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Kiviranta AM, Rusbridge C, Lappalainen AK, Junnila JJT, Jokinen TS. Persistent fontanelles in Chihuahuas. Part II: Association with craniocervical junction abnormalities, syringomyelia, and ventricular volume. J Vet Intern Med 2021; 35:1848-1856. [PMID: 33939205 PMCID: PMC8295681 DOI: 10.1111/jvim.16123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 12/13/2022] Open
Abstract
Background Persistent fontanelles (PFs) are, in Chihuahuas, almost ubiquitous. Furthermore, Chihuahuas are predisposed to other craniomorphological abnormalities, including syringomyelia (SM), ventriculomegaly, and craniocervical junction (CCJ) overcrowding resulting in neural tissue deviation. It is, however, undetermined if PFs are more common in dogs with these structural abnormalities, and their etiology is unknown. Hypothesis/Objectives Persistent fontanelles are more numerous and larger in Chihuahuas with low body weight, older age, SM, dilated fourth ventricle, ventriculomegaly, and CCJ overcrowding. Animals Fifty client‐owned Chihuahuas. Methods Cross‐sectional study evaluating the association of both the number of cranial sutures affected by PFs (NAS) and total fontanelle area (TFA), based on computed tomography with SM, fourth ventricle dilatation, lateral ventricle volume, and extent of neural tissue compression at the CCJ based on magnetic resonance images. Results The NASs was higher and TFA larger in dogs with low body weight (NAS: P = .007; 95% confidence interval [CI] = 0.384‐0.861; TFA: P = .002; 95% CI = −1.91 to −0.478), larger lateral ventricles (NAS: P ≤ .001; 95% CI = 1.04‐1.15; TFA: P ≤ .001; 95% CI = 0.099‐0.363), and more severe neural tissue compression at the CCJ (NAS: P ≤ .001; 95% CI = 1.26‐2.06; TFA: P = .03; 95% CI = 0.066‐1.13). Similarly, dogs with SM (NAS: P = .004; 95% CI = 1.26‐3.32; TFA: mean ± SD, 130 ± 217 mm2; P = .05) had higher NAS and larger TFA than did dogs without SM (43.7 ± 61.0 mm2). Age was not associated with NAS (P = .81; 95% CI = 0.989‐1.01) or TFA (P = .33; 95% CI = −0.269 to 0.092). Conclusions and Clinical Importance Persistent fontanelles are associated with small size, SM, ventriculomegaly, and CCJ overcrowding.
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Affiliation(s)
- Anna-Mariam Kiviranta
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Clare Rusbridge
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom.,Fitzpatrick Referrals Halfway Lane, Eashing Godalming, Surrey, United Kingdom
| | - Anu K Lappalainen
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | | | - Tarja S Jokinen
- Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
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The Need for Head Space: Brachycephaly and Cerebrospinal Fluid Disorders. Life (Basel) 2021; 11:life11020139. [PMID: 33673129 PMCID: PMC7918167 DOI: 10.3390/life11020139] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 12/12/2022] Open
Abstract
Brachycephalic dogs remain popular, despite the knowledge that this head conformation is associated with health problems, including airway compromise, ocular disorders, neurological disease, and other co-morbidities. There is increasing evidence that brachycephaly disrupts cerebrospinal fluid movement and absorption, predisposing ventriculomegaly, hydrocephalus, quadrigeminal cistern expansion, Chiari-like malformation, and syringomyelia. In this review, we focus on cerebrospinal fluid physiology and how this is impacted by brachycephaly, airorhynchy, and associated craniosynostosis.
