Force plate gait analysis in Doberman Pinschers with and without cervical spondylomyelopathy

Comparison of Two Surgical Techniques for the Treatment of Canine Disc Associated-Cervical Spondylomyelopathy

Objective

To compare prosthetic disc and vertebral distraction stabilization in dogs with disc-associated cervical spondylomyelopathy (DA-CSM).

Study Design

A retrospective clinical study.

Animals

25 dogs.

Methods

Dogs presenting with clinical signs and MRI findings compatible with DA-CSM underwent surgery. Implantation of the Adamo's prosthetic disc (PD) or vertebral distraction-stabilization (DS) with intervertebral cage, ventral locking plates, and dorsal transarticular screws was performed. All dogs were followed-up and evaluated clinically for a minimum of 1 year and radiographically for at least 3 months. In particular, we focused on the evaluation of subsidence (the degree of vertebral collapse).

Results

Twenty-five dogs were enrolled: 12 with PD implantation and 13 with DS implantation. Of these, 24 dogs were followed-up at 1 year. Overall, 12 dogs improved (4 PD and 8 DS), eight were stable (4 PD and 4 DS), and four deteriorated (3 PD and 1 DS). Deterioration was more common in PD cases, especially soon after surgery. In a few PD cases, a second surgery was necessary. The most common complication in dogs with DS was discospondylitis. Subsidence was detected in 11 PD and 7 DS dogs. Subsidence was more severe and occurred sooner after surgery in PD cases compared to DS cases. DS cases were more prone to clinical improvement and less prone to subsidence than PD cases in this study. However, the statistical evidence was weak owing to the small sample size.

Conclusion

The preliminary results suggest that prosthetic disc implantation is more prone to clinical and radiographic failures than distraction stabilization.

Clinical Relevance

The DS technique is a valuable surgical option for treating dogs with DA-CSM, with favorable short- and long-term clinical and radiographic outcomes.

Ex vivo Evaluation of the Dynamic Morphometry of the Caudal Cervical Intervertebral Disc Spaces of Small Dogs and Cats

The objective of this study was to provide a morphometric description of the caudal cervical intervertebral disc (IVD) spaces of small-breed dogs and cats. Specimens consisting of C4 through C7 from five small-breed dogs and six cats were positioned in neutral, flexion, extension, and lateral bending positions; and CT images were acquired. Height and width of the cranial and caudal vertebral endplates (VEPs), angle between the VEPs (IVD wedge angle), and craniocaudal distance (IVD width) between VEPs for the four loading positions were measured and compared for three segments (C4-C5, C5-C6, and C6-C7). VEP size normalized to body weight from medium-sized dogs was retrieved from a previous study and compared with data from small dogs and cats. A linear mixed model was used to compare outcome measures. Significance was set to p < 0.05. VEP size normalized to body weight was the largest in small dogs compared with cats (p = 0.0422) and medium-sized dogs (p = 0.0064). Cats and medium-sized dogs were similar (p = 0.2763) in this regard. Flexion and extension induced a reduction of IVD width in the ventral portion of the IVD and the area of the nucleus. The dorsal part of the IVD remained unchanged throughout loading conditions. Unique morphometric characteristics of the caudal cervical IVD space of small dogs and cats were detected that are different from those described in sizes of dogs (medium-sized) typically affected by caudal cervical spondylomyelopathy (CSM). These findings may help to understand the different pathomechanisms in cervical spinal disease between small- and medium-sized dogs, including caudal CSM.

Development of a simple method to measure static body weight distribution in neurologically and orthopedically normal mature small breed dogs

Background

Objective outcome measures capable of tracking different aspects of functional recovery in dogs with acute intervertebral disc herniation are needed to optimize physical rehabilitation protocols. Normal, pre-injury distribution of body weight in this population is unknown. The aims of this study were to quantify static weight distribution (SWD) using digital scales and to establish the feasibility of different scale methods in neurologically normal, mature, chondrodystrophic small breed dogs predisposed to intervertebral disc herniation.

