An anatomical study of the external bone graft axis from the pedicle to the endplate from T10 to L5 in compression healing fractures of the anterior vertebral column / 中华创伤骨科杂志

ABSTRACT

Objective:To anatomically study the external bone graft axis from the pedicle (canal) to the endplate designed for compression healing fractures of the anterior vertebral column in freshly dried vertebral specimens from T10 to L5.Methods:Eight groups of freshly dried vertebral specimens from T10 to L5 (128 vertebral bodies and 256 lateral pedicles and lateral vertebral bodies) were used to observe the vertebral axis of the pedicle (canal), the internal sagittal diameter of the pedicle (canal), and the sagittal diameter of the vertebral body, and the position of vertebral pedicle (canal) axis (f-angle) before design of the external bone graft axis from the pedicle (canal) to the endplate of the compression healing vertebral body. (1) The internal sagittal diameter of the pedicle (canal) was divided into 3 segments. The lateral segment of the vertebral plate was wide, the middle segment of the isthmus of the vertebral arch was narrow and the medial segment of the terminal segment of the vertebral arch was wide. The narrow isthmus of the middle arch (canal) was used as a transposition axis in the design of the axis of the bone graft from the vertebral arch (canal) to the endplate of the compression healing vertebral body. (2) The axis of the vertebral body of the pedicle (canal) was located medial to the transposition axis, parallel to the f-angle at 0° as described by Saillant G. (3) The compression degree of the vertebral body was measured at the outer edge of the lateral anterior column, with Ⅰ° for less than 1/4 compression of the anterior column of the vertebral body, Ⅱ° for 1/4 to 2/4, Ⅲ° for 2/4 to 3/4 and Ⅳ° for more than 3/4 of the compression. (4) The f-angle described by Salliant G at the entry end which was corresponding to the endplate of the compression healing vertebral body was used to design the pedicle (canal) to the outer implant axis of the endplate of the compression healing vertebral body.Results:At an f-angle of 8° to 10°, the bone graft axis was aligned with the Ⅱ° compression healing vertebral endplate on the superior endplate side of the vertebral body axis of the arch; at an f-angle of 16° to 18°, the bone graft axis corresponded to the superior endplate of the Ⅰ° compression healing vertebral body. At an f-angle of -10°~-8°, the bone graft axis corresponded to the Ⅲ° compression healing vertebral endplate on the inferior endplate side of the vertebral body axis of the arch; at an f-angle of -18°~-16°, the bone graft axis corresponded to the inferior endplate of the Ⅳ° compression healing vertebral body.Conclusions:The external axis from the pedicle (canal) to the endplate designed in the present anatomic study for compression healing fractures of the anterior vertebral column allows for safe and easy granular bone implantation due to the toughness of the cortical bone around the arch root (canal) in addition to the precise design of the bone graft axis from the pedicle to the endplate from T10 to L5.