Intervertebral Disc Extrusion Research Articles

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.

Introduction of Disc Material into the Vertebral Canal by Fenestration of Thoracolumbar Discs Following Decompressive Surgery.

Intervertebral disc extrusion is a common disease affecting chondrodystrophic dogs. It has been reported that fenestration of thoracolumbar intervertebral discs reduces recurrence of disc extrusion and is associated with a low complication rate. One complication reported is iatrogenic introduction of disc material into the canal directly following fenestration. This study aimed to ascertain if, and at what frequency, additional disc material may be introduced into the vertebral canal by fenestration of the affected disc following decompressive surgery. Twenty-one dogs that underwent hemilaminectomy and disc fenestration for the treatment of thoracolumbar intervertebral disc extrusion had intraoperative assessment of the vertebral canal before and after fenestration. The spinal cord was first decompressed by hemilaminectomy and removal of all visible extruded disc material within the vertebral canal. Once no further material was visible, manual fenestration of the affected disc was performed. The vertebral canal was re-inspected, and the presence or absence of additional material was noted and included in the surgery report. Seven dogs showed the presence of new disc material in the vertebral canal post fenestration.This preliminary study shows that additional disc material can be forced into the vertebral canal by fenestration following decompressive surgery, with a frequency of 7/21. This illustrates the importance of checking the vertebral canal after fenestration of an extruded intervertebral disc.

Intraoperative anaesthetic complications in dogs undergoing general anaesthesia for thoracolumbar hemilaminectomy: a retrospective analysis

ObjectiveTo establish the incidence of intraoperative anaesthetic complications in dogs undergoing general anaesthesia (GA) for thoracolumbar hemilaminectomy (TH), to determine whether GA duration affects incidence of intraoperative complications and to identify associations between intraoperative complications. Study designRetrospective observational study. AnimalsA total of 224 client-owned dogs of various breeds undergoing TH for intervertebral disc extrusion. MethodsAnaesthetic records of dogs undergoing TH at a university teaching hospital between 2010 and 2016 were analysed. Data recorded included breed, sex, body weight, GA duration, magnetic resonance imaging (MRI) under the same GA, pharmacological intervention to increase heart rate (PIHR), hypotension (mean arterial blood pressure < 60 mmHg for ≥ 10 minutes), mechanical ventilation (MV) for inadequate ventilation, hypothermia (oesophageal temperature < 37 °C), oesophageal temperature ≥ 39 °C (T ≥ 39 °C), temperature trend, regurgitation and use of alpha-2 adrenoreceptor agonists, acepromazine, ketamine or lidocaine. Multivariate logistic regression models were fitted for hypothermia, T ≥ 39 °C, hypotension and PIHR with forced inclusion of GA duration. ResultsHypothermia was the most common complication (63.8% incidence), followed by MV implementation (63.4%), hypotension (33.9%), PIHR (24.6%), T ≥ 39 °C (20.5%) and regurgitation (4.9%). Multivariate models revealed that MRI and hypotension were associated with an increased risk of hypothermia, whilst increasing body weight, alpha-2 adrenoreceptor agonists and MV were associated with a reduced risk. Alpha-2 adrenoreceptor agonists and GA duration were associated with an increased risk of T ≥ 39 °C, whilst hypotension was associated with a reduced risk. Hypothermia and PIHR were associated with an increased risk of hypotension, whereas increased body weight was associated with a reduced risk. MV and hypothermia were associated with an increased risk of PIHR, whereas increased body weight was associated with a reduced risk. Conclusions and clinical relevanceIncreasing GA duration was associated with increased risk of T ≥ 39 °C, but not any other intraoperative complications.

Urological Sequelae to Acute Spinal Cord Injury in Pet Dogs: A Natural Disease Model of Neuropathic Bladder Dysfunction

The authors review urologic dysfunction, including urine retention, incontinence, and recurrent and resistant urinary tract infection, in dogs as a sequela to acute spinal cord injury. Urologic sequelae to acute spinal cord injury (SCI) pose significant complications in human and canine patients impacting quality of life and long-term cost of treatment. Dogs with intervertebral disc extrusion may serve as a natural disease model of acute SCI for investigating translational interventions, both prophylactic and therapeutic, for urologic dysfunction in human SCI patients.