Results

Twenty-five healthy, mature dogs were enrolled with a mean age of 4.6 years (SD 2.7) and a mean total body weight of 11.5 kg (SD 3.6). SWD for the thoracic and pelvic limbs and between individual limbs was acquired in triplicate and expressed as a percentage of total body weight using commercially available digital scales in four combinations: two bathroom, two kitchen (with thoracic and pelvic limbs combined), four bathroom and four kitchen (with limbs measured individually). SWD was also obtained using a pressure sensing walkway for comparison to scale data. Feasibility for each method was determined and coefficients of variation were used to calculate inter-trial variability. Mean SWD values were compared between methods using an ANOVA. The two bathroom scales method had the highest feasibility and lowest inter-trial variability and resulted in mean thoracic and pelvic limb SWD of 63 % (SD 3 %) and 37 % (SD 3 %), respectively. Thoracic limb mean SWD was higher for the PSW compared to any of the scale methods (p < 0.0001).

Conclusions

SWD in a population of healthy chondrodystrophic dogs was simple to obtain using inexpensive and readily available digital scales. This study generated SWD data for subsequent comparison to dogs recovering from acute intervertebral disc herniation.

Center of Pressure in the Paws of Clinically Sound Dogs in Comparison with Orthopedically Diseased Dogs

Simple Summary

The analysis of the center of pressure is an important tool that allows conclusions to be drawn about the body balance of a patient. This balance can be altered by orthopedic or neurological diseases. To date, there are few data on the center of pressure in the paws of walking dogs. This study aimed to show the compensatory changes in the center of pressure parameters within the paw during stance-phase in the walking dog, with data being collected non-invasively by walking dogs with osteoarthritis and healthy dogs (control group) over a pressure platform. Differences in the center of pressure parameters were found between the affected and non-affected limbs of the diseased dogs, but also in comparison to the corresponding limbs of sound dogs. It was shown that dogs with osteoarthritis show different compensatory changes in the center of pressure parameters depending on whether a front or a hind limb are affected. This can reflect a compensatory redistribution of the body mass as well as compensatory changes of body balance. Based on these observations, a deeper investigation of the center of pressure within the paws of dogs would be of interest and a diagnostic application could become possible in the future.

Abstract

The center of pressure (COP) is recognized as a valuable tool for the assessment of orthopedic and neurologic disorders in humans. Relatively few studies are available in veterinary medicine, particularly concerning the COP in the individual paw. This study assessed the dynamic paw COP parameters during the stance phase of dogs with cox- or cubarthrosis (20 dogs each), as well as of 20 sound dogs. Data were obtained by walking over a pressure platform and analyzed within the diseased groups in comparison to the control group. Both diseased groups showed significant differences between the affected and non-affected limbs, but also in comparison to the reference limbs of sound animals. For coxathrosis, the primary increase was in the medio-lateral COP displacement and the COP area in both hind limbs. For cubarthrosis, the most prominent changes were an increase in the medio-lateral COP displacement in the ipsilateral hind limb and in the cranio-caudal COP displacement in the lame limb. Additionally, the COP area increased in both hind limbs. This can reflect a compensatory redistribution of the body mass as well as compensatory changes of body balance.

Development of a Novel Gait Analysis Tool Measuring Center of Pressure for Evaluation of Canine Chronic Thoracolumbar Spinal Cord Injury

Gait evaluation after spinal cord injury (SCI) is an important component of determining functional status. Analysis of center of pressure (COP) provides a dynamic reflection of global locomotion and postural control and has been used to quantify various gait abnormalities. We hypothesized that COP variability would be greater for SCI versus normal dogs and that COP would be able to differentiate varying injury severity. Our objective was to investigate COP, COP variability, and body weight support percentage in dogs with chronic SCI. Eleven chronically non-ambulatory dogs after acute severe thoracolumbar SCI were enrolled. COP measurements in x (right-to-left, COPx) and y (craniocaudal, COPy) directions were captured while dogs walked on a pressure-sensitive treadmill with pelvic limb sling support. Root mean square values (RMS_COPx and RMS_COPy) were calculated to assess variability in COP. Body weight support percentage was measured using a load cell. Gait also was quantified using an open field scale (OFS) and treadmill-based stepping and coordination scores (SS, RI). Mean COPx, COPy, RMS_COPx, and RMS_COPy were compared between dogs with SCI and previously evaluated healthy controls. RMS measurements and support percentage were compared with standard gait scales (OFS, SS, RI). Mean COPy was more cranial and RMS_COPx and RMS_COPy were greater in SCI versus normal dogs (p < 0.001). Support percentage moderately correlated with SS (p = 0.019; R² = 0.47). COP analysis and body weight support measurements offer information about post-injury locomotion. Further development is needed before consideration as an outcome measure to complement validated gait analysis methods in dogs with SCI.

