@article{lewis_thomovsky_moore_2023, title={Adaptation of land treadmill scoring system for underwater treadmill in dogs with thoracolumbar intervertebral disc extrusion}, volume={300}, ISSN={["1532-2971"]}, DOI={10.1016/j.tvjl.2023.106039}, abstractNote={The underwater treadmill (UWTM) is utilized in dogs recovering from thoracolumbar intervertebral disc extrusion (TL-IVDE). Gait scoring is validated for dogs with TL-IVDE walking on the land treadmill (LT) but has not been reported for the UWTM. Our objective was to investigate if LT gait analysis could be applied to the UWTM and if non-ambulatory dogs walking unassisted on the UWTM, at a standardized water level, would be more likely to generate gait scores compared to on the LT. This was a prospective, observational study in dogs with TL-IVDE managed surigcally. At 0, 2, 4, 8 and 12 weeks post-operatively, paired video footage of dogs walking on the LT and UWTM (water level at the greater trochanter) was used to generate 0-100 stepping (SS) and coordination (regularity index, RI) scores. Scores were compared between treadmill type and over time. Twenty dogs were enrolled and seventy-eight paired recordings were available for review. Median gait scores increased over time but did not differ by treadmill type (P = 0.262 for SS, P = 0.533 for RI). Combining SS and RI, more recordings received scores of 0 for the LT (n=58/156; 37.2%) compared to the UWTM (n=44/156; 28.2%; P = 0.043). Scores of 0, at visits when there was at least movement present at multiple joints, was more common on the LT (n=11/108; 10.2%) compared to the UWTM (n=2/108, 1.9%; P = 0.026). In dogs recovering from TL-IVDE, LT-based gait scoring was feasible in dogs walking on the UWTM and might complement other gait analysis methods, especially for non-ambulatory dogs.}, journal={VETERINARY JOURNAL}, author={Lewis, M. J. and Thomovsky, S. A. and Moore, G. E.}, year={2023} }
 @article{lewis_early_mariani_munana_olby_2020, title={Influence of Duration of Injury on Diffusion Tensor Imaging in Acute Canine Spinal Cord Injury}, volume={37}, ISSN={["1557-9042"]}, DOI={10.1089/neu.2019.6786}, abstractNote={Diffusion tensor imaging (DTI) quantifies microstructural lesion characteristics but impact of the interval between spinal cord injury (SCI) and examination on imaging characteristics is unclear. Our objective was to investigate the impact of duration of injury on DTI indices in dogs with acute, spontaneous SCI due to thoracolumbar intervertebral disc herniation (IVDH) and explore associations with clinical severity. Twenty-six dogs with acute thoracolumbar IVDH of variable severity who underwent DTI were included. Neurologic severity was graded using the Modified Frankel Score (0-V). Fractional anisotropy (FA) and mean diffusivity (MD) were calculated on regions of interest within and adjacent to the lesion epicenter. Relationships between FA or MD and duration (injury to imaging interval) or neurologic severity were determined using regression analysis and Wilcoxon rank sum. Median age was 6.8 years (1-13), median duration was 1.5 days (1-9) and neurologic signs ranged from ambulatory paraparesis (MFS II) to paraplegia with absent pain perception (MFS V). Mean FA was 0.61+/-0.09 cranial to the lesion, 0.57+/-0.12 at the epicenter and 0.55+/-0.10 caudally. Mean MD was 1.18x10-3+/-0.0002 cranially, 1.09x10-3+/-0.0002 at the epicenter and 1.14x10-3+/-0.0002 caudally. Accounting for neurologic severity and age, FA caudal to the epicenter decreased with increasing duration of injury (p = 0.02). Lower MD within the lesion epicenter was associated with worse neurologic severity (p = 0.01). Duration of injury should be considered when interpreting DTI results in dogs with acute thoracolumbar IVDH. MD might differentiate injury severity in the acute setting and be worthy of development as an imaging biomarker.}, number={21}, journal={JOURNAL OF NEUROTRAUMA}, author={Lewis, Melissa J. and Early, Peter J. and Mariani, Christopher L. and Munana, Karen R. and Olby, Natasha J.}, year={2020}, month={Nov}, pages={2261–2267} }
 @article{schreeg_evans_allen_lewis_luckring_evola_richard_piner_thompson_adin_et al._2019, title={Cardiac Leiomyosarcoma in a Cat Presenting for Bilateral Renal Neoplasia}, volume={168}, ISSN={["1532-3129"]}, DOI={10.1016/j.jcpa.2019.02.005}, abstractNote={A 10-year-old neutered female domestic longhair cat was presented to a tertiary care veterinary hospital for evaluation of a right renal mass that was identified incidentally on abdominal radiographs and classified further as a sarcoma based on fine needle aspiration cytology. Further diagnostic workup, including ultrasound and cytology, identified a sarcoma in the left kidney. After approximately 1 month of conservative medical management, the clinical condition deteriorated and the cat was humanely destroyed. Post-mortem examination confirmed bilateral renal masses with multifocal infarction and extensive necrosis, and further identified a large mass at the apex of the heart as well as multiple pulmonary nodules. Microscopical examination of the masses identified a population of poorly-differentiated neoplastic spindle cells, consistent with sarcoma. Immunohistochemically, the neoplastic cells expressed smooth muscle actin and muscle-specific actin, but were negative for myoglobin and factor VIII. Phosphotungstic acid–haematoxylin staining was unable to identify cross-striations in the neoplastic cells. Based on these results and the pattern of lesion distribution, the cat was diagnosed with cardiac leiomyosarcoma with pulmonary and bilateral renal metastasis.