The Pathogenesis and Treatment of Acute Spinal Cord Injuries in Dogs

Surface electromyography: A pilot study in canine spinal muscles

In veterinary practice, rehabilitation modalities are often used to help in the recovery of animals affected by InterVertebral Disc Disease (IVDD), a condition frequently observed in chondrodystrophic dog breeds and can lead to Spinal Cord Injury (SCI), resulting in pain, motor impairments and neurological deficits, but there is a lack of objective assessment tools for patient evolution. In this work, an innovative approach using surface ElectroMyoGraphy (sEMG) is proposed to be applied in the field of veterinary medicine rehabilitation. The observed results are thought to be a direct result of nerve compression, leading to unusual patterns of muscle activation; this phenomenon can be attributed to muscle denervation, where the loss of Motor Units (MU) is the primary cause. This is thought to be responsible for the decrease in recorded sEMG amplitude and the increase in frequency observed in the pathological group.•This study involved rigorous animal preparation and signal acquisition protocols, involving multiple exercises and sub-movements, which were subsequently analysed.•RMSA is most used metric to analyse amplitude in sEMG signals, as it results in a more representative measurement of the signal variability than the Mean amplitude or the Standard Deviation.

Efficacy of Medical Ozone as an Adjuvant Treatment in Dogs with Intervertebral Disc Protusions-A Retrospective Study

Ozone-therapy is used in humans as a coadjutant treatment in intervertebral disc diseases due to its analgesic, anti-inflammatory and antioxidant effects. References in dogs are scarce and limited to clinical cases (intradiscal/paravertebral infiltrations). The aim of this study was to assess the use of medical ozone (MO) as an adjunctive treatment in dogs with intervertebral disc protrusions (Hansen Type II/Chronic). A retrospective study was conducted in dogs diagnosed with intervertebral disc protrusions by MRI/CT in which MO was used as an adjuvant therapy to conventional medical treatment. Neurological examination and quality of life (QL) at the beginning and end of study were recorded, as well as posology and possible side effects. A total of 21 patients of different breeds and sex with a mean age of 12 years were included in this study. Results showed pain relief (7 ± 3 days) and improvement of neurologic signs (11 ± 9 days) with a consequent increasement in QL (13 ± 9 days). Thirteen out of the twenty-one patients (62%) showed a complete remission of the clinical signs. No serious adverse effects were observed. Medical ozone could be a potential complementary therapy to medical treatment in dogs with intervertebral disc protrusions. Prospective studies are necessary.

Case report: Traumatic hemorrhagic cervical myelopathy in a dog

A 1.5-year-old female entire French bulldog was referred for neurological evaluation, further diagnostic tests, and treatment 24 h after a road traffic accident. Initial emergency treatment, diagnostic tests, and stabilization had been performed by the referring veterinarian. Neurological examination revealed severe spastic non-ambulatory tetraparesis and was consistent with a C1-5 myelopathy. A magnetic resonance imaging (MRI) study revealed an irregular to elongated ovoid intramedullary lesion centered over the body of C2. The lesion showed marked signal heterogeneity with a central T2W and T2* hyperintense region, surrounded by a hypointense rim on both sequences. The lesion appeared heterogeneously T1W hypointense. The lesion was asymmetric (right-sided), affecting both white and gray matter. The C2-3 intervertebral disk appeared moderately degenerate with a Pfirrmann grade of 3. No evidence of vertebral fracture or luxation was found on radiographs or MRI of the vertebral column. Additional soft tissue abnormalities in the area of the right brachial plexus were suggestive of brachial plexus and muscle injury. A diagnosis of traumatic hemorrhagic myelopathy at the level of C2 and concurrent brachial plexus injury was formed. Conservative treatment was elected and consisted of physiotherapy, bladder care with an indwelling urinary catheter, repeated IV methadone based on pain scoring (0.2 mg/kg), oral meloxicam 0.1 mg/kg q24h, and oral gabapentin 10 mg/kg q8h. The dog was discharged after 4 days, with an indwelling urinary catheter and oral medication as described. The catheter was replaced two times by the referring veterinarian and finally removed after 10 days. Thereafter, voluntary urination was seen. During the 2 months after the road traffic accident, slow recovery of motor function was seen. The right thoracic limb recovery progressed more slowly than the left limb, also showing some lower motor neuron signs during follow-up. This was judged to be consistent with a right-sided brachial plexus injury. The dog was reported ambulatory with mild residual ataxia and residual monoparesis of the right thoracic limb at the last follow-up 3 months post-injury. This case report highlights the MRI-based diagnosis of traumatic hemorrhagic myelopathy in a dog. A fair short-term outcome was achieved with conservative treatment in this case.

Thoracolumbar Retrolaminar Block: Anatomical and Radiological Study of Injectate Pattern Distribution in Canine Cadavers

The retrolaminar block is a regional anaesthetic technique, first developed in humans, in which the local anaesthetic is deposited directly onto the dorsal aspect of the thoracic or lumbar vertebral lamina. This study aims to evaluate the distribution of landmark-guided thoracolumbar retrolaminar injections in greyhound cadavers. Thirteen injections of contrast-dye solution were performed in eight cadavers at the level of the twelfth thoracic vertebra (T12), with either 20 mL (n = 8, high volume, HV) or 10 mL (n = 5, low volume, LV) per site. The spread of the injectate was evaluated through computed tomography and transverse anatomical dissection. The groups were compared using the Mann-Whitney U test. The median (range) of the extent of the spread was 4 (2-5) and 3 (2-4) intervertebral foramina in the LV and HV groups, respectively. The median (range) of the spread along the retrolaminar space was 3 (2-3) retrolaminar segments in the LV and 3 (2-4) in the HV group. Epidural and retroperitoneal spread was identified in seven cadavers. Following landmark-guided retrolaminar injections, the injectate spread both in the retrolaminar and paravertebral spaces, without any obvious association between the volume of injectate and the extent of the spread. Further studies are warranted to determine the clinical efficacy of the technique.

Long-term changes of Th17 and regulatory T cells in peripheral blood of dogs with spinal cord injury after intervertebral disc herniation

BACKGROUND

Intervertebral disc herniation (IVDH) is one of the most common causes of spinal cord injury (SCI) in dogs. As a result of acute SCI, a complex inflammatory response occurs in the spinal cord. Th17 cells (Th17) produce pro-inflammatory cytokines, while regulatory T cells (Treg) have opposite effects producing anti-inflammatory cytokines. Therefore, the aim of this study was to determine whether Th17- and Treg cells are involved in the pathogenesis of SCI or whether cellular changes occur due to coexisting inflammatory diseases. We hypothesized that chronic alterations in the Th17/Treg ratio are associated with a worse outcome after SCI.

METHODS

Twenty-six paretic or plegic dogs with IVDH with and without coexisting inflammatory disease were investigated in the acute stage of the disease and after recovery of SCI. In addition, a healthy control group was included (n = 14). Quantification of Th17 and Treg cells, from peripheral blood samples, was performed by multicolor flow cytometry and IL17 was measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

After recovery significantly higher levels of Th17 (p = 0.0265) and Treg cells (p = 0.00025) were detected compared to acute IVDH but Th17/Treg ratio did not differ significantly. Recovered dogs and the control group did not differ significantly from each other. No association between an imbalance in the ratio and neurologic severity or underlying inflammatory diseases was found.

CONCLUSION

This study demonstrated that altered Th17 and Treg levels in peripheral blood are altered in the acute stage of IVDH, preexisting inflammatory diseases seem not to influence these cell populations. Th17 and Treg cells could be considered when evaluating new treatment strategies for SCI.