Peak forelimb ground reaction forces experienced by dogs jumping from a simulated car boot

Many dog owners allow their pets to jump out of a car boot; however, to date, there has been no study that has investigated whether this places dogs at risk of injury. The aim of this study was to investigate the relationship between height and peak vertical ground reaction force (vGRF) in static start jumps. Fifteen healthy adult dogs performed three jumps from a platform that represented common vehicle boot sill heights (0.55, 0.65, 0.75 m), landing on a single force platform. Kinetic data (mediolateral (Fx), craniocaudal (Fy) and vertical (Fz)) were normalised for body weight and analysed via a one-way repeated analysis of variance (ANOVA) and pairwise post hoc tests with a Bonferroni correction applied. There was a significant difference in peak forelimb vGRF between both the 0.55 m (27.35±4.14 N/kg) and the 0.65 m (30.84±3.66 N/kg) platform (P=0.001) and between the 0.65 and 0.75 m (34.12±3.63 N/kg) platform (P=0.001). There was no significant difference in mediolateral or craniocaudal forces between the heights examined. These results suggest that allowing dogs to jump from bigger cars with a higher boot sill may result in augmented levels of loading on anatomical structures. Further research is required to investigate the kinematic effects of height on static jump-down and how peak forelimb vGRF relates to anatomical loading and subsequent injury risk.

Kinetic and kinematic follow-up gait analysis in Doberman Pinschers with cervical spondylomyelopathy treated medically and surgically

Background

The efficacy of treatment of dogs with cervical spondylomyelopathy (CSM) is commonly based on the owner's and clinician's perception of the gait, which is highly subjective and suffers from observer bias.

Hypothesis/Objectives

To compare selected kinetic and kinematic parameters before and after treatments and to correlate the findings of gait analysis to clinical outcome.

Animals

Eight Doberman Pinschers with CSM confirmed by magnetic resonsance imaging.

Methods

Patients were prospectively studied and treated with either medical management (n = 5) or surgery (n = 3). Force plate analysis and 3‐D kinematic motion capture were performed at initial presentation and approximately 8 weeks later. Force plate parameters evaluated included peak vertical force (PVF). Kinematic parameters measured included number of pelvic limb strides, stifle flexion and extension, maximum and minimum thoracic limb distance, truncal sway, and thoracic limb stride duration.

Results

Kinematic analysis showed that deviation of the spine to the right (truncal sway) was significantly smaller (P < .001) and the degree of right stifle flexion was significantly larger (P = .029) after treatment. Force plate analysis indicated that PVF was significantly different after treatment (P = .049) and the difference of the PVF also was significantly larger (P = .027). However, no correlation was found with either method of gait analysis and clinical recovery.

Conclusions and Clinical Importance

Kinetic and kinematic gait analysis were able to detect differences in dogs with CSM before and after treatment. A correlation of gait analysis to clinical improvement could not be determined.

Assessing adverse effects of intra-articular botulinum toxin A in healthy Beagle dogs: A placebo-controlled, blinded, randomized trial

OBJECTIVE

To investigate the clinical, cytological, and histopathological adverse effects of intra-articularly injected botulinum toxin A in dogs and to study whether the toxin spreads from the joint after the injection.

