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Lumbosacral intervertebral disc herniation (IVDH) is a common cause of lower back pain in dogs and humans. In humans, the vertebral endplate to annulus fibrosus (AF) attachment was implicated as an alternative failure site besides rupture through the dorsal AF (AFF). Endplate junction failure (EPJF) is characterized by IVDH, accompanied by endplate irregularities (type A), rim avulsions (type B), or larger bony avulsions on one (type C) or both endplates (type D), associated with an adjacent endplate defect. This retrospective study reports the CT prevalence of presumed EPJF in dogs and its associations with signalment and other lumbosacral CT abnormalities. CT scans, including the lumbosacral spine of dogs obtained at two institutions, were assessed, yielding 324 scans. Presumed EPJF was found in 69 dogs (21%) and AFF in 68 dogs (21%), commonly at the caudal endplate of the last lumbar vertebra (71%). The remaining 187 dogs did not show presumed EPJF or AFF. Presumed EPJF type A occurred in 49/69, type B in 19/69, and type C in 1/69 dogs. Univariable logistic regression showed that presumed EPJF was associated with significantly higher IVDH grades than AFF. In the multiple regression model, presumed EPJF and AFF remained associated with increasing age and spondylosis deformans. Presumed EPJF was associated with vertebral endplate sclerosis and AFF with zygapophyseal joint osteoarthritis. In conclusion, presumed EPJF was observed on CT in 21% of dogs with lumbosacral IVDH. Prospective studies correlating EPJF on CT with clinical, surgical, and histopathological findings are needed for a better understanding of the underlying pathology and clinical relevance., (© 2024 The Author(s). Veterinary Radiology & Ultrasound published by Wiley Periodicals LLC on behalf of American College of Veterinary Radiology.)

A 3-year-old American Saddlebred gelding presented for progressive tetraparesis, ataxia, and cervical hyperaesthesia. Radiographic myelography identified spinal cord compression at C6-7 in neutral, extended, and flexed positions and at C4-5 in the flexed position. CT myelography and postmortem MRI identified severe vertebral canal stenosis/compression at C6-7. MRI further identified severe intervertebral disc herniation at C6-7 with intramedullary changes. Disc protrusion was confirmed macroscopically at postmortem. Lesions consistent with compressive myelopathy were confirmed microscopically at C6-7. This is the first report of equine disc protrusion and myelocompression confirmed by multiple advanced imaging modalities and postmortem examination., (© 2024 American College of Veterinary Radiology.)

Thoracolumbar hydrated nucleus pulposus extrusion (TL-HNPE) is an increasingly recognised pathology with a substantial lack of literature describing its features. The aim of this retrospective case-control study was to analyse the clinical and magnetic resonance imaging (MRI) features of dogs with TL-HNPE compared to dogs affected with thoracolumbar intervertebral disc extrusion (TL-IVDE). Data from dogs diagnosed with TL-HNPE and TL-IVDE via MRI at two referral hospitals, were retrospectively collected and compared in terms of clinical signs and MRI features. Cases diagnosed with TL-IVDE were deemed controls. The MRI features of the affected IVD space, herniated IVD material, affected overlying spinal cord and local epaxial musculature were evaluated for each group. Fifty-one cases with TL-HNPE and 105 randomly selected cases of TL-IVDE were included. Several signalment and neurological signs were identified as statistically distinct between groups in univariate analysis. Multivariate analysis identified that dogs affected with TL-HNPE were typically older, less likely to be chondrodystrophic (62.2 % vs. 91 %), more frequently experiencing a peracute onset (90.2 % vs. 61.9 %) often attributed to a suspected trauma linked with exercise (37.3 % vs. 10.5 %), being less frequently progressive (41.2 % vs. 86.5 %) and with herniated disc material less frequently lateralised (72.6 % vs. 89.5 %) than cases with TL-IVDE. MRI-identifiable intervertebral disc degeneration was found in every TL-IVDE case but only in 60 % of TL-HNPE cases. TL-HNPEs were associated to significantly less spinal cord compression and less hyperalgesia than TL-IVDE., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objective: To determine the occurrence of degenerative changes affecting the vertebral column in cats, assess their clinical significance, and determine the occurrence in cats with intervertebral disk herniation compared to other spinal diseases., Animals: 114 client-owned cats., Methods: Hospital records were retrospectively reviewed for cats with suspected myelopathy that had undergone spinal MRI. Signalment; history; neurological examination; neurolocalization; primary diagnosis; presence, type, and location of intervertebral disk herniation; and presence and location of other degenerative spinal changes (intervertebral disk degeneration [IVDD], spondylosis deformans [SD], end plate changes, dorsal compressions [DC], and foraminal stenosis [FS]) were recorded., Results: 70% of cats showed at least 1 spinal degenerative change. The most common change was IVDD, followed by SD and intervertebral disk protrusion (IVDP), while intervertebral disk extrusion (IVDE), end plate changes, DC, and FS were uncommon to rare. Primary complaint was attributed to a degenerative condition in 22% of cats, including 100% with IVDE, 9% with IVDP, and 43% with degenerative lumbosacral stenosis (DLSS). The occurrence of degenerative spinal changes and number of intervertebral disks affected by IVDD significantly increased with age and body weight. Age was positively correlated with the occurrence of SD and DLSS. Intervertebral disk degeneration, IVDP, SD, DC, and FS were more prevalent in the lumbosacral junction. Cats with IVDD were significantly more likely to show IVDE and IVDP., Clinical Relevance: This study revealed that in a population of cats presenting for signs of myelopathy, IVDE was always responsible for the clinical presentation, DLSS was commonly considered incidental, and IVDP was infrequently related to neurological signs.

Objective: To evaluate the breed-characteristic features of cervical intervertebral disc disease (C-IVDD) and associated vertebral instability in small-breed dogs and to present the concept of intervertebral disc degeneration and associated instability stage, method of diagnosis, treatment and outcomes., Animals: In total, 307 client-owned dogs with C-IVDD treated with spinal cord decompression with or without vertebral stabilization (2000-2021)., Methods: Information on age, sex, affected sites, stabilized sites, diagnostic methods for vertebral instability and outcomes were retrieved. The patient's age, affected sites (cranial vs caudal discs), and frequency of vertebral stabilization were compared in six CD and five NCD breed. Multivariable analyses of the chondrodystrophic (CD) vs non-CD (NCD) groups, and vertebral stabilization (dogs stabilized vs dogs not stabilized) were performed., Results: In total, 222 (72.3%) and 77 (25.1%) were CD and NCD breeds, respectively. Vertebral instabilities were diagnosed based on the survey radiographs with computed tomography/magnetic resonance imaging (n = 2), dynamic myelography (n = 29), intraoperative spinal manipulation (n = 11) or second surgery in dogs with persistent postoperative paraspinal pain (n = 3). Of these dogs, 295 (96.1%) recovered (median follow-up: 8.5 [range, 1-119] months). Significant differences in age, affected sites and frequency of stabilization were noted among the breeds. Older age and frequent vertebral stabilization were the associated factors for the NCD breed dogs. Male dogs, caudal discs affected (C5-T1) and the NCD breed dogs were risk factors for the dogs with vertebral stabilization., Conclusion: Vertebral stabilization is indicated for small-breed dogs with cervical disc-associated vertebral instability., (© 2024 Australian Veterinary Association.)

