The purpose of this study was to determine whether
it would be feasible to use oblique lumbar interbody fixation for
patients with degenerative lumbar disease who required a fusion
but did not have a spondylolisthesis. A series of CT digital images from 60 patients with abdominal
disease were reconstructed in three dimensions (3D) using Mimics
v10.01: a digital cylinder was superimposed on the reconstructed
image to simulate the position of an interbody screw. The optimal
entry point of the screw and measurements of its trajectory were
recorded. Next, 26 cadaveric specimens were subjected to oblique
lumbar interbody fixation on the basis of the measurements derived
from the imaging studies. These were then compared with measurements
derived directly from the cadaveric vertebrae. Our study suggested that it is easy to insert the screws for
L1/2, L2/3 and L3/4 fixation: there was no significant difference
in measurements between those of the 3-D digital images and the
cadaveric specimens. For L4/5 fixation, part of L5 inferior articular
process had to be removed to achieve the optimal trajectory of the
screw. For L5/S1 fixation, the screw heads were blocked by iliac
bone: consequently, the interior oblique angle of the cadaveric specimens
was less than that seen in the 3D digital images. We suggest that CT scans should be carried out pre-operatively
if this procedure is to be adopted in clinical practice. This will
assist in determining the feasibility of the procedure and will
provide accurate information to assist introduction of the screws. Cite this article:
We reviewed seven children with torticollis due to refractory atlanto-axial rotatory fixation who were treated in a halo vest. Pre-operative three-dimensional CT and sagittal CT imaging showed deformity of the superior articular process of C2 in all patients. The mean duration of halo vest treatment was 67 days (46 to 91). The mean follow-up was 34 months (8 to 73); at the latest review six patients demonstrated remodelling of the deformed articular process. The other child, who had a more severe deformity, required C1-2 fusion. We suggest that patients with atlanto-axial rotatory fixation who do not respond to conservative treatment and who have deformity of the superior articular process of C2 should undergo manipulative reduction and halo-vest fixation for two to three months to induce remodelling of the deformed superior articular process before C1-2 fusion is considered.