METHODS

A longitudinal, placebo-controlled, randomized clinical trial was conducted with six healthy laboratory Beagle dogs. Stifle joints were randomized to receive either 30 IU of onabotulinum toxin A or placebo in a 1:1 ratio. Adverse effects and spread of the toxin were examined by evaluating dynamic and static weight-bearing of the injected limbs, by assessing painless range of motion and pain on palpation of joints, and by performing synovial fluid analysis, neurological examination, and electrophysiological recordings at different examination time-points in a 12-week period after the injections. The dogs were then euthanized and autopsy and histopathological examination of joint structures and adjacent muscles and nerves were performed.

RESULTS

Intra-articular botulinum toxin A did not cause local weakness or injection site pain. Instead, static weight-bearing and painless range of motion of stifle joints decreased in the placebo limbs. No clinically significant abnormalities associated with intra-articular botulinum toxin A were detected in the neurological examinations. Electrophysiological recordings showed low compound muscle action potentials in two dogs in the botulinum toxin A-injected limb. No significant changes were detected in the synovial fluid. Autopsy and histopathological examination of the joint and adjacent muscles and nerves did not reveal histopathological adverse effects of the toxin.

CONCLUSION

Intra-articular botulinum toxin A does not produce significant clinical, cytological, or histopathological adverse effects in healthy dogs. Based on the electrophysiological recordings, the toxin may spread from the joint, but its clinical impact seems to be low.

Comparison of angle, shape, and position of articular processes in Dobermans and Great Danes with and without cervical spondylomyelopathy

Background

Cervical spondylomyelopathy (CSM), also known as wobbler syndrome, affects mainly large and giant-breed dogs, causing compression of the cervical spinal cord and/or nerve roots. Structural and dynamic components seem to play a role in the development of CSM; however, pathogenesis is not yet fully understood. Physiologic and pathologic movements of the cervical spine depend on the morphology and morphometry of articular processes, as well as on intervertebral discs and vertebral column ligaments. Moreover, the characteristics of the articular processes affect motion and stability of the vertebral column. The goal of this study was to investigate the angle, shape, and position of the articular surfaces within the articular processes and compare them between Doberman Pinschers and Great Danes with and without cervical spondylomyelopathy.

Results

Magnetic resonance images were obtained for 60 dogs: 15 clinically normal Dobermans (Dob-N), 15 CSM-affected Dobermans (Dob-CSM), 15 clinically normal Great Danes (GD-N), and 15 CSM-affected Great Danes (GD-CSM). Angle, shape, and position (lateral distance) of the articular surfaces from the articular processes were analyzed from C_2–3 to C₇-T₁. Results indicate that the mean angle was different between Dob-CSM and GD-CSM at C_4–5, C_5–6, and C_6–7, and between GD-N and GD-CSM at C_6–7. There were differences between Dob-N and GD-N, and between Dob-CSM and GD-CSM for the lateral distance at most locations, except C_2–3. Compared with Great Danes, Dobermans generally had a greater proportion of concave caudal surfaces at C_4–5, C_5–6, and C_6–7. Concave articular surfaces have been associated with greater axial rotation. This may explain the high proportion of disc-associated CSM in Dobermans compared to Great Danes. The differences between breeds suggest they may have different motion patterns in the caudal cervical vertebral column.

Conclusions

Considering that no differences in angle, shape, or position of the articular surfaces within the articular processes were found between normal and CSM-affected dogs, their relevance appears to have a secondary role in the pathogenesis of CSM.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-0997-4) contains supplementary material, which is available to authorized users.

Kinetic and kinematic gait analysis in the pelvic limbs of normal and post-hemilaminectomy Dachshunds

OBJECTIVE

To compare pelvic limb kinetic and kinematic gait parameters between Dachshunds six months following hemilaminectomy for treatment of thoracolumbar disc extrusion (post-hemilaminectomy; PHL) and Dachshunds without history and clinical evidence of spinal cord disease (control; CON).

METHODS

The CON (n = 8) and PHL (n = 6) Dachshunds were recruited for objective gait evaluation. Kinetic data collected included peak vertical force (PVF), stance phase duration and swing phase duration. Kinematic data collected included tarsal, stifle and hip range of motion (ROM) during stance and swing phases of the trot, tail ROM, and horizontal and vertical components of pelvis ROM.

