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Santifort K, Bellekom S, Carrera I, Mandigers P. Craniocervical Morphometry in Pomeranians-Part II: Associations with Chiari-like Malformation and Syringomyelia. Animals (Basel) 2024; 14:1859. [PMID: 38997971 DOI: 10.3390/ani14131859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 06/13/2024] [Accepted: 06/20/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND The aim of Part II of this two-part study is to describe and analyze the association of various aspects and measurements related to the morphometry of the skull and craniocervical region to CM/SM status of Pomeranians, by means of computed tomography (CT) and magnetic resonance imaging (MRI). METHODS Prospectively, Pomeranians were included that underwent both CT and MRI studies of the head and cervicothoracic vertebral column. For those cases where qualitative classifications differed between observers, the experienced observer re-evaluated the studies and decided on a final classification that was used for further analysis. For quantitative measurements, the means of the observers' measurements were used for analysis. RESULTS Among statistically significant differences in measurements, we found that dogs with SM had a significantly shorter clivus length based on both MRI (p = 0.01) and CT measurements (p = 0.01), and a significantly smaller caudal cranial fossa area based on both MRI (p = 0.02) and CT measurements (p = 0.02). CONCLUSIONS Significant morphometrical differences were identified between dogs with or without CM/SM. The findings in this study add to those already described in other breeds and provide further insight into factors that may play a role in the pathogenesis of CM/SM in Pomeranians.
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Affiliation(s)
- Koen Santifort
- IVC Evidensia Referral Hospital Arnhem, 6825 MB Arnhem, The Netherlands
- IVC Evidensia Referral Hospital Hart van Brabant, 5144 AM Waalwijk, The Netherlands
- Expertise Centre of Genetics, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CS Utrecht, The Netherlands
| | - Sophie Bellekom
- IVC Evidensia Referral Hospital Hart van Brabant, 5144 AM Waalwijk, The Netherlands
| | | | - Paul Mandigers
- IVC Evidensia Referral Hospital Arnhem, 6825 MB Arnhem, The Netherlands
- Expertise Centre of Genetics, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CS Utrecht, The Netherlands
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Santifort K, Bellekom S, Carrera I, Mandigers P. Craniocervical Morphometry in Pomeranians-Part I: Intra-Observer, Interobserver, and Intermodality (CT vs. MRI) Agreement. Animals (Basel) 2024; 14:1854. [PMID: 38997966 DOI: 10.3390/ani14131854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 06/17/2024] [Accepted: 06/19/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND Currently, there are no diagnostic imaging-based studies that have focused specifically on the craniocervical morphology of Pomeranian dogs in relation to Chiari-like malformation and syringomyelia (CM/SM). The aims of Part I of this two-part study are to assess the intra-observer, interobserver, and intermodality reliability and agreement for various aspects of the craniocervical morphology of Pomeranians with and without CM/SM. METHODS Prospectively, Pomeranians were included that underwent both CT and MRI studies of the head and cervicothoracic vertebral column. Two observers (experienced and novice) independently performed CM and SM classifications, qualitative assessments, and quantitative measurements. The experienced observer performed these assessments twice. A third observer (experienced) performed CM and SM normal or abnormal classifications. RESULTS Ninety-nine (99) dogs were included. Interobserver reliability was influenced by observer experience level. For the experienced versus novice observers, substantial interobserver agreement was found for classification of SM as normal or abnormal (Cohen's kappa = 0.63), while interobserver agreement was fair for classification of SM as normal or abnormal (Cohen's kappa = 0.31). Interobserver, intra-observer, and intermodality reliability were variable for different measurements and assessments, and best overall for the CT-based measurements. CONCLUSIONS Interobserver reliability and agreement results should be taken into account in the evaluation of results of future studies as well as the evaluation of imaging studies of Pomeranians presented clinically.