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Spiteri M, Knowler SP, Rusbridge C, Wells K. Using machine learning to understand neuromorphological change and image-based biomarker identification in Cavalier King Charles Spaniels with Chiari-like malformation-associated pain and syringomyelia. J Vet Intern Med 2019; 33:2665-2674. [PMID: 31552689 PMCID: PMC6872629 DOI: 10.1111/jvim.15621] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 08/29/2019] [Indexed: 11/30/2022] Open
Abstract
Background Chiari‐like malformation (CM) is a complex malformation of the skull and cranial cervical vertebrae that potentially results in pain and secondary syringomyelia (SM). Chiari‐like malformation‐associated pain (CM‐P) can be challenging to diagnose. We propose a machine learning approach to characterize morphological changes in dogs that may or may not be apparent to human observers. This data‐driven approach can remove potential bias (or blindness) that may be produced by a hypothesis‐driven expert observer approach. Hypothesis/Objectives To understand neuromorphological change and to identify image‐based biomarkers in dogs with CM‐P and symptomatic SM (SM‐S) using a novel machine learning approach, with the aim of increasing the understanding of these disorders. Animals Thirty‐two client‐owned Cavalier King Charles Spaniels (CKCSs; 11 controls, 10 CM‐P, 11 SM‐S). Methods Retrospective study using T2‐weighted midsagittal Digital Imaging and Communications in Medicine (DICOM) anonymized images, which then were mapped to images of an average clinically normal CKCS reference using Demons image registration. Key deformation features were automatically selected from the resulting deformation maps. A kernelized support vector machine was used for classifying characteristic localized changes in morphology. Results Candidate biomarkers were identified with receiver operating characteristic curves with area under the curve (AUC) of 0.78 (sensitivity 82%; specificity 69%) for the CM‐P biomarkers collectively and an AUC of 0.82 (sensitivity, 93%; specificity, 67%) for the SM‐S biomarkers, collectively. Conclusions and clinical importance Machine learning techniques can assist CM/SM diagnosis and facilitate understanding of abnormal morphology location with the potential to be applied to a variety of breeds and conformational diseases.
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Affiliation(s)
- Michaela Spiteri
- CVSSP, Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford, United Kingdom
| | - Susan P Knowler
- Faculty of Health & Medical Sciences, School of Veterinary Medicine, Guildford, United Kingdom
| | - Clare Rusbridge
- Faculty of Health & Medical Sciences, School of Veterinary Medicine, Guildford, United Kingdom.,Fitzpatrick Referrals Orthopaedics and Neurology, Godalming, United Kingdom
| | - Kevin Wells
- CVSSP, Centre for Vision, Speech and Signal Processing, University of Surrey, Guildford, United Kingdom
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Sparks CR, Robertson I, Olby NJ. Morphometric analysis of spinal cord termination in Cavalier King Charles Spaniels. J Vet Intern Med 2019; 33:717-725. [PMID: 30758868 PMCID: PMC6430917 DOI: 10.1111/jvim.15437] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 01/18/2019] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND There is an association between Chiari malformations, syringomyelia (CMSM) and tethered cord syndrome (TCS) in people, suggesting Cavalier King Charles Spaniels (CKCS) with CMSM could also have TCS. Currently there are no data on the position of the caudal spinal cord structures in CKCS. OBJECTIVE To describe and compare location of spinal cord termination in CKCS with weight-matched controls and to examine the relationship between SM and spinal cord termination. ANIMALS Thirty-nine CKCS and 33 controls with thoracolumbar MRIs; 34 of 39 CKCS also had cervical MRIs. METHODS Blinded retrospective study. Spinal cord and dural sac termination were determined from T2-weighted sagittal and transverse images and half-Fourier acquisition single-shot turbo spin echo sequences. Intra-observer reliability was determined using kappa analysis. Presence of SM was compared with location of spinal cord and dural sac termination. RESULTS Intra-observer reliability was moderate for identifying spinal cord termination (Kappa = 0.6) and good for dural sac termination (Kappa = 0.8). The spinal cord terminated at lumbar vertebra 6 (L6) in 1, 7 (L7) in 22, and sacrum in 16 CKCS versus 9 at L6, 23 at L7, 1 at sacrum in controls. Spinal cord (P < .001) and dural sac (P = .002) termination were significantly more caudal in CKCS compared to controls. The presence of thoracolumbar SM was associated with more caudal dural sac termination in CKCS (P = .03). CONCLUSIONS AND CLINICAL IMPORTANCE The relationship between TL SM and possible spinal cord tethering because of a more caudal dural sac termination should be investigated.