Neurogenic Bladder in Dogs, Cats and Humans: A Comparative Review of Neurological Diseases

Lower urinary tract disease (LUTD) includes abnormalities in the structure and function of the bladder and the urethra. LUTD caused by neurological disease is defined neurogenic bladder (NB). The integrity of the central nervous system (CNS) and peripheral nervous system (PNS) is required to explicate normal micturition, maintaining the proper function of bladder and urethra. The location and type of neurological lesions influence the pattern of clinical manifestations, potential treatment, and prognosis. Though, in dogs and cats, spinal cord injury is considered mainly responsible for bladder and/or urethra incompetence, other disorders, congenital or acquired, involving CNS or PNS, could play a role in NB. In veterinary medicine, the information about the epidemiology, prevalence, etiopathogenesis, diagnosis and treatment of NB are scattered. The aim of this study is to provide an overview of the epidemiology, prevalence, clinical findings, diagnosis and prognosis for NB in dogs and cats compared with humans.

Characterization of microglia/macrophage phenotypes in the spinal cord following intervertebral disc herniation

Dogs frequently suffer from traumatic spinal cord injury (SCI). Most cases of SCI have a favorable prognosis but 40-50% of dogs with paraplegia and absence of nociception do not regain ambulatory abilities, eventually leading to euthanasia. Microglia and infiltrating macrophages play a crucial role in inflammatory process after SCI. However, little is known about microglia/macrophage phenotypes representing a potential target for future therapeutic strategies. In the present study, the microglia/macrophage phenotype was characterized by immunohistochemistry in the morphologically unaltered canine spinal cord (10 control dogs) and during acute and subacute SCI (1-4 and 5-10 days post injury, 9 and 8 dogs, respectively) using antibodies directed against IBA1, MAC387, MHC-II, lysozyme, EGR2, myeloperoxidase, CD18, CD204 and lectin from Griffonia simplicifolia (BS-1). The expression of these markers was also analyzed in the spleen as reference for the phenotype of histiocytic cells. Histological lesions were absent in controls. In acute SCI, 4 dogs showed mild to moderate hemorrhages, 2 dogs bilateral gray matter necrosis and 6 dogs mild multifocal axonal swellings and myelin sheath dilation. One dog with acute SCI did not show histological alterations except for few dilated myelin sheaths. In subacute SCI, variable numbers of gitter cells, axonal changes and dilated myelin sheaths were present in all dogs and large areas of tissue necrosis in 2 dogs. Neuronal chromatolysis was found in 3 dogs with acute and subacute SCI, respectively. In control dogs, microglia/macrophage constitutively expressed IBA1 and rarely other markers. In acute SCI, a similar marker expression was found except for an increase in MAC387-positive cells in the spinal cord white matter due to an infiltration of few blood-borne macrophages. In subacute SCI, increased numbers of microglia/macrophages expressed CD18, CD204 and MHC-II in the gray matter SCI indicating enhanced antigen recognition, processing and presentation as well as cell migration and phagocytosis during this stage. Interestingly, only CD204-positive cells were upregulated in the white matter, which might be related to gray-white matter heterogeneity of microglia as previously described in humans. The present findings contribute to the understanding of the immunological processes during SCI in a large animal model for human SCI.

Overview of the Current Literature on the Most Common Neurological Diseases in Dogs with a Particular Focus on Rehabilitation

Simple Summary

This paper aims to report an overview of the most common neurological diseases (intervertebral disc herniation, degenerative myelopathy, fibrocartilaginous embolism, and polyradiculoneuritis), with a main focus on rehabilitative options and outcomes, reported in recent veterinary literature. Literature seems to be positively oriented on the efficacy of the rehabilitation approach, reporting a careful and prudent choice of the protocol to be applied for the correct recovery of the patient. However, blinded, controlled, prospective studies are still necessary, above all for degenerative myelopathy, fibrocartilaginous embolism, and polyradiculoneuritis.

Abstract

Intervertebral disc herniation, degenerative myelopathy, fibrocartilaginous embolism and polyradiculoneuritis often affect dogs; and physiotherapy may improve the patient’s quality of life and/or reduce recovery times. The aim of this review was to evaluate the current scientific outcomes on these four neurological diseases and on their physiotherapy approaches. From the analysis of the published articles, it emerged that intervertebral disc herniation can be treated, with different rates of success, through a conservative or a surgical approach followed by physiotherapy. The literature is generally oriented toward the efficacy of the rehabilitation approach in this specific canine disease, often proposing intensive post-surgery physiotherapy for the most severe conditions with the absence of deep pain perception. When degenerative myelopathy, fibrocartilaginous embolism or polyradiculoneuritis occur, the existing literature supports the use of a physiotherapeutic approach: allowing a delay in the onset and worsening of the clinical signs in degenerative myelopathy, physical improvement, and, sometimes, complete remission during fibrocartilaginous embolism or acute idiopathic polyradiculoneuritis. However, papers on rehabilitation in dogs affected by polyradiculoneuritis are currently limited to single clinical cases and further blinded, controlled, prospective studies are still advisable for all four neurological diseases.

Hypothermia as a potential remedy for canine and feline acute spinal cord injury: a review

Severe spinal cord injury (SCI) resulting in permanent sensory-motor and autonomic dysfunction caudal to a damaged spinal cord (SC) segment is a catastrophic event in human as well as in veterinary medicine. The situation of paraplegic/tetraplegic people or animals is further impaired by serious complications and often displays an image of permanent suffering. Therapeutic hypothermia (TH) has shown neuroprotective capacity in numerous experimental and several clinical studies or case reports. Hence, the method draws increasing attention of neuroscientists as well as health care workers. While systemic TH is a too complex procedure for veterinary practice, local application of TH with a reduced risk of the whole body temperature fluctuations and minimal side effects can become one of the therapeutic tools considered in the treatment of acute traumatic SCIs in bigger animals, especially when surgical decompression of spinal medulla and vertebral column reconstruction is indicated. Still, additional large prospective randomized studies are essential for the standardization of therapeutic protocols and the introduction of the method into therapeutic armamentarium in canine and feline spinal traumatology. The research strategy involved a PubMed, MEDLINE (Ovid), EMBASE (Ovid), and ISI Web of Science search from January 2000 to July 2021 using the terms “canine and feline spinal cord injuryˮ, “hypothermiaˮ, and “targeted temperature managementˮ in the English language literature; also references from selected studies were scanned and relevant articles included.

Stem cell treatment trials of spinal cord injuries in animals

BACKGROUND

Spinal cord injury (SCI) is a serious neurological spinal cord damage that resulted in the loss of temporary or permanent function. However, there are even now no effective therapies for it. So, a new medical promising therapeutic hotspot over the previous decades appeared which was (Stem cell (SC) cure of SCI). Otherwise, animal models are considered in preclinical research as a model for humans to trial a potential new treatment.

METHODOLOGY

Following articles were saved from different databases (PubMed, Google scholar, Egyptian knowledge bank, Elsevier, Medline, Embase, ProQuest, BMC) on the last two decades, and data were obtained then analyzed.

RESULTS

This review discusses the type and grading of SCI. As well as different types of stem cells therapy for SCI, including mesenchymal stem cells (MSCs), neural stem cells (NSCs), hematopoietic stem cells (HSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs). The review focuses on the transplantation pathways, clinical evaluation, and clinical signs of different types of SC on different animal models which are summarized in tables to give an easy to reach.

CONCLUSION

Pharmacological and physiotherapy have limited regenerative power in comparison with stem cells medication in the treatment of SCI. Among several sources of cell therapies, mesenchymal stromal/stem cell (MSC) one is being progressively developed as a trusted important energetic way to repair and regenerate. Finally, a wide-ranged animal models have been condensed that helped in human clinical trial therapies.

