Acute Intervertebral Disc Research Articles

Single cell RNA sequencing reveals a shift in cell function and maturation of endogenous and infiltrating cell types in response to acute intervertebral disc injury.

Intervertebral disc (IVD) degeneration contributes to disabling back pain. Degeneration can be initiated by injury and progressively leads to irreversible cell loss and loss of IVD function. Attempts to restore IVD function through cell replacement therapies have had limited success due to knowledge gaps in critical cell populations and molecular crosstalk after injury. Here, we used single cell RNA sequencing to identify the transcriptional changes of endogenous and infiltrating IVD cell populations, as well as the potential of resident mesenchymal stem cells (MSCs) for tissue repair. Control and Injured (needle puncture) tail IVDs were extracted from 12 week old female C57BL/6 mice 7 days post injury and clustering analyses, gene ontology, and pseudotime trajectory analyses were used to determine transcriptomic divergences in the cells of the injured IVD, while immunofluorescence was utilized to determine mesenchymal stem cell (MSC) localization. Clustering analysis revealed 11 distinct cell populations that were IVD tissue specific, immune, or vascular cells. Differential gene expression analysis determined that Outer Annulus Fibrosus, Neutrophils, Saa2-High MSCs, Macrophages, and Krt18+ Nucleus Pulposus (NP) cells were the major drivers of transcriptomic differences between Control and Injured cells. Gene ontology of DEGs suggested that the most upregulated biological pathways were angiogenesis and T cell related while wound healing and ECM regulation categories were downregulated. Pseudotime trajectory analyses revealed that cells were driven towards increased cell differentiation due to IVD injury in all IVD tissue clusters except for Krt18+ NP which remained in a less mature cell state. Saa2-High and Grem1-High MSCs populations drifted towards more IVD differentiated cells profiles with injury and localized distinctly within the IVD. This study strengthens the understanding of heterogeneous IVD cell populations response to injury and identifies targetable MSC populations for future IVD repair studies.

Results of routine thoracic radiographic examinations rarely impact the plan to proceed with anesthetic procedures in dogs with presumed acute intervertebral disc herniation.

Acute thoracolumbar intervertebral disc herniation (IVDH) constitutes an emergency because associated neurological clinical signs can be progressive, with prognosis dependent on preoperative presence of deep pain perception. Pre-anesthetic thoracic radiographs are routinely performed to evaluate for potential pathology that could result in increased risk or change in overall prognosis. However, due to the emergent nature of this disease, the weight of thoracic radiographic findings on treatment plans for these dogs in unknown. The objective of this study was to investigate the clinical benefit of thoracic radiographs prior to advanced spinal imaging and surgery for acute non-ambulatory dogs with suspected T3-L3 myelopathy. Consecutive dogs presented with presumed acute IVDH between July 2020-July 2022 were identified, and medical records were reviewed retrospectively. Age, body weight, and alteration of treatment plan were compared between the dogs with positive thoracic pathology identified on thoracic radiographs and those with negative thoracic pathology. Only 2/105 dogs had their diagnostic and treatment plans changed due to thoracic radiographic findings. Dogs with radiographic pathology diagnosed (2/16) were more likely to have their treatment plans changed than dogs with no radiographic pathology (0/89) (p = 0.014). The odds of radiographic thoracic pathology were 4.6 times higher in dogs aged 12 years or older [OR 4.6 (95%CI 1.2-17, p = 0.026]. Performing routine thoracic radiography prior to advanced (anesthetized) diagnostic spinal imaging in presumed IVDH cases rarely resulted in a change to the treatment plan, thought eh practice may be clinically relevant in dogs 12 years of age or older.

Investigating the weekend effect in decompressive thoracolumbar hemilaminectomy for acute intervertebral disc extrusion: An observational cohort study of 460 cases (2018-2023).