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Affiliation(s)
- Koen Santifort
- IVC Evidensia Referral Hospital Arnhem, 6825 MB Arnhem, The Netherlands
- IVC Evidensia Referral Hospital Hart van Brabant, 5144 AM Waalwijk, The Netherlands
- Expertise Centre of Genetics, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
| | - Sophie Bellekom
- IVC Evidensia Referral Hospital Hart van Brabant, 5144 AM Waalwijk, The Netherlands
| | | | - Paul Mandigers
- IVC Evidensia Referral Hospital Arnhem, 6825 MB Arnhem, The Netherlands
- Expertise Centre of Genetics, Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
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Weber SM, Hostnik ET, Drost WT, Hamlin AN, Ledesma MA, Timperman L, Hechler AC, Cole LK. Comparison of high-field MRI and multidetector CT for grading Chiari-like malformation and syringomyelia in Cavalier King Charles Spaniels. Vet Radiol Ultrasound 2020; 61:444-452. [PMID: 32329949 DOI: 10.1111/vru.12862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 12/23/2019] [Accepted: 02/06/2020] [Indexed: 11/29/2022] Open
Abstract
Chiari-like malformation (CM) and syringomyelia (SM) are common illnesses that can cause debilitating neuropathic pain in Cavalier King Charles spaniels (CKCS). The current imaging modality to screen CKCS for CM/SM is MRI of the brain and cervical spine. Magnetic resonance imaging provides good soft tissue detail and contrast of the cerebellum and cervical spinal cord. Computed tomography (CT) is another cross-sectional imaging technique that facilitates brain and neck evaluation; however, soft tissue resolution does not match that of MRI. Computed tomography benefits include identification of concurrent craniocervical junction anomalies (atlantooccipital overlap) and shorter imaging/anesthesia times with the ability to use only sedation. The aim of this retrospective, method comparison study is to assess the utility of multidetector CT for screening CM and SM in CKCS as compared to high-field MRI. Three groups of observers with different levels of experience graded CM and SM based on the British Veterinary Association/Kennel Club CM/SM classification criteria. Thirty CKCS underwent multidetector CT and 3 Tesla MRI studies. Computed tomography and MRI studies were reviewed at different timepoints to minimize bias. Computed tomography has lower Cohen's Kappa agreement for each observer group compared to MRI. The intraclass correlation coefficient averaging CM and SM for all groups was excellent using MRI, while CT was poor for SM and moderate for cerebellar herniation. Greater observer experience resulted in a higher agreement for CT and MRI. Magnetic resonance imaging should remain the standard for screening of CM and SM as CT can result in misclassification and greater disagreement.
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Affiliation(s)
- Sarah M Weber
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Eric T Hostnik
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Wm Tod Drost
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Alessandra N Hamlin
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Marc A Ledesma
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Lauren Timperman
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Ashley C Hechler
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
| | - Lynette K Cole
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio
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Hechler AC, Hostnik ET, Cook LB, Cole LK, Moore SA. Mechanical quantitative sensory testing in cavalier King Charles spaniels with and without syringomyelia. BMC Vet Res 2020; 16:94. [PMID: 32197618 PMCID: PMC7085174 DOI: 10.1186/s12917-020-02313-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 03/11/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Syringomyelia (SM) is a debilitating condition in the cavalier King Charles spaniel (CKCS) that results in neuropathic pain and diminished quality of life. Von Frey aesthesiometry (VFA) is a method of mechanical quantitative sensory testing that provides an objective sensory threshold (ST) value and can be used to quantify neuropathic pain (NP) and monitor response to therapy. The utility of VFA has been previously established in client-owned dogs with acute spinal cord injury but the technique has not been evaluated in dogs with SM. The goal of this study was to evaluate ST, as determined by VFA, in dogs with and without SM, to assess the utility of VFA in quantifying NP in SM-affected dogs. We hypothesized the SM-affected CKCS would have lower ST values, consistent with hyperesthesia, when compared to control CKCS. Additionally, we hypothesized that ST values in SM-affected dogs would be inversely correlated with syrinx size on MRI and with owner-derived clinical sign scores. RESULTS ST values for the thoracic and pelvic limbs differed significantly between the SM-affected and control CKCS (p = 0.027; p = 0.0396 respectively). Median ST value (range) for the thoracic limbs was 184.1 g (120.9-552) for control dogs, and 139.9 g (52.6-250.9) for SM-affected dogs. The median ST value (range) for the pelvic limbs was 164.9 g (100.8-260.3) in control dogs and 129.8 g (57.95-168.4) in SM-affected dogs. The ST values in SM-affected dogs did not correlate with syrinx height on MRI (r = 0.314; p = 0.137). Owner-reported clinical sign scores showed an inverse correlation with pelvic limb ST values, where dogs with lower ST values (hyperesthesia) were reported by their owners to display more frequent and severe clinical signs (r = - 0.657; p = 0.022). CONCLUSION ST values were lower in SM-affected CKCS compared to control dogs, suggesting the presence of neuropathic pain. Dogs with lower ST pelvic limb values were perceived by their owners to have more severe clinical signs classically associated with SM. Our results suggest that VFA might offer quantitative assessment of neuropathic pain in SM-affected dogs and could be useful for monitoring response to therapy in future clinical studies.
