The CT morphological difference of luscka joint between Hirayama disease patients and non-Hirayama disease patients

English Keywords:Hirayama disease  Uncovertebral joint  Uncinate process  Pathogenesis

English Abstract:

  【Abstract】 Objectives: To study the morphological difference of luscka joints between Hirayama disease patients and non-Hirayama disease patients on CT scan and to provide a new possible mechanism of Hirayama disease. Methods: 32 patients(all males) with a mean age of 19.4±4.1(range 16-37 years) and with Hirayama disease were treated in our hospital from October 2006 to January 2012, the mean course of disease was 31.7±23.7 months(range, 1-120 months). 32 patients(all males) with a mean of age was 19.1±4.3(range, 12-26 years) suffering from acute neck pain and having no Hirayama disease were reviewed as control. Both groups showed no age related difference. From the cervical CT coronal plane reconstruction images which passing through the transverse foramen center of C3-C7 in GE-PACS system, the following data were measured in both sides: ①The width of the uncinate process base: the distance between inner and outer margin of the uncinate process at the upper edge of the vertebral body. ②The height of the uncinate process: the vertical distance from the top of the uncinate process to the upper edge of the vertebral body. ③The distance between two uncinate processes: the distance between the tips of the bilateral uncinate processes. ④The inclination angle of the uncinate process: the angle between the uncinate process and the upper edge of the vertebral body. ⑤The inclination angle of the inferior endplate: the angle between the uncinate process: the vertical distance from the top of the uncinate process to the upper edge of the vertebral body. Results: There were no significant side-related differences on the width of the uncinate process base, the height of the uncinate process, the distance of the uncinate process, the inclination angle of the uncinate process and the inclination angle of the inferior endplate at the same segment from C3 to C7 in Hirayama disease patients(P>0.05). However, differences were found on the height of the uncinate process and the distance between two uncinate processes of C3-C7(P<0.05), C6 and C4 had the highest and lowest height of the uncinate process as C6>C5>C7>C3>C4. The distance of the uncinate process gradually increased from C3 to C7. There were no significant differences on the width of the uncinate process base, the inclination angle of the uncinate process and the inclination angle of inferior endplate(except for C3) of C3-C7(P>0.05). Then, using the mean value of the left and right sides as the width of the base of uncinate process, the height of uncinate process, and calculating the sum of inclination angle of the uncinate process, the sum of inclination angle of inferior endplate of the upper vertebra and the difference between the sums(the sum of inclination angle of uncinate process - the sum of inclination angle of inferior endplate of the upper vertebra), then calculating the mean value and standard deviation. Compared with the non-Hirayama disease patients, there were no significant differences on the uncinate process base, the distance of the uncinate process and the sum of inclination angle of the uncinate process at the same segment of Hirayama disease patients(P>0.05), while the height of the uncinate process and the sum of inclination angle of uncinate process of Hirayama disease patients were significantly smaller than those of the control group, respectively(P<0.05), and the differences between the sums were larger than those of the control group(P<0.05). Conclusions: Hirayama disease patients may possess a dysplasia in the luscka joint, manifesting the nonuniform development of the uncinate indicators. Lower uncinate process and smaller inclination angle of inferior endplate of the upper vertebra are common, The consequential cervical instability may play a significantly important role in the pathogenesis and progress of Hirayama disease.