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.

Spontaneous regression of a cervical intervertebral disc extrusion in French bulldogs documented on MRI after medical management

Spontaneous regression of cervical intervertebral disc extrusion (cIVDE) has been reported in people. It has also been reported in a dog after four months of medical management. Two French bulldogs...

Cervical hyperaesthesia in dogs: an epidemiological retrospective study of 185 cases.

To describe the prevalence, clinical findings and predictors of disease in dogs with cervical hyperaesthesia. Medical records of dogs referred for neurological investigation of cervical hyperaesthesia between 2009 and 2013 were retrospectively reviewed. Dogs were assigned to one of the following groups according to the final diagnosis: Non-Neurologic, Brain, Cervical Spine, Multifocal, and Chiari-like Malformation/Syringomyelia. Demographic data, clinical and neurological signs and laboratory findings were compared between groups using univariate analysis; predictors of disease location were assessed by multivariate analysis. Final diagnostic allocations of the 185 records included in the study were as follows: 2.7% Non-Neurologic, 2.2% Brain, 63.2% Cervical Spine, 22.2% Multifocal and 9.7% Chiari Malformation/Syringomyelia. Intervertebral disc extrusion and steroid-responsive meningitis arteritis were the most common diseases. Compared to Multifocal dogs, those allocated a Cervical Spine diagnosis were older, heavier, more frequently ataxic and lame on a thoracic limb; furthermore, they were less frequently depressed or hyperthermic at presentation. Leucocytosis, neutrophilia and monocytosis were more frequent in dogs allocated a Multifocal diagnosis. Dogs with cervical hyperaesthesia older than 36 months and non-hyperthermic at presentation were more likely to have a lesion of the cervical region rather than a multi-focal disease. Although non-specific, these results may be useful to guide clinicians in management of dogs presenting with cervical hyperaesthesia. Animal age and body temperature may support the suspicion of either focal or multi-focal cervical spinal disease.

Clinical presentation, magnetic resonance imaging features, and outcome in 6 cats with lumbar degenerative intervertebral disc extrusion treated with hemilaminectomy.

To describe the clinical presentation, magnetic resonance imaging features, and outcome of cats treated with hemilaminectomy for intervertebral disc extrusion (IVDE). Short case series. Six cats. Medical records were reviewed for signalment, onset, duration, and severity of clinical signs, magnetic resonance imaging features, surgical findings, and clinical outcome with a minimum postoperative follow-up of 4 weeks. Our population included 6 cats with a median age of 8.6 years, consisting predominantly of males (n = 5) and purebred cats (n = 4). An acute onset and short duration of progressive clinical signs of myelopathy was the most common presentation; spinal hyperesthesia was present in 3 cats. A large volume of extradural material was identified by MRI within the lumbar vertebral column of each cat, causing marked spinal cord compression. The most common sites affected were L2-L3 (n = 2) and L6-L7 (n = 2). Follow-up after hemilaminectomy was available in 5 cats: 4 had normal voluntary motor function, and 1 had recurrence of acute paraplegia, compromised nociception, and an extensive T2w hyperintense intramedullary lesion according to MRI. All 4 cats with preoperative urinary incontinence remained incontinent for at least 1 week despite good voluntary motor function of pelvic limbs. Intervertebral disc extrusion was diagnosed by MRI in all 6 cats, most commonly at L2-3 and L6-7. Hemilaminectomy resulted in a good to excellent outcome in 4 of 5 cats. Feline IVDE can be diagnosed by MRI and carry a good prognosis after surgical decompression, although urinary continence may be delayed despite good pelvic limb voluntary motor function.

Time course and prognostic value of serum GFAP, pNFH, and S100β concentrations in dogs with complete spinal cord injury because of intervertebral disc extrusion.