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Affiliation(s)
- Ashley C Hechler
- The Ohio State University Veterinary Medical Center, 601 Vernon L. Tharp Street, Columbus, OH, 43221, USA
| | - Eric T Hostnik
- The Ohio State University Veterinary Medical Center, 601 Vernon L. Tharp Street, Columbus, OH, 43221, USA
| | - Laurie B Cook
- The Ohio State University Veterinary Medical Center, 601 Vernon L. Tharp Street, Columbus, OH, 43221, USA
| | - Lynette K Cole
- The Ohio State University Veterinary Medical Center, 601 Vernon L. Tharp Street, Columbus, OH, 43221, USA
| | - Sarah A Moore
- The Ohio State University Veterinary Medical Center, 601 Vernon L. Tharp Street, Columbus, OH, 43221, USA.
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Kim YJ, Lee S, Jung J, Jung H, In S, Chang J, Chang D, Fahie M. Atlantoaxial bands in small breed dogs: influence of external pressure by the endotracheal tube tie. J Small Anim Pract 2020; 61:163-169. [PMID: 31960442 DOI: 10.1111/jsap.13094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To determine the prevalence of dorsal cervical spinal compression in a population of dogs susceptible to caudal occipital dysplasia. To determine whether endotracheal tube ties iatrogenically alter the dorsal compression ratio in the atlantoaxial region. MATERIALS AND METHODS Prospective, randomised, controlled, cross-over, blinded cohort study of dogs weighing <15 kg and presenting for neurologic signs localised to the cervical region. In mid-sagittal T2-weighted MR images, dorsal cervical compression and cerebellar compression were evaluated. Dorsal cervical compression ratios were calculated and compared to determine the effect of the endotracheal tube tie on the atlantoaxial region depending on whether dogs were in extended or flexed neck position. RESULTS Prevalence of dorsal cervical spinal compression consistent with an atlantoaxial band was 32/44 (73%) dogs without tie pressure and 37/44 (84%) dogs with tie pressure. Significantly higher compression ratios were found with tie placement over the craniocervical region. Dorsal compression ratios of dogs with cerebellar compression were significantly greater than those without it. CLINICAL SIGNIFICANCE The location of the endotracheal tube tie can influence interpretation of MR images of the craniocervical region of small breed dogs. These breeds more often had greater dorsal cervical spinal compression with tie pressure, especially when they had cerebellar compression.
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Affiliation(s)
- Y J Kim
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, 91766, USA
| | - S Lee
- Section of Medical imaging, Veterinary Medical Center, College of Veterinary Medicine, Chungbuk National University, Cheongju, 28644, South Korea
| | - J Jung
- Section of Medical imaging, Veterinary Medical Center, College of Veterinary Medicine, Chungbuk National University, Cheongju, 28644, South Korea
| | - H Jung
- Section of Medical imaging, Veterinary Medical Center, College of Veterinary Medicine, Chungbuk National University, Cheongju, 28644, South Korea
| | - S In
- Section of Medical imaging, Veterinary Medical Center, College of Veterinary Medicine, Chungbuk National University, Cheongju, 28644, South Korea
| | - J Chang
- Section of Medical imaging, Veterinary Medical Center, College of Veterinary Medicine, Chungbuk National University, Cheongju, 28644, South Korea
| | - D Chang
- Section of Medical imaging, Veterinary Medical Center, College of Veterinary Medicine, Chungbuk National University, Cheongju, 28644, South Korea
| | - M Fahie
- College of Veterinary Medicine, Western University of Health Sciences, Pomona, California, 91766, USA
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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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Takahashi F, Kouno S, Yamaguchi S, Hara Y. Evaluation of atlantooccipital overlapping and cerebral ventricle size in dogs with atlantoaxial instability. J Vet Med Sci 2019; 81:229-236. [PMID: 30584199 PMCID: PMC6395205 DOI: 10.1292/jvms.17-0553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study investigated cerebral ventricle size and concurrent craniocervical junction
abnormality in relation to atlantooccipital overlapping (AOO) in dogs with atlantoaxial
instability (AAI). A total of 61 dogs were treated with atlantoaxial ventral fixation.
Medical records of each dog, including magnetic resonance (MR) and computed tomography
(CT) images, were retrospectively reviewed. CT images were assessed for the presence of
AOO and the dogs were then assigned to either an AOO group or a non-AOO group accordingly.
CT images were also evaluated to determine the foramen magnum (FM) index. Syringomyelia,
cerebellar compression, dorsal compression, and the degree of enlargement of each cerebral
ventricle were evaluated using MR images. Of the 61 dogs, 23 had AOO and 38 did not.