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Affiliation(s)
- Courtney R Sparks
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - Ian Robertson
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, North Carolina
| | - Natasha J Olby
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina
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Rusbridge C, Stringer F, Knowler SP. Clinical Application of Diagnostic Imaging of Chiari-Like Malformation and Syringomyelia. Front Vet Sci 2018; 5:280. [PMID: 30547039 PMCID: PMC6279941 DOI: 10.3389/fvets.2018.00280] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 10/22/2018] [Indexed: 12/18/2022] Open
Abstract
Chiari-like malformation (CM) and syringomyelia (SM) is a frequent diagnosis in predisposed brachycephalic toy breeds since increased availability of MRI. However, the relevance of that MRI diagnosis has been questioned as CM, defined as identification of a cerebellar herniation, is ubiquitous in some breeds and SM can be asymptomatic. This article reviews the current knowledge of neuroanatomical changes in symptomatic CM and SM and diagnostic imaging modalities used for the clinical diagnosis of CM-pain or myelopathy related to SM. Although often compared to Chiari type I malformation in humans, canine CM-pain and SM is more comparable to complex craniosynostosis syndromes (i.e., premature fusion of multiple skull sutures) characterized by a short skull (cranial) base, rostrotentorial crowding with rostral forebrain flattening, small, and ventrally orientated olfactory bulbs, displacement of the neural tissue to give increased height of the cranium and further reduction of the functional caudotentorial space with hindbrain herniation. MRI may further reveal changes suggesting raised intracranial pressure such as loss of sulci definition in conjunction with ventriculomegaly. In addition to these brachycephalic changes, dogs with SM are more likely to have craniocervical junction abnormalities including rostral displacement of the axis and atlas with increased odontoid angulation causing craniospinal junction deformation and medulla oblongata elevation. Symptomatic SM is diagnosed on the basis of signs of myelopathy and presence of a large syrinx that is consistent with the neuro-localization. The imaging protocol should establish the longitudinal and transverse extent of the spinal cord involvement by the syrinx. Phantom scratching and cervicotorticollis are associated with large mid-cervical syringes that extend to the superficial dorsal horn. If the cause of CSF channel disruption and syringomyelia is not revealed by anatomical MRI then other imaging modalities may be appropriate with radiography or CT for any associated vertebral abnormalities.
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Affiliation(s)
- Clare Rusbridge
- Fitzpatrick Referrals, Godalming, United Kingdom.,School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, United Kingdom
| | | | - Susan P Knowler
- School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, United Kingdom
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Knowler SP, Galea GL, Rusbridge C. Morphogenesis of Canine Chiari Malformation and Secondary Syringomyelia: Disorders of Cerebrospinal Fluid Circulation. Front Vet Sci 2018; 5:171. [PMID: 30101146 PMCID: PMC6074093 DOI: 10.3389/fvets.2018.00171] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 07/04/2018] [Indexed: 01/01/2023] Open
Abstract
Chiari-like Malformation (CM) and secondary syringomyelia (SM), as well as their analogous human conditions, is a complex developmental condition associated with pain and accompanying welfare concerns. CM/SM is diagnosed ever more frequently, thanks in part to the increased availability of magnetic resonance imaging in veterinary medicine. Research over the last two decades has focused primarily on its pathophysiology relating to overcrowding of the cranial caudal fossa. More recent characterizations of CM/SM include brachycephaly with osseous reduction and neural parenchymal displacement involving the entire brain and craniocervical junction to include rostral flattening, olfactory bulb rotation, increased height of the cranium, reduced cranial base with spheno-occipital synchondrosis angulation, reduced supraoccipital and interparietal crest and rostral displacement of the axis and atlas with increased odontoid angulation. The most shared manifestation of CM is the development of fluid-filled pockets (syrinx, syringes) in the spinal cord that can be readily quantified. Dogs with symptomatic CM without SM have a reduced basioccipital bone, compensatory increased cranial fossa height with displaced parenchyma whereby the cerebellum is invaginated beneath the occipital lobes but without compromising cerebrospinal fluid channels enough to cause SM. Thus, broadly defined, CM might be described as any distortion of the skull and craniocervical junction which compromises the neural parenchyma and cerebrospinal fluid circulation causing pain and/or SM. The etiology of CM is multifactorial, potentially including genetically-influenced, breed-specific abnormalities in both skeletal and neural components. Since causation between specific morphologic changes and SM or clinical signs is unproven, CM might be more appropriately considered as a brachycephalic obstructive CSF channel syndrome (BOCCS) rather than a single malformation. Understanding the normal development of the brain, skull and craniocervical junction is fundamental to identifying deviations which predispose to CM/SM. Here we review its anatomical, embryological, bio-mechanical, and genetic underpinnings to update the profession's understanding of this condition and meaningfully inform future research to diminish its welfare impact.
