Abstract

Background
In many study reports, the cervical collar is effective in restricting 60 to 70 percent of cervical motion in 4 directions; flexion, extension, lateral bending, and rotation. But we discovered the phenomenon of “sliding”in the extensive motion of cervical vertebrae during the investigation about the effectiveness of cervical collars. Thus, the purpose of this study was to find out whether the cervical collars are effective in restricting the extensive motion of the cervical spine Methods: Fifteen volunteers, young men (23~32 years), with clinically and radiographically normal cervical spines were studied. The active cervical motion angles in flexion and extension were measured in each subject and were compared with the motion angles permitted in each of the two cervical orthoses (Philadelphia collar, Stifneck collar). We compared the restricting ability of cervical orthoses in the non-sliding state with the sliding state, especially during extension. One sample t-test, and paired t-test were used in the calculation of the statistics and the significant difference was indicated when p< 0.05. Results: With the pressure forced inferoposteriorly from the apex of the skull while extended, we created the “sliding”and compared the previously established method of measurement and the non-sliding state. The results showed significant difference among the three. The results, which the use of the previous method without considering the “sliding”was compared with the new method in consideration of the “sliding”, differed significantly. This phenomenon dimin-ished the effect of restricting the cervical motion of the cervical orthoses by 50%. Conclusion: With the pressure forced inferoposteriorly given to a person wearing cervical orthoses, we could observe the occurrence of the phenomenon that occiput was slid along the rear slope face of cervical orthoses and that reduced the restricting effect of cervical extensivemotion around 10%. Therefore, it must be considered that cervical orthoses need to be improved to reduce the motion for the direction.

• Keywords: Cervical collar, Sliding phenomenon, Efficacy