This study was to investigate ipsilateralhypertrophy of the mastoidprocess in the patients with congenitalmusculartorticollis(CMT).
Retrospective cross-sectional study.
Children with CMT.
A total of 212 surgicalcases of patients with CMT (age: 50.9 ± 44.3 months) and 212 age- and gender-matched controls (age: 50.4 ± 44.2 months) were included. The mastoidprocess volume was calculated and compared for both groups on the computed tomography axial images. A linear regression analysis was performed between the age and the intrasubject volume difference in the mastoidprocess.
The volume of the mastoidprocess in the CMT side was significantly larger than that of the non-CMT side in the CMT group (32.2 ± 30.3 cm3 vs 21.9 ± 22.8 cm3; P < .001). In the control group, there was no significant difference between the volume of the right and left mastoidprocess (21.6 ± 24.6 cm3 vs 21.2 ± 23.8 cm3; P = .472). The intrasubject volume difference in the mastoidprocess in the CMT group showed a linear increase with the age (adjusted R 2 = 0.286; P < .001), and the volumetric asymmetry of the mastoidprocess became more severe over age compared to the control group.
We showed ipsilateralhypertrophy of the mastoidprocess in patients with CMT and demonstrated that the volumetric asymmetry increased with age.