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Degenerative Myelopathy (DM)
Cervical spondylomyelopathy (Wobbler syndrome)
Arthritis
Syringomyelia

Dodgerslist Website on Intervertebral Disc Disease

Intervertebral Disk Disease, Chapter 62, Textbook of Small Animal Orthopedics. Andy Shores. 1982; U. Penn CAL small animal orthopedics.

Spondylosis Deformans, Chapter 61, Textbook of Small Animal Orthopedics. Joseph P. Morgan, Darryl N. Biery . 1982; U. Penn CAL small animal orthopedics.

Dysplasia of the caudal vertebral articular facets in four dogs: results of radiographic, myelographic and magnetic resonance imaging investigations. J. Penderis, T. Schwarz, J. F. McConnell, L. S. Garosi, C. E. Thomson, R. Dennis. Vet. Rec. May 2005;156:601–5. Quote: Congenital anomalies of the vertebral column associated with aberrations of one of the primary vertebral ossification centres have been frequently described in the veterinary literature, but clinically significant abnormalities of secondary vertebral ossification centres, particularly involving the caudal articular processes, are much less frequently reported. This paper describes three dogs with aplasia [two German shepherds and a 10-month-old cavalier King Charles spaniel] and one dog with hypoplasia of the caudal vertebral articular processes. Thoracolumbar spinal cord compression and ataxia was evident in the three dogs with aplasia but no clinical signs were evident in the dog with hypoplasia. The radiographic appearance was similar in all four cases, with aplasia or hypoplasia of the caudal articular facets at one or more intervertebral joints in the thoracolumbar region. Bone proliferation was evident secondary to an associated degenerative joint disease. Compensatory hyperplasia of the adjacent cranial articular facets and ligamentum flavum protruded into the vertebral canal, resulting in a compressive myelopathy observed by myelography and magnetic resonance imaging. ... The results of this study show that congenital abnormalities of the caudal articular facets occur in dogs, demonstrate the typical imaging findings and suggest that the total absence of the caudal articular facets may result in neurological deficits.

Neurological diseases of the Cavalier King Charles spaniel. C. Rusbridge. J.Sm.Ani.Pract. 2005; 46:265–272. Quote: "The CKCS is a chondrodystrophic-type breed and as such is prone to Hansen type I disc extrusions. The most common clinical sign is spinal pain, with or without paresis. Disc extrusion is uncommon in dogs younger than two years of age. Survey radiographs may indicate possible sites of disc extrusion by identifying a narrowed intervertebral disc space, foramen or joint spaces, or by finding calcified disc material within the vertebral canal. For confirmation of the diagnosis, further imaging such as myelography or magnetic resonance imaging (MRI) is required. MRI is preferred because of the tendency for CKCSs to have syringomyelia and subsequently a small cisterna magnum and subarachnoid space, presenting an increased risk of intrathecal spinal needle placement. Lumbar, as well as cisternal, myelography is risky in this breed. Management of disc disease may be medical (analgesia and exercise restriction for at least four weeks) or surgical. Surgical management is preferred for dogs with significant paresis or paralysis. For the optimum chance of return of function, dogs without deep pain perception should have decompressive surgery performed within 24 hours of loss of function."

Conservative Management of Chondrodystrophic Dogs with Thoracolumbar Intervertebral Disc Disease. Laurie Edge-Hughes. CHAP Newsletter. December 2007;4–6.

Transplantation of Mesenchymal Stem Cells in a Canine Disc Degeneration Model. Akihiko Hiyama, Joji Mochida, Toru Iwashina, Hiroko Omi, Takuya Watanabe, Kenji Serigano, Futoshi Tamura,Daisuke Sakai. J. Orthopaedic Res. January 2008;26(5):589-600. Quote: Transplantation of mesenchymal stem cells (MSCs) is effective in decelerating disc degeneration in small animals; much remains unknown about this new therapy in larger animals or humans. Fas-ligand (FasL), which is only found in tissues with isolated immune privilege, is expressed in IVDs, particularly in the nucleus pulposus (NP). Maintaining the FasL level is important for IVD function. This study evaluated whether MSC transplantation has an effect on the suppression of disc degeneration and preservation of immune privilege in a canine model of disc degeneration. Mature beagles were separated into a normal control group (NC), a MSC group, and the disc degeneration (nucleotomy-only) group. In the MSC group, 4 weeks after nucleotomy, MSCs were transplanted into the degeneration-induced discs. The animals were followed for 12 weeks after the initial operation. Subsequently, radiological, histological, biochemical, immunohistochemical, and RT-PCR analyses were performed. MSC transplantation effectively led to the regeneration of degenerated discs. FACS and RT-PCR analyses of MSCs before transplantation demonstrated that the MSCs expressed FasL at the genetic level, not at the protein level. GFP-positive MSCs detected in the NP region 8 weeks after transplantation expressed FasL protein. The results of this study suggest that MSC transplantation may contribute to the maintenance of IVD immune privilege by the differentiation of transplanted MSCs into cells expressing FasL.

Intervertebral Disc Disease (IVDD). Patty Khuly. Quote: "The more typical, Type I IVDD is common in the dachshund along with many other chondrodystrophic breeds of dogs including the basset hound, beagle, French bulldog, Lhasa apso, Pekingese, pomeranian, shih tzu, and Welsh corgi. Cocker spaniels, Cavalier King Charles spaniels and other semi-chondrodystrophic breeds are also predisposed."