To investigate if weekend surgery is associated with poorer outcomes in dogs with acute thoracolumbar intervertebral disc extrusion (IVDE) undergoing decompressive thoracolumbar hemilaminectomy. Retrospective observational cohort study. A total of 460 consecutive cases were reviewed, with 401 dogs undergoing weekday surgery (Cohort WD), and 59 dogs undergoing weekend surgery (Cohort WE). Medical records of a surgical referral center in the UK were reviewed. Preoperative patient demographic and clinical data, and postoperative outcome data were collected with a minimum 28-day follow-up period. Multivariable logistic regression analysis was used to model the odds of a negative outcome. Cohort WE had a higher preoperative proportion of nonambulatory dogs (p = .0115) but there were no significant differences between the nonambulatory (p = .3762) and deep-pain negative subgroups (p = .6199). Cohort WE had a higher risk of not recovering ambulation compared to Cohort WD [79.2% vs. 91.6% recovery; adjusted OR 3.010 (95% CI: 1.259-7.190); p = .0132] and had a higher risk of postoperative morbidity [32.2% vs. 17.2%; adjusted OR 2.015 (95% CI: 1.089-3.729); p = .0257]. There were no significant differences in other outcome measures between cohorts. Weekend surgery in canine decompressive thoracolumbar hemilaminectomy may be associated with poorer patient outcomes, specifically higher postoperative morbidity and a poorer rate of recovery of ambulation. This study demonstrates a weekend effect in veterinary surgery, which may be important in surgical decision-making in acute thoracolumbar IVDE. Further scrutiny of the patient's journey through the veterinary healthcare system is warranted.

Randomized Controlled Trial of Durotomy as an Adjunct to Routine Decompressive Surgery for Dogs With Severe Acute Spinal Cord Injury.

Although many interventions for acute spinal cord injury (SCI) appear promising in experimental models, translation directly from experimental animals to human patients is a large step that can be problematic. Acute SCI occurs frequently in companion dogs and may provide a model to ease translation. Recently, incision of the dura has been highlighted in both research animals and human patients as a means of reducing intraspinal pressure, with a view to improving perfusion of the injured tissue and enhancing functional recovery. Observational clinical data in humans and dogs support the notion that it may also improve functional outcome. Here, we report the results of a multi-center randomized controlled trial of durotomy as an adjunct to traditional decompressive surgery for treatment of severe thoracolumbar SCI caused by acute intervertebral disc herniation in dogs. Sample-size calculation was based on the proportion of dogs recovering ambulation improving from an expected 55% in the traditional surgery group to 70% in the durotomy group. Over a 3.5-year period, we enrolled 140 dogs, of which 128 had appropriate duration of follow-up. Overall, 65 (51%) dogs recovered ambulation. Recovery in the traditional decompression group was 35 of 62 (56%) dogs, and in the durotomy group 30 of 66 (45%) dogs, associated with an odds ratio of 0.643 (95% confidence interval: 0.320-1.292) and z-score of -1.24. This z-score indicates trial futility to reach the target 15% improvement over traditional surgery, and the trial was terminated at this stage. We conclude that durotomy is ineffective in improving functional outcome for severe acute thoracolumbar SCI in dogs. In the future, these data can be compared with similar data from clinical trials on duraplasty in human patients and will aid in determining the predictive validity of the "companion dog model" of acute SCI.

Evaluation of different methods of environmental enrichment to control anxiety in dogs undergoing hemilaminectomy after acute intervertebral disc extrusion: a randomized double-blinded study.

The goal of this randomized, double-blinded, placebo-controlled study was to evaluate the effect of environmental enrichment (EE) on post-operative pain and anxiety in dogs following hemilaminectomy for acute intervertebral disc extrusion (IVDE). Twenty healthy client-owned dogs undergoing a hemilaminectomy for IVDE with the same immediate post-operative analgesia protocol were randomly assigned to either the EE or standard environment (SE) group post-operatively. Recovery was achieved in an intensive care room (SE) or a separate quiet room (EE) equipped with white noise and classical music. EE dogs were also exposed to dog-appeasing pheromones, essential oil scents, and positive human interactions and were provided meals through food toys. A blinded evaluator assessed all dogs using the modified Glasgow Composite Pain Scale (mGCPS) on presentation and at several time points post-operatively. A rescue injection of the opioid methadone was given to the dogs with an mGCPS score of ≥5/20. Dogs received the antidepressant trazodone when anxious behaviors (5 mg/kg) were observed. The mGCPS scores, the latencies to receive the first methadone and trazodone doses and to eat the first meal, the number of methadone and trazodone doses, and the number of meals ingested in the first 24 and 48 h post-surgery were compared using Wilcoxon tests, and Benjamini-Hochberg correction for false discovery rate was applied. Although median mGCPS scores did not differ between the groups, compared to SE dogs (n = 10), EE dogs (n = 6) received trazodone earlier (p = 0.019), were administered fewer methadone injections at 24 h (p = 0.043), and ate more at 48 h post-surgery (p = 0.007). Therefore, EE and anti-anxiety medications could be beneficial in improving the wellbeing of dogs post-operatively.

