Anatomical projection of the cervical uncinate process in ventral, ventrolateral, and posterior decompressive surgery

Object. The cervical uncinate processes (UPs), their variations, and the re lationships between the neurovascular structures and surrounding bone were investigated in this anatomical study. The object of this study was to high light the important surgery-related considerations associated with ventral, ventrolateral, and posterior decompressive surgery. Methods. Forty-nine adult C3-7 dry bone samples were used, and 10 measureme nts were obtained for each vertebra. The anterior measurements involved the cervical uncinate process (UP): height, width, length, distance between it s tip and vertebral foramina, interuncinate process distance, sagittal angl e with the superior margin of the vertebral body (VB), VB anteroposterior d iameter, and VB width. Posterior measurements involved the vertical distanc e between the superior border of the lamina at the lamina-facet joint and t he tip of the UP, as well as the horizontal distance between the medial-mos t border of the superior facet and the tip of the UP. All symmetrical struc tures were measured bilaterally. There were no statistically significant di fferences between right- and left-sided measurements in this series. The height of the UP increased gradually at each segmental level between C- 3 and C-7. The width of the UP did not change with segmental level (5.0 mm at C-3 compared with 5.3 mm at C-7). On average, the length of the UP was r elatively constant. The distance from the tip of the UP to vertebral forami na averaged 1 mm at the C2-3 level and 1.5 mm at the C5-6 level. Interuncin ate distance and VB width gradually increased and were highly variable, whi ch appeared to be related with osteophyte formation. There was a slight gra dual increase from C-3 to lower segments, and it paralleled with the midlin e anteroposterior diameter of the same VB. The angle between the UP and the superior margin of the VB exhibited great variety. The posterior measureme nts decreased gradually from C-3 to C-7. Conclusions. Based on the data obtained in this study, a surgeon is provide d with a three-dimensional orientation as well as anatomical knowledge. Thi s knowledge also allows for a more effective neurovascular decompression by minimizing the surgery-related complications.