Objective—To evaluate the accuracy of specific magnetic resonance imaging (MRI) sequences in determining the site, lateralization, and extent of extruded intervertebral disk material (EIDM), compared with surgical findings, in Dachshunds with thoracolumbar intervertebral disk extrusion (TLIDE).
Design—Prospective clinical study.
Sample Population—16 Dachshunds with clinical signs of intervertebral disk disease.
Procedures—Preoperative T1-weighted, T2-weighted, and short tau inversion recovery (STIR) MRI measurements and description of the location of EIDM were compared with intraoperative measurements and determination of the EIDM position.
Results—The T12-13 intervertebral disk space was the most frequent site of EIDM (6/16 dogs). The EIDM lateralized with equal frequency to the left and right sides; no central extrusions were seen. There was moderate to substantial agreement (kappa, 0.59) between MRI and surgical findings for evaluation of the craniocaudal distribution of the EIDM. For measurement of the length of EIDM, the T1-weighted, T2-weighted, and STIR sequences had a mean error of −1.15, −0.38, and −1.93 mm, respectively; concordance correlation coefficients were 0.666, 0.904, and 0.458, respectively. Mean absolute errors were 2.54, 1.35, and 2.90 mm, respectively; these values did not differ significantly.
Conclusions and Clinical Relevance—In the thoracolumbar vertebral column of Dachshunds with clinical signs of intervertebral disk disease, MRI is a valuable technique for determining location and craniocaudal length of EIDM. Compared with T1-weighted and STIR images, T2-weighted images appeared to be more accurate and precise and are potentially more reliable for determination of the length of EIDM in those dogs.
Objective—To compare the analgesic effects of intra-articularly administered saline (0.9% NaCl) solution, morphine, dexmedetomidine, and a morphine-dexmedetomidine combination in dogs undergoing stifle joint surgery for cranial cruciate ligament rupture.
Design—Randomized, controlled, clinical trial.
Animals—44 dogs with cranial cruciate ligament rupture that underwent tibial tuberosity advancement (TTA) or tibial plateau leveling osteotomy (TPLO).
Procedures—Dogs received intra-articular injections of saline solution (0.2 mL/kg [0.09 mL/lb]), morphine (0.1 mg/kg [0.045 mg/lb]), dexmedetomidine (2.5 μg/kg [1.14 μg/lb]), or a combination of morphine (0.1 mg/kg) and dexmedetomidine (2.5 μg/kg). Intra-articular injections of the stifle joint were performed after completion of the corrective osteotomy procedure, just prior to skin closure. Signs of pain were assessed every 2 hours thereafter on the basis of mean behavioral and objective pain scores. Dogs with pain scores exceeding predetermined thresholds were given hydromorphone (0.05 mg/kg [0.023 mg/lb], SC) as rescue analgesia.
Results—Time to rescue analgesia did not significantly differ between dogs that underwent TTA versus TPLO. No significant difference in time to rescue analgesia was found among dogs receiving intra-articular injections of dexmedetomidine (median, 6 hours; range, 2 to 10 hours), morphine (median, 7 hours; range, 4 to 10 hours), or saline solution (median, 5 hours; range, 4 to 10 hours). However, time to rescue analgesia for dogs receiving intra-articular injection of the morphine-dexmedetomidine combination (median, 10 hours; range, 6 to 14 hours) was significantly longer than the time to rescue analgesia for other treatment groups.
Conclusions and Clinical Relevance—Intra-articular administration of the morphine-dexmedetomidine combination provided longer-lasting postoperative analgesia, compared with either morphine or dexmedetomidine alone, in dogs undergoing TTA or TPLO. (J Am Vet Med Assoc 2014;244:1291–1297)
OBJECTIVE To develop a model of hip joint synovitis on the basis of intra-articular injection of a sodium urate suspension in dogs and to characterize associated gait changes.
ANIMALS 6 healthy adult dogs.
PROCEDURES Each dog was sedated, and synovitis was induced by injection of 1 mL of a sodium urate suspension (20 mg/mL) into the right hip joint under ultrasonographic guidance. Observational and instrumented gait analyses to determine temporospatial, kinetic, and kinematic variables were performed prior to and 4, 8, and 24 hours after sedation and synovitis induction.
RESULTS Injection of a sodium urate suspension into the hip joint of healthy dogs resulted in lameness of the ipsilateral pelvic limb as determined by observational and instrumented gait analyses. For all dogs, lameness was clinically detectable within 1.5 to 2 hours after injection, reached its maximum intensity at 4 hours after injection, and had subsided by 24 hours after injection.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that injection of a sodium urate suspension into the hip joint of healthy dogs reliably induced synovitis and signs of pain and lameness in the ipsilateral pelvic limb that lasted 24 hours. This model can be used in conjunction with instrumented gait analysis to provide information on gait changes associated with hip joint disease and might be useful for evaluating the efficacy of analgesics or other interventions for the treatment of hip joint disease in dogs.
To use the small data approach of the Clinical and Laboratory Standards Institute (CLSI) to evaluate the transferability of reference intervals (RIs) for kinetic variables obtained with instrumented gait analysis (IGA) in dogs from an RI-originator laboratory to another laboratory that used the same data acquisition and analytic techniques for IGA in walking dogs.