No adverse consequences associated with targeting clinical signs to initiate antimicrobial treatment of postoperative subclinical bacteriuria in dogs following surgical decompression of Hansen type I thoracolumbar disk herniation.

To describe the prevalence of postoperative bacteriuria, clinical course of subclinical bacteriuria in the absence of antimicrobial intervention, clinical signs of bacteriuria that trigger antimicrobial treatment, and outcomes for dogs with subclinical bacteriuria following surgical decompression of acute intervertebral disc herniation (IVDH) Hansen type I. Twenty client-owned dogs undergoing hemilaminectomy for acute (≤ 6 days) IVDH Hansen type I affecting the thoracolumbar spinal cord segments between August 2018 and January 2019. In this prospective study, dogs were serially evaluated at presentation, hospital discharge, 2 weeks postoperatively, and between 4 and 6 weeks postoperatively. Dogs were monitored for clinical signs of bacteriuria, underwent laboratory monitoring (CBC, biochemical analyses, urinalysis, urine bacterial culture), and were scored for neurologic and urinary status. In the absence of clinical signs, bacteriuria was not treated with antimicrobials. Four of the 18 dogs developed bacteriuria without clinical signs 4 days to 4 to 6 weeks after surgery. In all 4 dogs, bacteriuria resulted in lower urinary tract signs 13 to 26 weeks postoperatively. No dogs had evidence of systemic illness despite delaying antimicrobial treatment until clinical signs developed. New-onset incontinence was the only clinical sign in 3 dogs. All bacterial isolates had wide antimicrobial susceptibility. Bacteriuria and clinical signs resolved with beta-lactam antimicrobial treatment. Postoperative bacteriuria occurs in some dogs with IVDH Hansen type I and, when present, may lead to clinical signs over time. Clinical signs of bacteriuria may be limited to new-onset urinary incontinence, inappropriate urination, or both. Delaying antimicrobial treatment until clinical signs of bacteriuria developed did not result in adverse consequences or systemic illness.

Comparison of Surgical Outcomes Associated With Compression Secondary to Hemorrhage and Intervertebral Disk Extrusions in Dogs.

Acute intervertebral disk extrusion (IVDE) is one of the most commonly reported neurologic disorders seen in veterinary practice. There is a recognized subset of IVDE cases that have a hemorrhagic inflammatory reaction within the epidural space that causes compression in addition to compression from herniated disk material. Previous reports have been conflicting in the outcomes of these cases. The goals of this retrospective case-control cross-sectional study are to (1) compare the success rate of routine surgical decompression in dogs with DEEH compression compared to Modified Frankel Score (MFS) matched dogs with non-hemorrhagic disk extrusions; (2) evaluate the extent of spinal cord compression on MRI compared to final patient outcomes in DEEH compression and (3) determine the surgical compression to decompression ratio and its relation to patient outcomes in cases of DEEH compression. A total of 143 dogs were included in this study and divided into two groups: DEEH compression dogs (n = 78) and non-hemorrhagic IVDE dogs (n = 65). Outcomes were assigned for each patient [0 = deceased, 1 = alive and non-ambulatory (MFS 0–3), 2 = alive and ambulatory (MFS 4 or 5)] in both groups. Outcomes of DEEH and non-hemorrhagic IVDE did not differ when taken to surgery with comparable success rates when stratified by MFS. Similarly, outcomes did not differ between DEEH and non-hemorrhagic IVDE dogs when assessed by compression to decompression ratio. Dogs with DEEH compression had more compressed sites than dogs with non-hemorrhagic IVDE (P = 0.001) and had more sites decompressed surgically than dogs with non-hemorrhagic IVDE (P < 0.001). Consequently, the compression to decompression ratio did not differ between the two groups (P = 0.52). Our results support the finding that when a similar level of surgical decompression is achieved, dogs with DEEH compression have similar outcomes to dogs with non-hemorrhagic IVDE for similar degrees of neurological dysfunction.