This retrospective study aimed to characterize and determine the prevalence of spinal disease in nondomestic felids within a sanctuary population. A review of 304 postmortem examination reports in Panthera species from 2003 to 2021 revealed that 86/304 (28%) were diagnosed with spinal disease. Spinal lesions were categorized according to pathologic process: degenerative (78/86, 91%), developmental (8/86, 9%), inflammatory (6/86, 7%), or neoplastic (8/86, 9%). Degenerative lesions included intervertebral disk disease (IVDD; 66/78, 85%), spondylosis without concurrent IVDD (4/78, 5%), and idiopathic (noncompressive) degenerative myelopathies (8/78, 10%). Fourteen individuals had lesions in more than 1 category. Developmental cases were vertebral (4/8) or spinal cord (3/8) malformations or both (1/8). Inflammatory lesions included meningitis (4/6) and meningomyelitis (2/6). Neoplasia included vertebral multiple myeloma (4/8) and others (4/8). IVDD often involved multiple disks but primarily affected the cervical (41/66, 62%) and thoracic spine (32/66, 48%). A multivariate binary logistic model predicted the diagnosis of IVDD at postmortem examination, where odds of being affected were highest for males, lions ( Panthera leo ), and geriatric age group ( > 14 years). The spinal lesions documented in this study provide insight into high-risk signalment categories and predominant associated lesions affecting captive Panthera populations. Specifically, spinal disease, especially cervical IVDD, is common among Panthera species, and lions, males, and older felids are at increased risk., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Intervertebral disc herniation (IVDH) is the most common spinal cord disease in dogs. Little information is available regarding the clinical presentation of nerve root signature (NRS) associated with cervical IVDH., Hypothesis/objective: To detail the clinical and magnetic resonance imaging (MRI) findings in dogs with NRS associated with cervical IVDH., Animals: Forty-seven client-owned dogs presenting with thoracic limb NRS and MRI confirmed IVDH., Methods: Medical records from 2010 to 2020 were retrospectively reviewed for dogs that met inclusion criteria. Imaging studies were evaluated by 2 individuals to characterize location and severity of neural tissue compression., Results: Chondrodystrophoid dogs comprised the majority of the study cohort, with dachshund the most common breed (n = 10). Three-quarters of dogs were ≥7 years of age. Interobserver agreement was moderate or good for all of the imaging variables evaluated. The C6-C7 intervertebral disc space was significantly overrepresented (P = .01), comprising 32% (15/47) of the affected discs. However, 42% (20/47) of cases involved C2-C3 though C4-C5 disc sites. Disc material was more frequently located laterally compared to medially within the vertebral canal (P = .0005), and to be associated with compression of the nerve root at the level of the intervertebral foramen (P = .012)., Conclusion/clinical Importance: NRS is most commonly associated with lateralized or foraminal cervical disc herniations. It is most prevalent with C6-C7 intervertebral disc involvement, suggesting that there might be unique anatomic factors that contribute to development of NRS at this site, but can be a clinical manifestation of IVDH occurring anywhere along the cervical spine., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Objective: Compare 3 methods of nucleus pulposus (NP) volume measurement using the rabbit lumbar spines as a preclinical model to determine the effectiveness of prophylactic intervertebral disk fenestration in dogs., Animals: Twelve 9-month-old, skeletally mature female entire New Zealand White rabbits weighing between 3.5 to 4.5 kg., Methods: NP volume measurements of dissected rabbit lumber spines between L1 and L6 were made and compared using gross measurements, reconstructed MRI images, and water volumetry based on Archimedes' principle. Water volumetry was used as the true gold standard volume measurement in this study., Results: The true volume (mean ± SD) of the nucleus pulposus NP as measured by water volumetry increased caudally from L1/L2 (16.26 ± 3.32 mm3) to L5/L6 (22.73 ± 6.09 mm3). Volume estimates made by MRI were significantly higher than those made using water volumetry at all sites (L1/L2 [P = .044], L2/L3 [P = .012], L3/L4 [P = .015], L4/L5 [P < .001], and L5/L6 [P < .001]). Gross measurements also significantly overestimated volume when compared to water volumetry at all sites; L1/L2 (P = .021), L2/L3 (P = .025), L3/L4 (P = .001), L4/L5 (P < .001), and L5/L6 (P < .001). MRI and gross volume estimates were significantly different at L4/L5 (P = .035) and L5/L6 (P = .030)., Clinical Relevance: The findings of this preclinical model might be relevant to veterinary surgeons who perform prophylactic fenestration for which there is no reliable method to determine the amount of NP to be removed. Preclinical ex vivo and in vivo fenestration studies with pre- and postoperative NP volume assessment are required.

Background: Dachshunds have a high prevalence of intervertebral disc disease (IVDD) to which they are predisposed due to early intervertebral disc (IVD) degeneration and calcification. Moreover, the recently found 12-FGF4 retrogene (RG) is associated with calcified discs visible on radiographs (CDVR) and IVDD. Earlier studies suggest that all IVDs of one-year-old Dachshunds show signs of degeneration. This prospective, analytical, blinded study aimed to investigate the extent and distribution of IVD degeneration in young adult (24-31 months) asymptomatic Dachshunds (n = 21) hypothesizing that not all IVDs of two-year-old Dachshunds are degenerated. Another aim was to explore the correlations between IVD degeneration evaluated with magnetic resonance imaging (MRI), the number of CDVR, and the dog's 12-FGF4RG status. The study protocol included grading the CDVR on spinal radiographs, grading the IVD degeneration on T2-weighted sagittal and transverse high-field MR images of all IVDs (n = 546), and 12-FGF4RG variant genotyping., Results: Of all IVDs evaluated, 2% (n = 11) were normal based on MRI grading. Despite the study population having moderately degenerated IVDs (median MRI grade 3), there was also variation in the degree of IVD degeneration between individuals and in the distribution of IVD degeneration between different vertebral regions. The number of CDVR correlated significantly with the magnitude of IVD degeneration based on MRI evaluation and with the 12-FGF4RG genotype. The odds for being 12-FGF4RG homozygous were higher for Dachshunds with CDVR. However, the 12-FGF4RG variant did not alone explain the phenotypic variation in IVD degeneration., Conclusions: The number of CDVR is a valid indicator of overall IVD degeneration, as it correlates with MRI-based IVD grading. Also, as the extent and distribution of IVD degeneration varies between individual Dachshunds, selective breeding against IVDD using radiographic screening and 12-FGF4RG variant genotyping is possible., (© 2023. The Author(s).)

Magnetic resonance imaging is the gold standard for diagnosing intervertebral disc (IVD) degeneration in dogs. However, published methods for quantifying severity or progression of IVD degeneration are currently limited. Mapping MRI sequences are used in humans for quantifying IVD degeneration but have rarely been applied in dogs. The objective of this prospective, method comparison study was to evaluate variable flip angle T1 mapping and multiecho T2 and T2* mapping as methods for quantifying canine lumbar IVD degeneration in twenty canine patients without clinical signs of spinal disease. Ventral and dorsal lumbar IVD widths were measured on radiographs, and lumbar IVDs were assigned a qualitative Pfirrmann grade based on standard T2-weighted sequences. T1, T2, and T2* relaxation times of the nucleus pulposus (NP) were measured on corresponding maps using manual-drawn ROIs. Strong intra- and interrater agreements were found (P < 0.01) for NP relaxation times. Radiographic IVD widths and T1, T2, and T2* mapping NP relaxation times were negatively correlated with Pfirrmann grading (P < 0.01). Significant differences in T1 NP relaxation times were found between Pfirrmann grade I and the other grades (P < 0.01). Significant differences in T2 and T2* NP relaxation times were found between grade I and the other grades and between grades II and III (P < 0.01). Findings indicated that T1, T2, and T2* MRI mapping sequences are feasible in dogs. Measured NP relaxation times were repeatable and decreased when Pfirrmann grades increased. These methods may be useful for quantifying the effects of regenerative treatment interventions in future longitudinal studies., (© 2023 The Authors. Veterinary Radiology & Ultrasound published by Wiley Periodicals LLC on behalf of American College of Veterinary Radiology.)

Objective: To compare the use of the video telescope operating monitor (VITOM) and use of a conventional unassisted surgical method for treatment of cervical intervertebral disc herniation in dogs., Animals: 39 dogs with cervical intervertebral disc disease., Methods: Prospective study. Dogs were prospectively nonrandomly assigned to either the VITOM (n = 19) or conventional surgery (20) group depending on VITOM system availability. Signalment and preoperative neurologic status were recorded for all dogs. Preoperative and postoperative CT myelography was performed to compare intervertebral space location, spinal cord dimensions at the decompression level, ventral slot dimensions, and residual disc material. Surgical complications and postoperative neurologic outcomes were recorded. Data were compared between the 2 groups using fixed-effects or mixed-effects models to consider double reading of CT myelography images., Results: No significant differences were noted between the 2 groups regarding the decompression ratio (P = .85), vertebral length body ratio (P = .13), ventral slot width ratio (P = .39), residual disc material (P = .30), and sinus bleeding (P = .12). No significant differences were found between the 2 groups regarding postoperative neurologic grade (P = .17)., Clinical Relevance: VITOM-assisted ventral slot decompression is equivalent to conventional surgery in treatment of cervical intervertebral disc herniation in dogs. The use of VITOM remains a good alternative to the conventional surgical method.