Subclinical Hypoventilation in Dogs Undergoing Ventral Slot Decompressive Surgery for Cervical Myelopathy Due to Intervertebral Disc Herniation

The objective of this prospective cohort study was to document the occurrence of post-operative hypoventilation in dogs undergoing decompressive ventral slot or hemilaminectomy for the treatment of intervertebral disc herniation (IVDH). Twenty dogs undergoing ventral slot surgery and 20 dogs undergoing hemilaminectomy surgery for the treatment of IVDH that presented to XX between 2017 and 2020 were enrolled. Dogs were anesthetized using a standard protocol. Blood gas samples were taken at up to 11 time points beginning during anesthetic recovery and continuing for a maximum of 72 h post-operatively. Dogs with cervical lesions that were non-ambulatory before surgery had more evidence of subclinical hypoventilation in the immediate peri-extubation period than dogs with less severe injuries or those undergoing hemilaminectomy surgery. We found no difference in the ventilation status in dogs undergoing cervical or thoracolumbar decompressive surgery for IVDH from 8 to 72 h post-operatively. Other markers of acid-base status indicated that subclinical hypoventilation within the peri-extubation period was transient and self-limiting. There was a moderate positive correlation between sedation scores and estimated PaCO₂. These data suggest that dogs with severe cervical spinal cord injuries may be at risk for subclinical hypoventilation in the immediate peri-extubation period. Increased sedation may be correlated with decreased ventilatory status in dogs recovering from decompressive vertebral column surgery.

A Canine's Behavior and Cognitive State as It Relates to Immobility and the Success of Physical Rehabilitation in the Non-ambulatory Spinal Cord Patient

Physical rehabilitation (PR) is recommended following spinal cord injury to help improve and maintain muscle elasticity, joint mobility, and nerve health. It can also be used to relieve pain and improve cardiopulmonary fitness in an immobile patient. There is evidence, in human medicine, that PR plays a critical role in mental health and the psychological state of the patient. As part of the assessment phase, human physical therapists often identify psychosocial symptoms and barriers at the start of PR that ultimately may affect improvement in human patients suffering from injury and the loss of mobility. Patient psychological state plays an integral role in healing and outcome during treatment and rehabilitation. Specific interventions set to address these symptoms can better outcome. Arguably, one of the most emotionally traumatizing injuries suffered by a canine patient can be immobility secondary to spinal cord injury. Poorly understood is the role the canine cognitive state plays in the success of rehabilitation following spinal cord injury. Should breed, age, sex, physical fitness, personality, previous experiences and history or home lifestyle, affect the PR assessment of these patients? Do these factors affect eventual outcome following PR? The purpose of this manuscript is to explore psychosocial barriers encountered during injury rehabilitation in humans and determine if the similar barriers need to be considered when assessing a canine patient for spinal cord injury rehabilitation.

Current Insights Into the Pathology of Canine Intervertebral Disc Extrusion-Induced Spinal Cord Injury

Spinal cord injury (SCI) in dogs is commonly attributed to intervertebral disc extrusion (IVDE). Over the last years substantial progress was made in the elucidation of factors contributing to the pathogenesis of this common canine disease. A detailed understanding of the underlying histopathological and molecular alterations in the lesioned spinal cord represents a prerequisite to translate knowledge on the time course of secondary injury processes into the clinical setting. This review summarizes the current state of knowledge of the underlying pathology of canine IVDE-related SCI. Pathological alterations in the spinal cord of dogs affected by IVDE-related SCI include early and persisting axonal damage and glial responses, dominated by phagocytic microglia/macrophages. These processes are paralleled by a pro-inflammatory microenvironment with dysregulation of cytokines and matrix metalloproteinases within the spinal cord. These data mirror findings from a clinical and therapeutic perspective and can be used to identify biomarkers that are able to more precisely predict the clinical outcome. The pathogenesis of progressive myelomalacia, a devastating complication of SCI in dogs, is not understood in detail so far; however, a fulminant and exaggerating secondary injury response with massive reactive oxygen species formation seems to be involved in this unique neuropathological entity. There are substantial gaps in the knowledge of pathological changes in IVDE with respect to more advanced and chronic lesions and the potential involvement of demyelination. Moreover, the role of microglia/macrophage polarization in IVDE-related SCI still remains to be investigated. A close collaboration of clinical neurologists and veterinary pathologists will help to facilitate an integrative approach to a more detailed understanding of the molecular pathogenesis of canine IVDE and thus to identify therapeutic targets.

Outcomes of dogs with progressive myelomalacia treated with hemilaminectomy or with extensive hemilaminectomy and durotomy

OBJECTIVE

To evaluate the ability of extensive hemilaminectomy and durotomy (EHLD) to control progressive myelomalacia (PMM) in dogs.

STUDY DESIGN

Retrospective clinical study.

ANIMALS

Twenty-eight client owned dogs that underwent EHLD (n = 10) or HL alone (n = 18).

METHODS

After diagnosis by MRI, dogs were immediately treated with HL alone or EHLD at the site of intramedullary hyperintensity on T2-weighted (T2W)-MRI. Medical records were retrospectively reviewed. Follow-up data were collected via telephone interviews with the referring veterinarian and a standardized questionnaire. Postoperative survival outcome between groups was compared (log-rank test) by using Cox's proportional hazard analysis with baseline characteristics entered as covariates.

RESULTS

The survival rate was higher in the EHLD group (P = .03) compared with the HL-alone group. Eleven of 18 dogs treated with HL survived, while seven of 18 dogs died (median, 5 days after surgery). In the EHLD group, 10 of 10 dogs survived postoperatively. Baseline characteristics were not associated with postoperative survival outcomes. According to multivariate analysis, EHLD was the independent factor associated with an increase in survival rate (P = .0002).

CONCLUSION

EHLD durotomy at the intramedullary hyperintense region on T2W-MRI improved the survival rate of dogs with PMM compared with dogs treated with standard HL.

CLINICAL SIGNIFICANCE

This study provides evidence that supports treatment with EHLD in dogs with PMM. Additional prospective studies are required.

Stiffness-matched biomaterial implants for cell delivery: clinical, intraoperative ultrasound elastography provides a 'target' stiffness for hydrogel synthesis in spinal cord injury

Safe hydrogel delivery requires stiffness-matching with host tissues to avoid iatrogenic damage and reduce inflammatory reactions. Hydrogel-encapsulated cell delivery is a promising combinatorial approach to spinal cord injury therapy, but a lack of in vivo clinical spinal cord injury stiffness measurements is a barrier to their use in clinics. We demonstrate that ultrasound elastography – a non-invasive, clinically established tool – can be used to measure spinal cord stiffness intraoperatively in canines with spontaneous spinal cord injury. In line with recent experimental reports, our data show that injured spinal cord has lower stiffness than uninjured cord. We show that the stiffness of hydrogels encapsulating a clinically relevant transplant population (olfactory ensheathing cells) can also be measured by ultrasound elastography, enabling synthesis of hydrogels with comparable stiffness to canine spinal cord injury. We therefore demonstrate proof-of-principle of a novel approach to stiffness-matching hydrogel-olfactory ensheathing cell implants to ‘real-life’ spinal cord injury values; an approach applicable to multiple biomaterial implants for regenerative therapies.

Same-day surgery may reduce the risk of losing pain perception in dogs with thoracolumbar disc extrusion

OBJECTIVES

To compare the proportions of dogs with thoracolumbar disc extrusion that lose pelvic limb pain perception if surgery is performed on the day of admission or delayed overnight. To describe the outcome of those dogs that deteriorate to lose pain perception.

MATERIALS AND METHODS

Retrospective, single centre study on 273 client-owned dogs with thoracolumbar disc extrusion and intact pain perception, but inability to walk unaided on their pelvic limbs. Dogs were subdivided into two groups: early surgery (spinal decompression between their examination at day of admission and the following morning), and delayed surgery (did not undergo surgery between admission and the following morning). The proportion of dogs that lost pelvic limb pain perception overnight was compared between the early and delayed surgery groups.