BackgroundA noninvasive biomarker is needed to predict recovery from severe spinal cord injury (SCI) because of thoracolumbar intervertebral disc extrusion (TL‐IVDE). Proteins released from neural and glial cells can be detected in the blood and show promise as prognostic tools, but their concentration is influenced by time after injury.Hypothesis/ObjectivesSerum concentrations of glial fibrillary acidic protein (GFAP), phosphorylated neurofilament heavy chain (pNFH), and S100β will follow different time courses; measurement of combinations of these proteins will predict outcome.AnimalsThirty‐one dogs with TL‐IVDE causing paralysis with no pain perception.MethodsProspective study. Serum samples were taken at presentation and intervals over 56 days and banked at −80°C. Glial fibrillary acidic protein, pNFH, and S100β concentrations were measured using ELISA tests and plotted against time from onset of nonambulatory status. Outcome was established at 6 months. The association between biomarker concentration and outcome was examined using logistic regression, receiver operator characteristics curve analysis, and model development.ResultsThirty‐one dogs participated, 3/31 (10%) developed progressive myelomalacia and 19/31 (62%) recovered ambulation. Glial fibrillary acidic protein and S100β concentrations rose for the first 1 to 3 days, and were undetectable by 14 and 28 days, respectively. Phosphorylated neurofilament heavy chain concentrations peaked at 14 days and were detectable at 56 days. Glial fibrillary acidic protein concentrations in the first 72 hours after onset of nonambulatory status predicted recovery with an accuracy of 76.7%‐89% depending on sample timing.Conclusions and Clinical ImportanceSerum GFAP concentrations can be used to predict outcome in clinically complete SCI. A rapid inexpensive bedside test is needed.

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.

Correlation Between Clinical And Magnetic Resonance Imaging Findings In Patients With Lumbosacral Radiculopathy

Low back pain accounts for a large amount of loss of productivity in the workforce. When the low back pain extends into the lower limb along the distribution of a dermatome then radiculopathy is said to be present. Although most people experience back pain during their lifetime, only a fraction experience lumbosacral radiculopathy as a consequence of nerve root compression or irritation. Almost 5% males and 2.5% females experience lumbosacral radiculopathy at some time in their lifetime. Magnetic resonance imaging (MRI) is the preferred investigation for the diagnosis of lumbosacral radiculopathy. So, in the evaluation of a patient of lumbosacral radiculopathy is essential to correlate clinical symptoms and signs with the finding detected in the MRI to arrive at a correct diagnosis and arrange an appropriate management. So this study was done to see the correlation between clinical and MRI finding of radiculopathy at different nerve root level in patients with lumbosacral radiculopathy. It was a cross sectional descriptive study. All 40 patients of lumbosacral radiculopathy who were presented to Rajshahi Medical College Hospital during the study period from 01/11/2011 to 30/10/2012 were included in the study. There were 30 males and 10 females having an M: F ratio of 3:1. Mean age of total patients 43 + 14.74 years. 67.5% patients were between 20 to 50 years and 60% patients were performing heavy work. 67.5% patients had unilateral involvement while 32.6% patients had bilateral involvement. 72.5% patients had muscle weakness and 27.5% had no muscle weakness. 67.5% patients had sensory impairment and 32.5% had no sensory involvement. Knee jerk changes were present in 60% patients and ankle jerk changes in 66.66% patients. As expected 52.18% had L5 and 32.61% had S1 radiculopathy. The difference in clinical and MRI detection of root involvement was statistically significant (p value &lt; 0.05) in both sides at L4, L5 and S1 root levels but there was no significant difference at the L3 root level (p value 1.00) Intervertebral disc herniation was the commonest cause of lumbosacral radiculopathy (72.32%) and second common cause was spinal canal stenosis (19.44%). Others are intervertebral disc budging (61.52%), disc protrusion (23.08%) and disc extrusion (15.38%). Correlation between clinical severity and MRI grading of lumbosacral radiculopathy which was statistically significant. So, it is concluded that clinical findings correlate well with MRI finding, but all MRI abnormalities need not have a clinical significanceTAJ 2015; 28(1): 32-39

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.

Relationship of preoperative neurologic score with intervals to regaining micturition and ambulation following surgical treatment of thoracolumbar disk herniation in dogs.