Objective: To compare the prognosis of small dogs with cervical intervertebral disc herniation (C-IVDH) when treated with ventral slot decompression (VSD) alone or with concomitant vertebral fixation (VF)., Animals: Small dogs (n = 303) weighing < 15 kg diagnosed with C-IVDH and treated with VSD., Procedures: We recorded signalment, cervical myelopathy grade, surgical site, use of VF, degree of adjacent disc degeneration, recovery, recurrence, recurrence site, and postoperative course, including the time elapsed from recovery to recurrence. We examined factors associated with recovery and recurrence during the 30-month postoperative period using multivariate logistic regression analysis., Results: VF did not affect recovery (P = .79). However, nonchondrodystrophic breeds had poorer recovery (OR, 5.89; P = .023) than chondrodystrophic breeds, and a higher preoperative cervical myelopathy grade (grade 3 or 4) was associated with poorer recovery (OR, 7.09 or 3.46, respectively; P = .019 or .042, respectively), compared with grade 1. VF did not affect recurrence (P = .79); however, increasing age was associated with recurrence (OR, 1.79; P = .001)., Clinical Relevance: In small dogs weighing < 15 kg, there was no difference in postoperative recovery and recurrence rates after VSD with or without concomitant VF. Therefore, in small dogs with C-IVDH, even if the slot volume is increased to remove sufficient disc material during VSD, a good prognosis can be achieved with or without VF.

Case History: A 7-year-old, male neutered French Bulldog was referred to a specialist veterinary hospital for evaluation of progressive paraparesis of 6-months' duration. The owners reported both faecal and urinary incontinence at home., Clinical Findings: The dog presented with ambulatory paraparesis and pelvic limb ataxia that was more pronounced in the right pelvic limb. The pelvic limb withdrawal response and sciatic myotatic response were reduced bilaterally. Postural reaction responses were delayed in both pelvic limbs, and this was more obvious in the right pelvic limb. The anal tone and perineal sensation were normal at the time of examination.An L4-S3 myelopathy was suspected. CT of the spine revealed a compressive, bilobed, extramedullary, cyst-like structure within the vertebral canal, between L7 and S3. Surgical removal of the cyst via a L7-S1 dorsal laminectomy was performed. Histopathological examination and additional immunohistochemistry of the excised structure indicated a probable ependymal cyst with a ciliated lining. The dog recovered well post-operatively, and at follow-up 3 weeks later had some improvement of his neurological signs. The paraparesis and pelvic limb ataxia had improved; however, the remaining neurological examination was similar to the pre-surgical examination., Diagnosis: Extradural cyst., Clinical Relevance: Spinal cysts can contribute to clinical signs that resemble other common chronic spinal cord diseases, such as intervertebral disc disease. Therefore, this disease should be considered as a differential when dealing with cases of progressive paraparesis and pelvic limb ataxia. This case report may potentially provide opportunities in the future for further understanding of the pathogenesis, behaviour, outcomes and subclassification of spinal cysts in dogs.

Background: Intervertebral disc disease (IVDD) is a common diagnosis and well-investigated pathological condition in French Bulldogs with neurological deficiencies. However there is currently only one recently published retrospective descriptive study looking for recurrence rates of IVDD in French Bulldogs. Medical reports of French Bulldogs with a first episode of IVDD and surgical treatment were evaluated and reviewed for clinical signs of recurrence. Risk factors for Total-Recurrence, Cervical- and Thoracolumbar-Recurrence were evaluated by means of logistic regression models. The aim of this study was to assess frequency and risk factors associated with the recurrence of IVDD in French Bulldogs., Results: One hundred twenty-seven French Bulldogs with a first episode of IVDD and surgical treatment were evaluated. 52.7% (67/127) of these patients showed signs of recurrence. The recurrence rate in the cervical spine was slightly lower (47%) compared to the thoracolumbar spine (56.6%). A significant association with recurrence could be found for the factor age: French Bulldogs with a first episode of IVDD ≤ 3 years seem to be prone for Total-Recurrence (P = 0.002) and Cervical-Recurrence (with ORs ranging from 0.02 to 0.03 for patients older than 3 years). 50% of the recurrences (median) occurred within the first 12 month after the first episode of IVDD., Conclusions: Recurrence of IVDD can be expected in more than half of French Bulldogs affected by IVDD. Especially young French Bulldogs are prone for recurrence in cervical spine. Almost every fourth patient with IVDD suffers from a recurrence within 12 months. Future dog owners should be informed about the risk of IVDD and the early onset of recurrences in French Bulldogs., (© 2023. The Author(s).)

Objectives: To evaluate the effects of the chondrodystrophy-associated FGF4L2 retrogene on intervertebral disc (IVD) calcification and vertebral geometry., Animals: 22 Nova Scotia Duck Tolling Retrievers (NSDTR) with no FGF4L2 retrogene (n = 7, wild-type dogs), 1 retrogene copy (8, heterozygous dogs), or 2 retrogene copies (7, homozygous dogs)., Procedures: Computed tomography (CT) scans of the vertebral column were analyzed using computer-aided design (CAD) software. IVD calcification, vertebral column length, and vertebral geometry of the third cervical (C3), 13th thoracic (T13), and first lumbar (L1) vertebrae were compared., Results: IVD calcification was not found in wild-type dogs. IVD calcification was more frequent in homozygous dogs than heterozygous (P = .008) or wild-type dogs (P < .001) and in heterozygous dogs compared to wild-type dogs (P < .001). Four IVDs were subclinically herniated in 3 dogs (2 homozygous, 1 heterozygous). Calcified IVD had a greater volume and surface area in heterozygous dogs than homozygous dogs. C3 vertebral canal height-to-width ratio was greater in homozygous dogs than heterozygous dogs (P = .044) and wild-type dogs (P = .010)., Clinical Relevance: IVD calcification and vertebral geometry can be analyzed using CAD software. The presence of 1 or 2 FGF4L2 copies in the absence of the FGF4L1 retrogene has an additive effect on the number of calcified IVD and a minor effect on vertebral geometry in NSDTR dogs. Data support the use of FGF4L2 phenotyping to reduce clinical disease in segregating breeds and to monitor the introduction of wild-type alleles into fixed breed populations.

Object and Purpose: The purpose of this first-time long-term observational study was to evaluate the changes of the caudal lumbar spine at the locations L5/6, L6/7, and L7/S1 in 5 German shepherd dogs over a 6-year time period using computed tomography (CT) and magnetic resonance imaging (MRI). The dogs had a mean age of 26 months at the time of the first examination. In addition, it was evaluated whether a breeding examination, with regard to disc degeneration, is justified in young dog., Material and Methods: The locations L7/S1, L6/7, and L5/6 were examined in more detail with regard to their signal intensity changes, the facet joint angle changes in dorsal (dors) and transverse (trans) planes, and disc surface changes in sagittal (sag) and transverse (trans) reconstruction planes with CT and MRT in 2015 and 2021. All data were collected computer-based and analyzed statistically. Subsequently, the results were compared to the measured signal intensity and to the subjective disc degeneration grading according to Seiler used in practice., Results: Over the period of 6 years a significant loss of the measured signal intensity of the intervertebral discs in the transverse plane and an overall facet joint widening in the transverse plane of 0.54° as well as in the dorsal plane of 1.8° was evident. In addition, there was no evidence of a relationship between the size of the facet joint angle and the degree of disc degeneration. Furthermore, regardless of the initial degree of degeneration, the discs showed low signal intensity and higher Seiler grade during follow-up., Conclusion and Clinical Relevance: The results of the present study group indicate that an inconspicuous condition of the lumbar intervertebral discs at the time of the initial breeding examination in the young dog does not allow an accurate prediction of the subsequent degree of degeneration and that there are ongoing remodeling processes at the facet joints even in healthy German shepherd dogs., Competing Interests: Die Autoren erklären, dass keine Interessenkonflikte bestehen., (Thieme. All rights reserved.)

Objectives: The aim of this study was to evaluate the outcome and prognosis of thoracolumbar feline intervertebral disc disease (IVDD) treated by surgical decompression., Methods: This was a multi-institutional retrospective study evaluating the age, breed, sex, body weight, presenting complaint, neuroanatomic diagnosis at presentation, diagnostic imaging results, surgery performed and the overall outcome at discharge and at recheck. Bivariable associations between variables were assessed using the Kruskal-Wallis test (age and grade of IVDD at presentation) and Fisher's exact test (grade of IVDD at presentation and outcome)., Results: A total of 35 cats met the inclusion criteria for the study. The most frequently reported clinical sign was difficulty walking (54.2%). The majority of cats presented with an L4-S3 localization (57%). The most common site of intervertebral disc herniation (IVDH) was at L6-L7 (34%). The majority of feline patients that received surgery had a positive outcome at the time of discharge (62.5%; n = 20/32) and at the time of the 2-week recheck (91.3%; n = 21/23). No association was identified between the age of the patient and the grade of IVDD. No association was identified between the presenting grade of IVDD and the clinical outcome at the time of discharge or at the time of recheck evaluation., Conclusions and Relevance: Cats undergoing spinal decompressive surgery for thoracolumbar IVDH appear to have a favorable prognosis independent of the initial presenting grade of IVDD. A larger sample size and a longer length of follow-up is necessary to obtain statistical associations between the presenting grade of IVDD and overall clinical outcome.