}, journal={JOURNAL OF COMPARATIVE PATHOLOGY}, author={Schreeg, M. E. and Evans, B. J. and Allen, J. and Lewis, M. C. and Luckring, E. and Evola, M. and Richard, D. K. and Piner, K. and Thompson, E. M. and Adin, D. B. and et al.}, year={2019}, month={Apr}, pages={19–24} }
 @article{lewis_williams_langley_jarvis_sawicki_olby_2019, title={Development of a Novel Gait Analysis Tool Measuring Center of Pressure for Evaluation of Canine Chronic Thoracolumbar Spinal Cord Injury}, volume={36}, ISSN={0897-7151 1557-9042}, url={http://dx.doi.org/10.1089/neu.2019.6479}, DOI={10.1089/neu.2019.6479}, abstractNote={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.}, number={21}, journal={Journal of Neurotrauma}, publisher={Mary Ann Liebert Inc}, author={Lewis, Melissa J. and Williams, Kimberly D. and Langley, Taylor and Jarvis, Leighanne M. and Sawicki, Gregory S. and Olby, Natasha J.}, year={2019}, month={Nov}, pages={3018–3025} }
 @article{lewis_laber_olby_2019, title={Predictors of Response to 4-Aminopyridine in Chronic Canine Spinal Cord Injury}, volume={36}, ISSN={0897-7151 1557-9042}, url={http://dx.doi.org/10.1089/neu.2018.5975}, DOI={10.1089/neu.2018.5975}, abstractNote={4-Aminopyridine (4AP), a potassium channel antagonist, can improve hindlimb motor function in dogs with chronic thoracolumbar spinal cord injury (SCI); however, individual response is variable. We hypothesized that injury characteristics would differ between dogs that do and do not respond to 4AP. Our objective was to compare clinical, electrodiagnostic, gait, and imaging variables between dogs that do and do not respond to 4AP, to identify predictors of response. Thirty-four dogs with permanent deficits after acute thoracolumbar SCI were enrolled. Spasticity, motor and sensory evoked potentials (MEPs, SEPs), H-reflex, F-waves, gait scores, and magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) were evaluated at baseline and after 4AP administration. Baseline variables were assessed as predictors of response; response was defined as ≥1 point change in open field gait score. Variables were compared pre- and post-4AP to evaluate 4AP effects. Fifteen of 33 (45%) dogs were responders, 18/33 (55%) were non-responders and 1 was eliminated because of an adverse event. Pre-H-reflex threshold <1.2 mA predicted non-response; pre-H-reflex threshold >1.2 mA and Canine Spasticity Scale overall score <7 were predictive of response. All responders had translesional connections on DTI. MEPs were more common post-4AP than pre-4AP (10 vs. 6 dogs) and 4AP decreased H-reflex threshold and increased spasticity in responders. 4-AP impacts central conduction and motor neuron pool excitability in dogs with chronic SCI. Severity of spasticity and H-reflex threshold might allow prediction of response. Further exploration of electrodiagnostic and imaging characteristics might elucidate additional factors contributing to response or non-response.}, number={9}, journal={Journal of Neurotrauma}, publisher={Mary Ann Liebert Inc}, author={Lewis, Melissa J. and Laber, Eric and Olby, Natasha J.}, year={2019}, month={May}, pages={1428–1434} }
 @article{lewis_cohen_olby_2017, title={Magnetic resonance imaging features of dogs with incomplete recovery after acute, severe spinal cord injury}, volume={56}, ISSN={1362-4393 1476-5624}, url={http://dx.doi.org/10.1038/s41393-017-0004-8}, DOI={10.1038/s41393-017-0004-8}, abstractNote={Retrospective case series. Describe the magnetic resonance imaging (MRI) features of dogs chronically impaired after severe spinal cord injury (SCI) and investigate associations between imaging variables and residual motor function. United States of America. Thoracolumbar MRI from dogs with incomplete recovery months to years after clinically complete (paralysis with loss of pain perception) thoracolumbar SCI were reviewed. Lesion features were described and quantified. Gait was quantified using an ordinal, open field scale (OFS). Associations between imaging features and gait scores, duration of injury (DOI), or SCI treatment were determined. Thirty-five dogs were included. Median OFS was 2 (0–6), median DOI was 13 months (3–83), and