Compensatory change of brain in recurrent anterior shoulder dislocation -fMRI study-
Authors: Hitoshi Shitara, Kenji Takagishi, Daisuke Shimoyama, Tsuyoshi Ichinose, Atsushi Yamamoto, Toshihisa Osawa, Tsutomu Kobayashi
References: Journal of Shoulder and Elbow Surgery - May 2014 (Vol. 23, Issue 5, Page 601,
It was revealed that the reorganization of the central nervous system (CNS) has occurred in not only brain disorders but also in spinal and musculoskeletal diseases. Then, the importance of considering the effect of CNS in orthopedic diseases was recognized. However, there was no research about compensatory change of the brain in recurrent anterior shoulder instability (RSI).
The purpose of this study is to investigate the compensatory change of the brain in RSI using functional magnetic resonance image (fMRI). Ten healthy volunteers (N-group) and 10 RSI patients (P-group) participated in this study. Brain activation was examined by fMRI technique. We applied active (AM) and passive (PM) shoulder motion task and motor imagery (MI) task during fMRI.
In AM, there was significant activation in the left primary motor cortex, bilateral inferior parietal lobules, supplementary motor area (SMA) and bilateral cerebellum (P-group minus N-group). During imagery of maintenance of heavy kettle in shoulder abduction in MI, there was significant activation in the left premotor cortex, SMA, right cerebellum, right amygdala and left fusiform gyrus (P-group minus N-group). During passive external rotation at abduction in PM, there was significant activation in the right premotor cortex (N-group minus P-group).
This study reveals that RSI can cause reorganization of the CNS, suggesting that such an injury might be regarded as a neurophysiologic dysfunction, not a simple peripheral musculoskeletal injury. This evidence could explain clinical symptoms that accompany this type of injury and lead to severe dysfunction.