Gross morphology of healthy and degenerated intervertebral discs (IVDs) is largely similar in horses as in dogs and humans. For further comparison, the biochemical composition and the histological and biochemical changes with age and degeneration were analyzed in 41 warmblood horses. From 33 horses, 139 discs and 2 fetal vertebral columns were evaluated and scored histologically. From 13 horses, 73 IVDs were assessed for hydration, DNA, glycosaminoglycans, total collagen, hydroxyl-lysyl-pyridinoline, hydroxylysine, and advanced glycation end-product (AGE) content. From 7 horses, 20 discs were assessed for aggrecan, fibronectin, and collagen type 1 and 2 content. Histologically, tearing of the nucleus pulposus (NP) and cervical annulus fibrosus (AF), and total histological score (tearing and vascular proliferation of the AF, and chondroid metaplasia, chondrocyte-like cell proliferation, presence of notochordal cells, matrix staining, and tearing of the NP) correlated with gross degeneration. Notochordal cells were not seen in IVDs of horses. Age and gross degeneration were positively correlated with AGEs and a fibrotic phenotype, explaining gross degenerative changes. In contrast to dogs and humans, there was no consistent difference in glycosaminoglycan content and hydration between AF and NP, nor decrease of these variables with age or degeneration. Hydroxylysine decrease and collagen 1 and AGEs increase were most prominent in the NP, suggesting degeneration started in the AP. In caudal cervical NPs, AGE deposition was significantly increased in grossly normal IVDs and total collagen significantly increased with age, suggesting increased biomechanical stress and likelihood for spinal disease in this part of the vertebral column.

Magnetic resonance imaging (MRI) is a standard test for diagnosis and treatment planning in dogs with degenerative thoracolumbar intervertebral disc disease (IVDD). However, published studies evaluating three-dimensional fast-spin echo (3D-FSE) pulse sequences for dogs with IVDD are currently limited. Aims of this retrospective, observational study were to compare findings from T2-weighted two- and three-dimensional fast spin-echo sequences (2D- and 3D-FSE, respectively) for a group of small breed dogs with thoracolumbar IVDD. Inclusion criteria were dogs with IVDD that underwent 1.5-Tesla MRI using both 2D-FSE and 3D-FSE sequences. For each dog and sequence, five pathologic indices were recorded: epidural fat discontinuation, vertebral canal compromise, spinal cord signal change, disc degeneration, and nerve root compression. Two independent investigators also scored visibility of the facet joint, intervertebral foramen, nerve roots, spinal cord grey-white matter differentiation, intervertebral discs, and epidural fat. The Wilcoxon signed-rank test was used to evaluate the between-sequence differences in pathologic indices and visibility scores. Interobserver agreement was measured using Cohen's weighted kappa along with 95% confidence intervals. A total of 21 dogs were sampled. The 3D-FSE sequences had higher pathologic indices of vertebral canal compromise (P = 0.020) and spinal cord signal change (P = 0.046) than 2D-FSE sequences. Furthermore, 3D-FSE sequences had higher visibility scores for the facet joint, intervertebral foramen, and nerve root structures (P < 0.001). Findings from the current supported the use of 3D-FSE sequences over 2D-FSE sequences for the evaluation of IVDD and visualization of spinal structures in small breed dogs., (© 2022 American College of Veterinary Radiology.)

Objective: To evaluate the intervertebral disk, vertebral endplates, and spinal cord for perioperative changes secondary to percutaneous laser disk ablation (PLDA) and correlate findings to clinical outcomes in dogs receiving thoracolumbar PLDA., Study Design: Blinded study., Animals: Thirty dogs., Methods: Magnetic resonance imaging (MRI) was performed before PLDA (control/Group C), immediately following PLDA (Group I), and 3 months later (perioperative/Group P). Dogs were followed 3 years. Groups and dogs were randomized for evaluation. Two radiologists were blinded to each MRI study and dog. Each radiologist evaluated the disk, vertebral body, and spinal cord at each disk space receiving PLDA., Results: Mean disk degeneration was increased in Group P at L1-2 (p < .0001) and L2-3 (p = .0081). Both radiologists identified mild diskitis (1%-15%) in Group P (radiologist 1, p < .0001; radiologist 2, p = .0012). Cranial endplate lesions were identified in Group P at T11-12 (p = .0353), T13-L1 (p = .0026), and L4-5 (p = .0210). Lesions were identified in the caudal endplates of all eight disk spaces in Group P: T10-11 (p = .0004), T11-12 (p < .0001), T12-13 (p < .0001), T13-L1 (p < .0001), L1-2 (p < .0001), L2-3 (p < .0001), L3-4 (p < .0001), and L4-5 (p < .0001). There was no disk extrusion or spinal cord lesions identified., Conclusion: This study evaluated effects that may occur secondary to PLDA, using MRI. Although vertebral body changes were identified, they did not correlate with clinical complications., Clinical Significance: PLDA appears to be a safe, effective procedure performed on thoracolumbar disks to reduce recurrence of intervertebral disk herniation (IVDH) in dogs that previously experienced IVDH, despite the appearance of visible vertebral endplate lesions and mild diskitis on MRI., (© 2021 American College of Veterinary Surgeons.)

Objective:  Intervertebral disc fenestration has been shown to reduce the risk of extrusion in the thoracolumbar region in dogs, but use of the technique varies between individual neurologists and surgeons. Our aim was to investigate opinions and practices regarding disc fenestration amongst those involved in neurosurgery in dogs., Study Design:  A web-based survey containing questions relating to the use of fenestration during treatment of intervertebral disc extrusion in dogs was distributed to board-certified neurologists and surgeons. Results were analysed using Microsoft Excel., Results:  There were 323 responses from 190 neurologists and 133 surgeons. Seventy-one per cent of respondents routinely used concurrent disc fenestration when performing decompressive surgery in the thoracolumbar region, although the rate was lower amongst surgeons (55%) than neurologists (82%). Only 25% of respondents performed concurrent fenestration in the cervical spine. Forty-five per cent of respondents reported having experienced complications, with haemorrhage being the most common., Conclusion:  Fenestration is widely used in the management of thoracolumbar intervertebral disc extrusion, but a universally accepted approach does not exist, and differences are seen between neurologists and surgeons., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Hyperproteinorrachia (raised cerebrospinal fluid total protein [CSF-TP]) without pleocytosis (HP) (also known as albuminocytologic dissociation) is identified in dogs with different neurologic diseases. However, the association between survival and increased CSF-TP is unknown., Objectives: (a) Identify conditions commonly associated with HP in dogs and (b) investigate whether higher CSF-TP concentrations or other relevant factors are associated with 1-year survival., Methods: This is a retrospective study that identified dogs with HP (Cisternal CSF-TP >0.30 g/L, Lumbar CSF-TP >0.45 g/L with total nucleated cell concentrations [TNCCs] and RBC counts within RIs) from 2008 to 2019: recording signalment, weight, vital parameters, inflammation, neuroanatomic localization, CSF-TP, sampling site, final diagnosis, etiologic classification, and 1-year survival. Corrected CSF-TP was calculated as CSF-TP minus 0.3 (cisternal) or 0.45 (lumbar or unknown). Descriptive statistics were produced, CSF-TP differences between groups (eg, neuroanatomic localizations) were evaluated using the Mann-Whitney U test or Kruskal-Wallis test (post-hoc testing). The Cox proportional hazards model was used for survival data. Statistical significance was set at a P < 0.05., Results: In all, 39 dogs had HP, associated with 17 conditions, including neoplasia (n = 6), meningoencephalitis of unknown origin (n = 4) (MUO), and intervertebral disc disease (n = 4) (IVDD) as the most common conditions. There was no significant difference between the CSF-TP/corrected CSF-TP between 1-year survivors and non-survivors, nor was there a difference between different neuroanatomic localizations or etiologic classifications (P > 0.05). Neoplasia, after adjustment for age, was the only variable associated with a worse survival (P = 0.01 HR: 2.08 (95% CI: 1.65-39.2). CSF-TP was not associated with age (P > 0.05)., Conclusions: HP in dogs is associated with a wide range of conditions; the most common conditions are neoplasia, MUO, and IVDD. Higher CSF-TP levels do not correlate with a worse 1-year survival; however, they do correlate with neoplastic lesions., (© 2021 The Authors. Veterinary Clinical Pathology published by Wiley Periodicals LLC on behalf of American Society for Veterinary Clinical Pathology.)

