2.3. Statistical Analysis
Chi-square test of homogeneity (Rx2) was performed to determine if the
proportions of pneumatized and non-pneumatized petrous apex and
perilabyrinthine cells and the proportions of fully pneumatized, diploic
and sclerotic mastoid cells were statistically significantly different
between healthy and diseased-side for group 1 and group 2.
The assumption of normality for volumes of paranasal sinuses was not
satisfied with the healthy-side and diseased-side of group 1 and group
2, as assessed by Shapiro-Wilk’s test. (p<0.05) Therefore, A
Mann-Whitney U test (as a non-parametric test) was run to determine if
there were differences in volumes of paranasal sinuses between
healthy-side and diseased-side for group 1 and group 2. Kruskal Wallis H
test was performed to compare the paranasal sinus volumes between the
related ears with grouped based on their mastoid pneumatization. Dunn’s
procedure was performed, and adjusted p-value (Bonferroni correction)
was calculated for posthoc analysis.
Statistical significance was accepted at p< 0.05.
Results
A total of 179 patients were screened. Thirty-one patients were excluded
due to age, 35 due to bilateral ear disease, 7 due to insufficient HRCT
images, and 5 due to sinonasal disease. Remaining 101 patients were
included in statistical analysis.
Group 1, COM with isolated tympanic membrane perforation, consists of 51
patients, of which 26 (51%) were female and 25 (49%) male. The average
age was 37.1(± 14.75).
Group 2, COM with cholesteatoma/retraction pocket, consists of 50
patients, of which 27 (54%) were female and 23 (46%) male. The average
age was 38.8 (±13.73).