Furthermore, the ventricle/brain height ratio, the fourth ventricle height/cerebellum
length ratio, and the fourth ventricle width/cerebellum length ratio were significantly
higher in the AOO group than in the non-AOO group. However, the FM index, third
ventricle/brain height ratio, and incidence of syringomyelia did not differ significantly
between the two groups. Dogs with concurrent AOO exhibited significantly more dilatation
of the lateral and fourth ventricles.
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Affiliation(s)
- Fumitaka Takahashi
- The Laboratory of Veterinary Surgery, Nippon Veterinary and Life Science University, 1-7-1 Kyonan, Musashino-shi, Tokyo 180-0023, Japan.,YPC Tokyo Animal Orthopedic Surgery Hospital, 7-1-13 Oojima, Koutou-ku, Tokyo 136-0072, Japan
| | - Shigenori Kouno
- The Laboratory of Veterinary Surgery, Nippon Veterinary and Life Science University, 1-7-1 Kyonan, Musashino-shi, Tokyo 180-0023, Japan
| | - Shinya Yamaguchi
- The Laboratory of Veterinary Surgery, Nippon Veterinary and Life Science University, 1-7-1 Kyonan, Musashino-shi, Tokyo 180-0023, Japan.,YPC Tokyo Animal Orthopedic Surgery Hospital, 7-1-13 Oojima, Koutou-ku, Tokyo 136-0072, Japan
| | - Yasushi Hara
- The Laboratory of Veterinary Surgery, Nippon Veterinary and Life Science University, 1-7-1 Kyonan, Musashino-shi, Tokyo 180-0023, Japan
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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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10
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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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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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Knowler SP, Kiviranta AM, McFadyen AK, Jokinen TS, La Ragione RM, Rusbridge C. Craniometric Analysis of the Hindbrain and Craniocervical Junction of Chihuahua, Affenpinscher and Cavalier King Charles Spaniel Dogs With and Without Syringomyelia Secondary to Chiari-Like Malformation. PLoS One 2017; 12:e0169898. [PMID: 28121988 PMCID: PMC5266279 DOI: 10.1371/journal.pone.0169898] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 12/23/2016] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVES To characterize and compare the phenotypic variables of the hindbrain and craniocervical junction associated with syringomyelia (SM) in the Chihuahua, Affenpinscher and Cavalier King Charles Spaniel (CKCS). METHOD Analysis of 273 T1-weighted mid-sagittal DICOM sequences of the hindbrain and craniocervical junction from 99 Chihuahuas, 42 Affenpinschers and 132 CKCSs. The study compared 22 morphometric features (11 lines, eight angles and three ratios) of dogs with and without SM using refined techniques based on previous studies of the Griffon Bruxellois (GB) using Discriminant Function Analysis and ANOVA with post-hoc corrections. RESULTS The analysis identified 14/22 significant traits for SM in the three dog breeds, five of which were identical to those reported for the GB and suggest inclusion of a common aetiology. One ratio, caudal fossa height to the length of the skull base extended to an imaginary point of alignment between the atlas and supraoccipital bones, was common to all three breeds (p values 0.029 to <0.001). Associated with SM were a reduced occipital crest and two acute changes in angulation i) 'sphenoid flexure' at the spheno-occipital synchondrosis ii) 'cervical flexure' at the foramen magnum allied with medulla oblongata elevation. Comparing dogs with and without SM, each breed had a unique trait: Chihuahua had a smaller angle between the dens, atlas and basioccipital bone (p value < 0.001); Affenpinschers had a smaller distance from atlas to dens (p value 0.009); CKCS had a shorter distance between the spheno-occipital synchondrosis and atlas (p value 0.007). CONCLUSION The selected morphometries successfully characterised conformational changes in the brain and craniocervical junction that might form the basis of a diagnostic tool for all breeds. The severity of SM involved a spectrum of abnormalities, incurred by changes in both angulation and size that could alter neural parenchyma compliance and/or impede cerebrospinal fluid channels.
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Affiliation(s)
- Susan P. Knowler
- School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom
| | - Anna-Mariam Kiviranta
- Department of Equine and Small Animal Medicine, 00014 University of Helsinki, Finland
| | | | - Tarja S. Jokinen
- Department of Equine and Small Animal Medicine, 00014 University of Helsinki, Finland
| | - Roberto M. La Ragione
- School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom
| | - Clare Rusbridge
- School of Veterinary Medicine, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom
- Fitzpatrick Referrals, Godalming, Surrey, United Kingdom
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