RESULTS

Seven of 151 dogs in the early surgery group lost pain perception overnight compared to 15 of 122 in the delayed surgery group (Fisher's exact test, P = 0.025). Number-needed-to-treat analysis suggested that 14 dogs (95% confidence interval: 7-106 dogs) need early surgery to prevent one losing pain perception overnight. Five of the seven dogs that lost pain perception in the early surgery group recovered pain perception by 3 weeks post-operatively, compared to eight of 14 in the delayed group.

CLINICAL SIGNIFICANCE

This study suggests that an overnight delay before spinal decompression increases the risk of clinically meaningful deterioration in dogs unable to walk following thoracolumbar disc extrusion.

Association between anesthesia duration and outcome in dogs with surgically treated acute severe spinal cord injury caused by thoracolumbar intervertebral disk herniation

Background

Retrospective research recently identified a possible relationship between duration of surgery and outcome in severely affected dogs treated surgically for acute thoracolumbar intervertebral disk herniation (TL‐IVDH).

Hypothesis

That increased duration of surgery is associated with poorer outcome in dogs with absent pain perception treated surgically for TL‐IVDH.

Animals

Two hundred ninety‐seven paraplegic dogs with absent pain perception surgically treated for acute TL‐IVDH.

Methods

Retrospective cohort study. Medical records of 5 institutions were reviewed. Inclusion criteria were paraplegia with absence of pain perception, surgical treatment of TL‐IVDH, and 1‐year postoperative outcome (ambulatory: yes or no). Canine data, outcome, and surgery and total anesthesia duration were retrieved.

Results

In this study, 183/297 (61.6%) dogs were ambulatory within 1 year, 114 (38.4%) dogs failed to recover, including 74 dogs (24.9%) euthanized because of progressive myelomalacia. Median anesthesia duration in dogs that regained ambulation within 1 year of surgery (4.0 hours, interquartile range [IQR] 3.2‐5.1) was significantly shorter than those that did not (4.5 hours, IQR 3.7‐5.6, P = .01). Multivariable logistic regression demonstrated a significant negative association between both duration of surgery and total anesthesia time and ambulation at 1 year when controlling for body weight and number of disk spaces operated on.

Conclusions and Clinical Importance

Findings support a negative association between increased duration of anesthesia and outcome in this group of dogs. However, the retrospective nature of the data does not imply a causal relationship.

MRI has limited agreement with CT in the evaluation of vertebral fractures of the canine trauma patient

Complete assessment of vertebral trauma in dogs currently requires CT and MRI for evaluation of the osseous and soft tissue structures that contribute to vertebral stability. Some studies in people have suggested that MRI may be sensitive and specific at detecting vertebral fractures making this potentially a single modality that could be used in spinal trauma evaluation. This study aimed to assess the ability for observers to evaluate vertebral fractures using MRI when compared to CT, which was used as the reference standard. Twenty-nine dogs with previously diagnosed acute vertebral fractures and four dogs with no vertebral fracture that had undergone sequential CT and MRI were included into the study. One hundred twenty-eight vertebrae were evaluated for the presence of fractures. Imaging studies were read by two observers blinded to the history. While both observers had similarly high sensitivity and specificity for simple detection of any fractured vertebrae, interobserver agreement was only moderate (κ = 0.584). When evaluations were specifically limited to detection of structurally unstable fractured vertebrae both observers showed improved specificity and interobserver agreement became substantial (κ = 0.650). Complete agreement for exact fracture location between MRI and CT results was only achieved in 14.3-32.6% of fractured vertebra with up to 79% of fractures being missed in some vertebral structures. This suggests that although MRI may be able to detect the presence of fractured vertebrae, it is not able to replace CT for the complete evaluation of the traumatized spine and documentation of fracture morphology.

Reactive Oxygen Species Are Key Mediators of Demyelination in Canine Distemper Leukoencephalitis but not in Theiler's Murine Encephalomyelitis

(1) Background: Canine distemper virus (CDV)-induced demyelinating leukoencephalitis (CDV-DL) in dogs and Theiler’s murine encephalomyelitis (TME) virus (TMEV)-induced demyelinating leukomyelitis (TMEV-DL) are virus-induced demyelinating conditions mimicking Multiple Sclerosis (MS). Reactive oxygen species (ROS) can induce the degradation of lipids and nucleic acids to characteristic metabolites such as oxidized lipids, malondialdehyde, and 8-hydroxyguanosine. The hypothesis of this study is that ROS are key effector molecules in the pathogenesis of myelin membrane breakdown in CDV-DL and TMEV-DL. (2) Methods: ROS metabolites and antioxidative enzymes were assessed using immunofluorescence in cerebellar lesions of naturally CDV-infected dogs and spinal cord tissue of TMEV-infected mice. The transcription of selected genes involved in ROS generation and detoxification was analyzed using gene-expression microarrays in CDV-DL and TMEV-DL. (3) Results: Immunofluorescence revealed increased amounts of oxidized lipids, malondialdehyde, and 8-hydroxyguanosine in CDV-DL while TMEV-infected mice did not reveal marked changes. In contrast, microarray-analysis showed an upregulated gene expression associated with ROS generation in both diseases. (4) Conclusion: In summary, the present study demonstrates a similar upregulation of gene-expression of ROS generation in CDV-DL and TMEV-DL. However, immunofluorescence revealed increased accumulation of ROS metabolites exclusively in CDV-DL. These results suggest differences in the pathogenesis of demyelination in these two animal models.

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.

Transient depression of pelvic limb reflexes in dogs with acute focal thoracolumbar myelopathy

OBJECTIVE To determine the prevalence of depressed pelvic limb reflexes and changes in those reflexes over time in dogs with acute thoracolumbar myelopathy. DESIGN Prospective study. ANIMALS 34 dogs. PROCEDURES Dogs with acute pelvic limb paralysis caused by acute noncompressive nucleus pulposus extrusion (ANNPE), fibrocartilaginous embolism (FCE), or compressive intervertebral disk herniation (IVDH) within the T3-L3 spinal cord segments were enrolled in the study. Dogs with depressed or absent pelvic limb withdrawal reflexes as determined by 2 examiners were classified as affected and underwent additional testing to rule out multifocal lesions. Pelvic limb reflexes of affected dogs were reassessed every 12 hours until they returned to normal. Neurologic examinations were performed at 4 and 8 weeks after initial examination for some dogs. RESULTS Compressive IVDH, ANNPE, and FCE were diagnosed in 30, 1, and 3 dogs, respectively. Nine (5 with compressive IVDH and all 4 with FCE or ANNPE) of 34 (26%) dogs were classified as affected. Patellar reflexes were depressed in 2 of 9 affected dogs. The median time required for withdrawal reflexes to return to normal was 60 hours (range, 12 to 156 hours). Onset duration of paralysis was negatively associated with the odds of a dog being classified as affected. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dogs with focal thoracolumbar spinal cord lesions, especially those with peracute onset of paralysis, can develop transient depression of pelvic limb reflexes. Awareness of this phenomenon is important for veterinarians to accurately localize lesions and develop appropriate diagnostic plans and prognoses.

Analysis of blood degradation products and ferritin in the cerebrospinal fluid of dogs with acute thoracolumbar intervertebral disk extrusion, a prospective pilot study

Background

Hemorrhage in the spinal canal leads to further damage of the spinal cord influencing outcome in dogs with intervertebral disk (IVD) extrusion. The aim of the study was to evaluate blood degradation products and ferritin in the cerebrospinal fluid (CSF) of dogs with thoracolumbar IVD extrusion, and their association to clinical parameters and MRI findings.

Results

In the CSF of dogs with IVD extrusion, both net oxyhemoglobin absorption (NOA) and net bilirubin absorption (NBA) were significantly higher compared to the control groups of dogs with steroid responsive meningitis arteritis (SRMA) and idiopathic epilepsy (IE) (P < 0.001), but NOA compared to the idiopathic epilepsy group contaminated artificially with blood (IEc) was not (P = 0.890). Ferritin concentration was significantly higher in dogs with IVD extrusion compared to dogs with IE (P = 0.034), but not to dogs with SRMA (P = 0.526). There was no association between NOA, NBA or ferritin concentration and severity or duration of clinical signs. In dogs with a higher ferritin concentration the outcome was better (P = 0.018). In dogs with evidence of hemorrhage on MRI, NOA and NBA were significantly higher (P = 0.016, P = 0.009), but not ferritin (P = 0.0628).