OBJECTIVE To estimate the times required for dogs to regain micturition and ambulation following surgical treatment for thoracolumbar Hansen type I intervertebral disk extrusion (IVDE) and determine whether these variables were associated with preoperative modified Frankel score (MFS). DESIGN Retrospective case series with nested cohort study. ANIMALS 54 dogs weighing < 20 kg (44 lb) that were surgically treated for Hansen type I IVDE at a referral hospital between January and December 2015. PROCEDURES Medical records and CT and MRI data were reviewed. Information was collected regarding dog signalment, type and duration of clinical signs, preoperative MFS, degree of spinal cord compression, type of medical and surgical treatment provided, and intervals from surgery to regaining micturition and ambulation (outcomes). Collected data were evaluated for correlations with outcomes. RESULTS Mean ± SD interval from surgery to regaining micturition was 4.1 ± 4.4 days, and mean interval from surgery to regaining ambulation was 13.8 ± 25.1 days. These intervals differed significantly. Significant negative correlations with MFS were identified for interval to regaining micturition (r = -0.63) and interval to regaining ambulation (r = -0.64). No other correlations with outcome were identified. CONCLUSIONS AND CLINICAL RELEVANCE The amount of time required for dogs to regain micturition and ambulation following surgery for thoracolumbar IVDE was correlated with preoperative severity of clinical signs, as reflected by preoperative MFSs. This information should be useful for pre- and postoperative decision-making and setting of expectations for owners of and clinicians treating affected dogs.

Radicular compression of the nerve root in the intervertebral foramen by an intervertebral cervical disc extrusion of a dachshund

This is an interesting case presentation of cervical intervertebral disc extrusion in a dachshund with acute neck pain and a nerve root signature in the right forelimb. There was no extradural compression of the spinal cord but lateralised extruded intervertebral disc material where the entire amount of disc material was located deep in the intervertebral foramen, leading to compression of the nerve root. The patient did not respond to conservative treatment, and the pain and nerve root sign persisted. A CT scan showed what was assumed to be a lateralised fragment of calcified extruded disc material in the intervertebral foramen. This necessitated a dorsolateral approach to remove the extruded disc material via a haemilaminectomy. The patient responded very well to surgery and made a full recovery.

Comments on the dilemma in the May issue: Slipped disk and dyspnoea in a French bulldog

In the dilemma discussed in the May issue of In Practice, Laura McLellan described a scenario where ‘Bella’, a four-year-old female French bulldog, is presented to you as an emergency...

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

Abstract 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.

Characteristics of and risk factors for intervertebral disk extrusions in Pekingese.

OBJECTIVE To characterize and identify risk factors for intervertebral disk extrusion (IVDE) in Pekingese. DESIGN Retrospective case-control study. ANIMALS 426 Pekingese (81 with confirmed IVDE and 345 without IVDE) admitted to a veterinary teaching hospital from 2005 through 2015. PROCEDURES Medical records were reviewed and data were extracted regarding age, sex, body weight, body condition score, coat color, chief reason for initial evaluation, body system involved, and diagnosis. Survey radiographs of the vertebral column were examined. Data were compared between the confirmed IVDE and non-IVDE groups. RESULTS Confirmed IVDE was uncommon in dogs < 2 years of age (2/81 [2%]). The extrusion was primarily located in the thoracolumbar (n = 57 [70%]) and cervical (22 [27%]) regions; the most common sites were T12-13 and C6-7. The number of radiographically visible calcified disks was significantly greater in the confirmed IVDE versus non-IVDE group, and the presence of calcified disks in the T10-L4 region was associated with increased odds of IVDE (OR, 21.2). Black coat color was significantly more prevalent in the confirmed IVDE versus non-IVDE group and was associated with increased odds of developing IVDE (OR, 1.6). Mean body weight and the proportion of spayed female dogs were significantly greater in the confirmed IVDE versus non-IVDE group. CONCLUSIONS AND CLINICAL RELEVANCE Several risk factors for confirmed IVDE in Pekingese were identified that could be useful for counseling clients about the disease or, with additional research, designing selective breeding programs to reduce the prevalence of IVDE in the breed.