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Affiliation(s)
- Susan P Knowler
- Department of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Gabriel L Galea
- Developmental Biology of Birth Defects, Great Ormond Street Institute of Child Health, University College London, London,, United Kingdom
| | - Clare Rusbridge
- Department of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Fitzpatrick Referrals Veterinary Specialist Hospital, Surrey, United Kingdom
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Ancot F, Lemay P, Knowler SP, Kennedy K, Griffiths S, Cherubini GB, Sykes J, Mandigers PJJ, Rouleau GA, Rusbridge C, Kibar Z. A genome-wide association study identifies candidate loci associated to syringomyelia secondary to Chiari-like malformation in Cavalier King Charles Spaniels. BMC Genet 2018; 19:16. [PMID: 29566674 PMCID: PMC5865342 DOI: 10.1186/s12863-018-0605-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 03/15/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Syringomyelia (SM) is a common condition affecting brachycephalic toy breed dogs and is characterized by the development of fluid-filled cavities within the spinal cord. It is often concurrent with a complex developmental malformation of the skull and craniocervical vertebrae called Chiari-like malformation (CM) characterized by a conformational change and overcrowding of the brain and cervical spinal cord particularly at the craniocervical junction. CM and SM have a polygenic mode of inheritance with variable penetrance. RESULTS We identified six cranial T1-weighted sagittal MRI measurements that were associated to maximum transverse diameter of the syrinx cavity. Increased syrinx transverse diameter has been correlated previously with increased likelihood of behavioral signs of pain. We next conducted a whole genome association study of these traits in 65 Cavalier King Charles Spaniel (CKCS) dogs (33 controls, 32 with extreme phenotypes). Two loci on CFA22 and CFA26 were found to be significantly associated to two traits associated with a reduced volume and altered orientation of the caudal cranial fossa. Their reconstructed haplotypes defined two associated regions that harbor only two genes: PCDH17 on CFA22 and ZWINT on CFA26. PCDH17 codes for a cell adhesion molecule expressed specifically in the brain and spinal cord. ZWINT plays a role in chromosome segregation and its expression is increased with the onset of neuropathic pain. Targeted genomic sequencing of these regions identified respectively 37 and 339 SNPs with significantly associated P values. Genotyping of tagSNPs selected from these 2 candidate loci in an extended cohort of 461 CKCS (187 unaffected, 274 SM affected) identified 2 SNPs on CFA22 that were significantly associated to SM strengthening the candidacy of this locus in SM development. CONCLUSIONS We identified 2 loci on CFA22 and CFA26 that contained only 2 genes, PCDH17 and ZWINT, significantly associated to two traits associated with syrinx transverse diameter. The locus on CFA22 was significantly associated to SM secondary to CM in the CKCS dog breed strengthening its candidacy for this disease. This study will provide an entry point for identification of the genetic factors predisposing to this condition and its underlying pathogenic mechanisms.