Conclusion and clinical importance

Quantification of blood degradation products and ferritin in the CSF of dogs to assess subarachnoidal hemorrhage is feasible; however, larger case numbers are needed to evaluate the relevance of NBA and ferritin as prognostic indicators.

Docosahexaenoic acid induces changes in microglia/macrophage polarization after spinal cord injury in rats

Docosahexaenoic acid (DHA, 22:6 (n-3)) leads to recovery of locomotor functions observed of spinal cord injury (SCI) in rats. In present study, we characterized the expression of iba-1, CD86, CD163 in microglia/macrophages, to assess activation state and M1 (pro-inflammatory)/M2 (anti-inflammatory) phenotypes respectively, in the rostral, central and caudal segment of the spinal cord on 7 and 35 days after SCI. We found that DHA treatment leads to: (1) an increased activation and proliferation of microglial cells; (2) an alteration in the dynamics between M1 and M2 microglia/macrophages phenotypes (3) and increased production of an antioxidant enzymes. Overall, our data demonstrates that DHA has a complex effect in post-traumatic process within the central nervous system, and supports the therapeutic potential of DHA-based drugs.

An allogenic therapeutic strategy for canine spinal cord injury using mesenchymal stem cells

This study was conducted to characterize canine bone marrow-derived mesenchymal stem cells (BMSCs); in vivo tracking in mice, and therapeutic evaluation in canine clinical paraplegia cases. Canine BMSCs were isolated, cultured, and characterized in vitro as per International Society for Cellular Therapy criteria, and successfully differentiated to chondrogenic, osteogenic, and adipogenic lineages. To demonstrate the homing property, the pGL4.51 vector that contained luciferase reporter gene was used to transfect BMSCs. Successfully transfected cells were injected around the skin wound in mice and in vivo imaging was done at 6, 12 and 24 hr post MSCs delivery. In vivo imaging revealed that transfected BMSCs migrated and concentrated predominantly toward the center of the wound. BMSCs were further evaluated for allogenic therapeutic potential in 44 clinical cases of spinal cord injuries (SCI) and compared with conventional therapy (control). Therapeutic potential as evaluated by different body reflexes and recovery score depicted significantly better results in stem cell-treated group compared to control group. In conclusion, allogenic canine BMSCs can serve as potent therapeutic candidate in cell-based therapies, especially for diseases like SCI, where the conventional medication is not so promising.

Estabilização vertebral segmentar modificada no tratamento de trauma medular em ouriço-cacheiro (Coendou spinosus): relato de caso

RESUMO Uma fêmea, adulta, de ouriço-cacheiro (Coendou spinosus, F. Cuvier, 1823), foi atendida com histórico de trauma medular. No exame neurológico, foi constatada paraplegia com nocicepção preservada e sinais compatíveis com choque espinhal. Exame radiográfico e mielografia apontaram presença de fratura e luxação vertebral torácica entre T10-11. O paciente foi submetido à técnica de estabilização vertebral segmentar modificada, com pinos de Steinmann e fios de cerclagem. A técnica utilizada mostrou-se eficaz na estabilização da fratura/luxação vertebral e na recuperação dos sinais neurológicos. O paciente apresentou recuperação progressiva da deambulação. Para o conhecimento dos autores, este é o primeiro relato utilizando estabilização vertebral segmentar modificada para o tratamento de fratura/luxação vertebral torácica em Coendou spinosus.

Spinal Cord Injuries in Dogs Part II: Standards of Care, Prognosis and New Perspectives

Severe spinal cord injuries (SCI), causing physical handicaps and accompanied by many serious complications, remains one of the most challenging problems in both, human and veterinary health care practices. The central nervous system in mammals does not regenerate, so the neurological deficits in a dog following SCI persists for the rest of its life and the affected animals display an image of permanent suffering. Diagnostics are based on: neurological examination, plain x-rays of vertebral column, x-rays of the vertebral column following intrathecal administration of a water-soluble contrast medium (myelography), x-rays of the vertebral column following epidural administration of a contrast medium (epidurography), computed tomography (CT) and/or magnetic resonance imaging (MRI). Currently, only limited therapeutic measures are available for the dogs with SCIs. They include: the administration of methylprednisolone sodium succinate (MPSS) during the acute stage; early spinal cord decompression; stabilisation of vertebral fractures or luxations; prevention and treatment of complications, and expert rehabilitation. Together with the progress in the understanding of pathophysiologic events occurring after SCI, different therapeutic strategies have been instituted, including the local delivery of MPSS, the utilisation of novel pharmacological agents, hypothermia, and stem/precursor cell transplantation have all been tested in the experimental models and preclinical trials with promising results. The aim of this review is the presentation of the generally accepted methods of diagnostics and management of dogs with SCIs, as well as to discuss new therapeutic modalities. The research strategy involved a PubMed, Medline (Ovid), Embase (Ovid) and ISI Web of Science literature search from January 2001 to December 2017 using the term “spinal cord injury”, in the English language literature; also references from selected papers were scanned and relevant articles included.

Spinal Cord Injuries in Dogs Part I: A Review of Basic Knowledge

Spinal cord injuries (SCI) in dogs are not frequent, but they are serious pathological conditions accompanied with high morbidity and mortality. The pathophysiology of SCI involves a primary insult, disrupting axons, blood vessels, and cell membranes by mechanical force, or causes tissue necrosis by ischemia and reperfusion. The primary injury is followed by a cascade of secondary events, involving vascular dysfunction, edema formation, continuing ischemia, excitotoxicity, electrolyte shifts, free radical production, inflammation, and delayed apoptotic cell death. The most frequent cause of SCI in dogs is an acute intervertebral disc extrusion, exogenous trauma or ischemia. Neurological symptomatology depends on the location, size and the type of spinal cord lesions. It is characterized by transient or permanent, incomplete or complete loss of motor, sensory, autonomic, and reflex functions caudal to the site of the lesion. In a case of partial spinal cord (SC) damage, one of the typical syndromes develops (e. g. Brown-Séquard syndrome, central SC syndrome, ventral SC syndrome, dorsal SC syndrome, conus medullaris syndrome, or traumatic cauda equina syndrome). The severe transversal spinal cord lesion in the cervical region causes paresis or plegia of all four extremities (tetraparesis, tetraplegia); in thoracic or lumbosacral region, paresis or plegia of the pelvic extremities (paraparesis, paraplegia), i. e. sensory-motor deficit, urinary and foecal incontinence and sexual incompetence. The central nervous system in mammals does not regenerate, so the neurological deficit in dogs following severe SCI persists for the rest of their lives and animals display an image of permanent suffering. The research strategy presented here involved a PubMed, Medline (Ovid) and ISI Web of Science literature search from Januray 2001 to December 2017 using the term “canine spinal cord injury” in the English language; also references from selected papers were scanned and relevant articles included.