Sheep are established models for intervertebral disc degeneration (IVDD) translational research. Objectives of this retrospective, secondary analysis, observational study were to evaluate reproducibility of two magnetic resonance imaging (MRI) measures of IVDD in sheep using open-source image analysis software. Sagittal planar, T2-weighted, lumbar MRI scans from a previous, prospective study were evaluated (4 sheep @ 3 treatment periods/sheep @ 7 lumbar discs /treatment period = 84 discs). A standardized protocol was developed for measuring MRI index (nucleus pulposus signal intensity × nucleus pulposus sagittal area), and nucleus pulposus signal intensity standard deviation (NPSISD). Scans were randomized and four observers with varying experience levels applied the protocol to independently perform triplicate measures. Mean coefficient of variation values for both the MRI index and NPSISD were within an acceptable range (< 10). Mean values for the three readers with at least 2 months of image analysis experience did not differ (P > .05)., (© 2021 American College of Veterinary Radiology.)

Background: Intervertebral disc extrusions in the thoracolumbar region are a common spinal neurologic disorder in dogs and usually considered a neurological emergency. Several factors, like timing of surgery, have previously been analysed in order to determine the effect on outcome and time of recovery. Most studies have investigated one defined population of dogs and the influence of a single factor on the overall outcome. In this retrospective study, a large cohort of dogs and the influence of one or combinations of several factors on outcome and time of recovery were analysed., Results: The bivariate analysis demonstrated a significant association between the following variables and the time of recovery: the time span between the onset of clinical signs and surgery (Cramers Phi [Formula: see text] = 0.14; P = 0.003), the grade of severity ([Formula: see text] = 0.23; P < 0.001) and the implementation of physical rehabilitation ([Formula: see text] = 0.2; P < 0.001). However, the analysis of a multivariable regression model demonstrated that a significant correlation only exists between the time span between the onset of clinical signs and surgery and the overall outcome (P = 0.007), as well as between the grade of severity and the time of recovery (P < 0.001). The percentage of dogs with lacking deep pain perception (DPP) that had to be euthanised due to their neurological condition, decreased from 20.0 to 2.9% when physical rehabilitation was implemented. Additionally, the proportion of dogs (same group) that improved to reach an ambulatory status increased from 80.0 to 91.4%., Conclusion: The results of the bivariate analysis demonstrated several correlations between some variables and overall outcome or time of recovery, whereas the multivariable regression model demonstrated only two associations. The time span between the onset of clinical signs and surgery was significantly associated with the overall outcome. We therefore suggest that a surgical intervention should be performed without unreasonable delay. Due to the correlation between the grade of severity and time of recovery, owners of dogs with more severe neurological deficits prior to surgery should be informed about the presumably prolonged time of recovery., (© 2021. The Author(s).)

Objectives: To identify the prevalence of recurrence of clinical signs after initial successful decompressive surgery for intervertebral disc extrusion in French bulldogs., Materials and Methods: A medical record search was performed to identify French bulldogs that experienced an initial successful outcome after surgery for thoracolumbar or cervical intervertebral disc extrusion. Collected information included signalment, neurological examination findings, intervertebral disc extrusion location, presence of vertebral malformations, kyphosis, type and extent of surgery. Decompressive surgery was not followed by extensive prophylactic fenestrations. Follow-up information was retrieved from medical records and telephone interviews with referring veterinary surgeons., Results: Eighty-four French bulldogs with thoracolumbar (n=55) or cervical (n=29) intervertebral disc extrusion were included. Forty-three (51%) dogs that had decompressive surgery for thoracolumbar (n=29) or cervical (n=14) intervertebral disc extrusion suffered recurrence of signs. The median time between decompressive surgery and recurrence of clinical signs was 9 months and 21 days. Of the 29 dogs suffering recurrence of clinical signs following surgery for thoracolumbar intervertebral disc extrusion, 24 returned for recurrence of clinical signs localised to the thoracolumbar segments, while five returned for recurrence of signs localised to the cervical region. Of the 14 dogs who suffered recurrence of signs following surgery for cervical intervertebral disc extrusion, nine returned for signs localised to the cervical region, while five returned for clinical signs localised to the thoracolumbar region., Clinical Significance: This study suggests a high rate of late onset recurrence of clinical signs after decompressive surgery for intervertebral disc extrusion in French bulldogs. This information can aid in the management of owner expectations., (© 2021 British Small Animal Veterinary Association.)

Objective: To compare the incidence of MRI lesions between dogs weighing < 15 kg (33 lb) and dogs weighing ≥ 15 kg., Animals: 494 dogs with clinical signs of thoracolumbar disease., Procedures: Electronic medical records of affected dogs that underwent MRI of the thoracolumbar vertebral column between January 2016 and July 2018 were reviewed. Data extracted included age, body weight, breed, sex, MRI findings, and lesion location. Data were compared between dogs weighing < 15 kg and dogs weighing ≥ 15 kg., Results: Of dogs weighing < 15 kg, 94.4% (371/393) were chondrodystrophic breeds. Only 24.8% (25/101) of dogs weighing ≥ 15 kg were chondrodystrophic breeds. Lesions consistent with intervertebral disk disease (IVDD) had an overall incidence of 87.2% (431/494). In dogs weighing < 15 kg, the incidence of IVDD was 94.7% (372/393), compared with 58.4% (59/101) in dogs weighing ≥ 15 kg. Dogs weighing < 15 kg had a significantly higher incidence of IVDD lesions in the T12-13 segment, compared with dogs weighing ≥ 15 kg. Dogs weighing ≥ 15 kg were 11.9 times (95% CI, 5.1 to 27.9) and 7.4 times (95% CI, 2.3 to 23) as likely to have a neoplastic lesion and fibrocartilaginous embolic myelopathy, respectively, compared with dogs weighing < 15 kg., Conclusions and Clinical Relevance: IVDD was the most common MRI finding in the study population. Dogs weighing ≥ 15 kg had a higher incidence of nonintervertebral disk lesions, compared with dogs weighing < 15 kg.

Case Description: 4 dogs, 7.5 to 10 years of age, were presented for evaluation of signs of chronic cervical pain and forelimb lameness secondary to cervical foraminal intervertebral disk protrusion (IVDP). All dogs were refractory to ≥ 2 weeks of conservative management including strict rest and pain management with anti-inflammatory drugs, methocarbamol, and gabapentin., Clinical Findings: The MRI findings included left foraminal IVDP at C2-3 causing mild C3 nerve root compression (dog 1), multifocal degenerative disk disease with mild focal left-sided disk protrusion at C6-7 without associated spinal cord or nerve root compression (dog 2), left foraminal C6-7 IVDP with suspected focal spinal cord atrophy or mild compression (dog 3), and right foraminal C6-7 IVDP and multifocal cervical intervertebral disk degeneration with annulus fibrosus protrusion (dog 4)., Treatment and Outcome: Ultrasound-guided paravertebral perineural injections with methylprednisolone acetate (1 mg/kg [0.45 mg/lb]) at the C3 nerve root in dog 1 and at the C7 nerve root in the other 3 dogs were performed. Injections were repeated at intervals of 4 weeks to 3 months on the basis of clinical response. None of the dogs had any complications from the procedures. For dogs 1 and 4, there was complete resolution of lameness and signs of cervical pain following perineural injections, and for dog 3, there was complete resolution of lameness and only minimal residual cervical pain. Dog 2 did not have long-lasting improvement., Clinical Relevance: Findings indicated that ultrasound-guided paravertebral perineural injection can be an effective treatment of cervical foraminal IVDP for some dogs. Additional studies to determine appropriate case selection and better assess the overall success rate and risks associated with this technique are warranted.