27 adult client-owned dogs without evidence of lameness.
Dogs were individually walked at their preferred velocity on a pressure-sensing walkway for IGA at the Colorado State University Animal Gait Laboratory (CSU-AGL), and 6 valid trials were analyzed for each dog. The small data approach of the CLSI was then used to evaluate transferability of RIs previously established at the Purdue University Animal Gait Laboratory (PU-AGL). A linear model was used to establish weight-dependent RIs for peak vertical force (PVF).
Results indicated that RIs of dynamic weight distribution (DWD), DWD symmetry index, DWD coefficient of variation, PVF symmetry index, and PVF coefficient of variation were transferable from PU-AGL to CSU-AGL, whereas the weight-dependent RIs for PVF were not. Regression slopes for PVF versus body weight were greater for all limbs in dogs tested at the CSU-AGL, compared with historic results for dogs tested at the PU-AGL.
CONCLUSIONS AND CLINICAL RELEVANCE
Use of the small data approach method of the CLSI to validate transference of RIs for IGA kinetic variables in walking dogs was simple and efficient to perform and may help facilitate clinical and research collaborations on gait analysis.
To compare mechanical properties (stiffness, yield load, failure load, and deformation at failure) of 2 pearl-type locking plate system (PLS) constructs (PLS 1 and PLS 2) in a simulated fracture gap model and to compare screw push-out forces of the 2 PLSs with and without plate contouring.
40 PLS constructs.
Mechanical properties of uncontoured PLS 1 (n = 8) and PLS 2 (8) constructs were evaluated in synthetic bone-plate models under axial compression. Screw push-out forces were evaluated in 6 uncontoured and 6 contoured PLSs of each type. Variables of interest were compared between PLS groups and between contoured and uncontoured plates by statistical methods.
Yield and failure loads were higher in the PLS 1 group than in the PLS 2 group, but stiffness did not differ significantly between groups. All constructs failed by plate bending, with greater deformation in the PLS 2 group. Push-out force to screw-plate uncoupling was higher in the PLS 2 group than in the PLS 1 group for uncontoured and contoured plates. Locking mechanism failure of PLS 1 specimens was through screw-thread stripping. The PLS 2 specimens failed by node deformation followed by screwhead stripping.
CONCLUSIONS AND CLINICAL RELEVANCE
Distinct mechanical differences were identified between the 2 PLSs. The clinical relevance of these differences is unknown. Further research including cyclic fatigue testing is needed to reveal more clinically pertinent information.
OBJECTIVE To evaluate the effects of selective hip joint denervation on gait abnormalities and signs of hip joint pain in dogs.
ANIMALS 6 healthy adult hound-type dogs.
PROCEDURES Minimally invasive denervation was performed on the right hip joint of each dog. Two weeks later, sodium urate was injected into the right hip joint to induce synovitis. Dogs were evaluated clinically and by use of instrumented gait analysis before and 2 weeks after minimally invasive denervation and 4, 8, and 24 hours after induction of synovitis. Dogs were euthanized, and necropsy and histologic examination were performed.
RESULTS No kinetic or kinematic gait modifications were detected 2 weeks after minimally invasive denervation. Denervation did not eliminate signs of pain and lameness associated with sodium urate–induced synovitis. Results of histologic examination confirmed that denervation was an effective method for transecting the innervation of the craniolateral and caudolateral aspects of the hip joint capsule.
CONCLUSIONS AND CLINICAL RELEVANCE In this study, minimally invasive denervation did not result in gait modifications in dogs. Denervation did not abolish the signs of pain and lameness associated with generalized induced synovitis of the hip joint. Further studies are required before conclusions can be drawn regarding the clinical usefulness of hip joint denervation for dogs with hip dysplasia.
OBJECTIVE To compare the effects of conventional and slanted ventral slot procedures on the biomechanical behavior of the C5-C6 vertebral motion unit (VMU) in dogs.
SAMPLE 14 vertebral columns (C4 through C7) from canine cadavers.
PROCEDURES Specimens were assigned to a conventional or slanted ventral slot group (n = 7/group). For each specimen, the C5-C6 VMU was tested in ventral and dorsal bending and positive and negative axial torsion before and after surgery. Range of motion (ROM), stiffness, and energy absorption were compared between the 2 groups.
RESULTS Both procedures significantly increased the ROM and stiffness and significantly decreased the energy absorption of the C5-C6 VMU in ventral and dorsal bending. Both procedures also increased the ROM in positive and negative axial torsion. In negative torsion, total stiffness and stiffness over the maximum ROM tested decreased less for the slanted slot procedure than for the conventional slot procedure. There were no significant differences between procedures for any of the other biomechanical outcomes examined.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the biomechanical response of the C5-C6 VMU to the conventional and slanted ventral slot procedures was not significantly different, especially when considering postsurgical instability induced by both procedures. This was most likely due to disruption of the nucleus pulposus and dorsal annulus fibrosus of the disk with both procedures. On the basis of these findings, neither procedure appeared biomechanically superior. Comparative clinical studies are warranted to further evaluate the 2 procedures.