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Affiliation(s)
- Frédéric Ancot
- Department of Neurosciences, CHU Sainte Justine Research Center, University of Montréal, 3175 Cote-Sainte-Catherine, Room 3.17.006, Montreal, QC, H3T 1C5, Canada
| | - Philippe Lemay
- Department of Neurosciences, CHU Sainte Justine Research Center, University of Montréal, 3175 Cote-Sainte-Catherine, Room 3.17.006, Montreal, QC, H3T 1C5, Canada
| | - Susan P Knowler
- School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7AL, UK
| | - Karen Kennedy
- Department of Medical Imaging, London Health Sciences Centre, London, ON, N6A 5A5, Canada
| | - Sandra Griffiths
- Stone Lion Veterinary Hospital, 42 High Street, Wimbledon, SW19 5AU, UK
| | | | - Jane Sykes
- Thames Valley Veterinary Services, London, ON, N6A 4V2, Canada
| | - Paul J J Mandigers
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, 3584, CM, The Netherlands
| | - Guy A Rouleau
- Montreal Neurological Institute and McGill University, Montreal, QC, H3A 2B4, Canada
| | - Clare Rusbridge
- School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7AL, UK.,Fitzpatrick Referrals, Godalming, Surrey, GU7 2QQ, UK
| | - Zoha Kibar
- Department of Neurosciences, CHU Sainte Justine Research Center, University of Montréal, 3175 Cote-Sainte-Catherine, Room 3.17.006, Montreal, QC, H3T 1C5, Canada.
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Hechler AC, Moore SA. Understanding and Treating Chiari-like Malformation and Syringomyelia in Dogs. Top Companion Anim Med 2018; 33:1-11. [DOI: 10.1053/j.tcam.2018.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 11/11/2022]
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Sparks CR, Cerda-Gonzalez S, Griffith EH, Lascelles BDX, Olby NJ. Questionnaire-based Analysis of Owner-reported Scratching and Pain Signs in Cavalier King Charles Spaniels Screened for Chiari-like Malformation and Syringomyelia. J Vet Intern Med 2017; 32:331-339. [PMID: 29105875 PMCID: PMC5787193 DOI: 10.1111/jvim.14856] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/25/2017] [Accepted: 09/19/2017] [Indexed: 12/14/2022] Open
Abstract
Background Chiari‐like malformation (CM) and syringomyelia (SM) cause a pain syndrome in Cavalier King Charles spaniels (CKCS). Clinical signs are not consistently apparent on neurologic examination, and owner reporting of signs provides vital clinical history. However, owner questionnaires for this disease are not well developed. Objectives To develop a tool to capture owner‐reported clinical signs for use in clinical trials and to compare owner‐reported signs with the presence of pain on neurologic examination and SM on magnetic resonance imaging (MRI). Animals Fifty client‐owned CKCS. Methods Owners completed a questionnaire and pain/scratch map. Each dog underwent a neurologic examination and craniocervical magnetic resonance imaging (MRI). Questionnaire responses were developed into scores, area of shading for pain/scratch maps was measured, and consistency of responses between these tools was assessed. Owner‐reported findings were compared with neurologic examination findings and presence and severity of SM on MRI. Results Thirty‐three dogs were symptomatic and 17 asymptomatic; 30 had SM. The most common sign of pain was crying out when lifted (n = 11). Extent of shaded areas on maps positively correlated with questionnaire scores for pain (r2 = 0.213, P = 0.006) and scratch (r2 = 0.104, P = 0.089). Owner‐reported findings were not significantly associated with presence or severity of SM or neurologic examination findings. Owner‐reported lateralization of signs was significantly associated with SM lateralization (P < 0.0001). Conclusions The questionnaire and maps may be useful for clinical trials. Lack of association of owner‐reported signs with SM highlights our lack of understanding of the pathophysiology of pain in this disease.