A systematic review of large animal and human studies of stem cell therapeutics for acute adult traumatic spinal cord injury

Background: Traumatic spinal cord injury (TSCI) is a devastating condition and the search for a cure remains one of the most tenacious healthcare challenges to date. Current therapies are limited in their efficacy to restore full neurological function – resulting in lifelong disability and loss of autonomy. Whilst there remains a necessity to refine therapeutic protocols, stem cell (SC) studies have shown promise in the mending and re-establishment of the spinal cord neuroanatomy. Objectives: We conducted a systematic review of functional outcomes in stem cell therapeutics over the last three decades in large animals and humans. Methods: Medline, Embase, Cochrane and SCOPUS databases were searched for potentially pertinent articles from 1990 to 2020. Studies published in English were included if the stem cells were directly injected into the intraspinal, epidural or intrathecal compartments within two weeks of a traumatic mechanism of injury, including acute intervertebral disc prolapse. The participants were either large animals – defined as canine, porcine or non-human primate in-vivo models – or human patients. Results: Nine studies were included in this review. Statistically significant improvements in motor function and deep pain perception were seen at 8 weeks to 6 months post-SC injection compared to controls. Limitations: Functional outcomes are variably measured across studies. Almost all studies used experimentally induced trauma, which may not accurately represent the complexity of human spinal cord injury. Due to the exclusion criteria, there were no non-human primate studies included, yet these animal models are considered a closer anatomical match to humans than other large mammals. No human studies were included. Conclusions and Implications: Autologous and allogeneic stem cells have been trialled for the reconstitution of damaged and lost cells, remyelination of axons and remodelling of the pathophysiological microenvironment within the injured spinal cord, with some promising outcome data. This may translate to more successful future Phase I/II human clinical trials into the use of stem cells after TSCI in adults.

A Controlled Clinical Study of Intensive Neurorehabilitation in Post-Surgical Dogs with Severe Acute Intervertebral Disc Extrusion.

Simple SummaryThis study explores the potential intensive neurorehabilitation plasticity effects in post-surgical paraplegic dogs with severe acute intervertebral disc extrusion aiming to achieve ambulatory status. The intensive neurorehabilitation protocol translated in 99.4% (167/168) of recovery in deep pain perception-positive dogs and 58.5% (55/94) in deep pain perception-negative dogs. There was 37.3% (22/59) spinal reflex locomotion, obtained within a maximum period of 3 months. Thus, intensive neurorehabilitation may be a useful approach for this population of dogs, avoiding future euthanasia and promoting an estimated time window of 3 months to recover.This retrospective controlled clinical study aimed to verify if intensive neurorehabilitation (INR) could improve ambulation faster than spontaneous recovery or conventional physiotherapy and provide a possible therapeutic approach in post-surgical paraplegic deep pain perception-positive (DPP+) (with absent/decreased flexor reflex) and DPP-negative (DDP−) dogs, with acute intervertebral disc extrusion. A large cohort of T10-L3 Spinal Cord Injury (SCI) dogs (n = 367) were divided into a study group (SG) (n = 262) and a control group (CG) (n = 105). The SG was based on prospective clinical cases, and the CG was created by retrospective medical records. All SG dogs performed an INR protocol by the hospitalization regime based on locomotor training, electrical stimulation, and, for DPP−, a combination with pharmacological management. All were monitored throughout the process, and measuring the outcome for DPP+ was performed by OFS and, for the DPP−, by the new Functional Neurorehabilitation Scale (FNRS-DPP−). In the SG, DPP+ dogs had an ambulation rate of 99.4% (n = 167) and, in DPP−, of 58.5% (n = 55). Moreover, in DPP+, there was a strong statistically significant difference between groups regarding ambulation (p < 0.001). The same significant difference was verified in the DPP– dogs (p = 0.007). Furthermore, a tendency toward a significant statistical difference (p = 0.058) regarding DPP recovery was demonstrated between groups. Of the 59 dogs that did not recover DPP, 22 dogs achieved spinal reflex locomotion (SRL), 37.2% within a maximum of 3 months. The progressive myelomalacia cases were 14.9% (14/94). Therefore, although it is difficult to assess the contribution of INR for recovery, the results suggested that ambulation success may be improved, mainly regarding time.

