Three-dimensional analysis of the cervical spine kinematics: effect of age and gender in healthy subjects.

STUDY DESIGN.: A three-dimensional (3D) analysis of the cervical spine kinematics in vivo about a large asymptomatic database in order to evaluate the impact of age and gender on the neck's performances. OBJECTIVE.: To investigate the effect of age and gender on kinematical parameters of the cervical spine, specifically quantitative parameters concerning coupled movements and proprioception, using the infra-red POLARIS measurement system. SUMMARY OF BACKGROUND DATA.: Cervical spine kinematics has been investigated in vivo by numerous authors using various devices. However, few is known about the influence of gender and age on the 3D cervical biomechanics, specifically regarding coupled movements and proprioceptive abilities. METHODS.: A total of 140 asymptomatic volunteers (70 men and 70 women) aged 20 to 93 years old were enrolled. The noninvasive infrared system Polaris was used to quantify the 3D range of motion (ROM) of cervical spine and to evaluate proprioceptive abilities. For validating the protocol in terms of reproducibility, 12 volunteers were tested 3 times by 2 independent operators. RESULTS.: The standard error of measurement for the maximal ROM in the 3 space planes was 5%. Gender had no significant influence on the 3D cervical ROM, except for the "70-79 years old" group. Age had a significant influence on all main movements showing 0.55 degrees to 0.79 degrees magnitude decrease per decade. Age and gender had no significant influence on coupled movements. "Head-to-Target" proprioception was significantly affected by the age only in the horizontal plane. CONCLUSION.: A data base for cervical ROM, pattern of motion, and proprioceptive capability was established in population of 140 healthy subjects of various age and gender. Significant age-related decrease in ROM and proprioceptive abilities were observed in this study. Coupled movements did not vary with gender or age; however, their role in the cervical performance increased with age since main movements were limited.