To verify the validity of finite element analysis (FEA) predictions obtained from a canine lumbar segment model in comparison with experimental biomechanical testing results from the same subjects.
6 healthy beagle dogs were euthanized for other purposes.
The L1–2 and L5–6 segments were harvested from euthanized animals and subjected to rotation tests and compression tests, respectively, using both ex vivo mechanical testing and FEA. For each method, we recorded the maximum torque value and angle of vertebral body rotation at rupture observed in rotation tests, as well as the maximum stress value and displacement of the vertebral body endplate at rupture measured from compression tests. We then calculated Pearson’s correlation coefficient to determine correlations between the angle of gyration and displacement at rupture determined by mechanical testing and FEA. The study started on March 26, 2021, and ended on March 18, 2023.
For the rotation test, correlation coefficients for the maximum torque and rotation angle of the vertebral body at rupture were r = 0.92 and 0.96, respectively. For the compression test, correlation coefficients for the maximum stress and displacement of the vertebral body endplate at rupture were r = 0.73 and 0.94, respectively. All results showed strong correlations between the FEA predictions and ex vivo mechanical test results.
These findings suggest that FEA predictions are sufficiently reliable for ex vivo mechanical test results for biomechanical studies of canine lumbar segment models.
To compare the prognosis of small dogs with cervical intervertebral disc herniation (C-IVDH) when treated with ventral slot decompression (VSD) alone or with concomitant vertebral fixation (VF).
Small dogs (n = 303) weighing < 15 kg diagnosed with C-IVDH and treated with VSD.
We recorded signalment, cervical myelopathy grade, surgical site, use of VF, degree of adjacent disc degeneration, recovery, recurrence, recurrence site, and postoperative course, including the time elapsed from recovery to recurrence. We examined factors associated with recovery and recurrence during the 30-month postoperative period using multivariate logistic regression analysis.
VF did not affect recovery (P = .79). However, nonchondrodystrophic breeds had poorer recovery (OR, 5.89; P = .023) than chondrodystrophic breeds, and a higher preoperative cervical myelopathy grade (grade 3 or 4) was associated with poorer recovery (OR, 7.09 or 3.46, respectively; P = .019 or .042, respectively), compared with grade 1. VF did not affect recurrence (P = .79); however, increasing age was associated with recurrence (OR, 1.79; P = .001).
In small dogs weighing < 15 kg, there was no difference in postoperative recovery and recurrence rates after VSD with or without concomitant VF. Therefore, in small dogs with C-IVDH, even if the slot volume is increased to remove sufficient disc material during VSD, a good prognosis can be achieved with or without VF.
Objective—To compare activities of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and matrix
metalloproteinase (MMP)-3 and contents of sulfated
glycosaminoglycan (S-GAG) in joint fluid obtained
from dogs with hip dysplasia (HD) and clinically normal
dogs, evaluate correlations among these markers
in joint fluid obtained from dogs with HD, and evaluate
correlations between each marker and clinical and
Animals—26 dogs with HD (clinical group) and 43
clinically normal Beagles (control group).
Procedure—Joint fluid was aseptically collected from
the hip joints of all dogs. For each dog in the clinical
group, age, duration of lameness, radiographic
osteoarthritis (OA) score, and Norberg angle in each
affected joint were recorded. Activities of IL-1β, IL-6,
TNF-α, and MMP-3 and S-GAG contents were measured.
Values were compared between groups by use
of Mann-Whitney U tests, and the Spearman rank correlation
test was used to evaluate correlations among
markers and between each marker and clinical or
Results—Values of all markers were significantly
higher for the clinical group, compared with values for
the control group. There was a moderate positive correlation
between lameness duration and IL-6 activity
and a strong negative correlation between the
Norberg angle and IL-1β activity.
Conclusions and Clinical Relevance—Analysis of
our results indicated that there was a significant
increase in markers of OA in dogs with HD. Activities
of IL-1β and IL-6 in joint fluid of dogs with HD may be
influenced by the severity of laxity in the hip joint and
lameness duration, respectively. (Am J Vet Res
OBJECTIVE To retrospectively evaluate the epidemiological and morphological features and outcome of surgical treatment of incomplete ossification of the dorsal neural arch of the atlas (IODA) in dogs with atlantoaxial instability (AAI).
ANIMALS 106 AAI-affected dogs that underwent ventral fixation of the atlantoaxial joint.
PROCEDURES Medical records and CT images for each dog were reviewed. Dogs were allocated to 1 of 2 groups on the basis of the presence or absence of IODA or of dens abnormalities (DAs) in CT images.
RESULTS Of the 106 dogs with AAI, 75 had and 31 did not have IODA; 70 had and 36 did not have DAs. Incomplete ossification was present in the cranialmost, central, or caudalmost portion of the dorsal neural arch of the atlas in 59, 39, and 28 dogs, respectively; 2 or 3 portions were affected in 29 and 11 dogs, respectively. The mean CT value (in Hounsfield units) for the midline of the dorsal neural arch of the atlas in dogs with IODA was significantly lower than that for the same site in the dogs without IODA. The mean age at surgery for dogs with central IODA was significantly higher than that of the non-IODA group. The severity of spinal cord injury before or after atlantoaxial ventral fixation did not differ between the IODA and non-IODA groups.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that concomitant DAs or IODA is common in dogs with AAI. In dogs with incomplete ossification in the central part of the dorsal neural arch of the atlas, surgical treatment of AAI generally occurs at a middle to advanced age.
OBJECTIVE To evaluate and compare morphological characteristics of the dens in atlantoaxial instability (AAI)-predisposed toy-breed dogs (TBDs) with and without AAI and non–AAI-predisposed healthy Beagles.
ANIMALS 80 AAI-affected and 40 nonaffected TBDs and 40 Beagles.
PROCEDURES Each dog underwent CT examination of the cervical vertebral column. On median 3-D multiplanar reconstruction images, the dens angle (DA) was measured as were the lengths of the dens and the body of the axis; the dens-to-axis length ratio (ratio of the dens length to the axis body length [DALR]) was calculated. Data were compared among dog groups.
RESULTS The DALR in nonaffected TBDs and Beagles did not differ significantly. The mean DALR for AAI-affected TBDs was significantly lower than that for nonaffected TBDs. The mean DA of AAI-affected TBDs was significantly greater than that of Beagles and nonaffected TBDs.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a low DALR might be associated with a high probability of dens abnormalities in TBDs. Additionally, dens length in AAI-affected TBDs appeared to be smaller than that in non–AAI-affected TBDs, given the low DALR in AAI-affected TBDs. Further investigations to determine reference ranges of the DA and DALR and the potential usefulness of those variables as diagnostic markers for AAI in TBDs are warranted.