Objective: To describe the clinical presentation, magnetic resonance imaging (MRI) findings, and outcome of dogs treated surgically for lumbosacral intervertebral disk extrusion (IVDE)., Study Design: Retrospective study., Animals: Thirteen dogs., Methods: Records and MRI studies of dogs with intraoperatively confirmed lumbosacral IVDE were reviewed. MRI features of thoracolumbar IVDE were applied to all cases. Postoperative outcome was subjectively assessed as excellent, good, or poor., Results: All dogs had an acute or subacute onset of lumbosacral pain and nerve root signature. Seven dogs had neurological deficits. MRI revealed lateralized herniated disk material and partial to complete disk degeneration in all cases; the extradural material extended cranial and/or caudally from the disk space in 10 cases. All dogs underwent L7-S1 dorsal laminectomy and removal of extruded disk material. In six dogs, surgery was complicated by inflammatory changes, including one case of epidural steatitis. On reexamination 4-6 weeks postsurgery, outcome was judged as excellent in 11 dogs and poor in the remaining 2 due to contralateral nerve root signature in one case and nonambulatory paraparesis and urinary incontinence in the case with steatitis., Conclusion: Lumbosacral IVDE in dogs was characterized by acute/subacute onset of lumbosacral pain and nerve root signature and lateralized and often dispersed extradural material over a degenerated L7-S1 intervertebral disk on MRI. Early decompressive dorsal laminectomy generally resulted in excellent clinical outcome., Clinical Significance: Observation of these clinical and imaging features in dogs should prompt clinical suspicion of lumbosacral IVDE., (© 2021 The Authors. Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.)

We analyzed the mRNA expression of matrix metalloproteinases (MMPs), metalloproteinases with thrombospondin motifs (ADAMTSs), and tissue inhibitors of metalloproteinases (TIMPs) in degenerated and herniated intervertebral disks (IVDs) in chondrodystrophic dogs. In degenerated IVDs, MMP3, 7, 13, and 14; ADAMTS4 and 5; and TIMP1-3 expression was significantly higher vs healthy controls (P<0.05). In herniated IVDs, MMP2, 3, 9, 13, and 14; ADAMTS4 and 5; and TIMP1 expression was significantly greater, and MMP7 expression was significantly lower vs degenerated IVDs (P<0.05). These results suggest that metalloproteinase may play a role in extracellular matrix degradation in IVD degeneration. Decreased MMP7 transcription may prevent proteoglycan degradation and reduces macrophage infiltration, which might affect the resorption process of herniated IVDs.

Background: Canine cervical spondylomyelopathy can be separated into osseous and disc-associated (DA-CSM) forms. Our aim was to describe the magnetic resonance imaging (using a high-field scanner) and neurological findings in dogs with DA-CSM and investigate a relationship between these findings., Results: Sixty-three dogs were included: 60/63 (95 %) were large breeds, with Doberman Pinschers and males over-represented (70 %). Mean and median age at the time of diagnosis was 7.25 and 7.2 years (range 0.41-12 years). Chronic signs were noted in 52/63 (83 %) dogs, with proprioceptive ataxia the most common. Main site of spinal cord compression was commonly C6-7 or C5-6. Thirty-six (57 %) dogs had various sites of spinal cord compression. Most dogs younger than 6 years of age had a single affected site. Foraminal stenosis was present in 51/63 dogs (81 %). T2-weighted hyperintensity was present in 40/63 dogs (63 %). 88 % of the articular processes showed degenerative changes, which correlated strongly with intervertebral disc degeneration. Ligamentum flavum hypertrophy was seen in 38 % of dogs. No correlation was observed between neurologic signs and number of affected sites. A moderate positive correlation was observed between severity of spinal cord compression and neurologic grade (r 0.48; p < 0.001)., Conclusions: DA-CSM was predominantly observed in older, male Dobermans, with lesions located in the caudal cervical vertebral region. It was also seen in dogs 3 years of age or even younger (8 %). Single compressive lesions were more common in dogs younger than 6 years of age. Many dogs had concomitant changes (e.g.: ligamentum flavum hypertrophy and foraminal stenosis). Most dogs with ligamentum flavum hypertrophy were 6 years or older. A positive correlation was observed between severity of spinal cord compression and neurologic grade, but multilevel compression was not associated with more severe neurologic signs. A very high percentage of dogs had articular process degenerative changes. Possible biomechanical or genetic relationships between degenerative changes in articular processes, ligamentum flavum, and intervertebral discs warrants further investigation.

Objective: To evaluate outcomes and prognostic factors after decompressive hemilaminectomy in paraplegic medium to large breed dogs with extensive epidural hemorrhage (DEEH) and thoracolumbar intervertebral disc extrusion (TL-IVDE)., Study Design: Retrospective, cohort, descriptive study., Animals: Fifty-nine client-owned dogs., Methods: Medical records and advanced imaging were reviewed for paraplegic dogs with DEEH. Ambulatory status 6 months after surgery and postoperative complications were recorded. Multiple logistic regression models were constructed to explore prognostic factors., Results: Records of 22 dogs with and 37 dogs without pelvic limb pain perception at presentation were included. Median age of dogs was 5 years (interquartile range, 4-7), and mean weight was 26.9 kg (SD, ±9.71). Labradors and Labrador mixes were most common (17/59 [28.8%]). Recovery of ambulation occurred in 17 of 22 (77.3%) dogs with and in 14 of 37 (37.8%) dogs without pain perception prior to surgery. Progressive myelomalacia was recorded in three of 59 (5.1%) dogs, one with pain perception and two without pain perception at presentation. Postoperative complications (14/59 [23.7%]) were common. Factors independently associated with outcome included clinical severity (odds ratio [OR] 0.179, P = .005), number of vertebrae with signal interruption in half Fourier single-shot turbo spin-echo sequences (HASTEi; OR, 0.738; P = .035), and ratio of vertebral sites decompressed to HASTEi (OR, 53.79; P = .03)., Conclusion: Paraplegic medium to large breed dogs with DEEH have a less favorable outcome after surgical decompression than paraplegic dogs with TL-IVDE., Clinical Significance: Dogs with DEEH can have severe postoperative complications. Loss of pain perception and increased HASTEi are associated with a poor outcome, while more extensive decompression improves outcome., (© 2021 The American College of Veterinary Surgeons.)

Although lameness of the thoracic limb typically is due to orthopedic disease, there are several important neurologic conditions that result in lameness. Neurologic diseases cause lameness due to disease of the nerves, nerve roots, spinal cord, or muscles. Common differentials include lateralized intervertebral disc extrusions, caudal cervical spondylomyelopathy (wobbler disease), brachial plexus avulsion, neuritis, and peripheral nerve sheath tumors. Many of these diseases compress or destroy the nerve roots of the cervical intumescence, resulting in non-weight-bearing lameness, or root signature. Advanced diagnostics, such as magnetic resonance imaging, are necessary in these cases to determine the underlying cause., Competing Interests: Disclosure The authors of this article have no commercial or financial conflicts of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Magnetic resonance imaging hyperintensity on T2-weighted turbo SE and STIR sequences of the paraspinal musculature in canine patients being imaged for thoracolumbar intervertebral disc extrusion is frequently observed but poorly understood in veterinary medicine. The objective of this prospective analytical study was to describe the histopathology of muscle hyperintensity in dogs with thoracolumbar intervertebral disc extrusions and to determine if a relationship exists between the presence of this hyperintensity and various patient factors. Twenty privately owned dogs who underwent surgical decompression of intervertebral disc extrusions diagnosed on MRI were enrolled (10 normal "control or nonaffected cases" without MRI paraspinal musculature hyperintensity and 10 "affected cases" with hyperintensity). Surgical biopsies of the epaxial musculature at the region of hyperintensity (affecteds) and at the site of the disc herniation (controls) were submitted for histopathology. The degree of myofiber degeneration and necrosis was scored using an ordinal scoring system: absent (0), minimal (10), mild (20), moderate (30), marked/severe (40), and massive (50). Associations between hyperintensity presence and patient age, weight, body condition, neurologic status, acuteness of onset, number of disc herniation sites, degree of spinal cord compression, and volume of herniated material were investigated. Nonaffected patients were significantly older (median age = 9.4 years) than affected patients (median age = 3.5 years), but no other significant associations were found. Acute myofiber degeneration/necrosis and intramuscular inflammation were observed in half of affected patients. Therefore, T2/STIR muscle hyperintensity in some patients with intervertebral disc extrusion may represent muscle degeneration and inflammation., (© 2020 American College of Veterinary Radiology.)

Case Report: A 12-year-old castrated male dog with nonambulatory tetraplegia was diagnosed with spinal stenosis at C3-C4 through X-ray examination and with ventral extradural spinal compression at C3-C4 through myelography and computed tomography. The diagnosis of traditional Chinese veterinary medicine was local Qi and blood stagnation, spleen Qideficiency, blood deficiency, and kidney Yang deficiency. We initiated treatment using a combination of acupuncture and Chinese medicine iontophoresis with laser therapy. After 12 treatment days, there was a significant improvement in the dog's ambulation function, which was indicated by proper walking and flexible head-turning., Conclusion: This indicates that combining acupuncture and Chinese medicine iontophoresis could be a potential treatment for chronic progressive cervical intervertebral disk disease in dogs., (© 2020 S. Karger AG, Basel.)