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Affiliation(s)
- C R Sparks
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC
| | - S Cerda-Gonzalez
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY
| | - E H Griffith
- Department of Statistics, North Carolina State University, Raleigh, NC
| | - B D X Lascelles
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC.,Comparative Medicine Institute, North Carolina State University, Raleigh, NC.,Comparative Pain Research and Education Center, North Carolina State University, Raleigh, NC
| | - N J Olby
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC.,Comparative Medicine Institute, North Carolina State University, Raleigh, NC
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Kiviranta AM, Rusbridge C, Laitinen-Vapaavuori O, Hielm-Björkman A, Lappalainen AK, Knowler SP, Jokinen TS. Syringomyelia and Craniocervical Junction Abnormalities in Chihuahuas. J Vet Intern Med 2017; 31:1771-1781. [PMID: 28892202 PMCID: PMC5697179 DOI: 10.1111/jvim.14826] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/19/2017] [Accepted: 08/07/2017] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND Chiari-like malformation (CM) and syringomyelia (SM) are widely reported in Cavalier King Charles Spaniels and Griffon Bruxellois dogs. Increasing evidence indicates that CM and SM also occur in other small and toy breed dogs, such as Chihuahuas. OBJECTIVES To describe the presence of SM and craniocervical junction (CCJ) abnormalities in Chihuahuas and to evaluate the possible association of CCJ abnormalities with SM. To describe CM/SM-related clinical signs and neurologic deficits and to investigate the association of CM/SM-related clinical signs with signalment, SM, or CCJ abnormalities. ANIMALS Fifty-three client-owned Chihuahuas. METHODS Prospective study. Questionnaire analyses and physical and neurologic examinations were obtained before magnetic resonance and computed tomography imaging. Images were evaluated for the presence of SM, CM, and atlantooccipital overlapping. Additionally, medullary kinking, dorsal spinal cord compression, and their sum indices were calculated. RESULTS Scratching was the most common CM/SM-related clinical sign and decreased postural reaction the most common neurologic deficit in 73 and 87% of dogs, respectively. Chiari-like malformation and SM were present in 100 and 38% of dogs, respectively. Syringomyelia was associated with the presence of CM/SM-related clinical signs (P = 0.034), and medullary kinking and sum indices were higher in dogs with clinical signs (P = 0.016 and P = 0.007, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE Syringomyelia and CCJ abnormalities are prevalent in Chihuahuas. Syringomyelia was an important factor for the presence of CM/SM-related clinical signs, but many dogs suffered from similar clinical signs without being affected by SM, highlighting the clinical importance of CCJ abnormalities in Chihuahuas.
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Affiliation(s)
- A-M Kiviranta
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - C Rusbridge
- and School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - O Laitinen-Vapaavuori
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - A Hielm-Björkman
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - A K Lappalainen
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - S P Knowler
- and School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - T S Jokinen
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
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Use of Morphometric Mapping to Characterise Symptomatic Chiari-Like Malformation, Secondary Syringomyelia and Associated Brachycephaly in the Cavalier King Charles Spaniel. PLoS One 2017; 12:e0170315. [PMID: 28122014 PMCID: PMC5266281 DOI: 10.1371/journal.pone.0170315] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 01/02/2017] [Indexed: 11/19/2022] Open
Abstract
Objectives To characterise the symptomatic phenotype of Chiari-like malformation (CM), secondary syringomyelia (SM) and brachycephaly in the Cavalier King Charles Spaniel using morphometric measurements on mid-sagittal Magnetic Resonance images (MRI) of the brain and craniocervical junction. Methods This retrospective study, based on a previous quantitative analysis in the Griffon Bruxellois (GB), used 24 measurements taken on 130 T1-weighted MRI of hindbrain and cervical region. Associated brachycephaly was estimated using 26 measurements, including rostral forebrain flattening and olfactory lobe rotation, on 72 T2-weighted MRI of the whole brain. Both study cohorts were divided into three groups; Control, CM pain and SM and their morphometries compared with each other. Results Fourteen significant traits were identified in the hindbrain study and nine traits in the whole brain study, six of which were similar to the GB and suggest a common aetiology. The Control cohort had the most elliptical brain (p = 0.010), least olfactory bulb rotation (p = 0.003) and a protective angle (p = 0.004) compared to the other groups. The CM pain cohort had the greatest rostral forebrain flattening (p = 0.007), shortest basioccipital (p = 0.019), but a greater distance between the atlas and basioccipital (p = 0.002) which was protective for SM. The SM cohort had two conformation anomalies depending on the severity of craniocervical junction incongruities; i) the proximity of the dens (p <0.001) ii) increased airorhynchy with a smaller, more ventrally rotated olfactory bulb (p <0.001). Both generated ‘concertina’ flexures of the brain and craniocervical junction. Conclusion Morphometric mapping provides a diagnostic tool for quantifying symptomatic CM, secondary SM and their relationship with brachycephaly. It is hypothesized that CM pain is associated with increased brachycephaly and SM can result from different combinations of abnormalities of the forebrain, caudal fossa and craniocervical junction which compromise the neural parenchyma and impede cerebrospinal fluid flow.