Serum C-reactive protein in dogs with paraplegia secondary to acute intervertebral disc extrusion.

BackgroundApart from the absence of nociception, there is no readily available prognostic test for dogs presenting with paraplegia secondary to acute intervertebral disc extrusion (IVDE).ObjectiveTo assess if serum C‐reactive protein (CRP) can predict the postoperative outcome in paraplegic dogs undergoing surgery for IVDE and to assess the association between serum CRP and presence/absence of nociception on admission, and serum CRP and presence/absence of intramedullary changes seen on magnetic resonance imaging (MRI).AnimalsOne hundred dogs that underwent surgery at our hospital between 2018 and 2020 because of acute paraplegia secondary to IVDE and in which serum CRP was measured.MethodsRetrospective observational cohort study. Dogs were classified as 4 or 5 according to the modified Frankel score (MFS) depending on presence/absence of nociception, respectively. MRI images were reviewed and the T2‐weighted hyperintensity: L2 vertebral body length was measured. Postoperative outcome was defined as positive if nociception, ambulation or both returned after decompressive surgery.ResultsThe median (95% CI) serum CRP was 4 (4‐5) and 6 (4‐7) mg/L in MSF4 and MSF5, respectively (P = .03). A weak linear relationship (R 2 = 0.049, P = .03) was found between CRP and the T2‐weighted hyperintensity: L2 vertebral length. Outcome data was available for 85 dogs: CRP was 4 (4‐5) and 5 (4‐10) mg/L in positive and negative outcome dogs, respectively (P = .32).Conclusion and Clinical ImportanceSerum CRP did not predict outcome after surgery in dogs with paraplegia secondary to IVDE.

Perianaesthetic management of a Patagonian cavy (Dolichotis patagonum) undergoing hemilaminectomy for treatment of acute intervertebral disk herniation

AbstractA 7.5‐year‐old, 5.6 kg female Patagonian cavy (Dolichotis patagonum) in thin body condition presented for bilateral pelvic limb paresis. Lumbar intervertebral disk extrusion was diagnosed using MRI and neurological examination. Emergency hemilaminectomy was done on the same day of diagnostics. The cavy was premedicated with intravenous (IV) midazolam (0.3 mg/kg) and ketamine (5 mg/kg) followed by alphaxalone (to effect) for induction and tracheal intubation. Anaesthesia was maintained with isoflurane‐in‐oxygen and an IV constant rate infusion (CRI) of ketamine and lidocaine (both 0.3 mg/kg/h) and morphine (0.1 mg/kg, once). The CRI continued for 24 hours followed by once daily intravenous buprenorphine (0.03 mg/kg) and subcutaneous meloxicam (0.5 mg/kg). Recovery was calm. The cavy returned to its preoperative behaviour within hours and began eating soon after anaesthesia. Subjectively, the analgesic plan was successful in mitigating post‐operative pathological pain. This case report discusses the perianaesthetic management for spinal surgery in a cavy.

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

BackgroundObjective 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.ResultsTwenty-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).ConclusionsSWD 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.

Prognostic Factors in Canine Acute Intervertebral Disc Disease.