Background: Radiographic signs of intervertebral disc mineralization are thought to indicate sites of future recurrence of disc extrusion (Hansen type I) but the relationship between evidence of disc degeneration on magnetic resonance imaging (MRI) and future disc extrusion with recurrence of clinical signs has not been examined., Objectives: To examine the relationship between MRI-assessed degeneration of thoracolumbar intervertebral discs and late recurrence of clinical signs in dogs presented with acute thoracolumbar intervertebral disc extrusion and treated by hemilaminectomy alone., Animals: Ninety-two client-owned dogs presented to 2 referral hospitals between 2009 and 2014., Methods: Retrospective analysis of association between clinical signs consistent with recurrent thoracolumbar intervertebral disc extrusion and MRI evidence of disc degeneration in dogs undergoing hemilaminectomy for acute thoracolumbar intervertebral disc extrusion. Univariable and multivariable Cox regression analyses were used to explore associations between recurrence of clinical signs and several characteristics of T10-L3 discs at initial diagnosis., Results: Ninety-two cases were included, of which 42 (46%) were Dachshunds and median age was 5.3 years. Clinical signs recurred in 33/92 (36%) dogs. Finding a completely degenerate disc in the T10 to L3 region (in addition to the operated site) at the time of surgery was associated with a hazard ratio of 2.92 (95% confidence interval: 1.37-6.20) for recurrence of clinical signs., Conclusions and Clinical Importance: Our results suggest that in cases of thoracolumbar intervertebral disc extrusion in dogs, recurrence of signs is likely if at least 1 completely degenerate disc in addition to the currently symptomatic disc is visible on MRI., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.)

Background: Acute paralysis is a common presentation in small animal emergency clinics, but the aetiological prevalence has not been reported. Knowledge of diagnosis frequency aids prioritisation of differential diagnoses, facilitates resource planning and clinical trial design., Methods: Medical records from NC State Veterinary Hospital Emergency Room were searched over a five-year period to identify cases presenting with acute non-ambulatory paraparesis or paralysis. Signalment and diagnosis category were extracted., Results: Acute paralysis was the presenting problem in 845 of 21,535 (3.9 per cent) dogs and 66 of 4589 (1.4 per cent) cats admitted over this period. Intervertebral disc disease (IVDD) was the most common cause (608 of 845; 72 per cent) in dogs, followed by vascular disease (34 of 845; 4.0 per cent). Other diagnostic categories accounted for the remaining 20 per cent. Dachshunds were the most common breed (263 of 845; 31.1 per cent), then Labrador retrievers (57 of 845; 6.7 per cent). In cats, aortic thromboembolism (ATE) was the most common diagnosis, occurring in 40 of 66 (60.6 per cent), followed by IVDD (7 of 66; 10.6 per cent). Other diagnostic categories accounted for 30.3 per cent. Six of 845 (0.7 per cent) dogs and two of 66 (3 per cent) cats were categorised as pseudoparalysis with a non-neurological diagnosis., Conclusions: IVDD and ATE are the overwhelming causes of acute paralysis in dogs and cats, respectively, with approximately 28 per cent of dogs and 40 per cent of cats having a different diagnosis., Competing Interests: Competing interests: None declared., (© British Veterinary Association 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Quantitative magnetic resonance imaging (QMRI) techniques of magnetization transfer ratio (MTR) and diffusion tensor imaging (DTI) provide microstructural information about the spinal cord., Objective: Compare neurologic grades using the modified Frankel scale with MTR and DTI measurements in dogs with thoracolumbar intervertebral disk herniation (IVDH)., Animals: Fifty-one dogs with thoracolumbar IVDH., Methods: Prospective cohort study. Quantitative MRI measurements of the spinal cord were obtained at the region of compression. A linear regression generalized estimating equations model was used to compare QMRI measurements between different neurological grades after adjusting for age, weight, duration of clinical signs, and lesion location., Results: Grade 5 (.79  ×  10 -3 mm 2 /s [median], .43-.91 [range]) and axial (1.47 × 10 -3 mm 2 /s, .58-1.8) diffusivity were lower compared to grades 2 (1.003, .68-1.36; P = .02 and 1.81 × 10 -3 mm 2 /s, 1.36-2.12; P < .001, respectively) and 3 (1.07 × 10 -3 mm 2 /s, .77-1.5; P = .04 and 1.92 × 10 -3 mm 2 /s, 1.83-2.37;P < .001, respectively). Compared to dogs with acute myelopathy, chronic myelopathy was associated with higher mean (1.02 × 10 -3 mm 2 /s, .77-1.36 vs. .83 × 10 -3 mm 2 /s, .64-1.5; P = .03) and radial diffusivity (.75 × 10 -3 mm 2 /s, .38-1.04 vs. .44 × 10 -3 mm 2 /s, .22-1.01; P = .008) and lower MTR (46.76, 31.8-56.43 vs. 54.4, 45.2-62.27; P = .004) and fractional anisotropy (.58, .4-0.75 vs. .7, .46-.85; P = .02). Fractional anisotropy was lower in dogs with a T2-weighted intramedullary hyperintensity compared to those without (.7, .45-.85 vs. .54, .4-.8; P = .01)., Conclusion and Clinical Relevance: Mean diffusivity and AD could serve as surrogates of severity of spinal cord injury and are complementary to the clinical exam in dogs with thoracolumbar IVDH., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

A 17-year-old mongrel dog and 12-year-old Shiba Inu dog presented with ataxia and paresis of the pelvic limbs, respectively. Gas accumulation within the spinal canal adjacent to the herniated disc was suspected in both cases. Since the gas remained accumulated for a prolonged period, hemilaminectomy was performed to decompress the spinal cord. The bulged external lamina of the dura matter was removed and histopathologically examined. Granulomatous inflammation and hyperplasia of fibrous connective tissues was noted, suggesting that the gas was encapsulated and the fibrous nodules made reabsorption difficult. Clinical signs resolved post-surgery. This is the first report describing histopathological features of pneumorrhachis in dogs. The accumulated gas was successfully removed by surgery. Postoperative course remained uneventful in both cases.

Case Description: 3 dogs were examined because of a sudden onset of signs of pain (1 dog) or paraparesis (2 dogs)., Clinical Findings: Neurologic findings consisted of myelopathy affecting the lumbar intumescence (1 dog) and T3-L3 myelopathy (2 dogs). In all dogs, MRI revealed spinal cord compression caused by L3-4 disk herniation. All dogs underwent routine surgical decompression of the intervertebral disk herniation. During MRI and decompressive surgery, physiologic variables were monitored. Immediately after surgery, all dogs were paraplegic with pelvic limb neurologic dysfunction consistent with myelopathy affecting the L4 through caudal spinal cord segments., Treatment and Outcome: Within 24 hours after surgery, repeated MRI in all dogs revealed hyperintensity in the spinal cord gray matter of the lumbar intumescence on T2-weighted images. In the absence of neurologic improvement, dogs were euthanized at 3, 91, and 34 days after surgery. Postmortem microscopic examination of each dog's spinal cord at the lumbar intumescence revealed necrosis of the gray matter with relative white matter preservation suggestive of an ischemic injury., Clinical Relevance: Dramatic neurologic deterioration following decompressive surgery for intervertebral disk herniation in dogs may be associated with the development of poliomyelomalacia secondary to ischemia. In these 3 dogs, ischemia developed despite probable maintenance of normal spinal cord blood flow and perfusion during anesthesia. To exclude other causes, such as compression or hemorrhage, MRI was repeated and revealed hyperintensity of the spinal cord gray matter on T2-weighted images, which microscopically corresponded with ischemic neurons and neuronal loss.

Two transcribed retrocopies of the fibroblast growth factor 4 ( FGF4 ) gene have previously been described in the domestic dog. An FGF4 retrocopy on chr18 is associated with disproportionate dwarfism, while an FGF4 retrocopy on chr12 is associated with both disproportionate dwarfism and intervertebral disc disease (IVDD). In this study, whole-genome sequencing data were queried to identify other FGF4 retrocopies that could be contributing to phenotypic diversity in canids. Additionally, dogs with surgically confirmed IVDD were assayed for novel FGF4 retrocopies. Five additional and distinct FGF4 retrocopies were identified in canids including a copy unique to red wolves ( Canis rufus ). The FGF4 retrocopies identified in domestic dogs were identical to domestic dog FGF4 haplotypes, which are distinct from modern wolf FGF4 haplotypes, indicating that these retrotransposition events likely occurred after domestication. The identification of multiple, full length FGF4 retrocopies with open reading frames in canids indicates that gene retrotransposition events occur much more frequently than previously thought and provide a mechanism for continued genetic and phenotypic diversity in canids.