intervertebral disk herniation was the most common diagnosis (n = 27). Myelomalacia was the most common qualitative feature followed by cystic change; syringomyelia and fibrosis were uncommon. Lesion length corrected to L2 length (LL:L2) was variable (median LL:L2 = 3.5 (1.34–11.54)). Twenty-nine dogs had 100% maximum cross-sectional spinal cord compromise (MSCC) at the lesion epicenter and the length of 100% compromised area varied widely (median length 100% MSCC:L2 = 1.29 (0.39–7.64)). Length 100% MSCC:L2 was associated with OFS (p = 0.012). OFS was not associated with any qualitative features. DOI or treatment type were not associated with imaging features or lesion quantification. Lesion characteristics on MRI in dogs with incomplete recovery after severe SCI were established. Length of 100% MSCC was associated with hind limb motor function. Findings demonstrate a spectrum of injury severity on MRI among severely affected dogs, which is related to functional status.}, number={2}, journal={Spinal Cord}, publisher={Springer Nature}, author={Lewis, Melissa J. and Cohen, Eli B. and Olby, Natasha J.}, year={2017}, month={Oct}, pages={133–141} }
 @article{lewis_howard_olby_2017, title={The Relationship between Trans-Lesional Conduction, Motor Neuron Pool Excitability, and Motor Function in Dogs with Incomplete Recovery from Severe Spinal Cord Injury}, volume={34}, ISSN={0897-7151 1557-9042}, url={http://dx.doi.org/10.1089/neu.2017.5012}, DOI={10.1089/neu.2017.5012}, abstractNote={Spontaneous, acute, complete thoracolumbar spinal cord injury (TL-SCI) in dogs frequently results in permanent deficits modeling chronic paralysis in people. Recovery of walking without recovery of sensation has been interpreted in dogs as reflexive spinal walking. To evaluate this assumption, this study characterized the electrophysiological status of motor and sensory long tracts and local reflex circuitry in dogs with absent recovery of sensation after acute TL-SCI and correlated findings to gait scores. Twenty dogs with permanent deficits after acute, clinically complete TL-SCI and 6 normal dogs were prospectively enrolled. Transcranial magnetic motor evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), H-reflex, and F-waves were evaluated. Gait was quantified using an ordinal, open field scale (OFS) and treadmill-based stepping and coordination scores (SS, RI). MEP latency and H-reflex variables were compared between cases and controls. Associations between presence of MEPs, SSEPs, F-waves or H-reflex variables, and gait scores were determined. Pelvic limb MEPs were detected in 4 cases; no case had trans-lesional sensory conduction. Latency was longer and conduction velocity slower in cases than controls (pa = 0.0064, 0.0023, respectively). Three of 4 cases with pelvic limb MEPs were ambulatory, and gait scores (OFS, SS, RI) were each associated with presence of trans-lesional conduction (pa = 0.006, 0.006, 0.003, respectively). H threshold in cases (mean, 3.2mA ±2.5) was lower than controls (mean, 7.9mA ±3.1; pa = 0.011) and was inversely associated with treadmill-based scores, SS, and RI (pa = 0.042, 0.043, respectively). The association between pelvic limb MEPs and gait scores supports the importance of descending influence on regaining walking after severe TL-SCI in dogs rather than just activation of spinal walking. The inverse association between H-reflex threshold and gait scores implies that increases in motor neuron pool excitability might also contribute to motor recovery.}, number={21}, journal={Journal of Neurotrauma}, publisher={Mary Ann Liebert Inc}, author={Lewis, Melissa J. and Howard, James F., Jr and Olby, Natasha J.}, year={2017}, month={Nov}, pages={2994–3002} }
 @article{lewis_olby_early_mariani_muñana_seiler_griffith_2016, title={Clinical and Diagnostic Imaging Features of Brain Herniation in Dogs and Cats}, volume={30}, ISSN={0891-6640}, url={http://dx.doi.org/10.1111/jvim.14526}, DOI={10.1111/jvim.14526}, abstractNote={BackgroundQuantification of brain herniation on MRI and its immediate clinical implications are poorly described.}, number={5}, journal={Journal of Veterinary Internal Medicine}, publisher={Wiley}, author={Lewis, M.J. and Olby, N.J. and Early, P.J. and Mariani, C.L. and Muñana, K.R. and Seiler, G.S. and Griffith, E.H.}, year={2016}, month={Sep}, pages={1672–1680} }
 @article{lewis_olby_sharp_early_2013, title={Long-Term Effect of Cervical Distraction and Stabilization on Neurological Status and Imaging Findings in Giant Breed Dogs With Cervical Stenotic Myelopathy}, volume={42}, ISSN={0161-3499}, url={http://dx.doi.org/10.1111/j.1532-950X.2013.12034.x}, DOI={10.1111/j.1532-950x.2013.12034.x}, abstractNote={Abstract}, number={6}, journal={Veterinary Surgery}, publisher={Wiley}, author={Lewis, Melissa and Olby, Natasha J and Sharp, Nick JH. and Early, Peter}, year={2013}, month={Jul}, pages={701–709} }