Hypothermia, bradycardia and hypotension in a Dachshund undergoing a hemilaminectomy

A 3-year-10-month-old female neutered Dachshund was presented for investigation of acute onset paraparesis. Magnetic resonance imaging showed an intervertebral disc extrusion, therefore a dorsal hemilaminectomy was performed. While under general anaesthesia, the patient became hypothermic (33.1 °C) and severely bradycardic, with a concurrent severe decrease in blood pressure. Initial management of the bradycardia included glycopyrrolate at a dose rate of 10 μg/kg, administered twice, however the patient was unresponsive to this. Active warming was initiated and the patient's body temperature slowly increased. A single dose of atropine was administered, following which the patient's bradycardia resolved. It is likely that once the patient's temperature increased, all the vasoactive substances were able to take effect. This suggests that the bradycardia was probably, in part, due to the hypothermia, although other factors may have contributed.

Magnetic Resonance Imaging Signal Alterations in Paraspinal Muscles in Dogs with Acute Thoracolumbar Intervertebral Disk Extrusion.

Muscle signal alteration detected on MRI is seen in diverse pathologic conditions. We observed signal alterations within the paraspinal muscles in dogs with acute thoracolumbar intervertebral disk extrusion. The aim of this retrospective study was to describe MRI features of paraspinal muscle signal alteration in dogs with acute thoracolumbar intervertebral disk extrusion and to investigate an association of the signal alterations with neurological grade, type and location of intervertebral disk extrusion, degree of spinal cord compression, and presence of epidural hemorrhage. Medical records of dogs undergoing MRI because of thoracolumbar intervertebral disk extrusion between August 2014 and June 2016 were reviewed. MRI was evaluated for SI changes within the paravertebral musculature, their location, extension, affected muscles, contrast enhancement, and signal void in T2* sequences. Intervertebral disk herniation was categorized as acute non-compressive nucleus pulposus extrusion (ANNPE) or compressive intervertebral disk disease. In five patients, muscle biopsies of areas with signal intensity changes were taken during surgery. In total, 103 dogs were enrolled in the study. Paraspinal muscle signal alterations were visible in 37 dogs (36%) affecting the epaxial musculature (n = 17), hypaxial musculature (n = 12), or both (n = 8). All signal alterations were hyperintense on T2-weighted images and iso- or hypointense in T1-weighted images. Signal void in T2* was not observed in any dog. Postcontrast sequences were available in 30 of the 37 dogs and showed enhancement in 45%. There was neither an association with degree of compression nor epidural hemorrhage. Intervertebral disk extrusion caudal to L1 and a higher neurological grade was associated with the presence of muscle changes. Histopathology revealed mild to moderate acute muscle fiber degeneration with edema and necrosis in three of five samples. The MRI, as well as the muscle samples, show rather unspecific changes. The underlying pathomechanism might be related to ischemia or muscle spasm, but also denervation edema may explain the signal alteration.

Diagnóstico por tomografia computadorizada da extrusão de disco intervertebral em paciente geriatra: Relato de Caso

Intervertebral disc disease (IVDD) is the most common cause of spinal cord compression in dogs, resulting in neurological problems, which can be classified into two types: Hansen type I (disc extrusion) and Hansen type II (disc protrusion), pressing the nerves of the marrow causing pain, ataxia, paralysis and paraplegia. The indicated treatment should be based on the degree of injury, and may be the clinical treatment associated with physical therapy, for less severe cases, based on the successes in the recovery of the condition, reported in the literature. The objective of this study was to report the efficiency of computed tomography as a complementary tool for conclusive diagnosis of DDIV and the success of clinical and physiotherapeutic treatment for this disease. The animal in question was an 11-year-old poodle that presented ataxia and motor incoordination and was diagnosed with an intervertebral disc extrusion between the T12 and T13 vertebrae by means of computed tomography. The treatment chosen was based on anti-inflammatories and physiotherapy focusing on the strengthening of the epaxial and hipaxial musculature. After 45 days of initiation of treatment, a significant improvement of the animal was observed, however, a future surgical intervention was not ruled out.