Laterality of cervical disc herniation

Purpose: Cervical disc herniation (CDH) is found more frequently at the lower cervical spine than at the upper or middle level. However, there is scarcity of data about the laterality of CDH. The aim of this study is to detect the laterality of CDH. Methods: We retrospectively evaluated preoperative computed tomography myelograms and magnetic resonance images of 75 cases of CDH who underwent single level anterior cervical discectomy and fusion at C4-5, C5-6, or C6-7 levels from 2008 to 2010 in our institute. Statistical analyses were performed using the Chi-square test. Results: Eleven cases were found at C4-5 level, 42 cases at C5-6 level, and 22 cases at C6-7 level. At C4-5 level, CDH was recognized at the right side in 2 cases, at the left side in 2 cases, and at the center in 7 cases. At C5-6 level, CDH was found at the right side in 20 cases and at the left side in 22 cases. At C6-7 level, CDH was found at the right side in 3 cases and at the left side in 19 cases with significantly high frequency of left-sided CDH (p < 0.025). Conclusions: In this study, it was revealed that the left-sided CDH was more frequent than the right-sided CDH at C6-7 level.