RESULTS

No significant differences were identified between tarsal, stifle, hip, and tail ROM between CON and PHL Dachshunds. Although PVF was not significantly different between CON and PHL Dachshunds, PVF varied on average by 14% between the pelvic limbs in PHL Dachshunds (p <0.01). Horizontal and vertical components of pelvic ROM were on average 51% and 36% greater in PHL Dachshunds compared to CON Dachshunds (p = 0.04 and p = 0.02 respectively).

CLINICAL SIGNIFICANCE

Six months after decompressive hemilaminectomy, Dachshunds have abnormal pelvic motion and asymmetric pelvic limb weight bearing. Pelvic sway (ROM) may be a more sensitive indicator of myelopathy than pelvic limb joint ROM and may serve as a useful objective tool to characterize response to treatment in patients with spinal cord disease.

A preliminary evaluation of the reliability of a modified functional scoring system for assessing neurologic function in ambulatory thoracolumbar myelopathy dogs

BACKGROUND

The objective of this study was to develop and assess the reliability of a modified scoring system for evaluating the function of the two pelvic limbs separately, in ambulatory thoracolumbar myelopathy dogs. A previously established neurologic score scale for dogs with T3-L3 lesions was modified in order to provide a separate score for each pelvic limb.

RESULTS

Seventeen ambulatory dogs with thoracolumbar myelopathies were evaluated. Using the new scale, two observers independently performed 22 observational gait analyses (OGAs) in ten dogs without videotape. Another 18 OGAs were performed in seven dogs by watching videotapes of them ambulating. There was poor agreement (concordance correlation coefficient, 0.87) between the two observers for all 40 OGAs. When stratified, the agreement was moderate (concordance correlation coefficient, 0.90) in the OGAs without videotaping and poor (concordance correlation coefficient, 0.80) for the OGAs based on videotapes. For the decision regarding which pelvic limb was more severely affected, a fair agreement (kappa value, 0.30) between the two observers was noted. Without videotape there was only slight agreement (kappa value, 0.05), but with videotape there was moderate agreement (kappa value, 0.56).

CONCLUSIONS

The modified scoring system in this study provides moderate reliability in assessing the functional neurologic status of each pelvic limb, by OGA without videotape, in canine T3-L3 patients. Further development of this scoring system is required. However, imperfect agreement when visually quantifying neurological deficits is not unexpected.

A comparison of ground reaction forces during level and cross-slope walking in Labrador Retrievers

Background

Inclined or slippery surfaces and various other types of obstacles are common demands in our environment. Dogs with impaired locomotion might have difficulties to manage rough terrain. Gait analyses using force plates or pressure plates, which are well established to characterize limb loads in human medicine as well as in animals, are mostly limited to level surfaces. Therefore, the aim of this study was to investigate the effect of cross-slope walking in ten healthy Labrador Retrievers using a pressure plate walkway system. The dogs walked over the pressure plate on a level surface, with a lateral elevation angle of 10° (CS1) or 15° (CS2) until five valid trials were achieved. Three measurements were obtained at weekly intervals. Peak vertical force (PFz), vertical impulse (IFz), step length, and velocity were determined.

Results

Compared to level walking (LW), cross-slope walking was associated with a significant decrease in GRF of the up-slope (US) hindlimb, which was compensated for by the down-slope (DS) forelimb. The other diagonal limb pair showed less pronounced effects during CS1, but in CS2 more weight was shifted onto the DS hindlimb during the first two measurements, thus reducing weight on the US forelimb (for IFz). The effect diminished from trial to trial, with GRF values approaching LW standards finally. The IFz was a more sensitive measure than the PFz. The step length of the DS forelimb was significantly decreased in both cross-slope conditions, while the step length of the US forelimb only decreased during CS2.

Conclusions

The dogs adapted their gait pattern and step length to compensate for the discrepancy in apparent leg length caused by the cross-slope. The results suggest that cross-slope walking requires functional musculoskeletal adaptations that may be difficult for animals with impaired locomotion. Further, this knowledge might be of clinical impact for early diagnosis of neurological disorders, mild lameness and proprioceptive deficits.