Veterinary Neurologic Rehabilitation: The Rationale for a Comprehensive Approach

The increase in client willingness to pursue surgical procedures, the heightened perceived value of veterinary patients, and the desire to provide comprehensive medical care have driven the recent demand of using an integrative treatment approach in veterinary rehabilitation. Physical therapy following neurologic injury has been the standard of care in human medicine for decades, whereas similar rehabilitation techniques have only recently been adapted and utilized in veterinary medicine. Spinal cord injury is the most common neurologic disease currently addressed by veterinary rehabilitation specialists and will be the primary focus of this review; however, research in other neurologic conditions will also be discussed. Of particular interest, to clients and veterinarians are techniques and modalities used to promote functional recovery after neurologic injury, which can mean the difference between life and death for many veterinary patients. The trend in human neurologic rehabilitation, often regardless of etiology, is a multimodal approach to therapy. Evidence supports faster and improved recoveries in people after neurologic injury using a combination of rehabilitation techniques. Although the primary neurological disorders researched tend to be spinal cord injury, peripheral neuropathies, allodynia, multiple sclerosis, and strokes-many correlations can be made to common veterinary neurological disorders. Such comprehensive protocols entail gait training activities in combination with neuromuscular electrical stimulation and directed exercises. Additionally, pain-relieving and functional benefits are bolstered when acupuncture is used in addition to rehabilitation. Studies, both laboratory and clinical, support the use of acupuncture in the management of neurologic conditions in small animals, specifically in cases of intervertebral disc disease, other myelopathies, and neuropathic pain conditions. Acupuncture's ability to promote analgesia, stimulate trophic factors, and decrease inflammation, including neuroinflammation, make it an alluring adjunct therapy after neurologic injury. Although there is limited research in veterinary medicine on physical techniques that expedite recovery after neurologic injury, there are sparse publications on clinical veterinary research suggesting the benefits of acupuncture, rehabilitation, and LASER in dogs with intervertebral disk disease. Accordingly, due to the relative lack of evidence-based studies in veterinary neurologic rehabilitation, much of the data available is human or laboratory-animal based, however, evidence supports the utilization of an early, comprehensive treatment protocol for optimal neurologic recovery. The rationale for why an integrative approach is critical will be detailed in this review; in addition, literature on specific physical rehabilitation techniques that have evidence of improved recoveries after neurologic injury, will be addressed.

Biochemical events related to glial response in spinal cord injury

Introducción. La lesión de la médula espinal (LME) es un evento devastador con implicaciones físicas, psicológicas y socioeconómicas. En el tejido cercano a la lesión se instauran cambios morfofisiológicos que determinan la recuperación funcional del segmento medular y de los órganos efectores dependientes de los tractos axonales lesionados.Objetivo. Describir los eventos bioquímicos secuenciales más relevantes de la respuesta de las células gliales posterior a la LME.Materiales y métodos. Se realizó una búsqueda de publicaciones científicas de los últimos 18 años en las bases de datos PubMed y ScienceDirect, bajo los términos en inglés spinal cord injury (SCI), SCI pathophysiology, SCI inflammation, microglia in SCI, glial scar y chondroitin sulfate proteoglycans (CSPG).Resultados. Los procesos fisiopatológicos que se producen después de la LME determinan la recuperación neurológica de los pacientes. La activación de las células gliales juega un papel importante, ya que promueve la producción de moléculas bioactivas y la formación de barreras físicas que inhiben la regeneración neural.Conclusión. El conocimiento de los cambios neurobiológicos ocurridos tras la LME permite una mayor comprensión de la fisiopatología y favorece la búsqueda de nuevas alternativas terapéuticas que limiten la progresión de la lesión primaria y que minimicen el daño secundario responsable de la disfunción neurológica.

AVALIAÇÃO DO EFEITO DA ACUPUNTURA E TÉCNICAS AFINS E PERFIL CLÍNICO E EPIDEMIOLÓGICO DE CÃES COM DOENÇAS NEUROLÓGICAS E OSTEOMUSCULARES ATENDIDOS EM SERVIÇO DE REABILITAÇÃO VETERINÁRIA

Resumo Este estudo retrospectivo avaliou 181 cães com doenças neurológicas e osteomusculares atendidos em um serviço de reabilitação e dor crônica, durante o período de 2013 a 2015. Objetivou-se caracterizar o perfil epidemiológico e clínico dos animais e analisar a eficácia da acupuntura (AP) e terapias afins e respectiva evolução clínica. O diagnóstico baseou-se no exame físico, neurológico, ortopédico e de imagem. As afecções mais prevalentes foram as do sistema nervoso central, sobretudo doença do disco toracolombar e traumas vertebromedulares agudos. Nas enfermidades neurológicas, o tratamento foi considerado eficaz quando os pacientes foram capazes de recuperar a deambulação e para as lesões medulares, quando houve melhora clínica do quadro neurológico avaliado por meio de escores. O sucesso obtido nos quatro segmentos medulares foi de 69,5%. Nas enfermidades osteomusculares, 47% dos cães apresentavam lesões no joelho e 44% displasia coxofemoral (DCF). Adotou-se a escala analógica visual (EAV) de locomoção para definir o sucesso do tratamento nestas doenças, que foi de 52,8%. As técnicas que mais se associaram à AP manual foram, por ordem decrescente, a eletroacupuntura, a ozonioterapia e o LASER. O número de sessões de AP foi em média de 7,6±3,5. Conclui-se que a AP e técnicas afins melhoraram o escore de déficit neurológico nas doenças neurológicas avaliadas quando usadas de forma isolada e quando associadas à medicina convencional.

Docosahexaenoic acid improves motor function in the model of spinal cord injury

The present study demonstrates that docosahexaenoic acid (DHA, 22:6n-3) injected subcutaneously leads to recovery of locomotor functions observed within 5 weeks after traumatic spinal cord injury. This activity is confirmed by improving of BBB locomotor rating scale indicators. We assume that this activity is related to (1) enhancement of remyelination process, (2) proliferative activity, (3) antioxidant activity, (4) increase in GFAP staining and (5) enhancement of vimentin expression. In general, the results of the study show that DHA has a complex effect on post-traumatic central nervous system recovery, indicating its high therapeutic potential.

Differences in Epidural Pathology between Cervical and Thoracolumbar Intervertebral Disk Extrusions in Dogs

Background

Although the basic pathophysiology is the same in both cervical and thoracolumbar intervertebral disk (IVD) extrusions, there are considerable clinical differences that have only been partially explained.

Hypothesis/Objectives

The epidural inflammatory response differs between cervical and thoracolumbar IVD extrusions.

Animals

Fifty‐five dogs with cervical and 80 dogs with thoracolumbar IVD extrusions.

Methods

Clinical data and histopathologic variables were investigated. Associations between severity of epidural inflammation and clinical and pathologic variables, impact of chondrodystrophic phenotype, and localization (cervical versus thoracolumbar) were evaluated statistically.

Results

Dogs with cervical IVD extrusion were significantly older (P < 0.001), had less severe and longer duration of neurologic signs (both P < 0.001), were more painful (P = 0.038), and had a better outcome (P = 0.005) than dogs with a thoracolumbar IVD extrusion. On histopathology, cervical epidural material had less severe calcification (P = 0.002) and inflammation (P < 0.001). No significant differences regarding chondrodystrophic phenotype were found.

Conclusion and Clinical Importance

There was significantly less intensive inflammatory response in the cervical epidural space. This observation correlated positively with less nucleus pulposus calcification in cervical extrusions indicating biochemical, metabolic, and biomechanical differences between the 2 locations, which remain to be characterized in future studies.

