left side means ±34.14, and SD ±5.66, right side mean ± 34.12, and SD ±6.04.
If the straight length (SL) value is equal to 31.33 or less, the case sample is classified as an otitis media patient. There is a highly significant difference in the SL between male patients and healthy a p-value <0.061 and between females' patients and healthy as a p-value<0.016. and significance differences comparing the patients and healthy groups with the gender, result shown that t =2.909 in males and females t=2,456.