No effects of cervical spine motion on cranial dura mater strain

Objective. The aim of this study was to analyze the effects of cervical spine motion on cranial dura mater length variations in anatomical specimens using high-resolution linear displacement transducers. We hypothesized that transducer resolution was sufficient to measure dura mater length changes if they occurred during cervical spine motion. Design. Cranial dura mater strain was measured using differential variable reluctance transducers during cervical spine motion in 11 formaldehyde-fixed whole-body anatomical specimens (mean age: 82 years). Background. Several theories hypothesize that functional maneuvers carried out on the spine have an effect on intra-cranial structures due to the supposed continuity of spinal and cranial dura mater. The displacements of the spinal dura mater are supposed to be transmitted to the cranial dura mater. Methods. Eleven anatomical specimens were used. Each specimen (positioned supine) was provided with three openings in the skull (frontal and parietal regions), leaving the dura mater intact. A differential variable reluctance transducer was inserted in frontal or sagittal orientation in the dura mater exposed in each opening. Strain was recorded during cyclic motions of cervical spine flexion-extension, lateral bending and axial rotation. Results. Average length changes ranged from 0.01 to 0.13% (SD 0.01–0.21%) of initial length for all motions and locations studied, which in all cases was less than the accuracy of the transducers. Conclusion. It can thus be concluded that cervical spine motion does not induce significant strain of the cerebral dura mater.