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., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Intradural-intramedullary intervertebral disc extrusion (IIVDE) is a rare condition of intervertebral disc disease. However, the diagnosis of IIVDE is challenging because the prognosis and imaging characteristics are poorly characterized., Objectives: We aimed to describe the clinical and imaging characteristics of tentatively diagnosed IIVDE in dogs to assess the prognostic utility of neurological grade and magnetic resonance imaging (MRI) findings., Methods: Twenty dogs were included in this retrospective cohort study., Results: Nonchondrodystrophic breeds (n = 16) were more predisposed than chondrodystrophic breeds. Most dogs showed acute onset of clinical signs. Neurological examination at admission showed predominant non-ambulatory paraparesis (n = 9); paresis (n = 16) was confirmed more frequently than paralysis (n = 4). Follow-up neurological examination results were only available for 11 dogs, ten of whom showed neurological improvement and 8 showed successful outcomes at 1 month. The characteristic MRI findings include thoracic vertebra (T)2 hyperintense, T1 hypointense, intramedullary linear tracts with reduced disc volume, and cleft of the annulus fibrosus. None of the MRI measurements were significantly correlated with neurological grade at admission. Neurological grade did not differ according to the presence of parenchymal hemorrhage, parenchymal contrast enhancement, and meningeal contrast enhancement. Neurological grades at admission showed a statistical correlation with those observed at the 1-month follow-up ( r = 0.814, p = 0.02)., Conclusions: IIVDE is a rare form of disc extrusion commonly experienced after physical activity or trauma and most frequently affects the cranial-cervical and thoracolumbar regions of nonchondrodystrophic dog breeds. Neurological score at admission emerged as a more useful prognostic indicator than MRI findings in dogs with suspected IIVDE., Competing Interests: The authors declare no conflicts of interest., (© 2020 The Korean Society of Veterinary Science.)

Objective: To assess the effect of perioperative pregabalin on pain behavior in dogs after intervertebral disc surgery., Study Design: Prospective, randomized, controlled clinical trial with a blinded observer., Animals: Forty-six client-owned dogs undergoing intervertebral disc surgery., Methods: Dogs were randomly assigned to two groups, with the placebo group receiving opioids alone and the pregabalin group receiving opioids plus pregabalin. Opioid analgesia consisted of 0.6 mg/kg l-methadone given intravenously at anesthetic induction, followed by 0.2 mg/kg given at 8, 16, and 24 hours after extubation and fentanyl patches applied at the end of surgery. Pregabalin was given orally (4 mg/kg) 1 hour before anesthesia, followed by postoperative treatment three times per day (4 mg/kg) for 5 days. The outcome measures were the treatment-group differences in peri-incisional mechanical sensitivity and Glasgow Composite Measure Pain Scale (CMPS-SF) assessed during the first 5 postoperative days. Pregabalin serum concentrations were measured after 24, 72, and 120 hours., Results: Pregabalin reduced pain levels in the treatment group by a mean of 2.5 CMPS-SF units (95% confidence interval [CI] = -3.19 to -1.83, P < .001) compared with the control group during the study period. Pregabalin increased the mechanical nociceptive threshold by a mean of 6.89 N per day (95% CI = 1.87-11.92, P < .001) and of 7.52 N per day (95% CI = 2.29-12.77, P < .001) during the study period, depending on location. Mean levels of serum pregabalin were 5.1, 4.71, and 3.68 μg/mL at 24, 72, and 120 hours postoperatively, respectively., Conclusion: Postoperative signs of pain after surgical treatment of intervertebral disc herniation (IVDH) were reduced when dogs received perioperative pregabalin rather than opioids alone., Clinical Significance: Perioperative pregabalin reduces postoperative pain after surgical treatment of IVDH., (© 2020 The American College of Veterinary Surgeons.)

Objective: To determine values of F-wave parameters for the tibial nerve in clinically normal Miniature Dachshunds and those with thoracolumbar intervertebral disk herniation (IVDH)., Animals: 53 Miniature Dachshunds (10 clinically normal and 43 with various clinical grades of thoracolumbar IVDH)., Procedures: F-waves were elicited in the interosseous muscles of 1 hind limb in each dog by stimulation of the tibial nerve. F-wave parameters were measured for 32 stimuli/dog, and mean values were calculated. Linear regression was performed to assess correlations between F-wave parameters and clinical severity of IVDH., Results: For clinically normal dogs, mean ± SD values of shortest F-wave latency, mean F-wave conduction velocity, mean F-wave duration, and ratio of the mean F-wave amplitude to M response amplitude were 8.6 ± 0.6 milliseconds, 83.7 ± 6.1 m/s, 6.6 ± 1.5 milliseconds, and 9.8 ± 8.5%, respectively. F-wave persistence was 100%. Mean F-wave duration was positively correlated with clinical grade of IVDH. Linear regression yielded the following regression equation: F-wave duration (milliseconds) = 6.0 + 2.7 × IVDH grade. One dog with grade 2 IVDH had a mean F-wave duration shorter than that of all 5 dogs with grade 1 IVDH; 1 dog with grade 3 IVDH had a longer duration than that of all 10 dogs with grade 4 IVDH., Conclusions and Clinical Relevance: Mean F-wave duration was correlated with the severity of inhibitory motor tract dysfunction in the spinal cord of dogs. F-wave examination may be useful for objective functional evaluation of upper motor neurons in the spinal cord.

Background: Recent studies have reported contrasting results of the effects of laser therapy on post-operative intervertebral disk herniation, with a lack of evidence-based advantages of this modality within a rehabilitation protocol. The aim of this study was to report the clinical effects of photobiomodulation therapy within a post-operative rehabilitation protocol in dogs submitted to surgery for thoracolumbar disk extrusion. Twenty-four dogs were included in the study (12 dogs treated with laser therapy and rehabilitation protocol and 12 dogs treated with same rehabilitation protocol but without laser therapy)., Results: All dogs treated with laser therapy showed improved neurological status (Modified Frankel Score more than 3 within 30 days of physiotherapy starting) if deep nociception on admission was maintained (P = 0.04). However, Kaplan-Meier analysis did not show any statistical difference in time to regain ambulatory ability, although there was a tendency for a shorter mean time of 14.2 ± 8.55 days in the laser group versus 24 ± 18.49 days in the no laser group., Conclusions: The use of laser therapy in the post-operative rehabilitation of dogs affected by intervertebral disc extrusion and submitted to surgery for spinal decompression could help improve their neurological status.

Objective: To evaluate agreement in results obtained with an MRI-based grading scheme and a macroscopic observation-based grading scheme when used to assess intervertebral disk (IVD) degeneration in cats., Sample: 241 MRI and 143 macroscopic images of singular IVDs in 44 client-owned cats (40 cadaveric and 4 live)., Procedures: Singular images of IVDs were obtained of live cats admitted for treatment of suspected neurologic disease (MRI images of IVDs) and of cadavers of cats euthanized for reasons unrelated to spinal disease (MRI and macroscopic images of IVDs) at the Small Animal Hospital, Vetsuisse Faculty, Zurich, Switzerland, between January 12, 2015, and October 19, 2015. The IVD images were randomized and evaluated twice by 4 observers for each grading scheme. Inter- and intraobserver reliability for the grading schemes was assessed with Cohen weighted κ analysis. Agreement and correlation between results obtained with the 2 grading schemes were determined with Cohen weighted κ and Spearman correlation coefficient (ρ) analyses, respectively., Results: Inter- and intraobserver agreement between results was substantial to almost perfect (mean weighted κ, 0.66 to 0.83 and 0.71 to 0.86, respectively) for the MRI-based grading scheme and moderate to substantial (mean weighted κ, 0.42 to 0.80 and 0.65 to 0.79, respectively) for the macroscopic observation-based grading scheme. Between the 2 grading schemes, agreement in results was moderate (mean ± SE weighted κ, 0.56 ± 0.05), and the correlation was strong (ρ = 0.73)., Conclusions and Clinical Relevance: Results indicated that the MRI-based and macroscopic observation-based grading schemes used in the present study could be used reliably for classifying IVD degeneration in cats.