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Abstract
Chiari-like malformation is a condition of the craniocervical junction in which there is a mismatch of the structures of the caudal cranial fossa causing the cerebellum to herniate into the foramen magnum. This herniation can lead to fluid buildup in the spinal cord, also known as syringomyelia. Pain is the most common clinical sign followed by scratching. Other neurologic signs noted are facial nerve deficits, seizures, vestibular syndrome, ataxia, menace deficit, proprioceptive deficits, head tremor, temporal muscle atrophy, and multifocal central nervous system signs. MRI is the diagnostic of choice, but computed tomography can also be used.
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Knowler SP, McFadyen AK, Freeman C, Kent M, Platt SR, Kibar Z, Rusbridge C. Quantitative analysis of Chiari-like malformation and syringomyelia in the Griffon Bruxellois dog. PLoS One 2014; 9:e88120. [PMID: 24533070 PMCID: PMC3922758 DOI: 10.1371/journal.pone.0088120] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 01/04/2014] [Indexed: 11/28/2022] Open
Abstract
This study aimed to develop a system of quantitative analysis of canine Chiari-like malformation and syringomyelia on variable quality MRI. We made a series of measurements from magnetic resonance DICOM images from Griffon Bruxellois dogs with and without Chiari-like malformation and syringomyelia and identified several significant variables. We found that in the Griffon Bruxellois dog, Chiari-like malformation is characterized by an apparent shortening of the entire cranial base and possibly by increased proximity of the atlas to the occiput. As a compensatory change, there appears to be an increased height of the rostral cranial cavity with lengthening of the dorsal cranial vault and considerable reorganization of the brain parenchyma including ventral deviation of the olfactory bulbs and rostral invagination of the cerebellum under the occipital lobes.
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Affiliation(s)
- Susan P. Knowler
- Neurology Department, Fitzpatrick Referrals, Godalming, Surrey, United Kingdom
| | | | - Courtenay Freeman
- Department of Small Animal Medicine & Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Marc Kent
- Department of Small Animal Medicine & Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Simon R. Platt
- Department of Small Animal Medicine & Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Zoha Kibar
- Department of Neurosciences, Justine University Hospital Research Center, University of Montreal, Quebec, Canada
| | - Clare Rusbridge
- Neurology Department, Fitzpatrick Referrals, Godalming, Surrey, United Kingdom
- School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, United Kingdom
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Driver CJ, Volk HA, Rusbridge C, Van Ham LM. An update on the pathogenesis of syringomyelia secondary to Chiari-like malformations in dogs. Vet J 2013; 198:551-9. [PMID: 23938004 DOI: 10.1016/j.tvjl.2013.07.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 06/19/2013] [Accepted: 07/09/2013] [Indexed: 11/16/2022]
Abstract
Syringomyelia (SM) is a spinal cord disease that can cause neuropathic pain in dogs. The pathogenesis of SM secondary to Chiari-like malformation (CM) has been the focus of intense research in recent years. The gulf in our understanding of CM/SM in dogs relative to the analogous human condition has progressively narrowed. CM is primarily a disease of abnormal geometric morphometry affecting the caudal cranial fossa and the brain parenchyma contained within it. This review describes how advanced imaging techniques have revealed a series of morphometric abnormalities associated with CM/SM. The series is presented in a logical order to help describe the pathogenesis of CM and the subsequent formation of syringes, with particular reference to the concepts of craniospinal compliance and cerebrospinal fluid pulse pressure timing.
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Affiliation(s)
- C J Driver
- Department of Veterinary Clinical Sciences, Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, UK.
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