The Relationship between Lesion Severity Characterized by Diffusion Tensor Imaging and Motor Function in Chronic Canine Spinal Cord Injury

Lesion heterogeneity among chronically paralyzed dogs after acute, complete thoracolumbar spinal cord injury (TLSCI) is poorly described. We hypothesized that lesion severity quantified by diffusion tensor imaging (DTI) is associated with hindlimb motor function. Our objectives were to quantify lesion severity with fractional anisotropy (FA), mean diffusivity (MD), and tractography and investigate associations with motor function. Twenty-two dogs with complete TLSCI in the chronic stage were enrolled and compared with six control dogs. All underwent thoracolumbar magnetic resonance imaging (MRI) with DTI and gait analysis. FA and MD were calculated on regions of interest (ROI) at the lesion epicenter and cranial and caudal to the visible lesion on conventional MRI and in corresponding ROI in controls. Tractography was performed to detect translesional fibers. Gait was quantified using an ordinal scale (OFS). FA and MD values were compared between cases and controls, and relationships between FA, MD, presence of translesional fibers and OFS were investigated. The FA at the epicenter (median: 0.228, 0.107-0.320), cranial (median: 0.420, 0.391-0.561), and caudal to the lesion (median: 0.369, 0.265-0.513) was lower than combined ROI in controls (median: 0.602, 0.342-0.826, p < 0.0001). The MD at the epicenter (median: 2.06 × 10^-3, 1.33-2.96 × 10^-3) and cranially (median: 1.52 × 10^-3, 1.03-1.87 × 10^-3) was higher than combined ROI in controls (median: 1.28 × 10^-3, 0.81-1.44 × 10^-3, p ≤ 0.001). Four dogs had no translesional fibers. Median OFS was 2 (0-6). The FA at the lesion epicenter and presence of translesional fibers were associated with OFS (p ≤ 0.0299). DTI can detect degeneration and physical transection after severe TLSCI. Findings suggest DTI quantifies injury severity and suggests motor recovery in apparently complete dogs is because of supraspinal input.

Clinical Characteristics of Dogs with Progressive Myelomalacia Following Acute Intervertebral Disc Extrusion

Background

Progressive myelomalacia (PMM) is a catastrophic disease associated with acute intervertebral disc extrusion (IVDE). Published data on the clinical characteristics of this disease are limited.

Objective

To describe the onset and progression of clinical signs of PMM in a large case cohort.

Animals

Fifty‐one dogs, 18 with histopathologically confirmed PMM, 33 presumptively diagnosed based on clinical signs and diagnostic imaging.

Methods

Retrospective study. Dogs with confirmed IVDE and either a histopathologic diagnosis of PMM or a high clinical suspicion were identified by medical record search. Data on nature and progression of signs were extracted.

Results

Twenty‐four of 51 dogs were Dachshunds. T12–T13 was the most common site of disc extrusion (12 of 56), and 18 of 55 of mid‐to‐caudal lumbar discs (between L3 and L6) were affected. Onset of PMM signs ranged from present at first evaluation (17/51) to 5 days after presentation, with 25 of 51 cases developing signs within 48 hours. Progression of signs from onset of PMM to euthanasia or death, excluding 7 cases euthanized at presentation, ranged from 1 to 13 days with 23 being euthanized within 3 days. Nonspecific systemic signs were documented in 30 of 51 dogs.

Conclusion and Clinical Importance

The majority of dogs developed PMM within 2 days of presentation and was euthanized within another 3 days. However, onset can be delayed up to 5 days after presentation with progression to euthanasia taking as long as 2 weeks. Mid‐to‐caudal lumbar discs might be associated with an increased risk of PMM.

The Relationship between Trans-Lesional Conduction, Motor Neuron Pool Excitability, and Motor Function in Dogs with Incomplete Recovery from Severe Spinal Cord Injury

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 (p_a = 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 (p_a = 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; p_a = 0.011) and was inversely associated with treadmill-based scores, SS, and RI (p_a = 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.

A review of associated controversies surrounding glucocorticoid use in veterinary emergency and critical care

OBJECTIVE

To review the literature in human and veterinary medicine regarding the indications for, efficacy of, and controversies surrounding glucocorticoid (GC) administration in the emergency and critical care (ECC) setting, and to provide an overview of the most commonly used synthetic GC formulations.

MEDICATIONS

Synthetic GCs vary in GC and mineralocorticoid potency, hypothalamic pituitary axis suppression, duration of action, route of administration, and clinical indication for use. Some of the GC compounds commonly used in human and veterinary ECC include hydrocortisone, prednisone, methylprednisolone, and dexamethasone.

INDICATIONS FOR USE

GCs are used in human and veterinary ECC for a variety of disorders including anaphylaxis, acute lung injury/acute respiratory distress syndrome, septic shock, and spinal cord injury. Evidence for morbidity or mortality benefit with administration of GC within these populations exists; however, data are sparse and often conflicting.

ADVERSE EFFECTS AND CONTRAINDICATIONS

Routine use of GC in some conditions such as trauma, hemorrhagic shock, and traumatic brain injury is likely contraindicated. GC use has been associated with hyperglycemia, pneumonia, urinary tract infection, gastrointestinal ulceration, or increased mortality in some populations.

Associations Between Anesthetic Variables and Functional Outcome in Dogs With Thoracolumbar Intervertebral Disk Extrusion Undergoing Decompressive Hemilaminectomy

Background

Outcome of acute experimental spinal cord injury is strongly associated with tissue perfusion and oxygenation. Cardiopulmonary depression could affect outcome in dogs undergoing general anesthesia for surgical treatment of thoracolumbar intervertebral disk extrusion (IVDE).

Hypothesis/Objectives

To evaluate the effects of general anesthesia on functional outcome in dogs undergoing surgery to treat thoracolumbar IVDE.

Animals

Eighty‐four client‐owned dogs with acute thoracolumbar IVDE treated by decompressive hemilaminectomy.

Methods

Exploratory, retrospective observational study. Medical records were reviewed for clinical presentation and anesthetic monitoring variables, including duration of anesthesia and surgery, hypotension, bradycardia, temperature, and respiratory parameters. Multivariable regression tree analysis was performed to explore associations between anesthetic variables and functional outcome scores after 6 weeks, as well as return to ambulatory status.

Results

Episodes of bradycardia (69%) and hypotension (57%) were frequent. Across all outcome measures, regression tree analysis highlighted functional grade at presentation as the primary determining factor, and among pain perception negative dogs, there was a possible association between increased duration of surgery and poorer outcome. In dogs with intact pain perception, duration of bradycardia, mean body temperature, and mean end‐tidal carbon dioxide were highlighted.

Conclusions and Clinical Importance

Exploratory statistical methods can facilitate hypothesis‐generating studies to inform prospective investigations in veterinary medicine. Although the mechanism is uncertain, increased duration of surgery might be associated with poorer outcome in pain perception negative dogs with thoracolumbar IVDE.

Urinary 3-hydroxypropyl mercapturic acid (3-HPMA) concentrations in dogs with acute spinal cord injury due to intervertebral disc herniation

The aim of this study was to investigate urinary 3-hydroxypropyl mercapturic acid (3-HPMA), a metabolite of acrolein, as a novel biomarker in acute spinal cord injury (ASCI) due to intervertebral disc herniation in dogs. Urine from 10 client-owned dogs with ASCI collected at presentation and 10 control dogs was analyzed for 3-HPMA. The median urinary 3-HPMA concentration in ASCI dogs was significantly higher than in control dogs, but was not correlated with the severity of ASCI. The median urinary 3-HPMA concentration in intact dogs was higher than in neutered dogs. Higher urinary 3-HPMA concentrations in dogs after ASCI support a role for acrolein, a cytotoxic by-product of lipid peroxidation, in canine ASCI. Urinary 3-HPMA could be used as a biomarker in future clinical trials to measure the effect of therapeutic intervention of reducing acrolein after ASCI.

A Review of Stem Cell Therapy for Spinal Cord Injury: Large Animal Models and the Frontier in Humans

OBJECTIVE

To review the literature of spinal cord injury and stem cell therapy for large animal models and incorporate those results into an understanding of stem cell therapy for human cord injury.

METHODS

Review of the literature.

RESULTS

Eleven canine studies were identified and 3 sub-human primate studies were identified showing variable results.

CONCLUSIONS

Stem cell therapy is a promising therapeutic option for patients with spinal cord injury; however, the technology has many un-answered questions and further research is needed.

Endothelin-1 Immunoreactivity and its Association with Intramedullary Hemorrhage and Myelomalacia in Naturally Occurring Disk Extrusion in Dogs

Background

The pathophysiology of ascending/descending myelomalacia (ADMM) after canine intervertebral disk (IVD) extrusion remains poorly understood. Vasoactive molecules might contribute.