Knowledge of the prognosis of acute spinal cord injury is critical to provide appropriate information for clients and make the best treatment choices. Acute intervertebral disc extrusions (IVDE) are a common cause of pain and paralysis in dogs with several types of IVDE occurring. Important prognostic considerations are recovery of ambulation, return of urinary and fecal continence, resolution of pain and, on the negative side, development of progressive myelomalacia. Initial injury severity affects prognosis as does type of IVDE, particularly when considering recovery of continence. Overall, loss of deep pain perception signals a worse outcome. When considering Hansen type 1 IVDE, the prognosis is altered by the choice of surgical vs. medical therapy. Concentration of structural proteins in the plasma, as well as inflammatory mediators, creatine kinase, and myelin basic protein in the cerebrospinal fluid (CSF) can provide additional prognostic information. Finally, cross-sectional area and length of T2 hyperintensity and loss of HASTE signal on MRI have been associated with outcome. Future developments in plasma and imaging biomarkers will assist in accurate prognostication and optimization of patient management.

Clinical Trial Design-A Review-With Emphasis on Acute Intervertebral Disc Herniation.

There is a clear need for new methods of treatment of acute disc herniation in dogs, most obviously to address the permanent loss of function that can arise because of the associated spinal cord injury. Clinical trials form the optimal method to introduce new therapies into everyday clinical practice because they are a reliable source of unbiased evidence of effectiveness. Although many designs are available, parallel cohort trials are most widely applicable to acute disc herniation in dogs. In this review another key trial design decision—that between pragmatic and explanatory approaches—is highlighted and used as a theme to illustrate the close relationship between trial objective and design. Acute disc herniation, and acute spinal cord injury, is common in dogs and there is a multitude of candidate interventions that could be trialed. Most current obstacles to large-scale clinical trials in dogs can be overcome by collaboration and cooperation amongst interested veterinarians.

Extended durotomy to treat severe spinal cord injury after acute thoracolumbar disc herniation in dogs.

To report recovery of ambulation of dogs treated with extended thoracolumbar durotomy for severe spinal cord injury caused by intervertebral disc herniation. Descriptive cohort. Twenty-six consecutive paraplegic dogs presented with loss of deep pain sensation after acute thoracolumbar intervertebral disc herniation. Each dog underwent routine diagnostic assessment and surgery for removal of extradural herniated intervertebral disc, followed by a four-vertebral body length durotomy centered on the herniated disc. Each dog was followed up until it was able to walk 10 steps without assistance or until 6 months after surgery. Sixteen of 26 dogs recovered to walk unaided (all but one also recovered fecal and urinary continence), and six dogs did not; four dogs were lost to follow-up. One dog was euthanized because of signs consistent with progressive myelomalacia. There was no evidence of detrimental effects of durotomy within the period of study. Using Bayesian analysis, we found a point estimate of successful outcome of 71% with 95% credible interval from 52% to 87%. Extended durotomy seemed to improve the outcome of dogs in our case series without increase in morbidity. Extended durotomy appears safe and may improve the outcome of dogs with severe thoracolumbar mixed contusion and compressive injuries associated with acute intervertebral disc extrusion.

Risk factors associated with progressive myelomalacia in dogs with complete sensorimotor loss following intervertebral disc extrusion: a retrospective case-control study

BackgroundProgressive myelomalacia (PMM) is a usually fatal complication of acute intervertebral disc extrusion (IVDE) in dogs but its risk factors are poorly understood. The objective of this retrospective case-control study was to identify risk factors for PMM by comparing dogs with complete sensorimotor loss following IVDE that did and did not develop the disease after surgery. We also investigated whether any risk factors for PMM influenced return of ambulation. Medical records of client-owned dogs with paraplegia and loss of pain perception that underwent surgery for IVDE from 1998 to 2016, were reviewed. Dogs were categorized as PMM yes or no based on clinical progression or histopathology. Walking outcome at 6 months was established. Signalment, onset and duration of signs (categorized), steroids, non-steroidal anti-inflammatory drugs (yes or no), site of IVDE (lumbar intumescence or thoracolumbar) and longitudinal extent of IVDE were retrieved and their associations with PMM and walking outcome were examined using logistic regression.ResultsOne hundred and ninety seven dogs were included, 45 with and 152 without PMM. A 6-month-outcome was available in 178 dogs (all 45 PMM dogs and 133 control dogs); 86 recovered walking (all in the control group). Disc extrusions at the lumbar intumescence were associated with PMM (p = 0.01, OR: 3.02, CI: 1.3–7.2). Surgery performed more than 12 h after loss of ambulation was associated with PMM (OR = 3.4; CI = 1.1–10.5, p = 0.03 for 12-24 h and OR = 4.6; CI = 1.3–16.6, p = 0.02 for the > 24 h categories when compared with the ≤12 h category). Treatment with corticosteroids was negatively associated with PMM (OR: 3.1; CI: 1.3–7.6, p = 0.01). The only variable to affect walking outcome was longitudinal extent of IVDE (OR = 2.6; CI = 1.3–5.3, p = 0.006).ConclusionDogs with lumbar intumescence IVDE are at increased risk of PMM. Timing of surgery and corticosteroid use warrant further investigations. PMM and recovery of walking are influenced by different factors.

