Variation of disc-facet orientation between Hirayama disease and non-Hirayama disease

English Keywords:Hirayama disease  Disc-facet angle  Pathogenesis

English Abstract:

  【Abstract】 Objectives: To study the variation of disc-facet orientation between Hirayama disease and non-Hirayama disease and provide a new possible mechanism of Hirayama disease. Methods: 45 patients including 44 males and 1 female with a mean age of 19.3±3.9 years(range 13-37 years) and with Hirayama disease treated in our hospital from October 2006 to January 2012, the mean course of disease was 35.6±23.2 months(range, 1 to 120 months). 45 patients including 41 males and 4 female with a mean of age was 19.5±4.3 years(range 11-26 years) suffering from acute neck pain and having normal cervical CT in the same period were selected as control. Both groups showed no age or sex related difference. The disc-facet angles of C3-T1 of the two groups were measured in GE-PACS system. The disc-facet angle was defined as the angle between the line crossing midpoint of the vertebral upper zygapophyseal facet and the line of objective vertebral upper edge in the CT sagittal plane. Results: There were no significant side-related differences for disc-facet angles from C3 to T1 in both groups(P<0.05). After merging the left and right side data of the same segment, C5 was the center of C3-T1 disc-facet angle distribution in both groups, which indicated that disc-facet angle increased gradually from C3 to C5, while decreased gradually from C5 to T1. The disc-facet angles of C3-T1 in the surgical group were greater than those in the control group(P<0.05). Conclusions: The disc-facet angles of Hirayama disease are greater than those of non-Hirayama disease, dysplastic zygapophyseal facets may lead to the articular surface tend to be horizontal, and subsequent cervical instability, which may play an important role in the pathogenesis and progress of Hirayama disease.