Hypothesis/Objectives

To investigate the immunoreactivity of endothelin‐1 (ET‐1) in the uninjured and injured spinal cord of dogs and its potential association with intramedullary hemorrhage and extension of myelomalacia.

Animals

Eleven normal control and 34 dogs with thoracolumbar IVD extrusion.

Methods

Spinal cord tissue of dogs retrospectively selected from our histopathologic database was examined histologically at the level of the extrusion (center) and in segments remote from the center. Endothelin‐1 immunoreactivity was examined immunohistochemically and by in situ hybridization. Associations between the immunoreactivity for ET‐1 and the severity of intramedullary hemorrhage or the extension of myelomalacia were examined.

Results

Endothelin‐1 was expressed by astrocytes, macrophages, and neurons and only rarely by endothelial cells in all dogs. At the center, ET‐1 immunoreactivity was significantly higher in astrocytes (median score 4.02) and lower in neurons (3.21) than in control dogs (3.0 and 4.54) (P < .001; P = .004) irrespective of the grade of hemorrhage or myelomalacia. In both astrocytes and neurons, there was a higher ET‐1 immunoreactivity in spinal cord regions remote from the center (4.58 and 4.15) than in the center itself (P = .013; P = .001). ET‐1 mRNA was present in nearly all neurons with variable intensity, but not in astrocytes.

Conclusion and Clinical Importance

Enhanced ET‐1 immunoreactivity over multiple spinal cord segments after IVD extrusion might play a role in the pathogenesis of ADMM. More effective quantitative techniques are required.

CLINICAL AND MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF THORACOLUMBAR INTERVERTEBRAL DISK EXTRUSIONS AND PROTRUSIONS IN LARGE BREED DOGS

Treatment recommendations differ for dogs with intervertebral disk extrusion vs. intervertebral disk protrusion. The aim of this retrospective, cross-sectional study was to determine whether clinical and magnetic resonance imaging (MRI) variables could be used to predict a diagnosis of thoracolumbar intervertebral disk extrusion or protrusion in dogs. Dogs were included if they were large breed dogs, had an MRI study of the thoracolumbar or lumbar vertebral column, had undergone spinal surgery, and had the type of intervertebral disk herniation (intervertebral disk extrusion or protrusion) clearly stated in surgical reports. A veterinary neurologist unaware of surgical findings reviewed MRI studies and recorded number, location, degree of degeneration and morphology of intervertebral disks, presence of nuclear clefts, disk space narrowing, extent, localization and lateralization of herniated disk material, degree of spinal cord compression, intraparenchymal intensity changes, spondylosis deformans, spinal cord swelling, spinal cord atrophy, vertebral endplate changes, and presence of extradural hemorrhage. Ninety-five dogs were included in the sample. Multivariable statistical models indicated that longer duration of clinical signs (P = 0.01), midline instead of lateralized disk herniation (P = 0.007), and partial instead of complete disk degeneration (P = 0.01) were associated with a diagnosis of intervertebral disk protrusion. The presence of a single intervertebral herniation (P = 0.023) and dispersed intervertebral disk material not confined to the disk space (P = 0.06) made a diagnosis of intervertebral disk extrusion more likely. Findings from this study identified one clinical and four MRI variables that could potentially facilitate differentiating intervertebral disk extrusions from protrusions in dogs.

A Placebo-Controlled, Prospective, Randomized Clinical Trial of Polyethylene Glycol and Methylprednisolone Sodium Succinate in Dogs with Intervertebral Disk Herniation

BACKGROUND

Acute intervertebral disk herniation (IVDH) is a common cause of spinal cord injury in dogs and currently there is no proven medical treatment to counter secondary injury effects. Use of methylprednisolone sodium succinate (MPSS) or polyethylene glycol (PEG) as neuroprotectants is advocated but controversial because neither treatment has been tested in placebo-controlled, randomized, blinded trials in dogs.

HYPOTHESIS

Polyethylene glycol will improve the outcome of severe spinal cord injury caused by IVDH compared to MPSS or placebo.

ANIMALS

Client-owned dogs with acute onset of thoracolumbar IVDH causing paralysis and loss of nociception for <24 hours.

METHODS

Dogs were randomized to receive MPSS, PEG, or placebo; drugs appeared identical and group allocation was masked. Drug administration was initiated once the diagnosis of IVDH was confirmed and all dogs underwent hemilaminectomy. Neurologic function was assessed 2, 4, 8, and 12 weeks postoperatively using an open field gait score (OFS) as the primary outcome measure. Outcomes were compared by the Wilcoxon rank sum test.

RESULTS

Sixty-three dogs were recruited and 47.6% recovered ambulation. 17.5% developed progressive myelomalacia but there was no association with group. There was no difference in OFS among groups. Although full study power was not reached, conditional power analyses indicated the futility of continued case recruitment.

CONCLUSIONS

This clinical trial did not show a benefit of either MPSS or PEG in the treatment of acute, severe thoracolumbar IVDH when used as adjunctive medical treatment administered to dogs presenting within 24 hours of onset of paralysis.

Stem cells in canine spinal cord injury--promise for regenerative therapy in a large animal model of human disease

The use of cell transplantation for spinal cord injury is a rapidly evolving field in regenerative medicine. Numerous animal models are currently being used. However, translation to human patients is still a challenging step. Dogs are of increasing importance as a translational model for human disease since there is a greater awareness of the need to increase the quality of preclinical data. The use of dogs ultimately brings benefit to both human and veterinary medicine. In this review we analyze experimental and clinical studies using cell transplantation for canine spinal cord injury. Overall, in experimental studies, transplantation groups showed improvement over control groups. Improvements were measured at the functional, electrophysiological, histological, RNA and protein levels. Most clinical studies support beneficial effects of cell transplantation despite the fact that methodological limitations preclude definitive conclusions. However, the mechanisms of action and underlying the behavior of transplanted cells in the injured spinal cord remain unclear. Overall, we conclude here that stem cell interventions are a promising avenue for the treatment of spinal cord injury. Canines are a promising model that may help bridge the gap between translational research and human clinical trials.

Clinical, magnetic resonance imaging, and histopathologic findings in 6 dogs with surgically resected extraparenchymal spinal cord hematomas

BACKGROUND

Extraparenchymal spinal cord hematoma has been described in veterinary medicine in association with neoplasia, intervertebral disk disease, and snake envenomation. There are rare reports of spontaneous extraparenchymal spinal cord hematoma formation with no known cause in human medicine. Multiple cases of spontaneous extraparenchymal spinal cord hematoma have not been described previously in veterinary medicine.

OBJECTIVES

To describe the signalment, clinical findings, magnetic resonance imaging (MRI) features, and surgical outcomes in histopathologically confirmed extraparenchymal spinal cord hematomas in dogs with no identified underlying etiology.

ANIMALS

Six dogs had MRI of the spinal cord, decompressive spinal surgery, and histopathologic confirmation of extraparenchymal spinal cord hematoma not associated with an underlying cause.

METHODS

Multi-institutional retrospective study.

RESULTS

Six patients had spontaneous extraparenchymal spinal cord hematoma formation. MRI showed normal signal within the spinal cord parenchyma in all patients. All hematomas had T2-weighted hyperintensity and the majority (5/6) had no contrast enhancement. All dogs underwent surgical decompression and most patients (5/6) returned to normal or near normal neurologic function postoperatively. Follow-up of the patients (ranging between 921 and 1,446 days) showed no progression of neurologic clinical signs or any conditions associated with increased bleeding tendency.

CONCLUSIONS AND CLINICAL IMPORTANCE

Before surgery and histopathology confirming extraparenchymal hematoma, the primary differential in most cases was neoplasia, based on the MRI findings. This retrospective study reminds clinicians of the importance of the combination of advanced imaging combined with histopathologic diagnosis. The prognosis for spontaneous spinal cord extraparenchymal hematoma with surgical decompression appears to be favorable in most cases.