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

BackgroundHemorrhage 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.ResultsIn 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 importanceQuantification 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.

Low-field magnetic resonance changes in the paravertebral musculature of dogs with acute intervertebral disc extrusion.

To describe the MRI features and prevalence of paravertebral muscle signal intensity changes in dogs with acute intervertebral disc extrusion and to search for associations between the signal changes and clinical history, signalment, neurological examination, serum creatine kinase activity and MRI characteristics of the disc herniation. Medical records and MRI examinations from 688 dogs with surgically confirmed acute intervertebral disc extrusion were reviewed retrospectively. T2-weighted and STIR MRI sequences were available for 276 cases and were examined for paravertebral muscle signal intensity changes. When present, extension, lateralisation and signal characteristics of these changes were recorded. Exclusion criteria were muscle injections 24 hours before MRI scan, trauma and previous spinal surgery. Nineteen dogs met the inclusion criteria. There were signal changes in the multifidus muscle, mostly in the thoracolumbar region and often extending caudally from the level of the intervertebral disc herniation. Two cases had paravertebral muscle signal intensity changes in the cervical region. MRI signal changes were seen more frequently in the muscles of non-ambulatory dogs. Clinical history and neuro-examination did not allow differentiation between dogs with and without paravertebral muscle signal intensity changes. Paravertebral muscle signal intensity changes were observed infrequently in the epaxial musculature of 6.9% dogs with acute intervertebral disc extrusion in both the thoracolumbar and cervical regions. The pathophysiological processes responsible for these MRI changes remain unknown.

A Case of Acute Intervertebral Disc Herniation into Both the Upper and Lower Vertebral Body.

A Case of Acute Intervertebral Disc Herniation into Both the Upper and Lower Vertebral Body.

Effect of 5% transdermal lidocaine patches on postoperative analgesia in dogs undergoing hemilaminectomy.

To investigate the effect of 5% lidocaine patches on postoperative analgesia in dogs undergoing hemilaminectomy. Client-owned dogs undergoing hemilaminectomy for a single acute intervertebral thoracolumbar disc extrusion were enrolled in this prospective, randomised, blinded clinical trial. Following methadone administration, anaesthesia was induced with propofol, and maintained with isoflurane in oxygen and fentanyl infusion, in both groups. After skin closure, two 1∙5cm wide 5% lidocaine patch strips were attached along both sides of the wound in dogs allocated to Group L. In Group C, the two lidocaine patch strips were applied but the transparent isolating liner was not removed. Postoperatively, all dogs received a non-steroidal anti-inflammatory drug, gabapentin and diazepam. Methadone was administered according to the short form of Glasgow Composite Pain Scale with pain assessed every 2hours for 48 hours by observers unaware of the treatment. Thirty-nine dogs completed the study. Demographic data, end-expiratory fraction of isoflurane, fentanyl consumption, anaesthesia and surgical times were similar between groups. The number of dogs requiring postoperative methadone and the number of doses of methadone administered were not different between groups. No macroscopic skin reaction was noticed once the patches were removed. In this setting, 5% lidocaine patches did not provide additional postoperative analgesia in dogs undergoing hemilaminectomy.