Objective—To compare biomechanical characteristics of vertebral segments after vertebral body plating or laminar stabilization following complete incision of the annulus fibrosus.
Sample—Vertebral segments from T13 through L3 obtained from 18 canine cadavers.
Procedures—A 4-point bending moment was applied in flexion and extension to the intact vertebral segments to determine a baseline range of motion (ROM) and neutral zone (NZ). Vertebral columns were then destabilized by creating a defect in the intervertebral disk via complete incision of the ventral aspect of the annulus fibrosus. The bending moment was applied again after stabilization was accomplished via vertebral body plating or with laminar stabilization (n = 9 vertebral segments/stabilization technique). The ROM and NZ were compared with their baseline values and among treatment groups. Finally, load-to-failure testing was performed in flexion.
Results—Mean relative ROM and NZ for segments treated with laminar stabilization were significantly lower than those for segments treated with vertebral plates.
Conclusions and Clinical Relevance—Analysis of in vitro results suggested that laminar stabilization of vertebral segments provided greater stiffness than did vertebral body plating.
Objective—To determine the association between the 3-dimensional (3-D) motion pattern of the caudal lumbar and lumbosacral portions of the canine vertebral column and the morphology of vertebrae, facet joints, and intervertebral disks.
Sample Population—Vertebral columns of 9 German Shepherd Dogs and 16 dogs of other breeds with similar body weights and body conditions.
Procedure—Different morphometric parameters of the vertebral column were assessed by computed tomography (CT) and magnetic resonance imaging. Anatomic conformation and the 3-D motion pattern were compared, and correlation coefficients were calculated.
Results—Total range of motion for flexion and extension was mainly associated with the facet joint angle, the facet joint angle difference between levels of the vertebral column in the transverse plane on CT images, disk height, and lever arm length.
Conclusions and Clinical Relevance—Motion is a complex process that is influenced by the entire 3-D conformation of the lumbar portion of the vertebral column. In vivo dynamic measurements of the 3-D motion pattern of the lumbar and lumbosacral portions of the vertebral column will be necessary to further assess biomechanics that could lead to disk degeneration in dogs.
Objective—To evaluate the 3-dimensional motion
pattern including main and coupled motions of the
caudal lumbar and lumbosacral portions of the vertebral
column of dogs.
Animals—Vertebral columns of 9 German Shepherd
Dogs (GSDs) and 16 dogs of other breeds with similar
body weights and body conditions .
Procedure—Main and coupled motions of the caudal
lumbar and lumbosacral portions of the vertebral column
(L4 to S1) were determined by use of a testing
apparatus that permitted precise application of known
pure moments to the vertebral column. Motion was
compared between GSDs and dogs of other breeds.
Results—All specimens had a similar motion pattern
consisting of main motion and a certain amount of
coupled motion including translation. Vertebral
columns of GSDs had significantly less main motion
in all directions than that of dogs of other breeds.
Translation was similar in GSDs and dogs of other
breeds and was smallest at the lumbosacral motion
Conclusions and Clinical Relevance—Results indicated
that motion in the caudal lumbar and lumbosacral
portions of the vertebral column of dogs is
complex and provided a basis for further studies evaluating
abnormal vertebral columns. ( Am J Vet Res 2004;65:544–552)