Intervertebral Disc Repair Using Adipose Tissue-Derived Stem and Regenerative Cells: Experiments in a Canine Model. Ganey, Timothy, Hutton, William C., Moseley, Timothy, Hedrick, Mark, Meisel, Hans-Joerg. Spine. October 2009;34(21):2297-2304. Quote: Study Design: Therapeutic treatment of intervertebral disc repair using cells. Objective: The goal of the study was to test the hypothesis that repair of a damaged disc is possible using autologous adipose tissue derived stem and regenerative cells (ADRCs). Summary of Background Data: Degradation resulting from either acute or chronic repetitive disc injury leads to disc degeneration. However, if a damaged disc could be repaired in the early stages, before the onslaught of degradation, then the disc degeneration process may be slowed down. Methods: Twelve dogs underwent a partial nucleotomy at 3 lumbar levels (L3–L4, L4–L5, and L5–L6); adjacent levels served as nonoperated controls. The animals (or discs) were allowed to recover from the surgery for 6 weeks. At that time subcutaneous adipose tissue was harvested and ADRCs were isolated. The 3 experimental discs that had undergone a partial nucleotomy were randomized to receive: (1) ADRCs in hyaluronic acid carrier (Cells/HA); (2) HA only; or (3) No Intervention. Assessments of the 3 experimental discs plus the 2 adjacent untouched discs were made using MRI, radiography, histology, and biochemistry. The animals were killed at 6 months and at 12 months. Results: Repair in this study was specifically demonstrated through histology and biochemical analysis. Disc levels receiving ADRCs more closely resembled the healthy controls as evidenced in matrix translucency, compartmentalization of the anulus, and in cell density within the nucleus pulposus. Matrix analysis for Type-II collagen and aggrecan demonstrated evidence of a statistically better regenerative stimulation to the disc provided by ADRCs when compared to either the HA only or no intervention treatments. Conclusion: Autologous adipose tissue derived stem and regenerative cells, as used in this disc injury model, were effective in promoting disc regeneration, as evidenced by disc matrix production and overall disc morphology.

Presumptive exercise-associated peracute thoracolumbar disc extrusion in 48 dogs. W. M. McKee, C. J. Downes, J. J. Pink, T. J. Gemmill. Vet.Rec. April 2010; 166:523-528. Quote: "Forty-eight dogs [including a cavalier King Charles spaniel] were diagnosed with presumptive exercise-associated peracute thoracolumbar disc extrusion. The median age was seven years (range two to 11 years), and median bodyweight was 23 kg (range 10 to 41 kg). The duration of signs before presentation ranged from 0.5 to four days. Twenty-nine dogs were non-ambulatory, of which 17 were incontinent and two had lost pain perception. Pelvic limbs were hyporeflexic or areflexic in 11 dogs. Intervertebral disc narrowing was evident on radiographs in 44 dogs. Myelography demonstrated a small, extradural space-occupying lesion dorsal to an intervertebral disc between T11-12 and L3-4 with adjacent spinal cord swelling. Forty-six dogs were treated non-surgically, one was euthanased and one was managed by hemilaminectomy (and subsequently euthanased). Follow-up information was available for 46 dogs 1.5 to 55 months after injury (median 22 months) showing that pelvic limb function had improved in all cases and all non-ambulatory dogs had regained the ability to walk. Six dogs remained faecally incontinent, and one dog remained urinarily and faecally incontinent."

Effect of cell number on mesenchymal stem cell transplantation in a canine disc degeneration model. Kenji Serigano, Daisuke Sakai, Akihiko Hiyama, Futoshi Tamura, Masahiro Tanaka, Joji Mochida. J. Orthopaedic Res. October 2010;28(10):1267-1275. Quote: Transplantation of mesenchymal stem cells (MSCs) inhibits the progression of disc degeneration in animal models. We know of no study to determine the optimal number of cells to transplant into the degenerated intervertebral disc (IVD). To determine the optimal donor cell number for maximum benefit, we conducted an in vivo study using a canine disc degeneration model. Autologous MSCs were transplanted into degenerative discs at 105, 106, or 107 cells per disc. The MSC-transplanted discs were evaluated for 12 weeks using plain radiography, magnetic resonance imaging, and gross and microscopic evaluation. Preservation of the disc height, annular structure was seen in MSC-transplantation groups compared to the operated control group with no MSC transplantation. Result of the number of remaining transplanted MSCs, the survival rate of NP cells, and apoptosis of NP cells in transplanted discs showed both structural microenvironment and abundant extracellular matrix maintained in 106 MSCs transplanted disc, while less viable cells were detected in 105 MSCs transplanted and more apoptotic cells in 107 MSCs transplanted discs. The results of this study demonstrate that the number of cells transplanted affects the regenerative capability of MSC transplants in experimentally induced degenerating canine discs. It is suggested that maintenance of extracellular matrix by its production from transplanted cells and/or resident cells is important for checking the progression of structural disruption that leads to disc degeneration.

Dorsolateral spinal cord compression at the C2-C3 junction in two Cavalier King Charles spaniels. K. P. Harris, T. C. Saveraid, and S. Rodenas. Vet. Rec. 2011;169(16):416. Quote: Due to the high incidence of Chiari-like malformation (CM) and syringomyelia (SM) in Cavalier King Charles spaniels (CKCS), the presentation of this breed with a history of apparent neck pain often prompts an early suspicion for CM-SM. Conversely, CM-SM findings upon MRI have been reported in many asymptomatic CKCS, and thus other differentials for neck pain such as vertebral trauma, meningioencephalomyelitis or myelocompression must be exhaustively excluded. Cervical spondylomyelopathy (CSM), also referred to as cervical vertebral malformation-malarticulation syndrome, cervical vertebral stenotic myelopathy and wobbler syndrome among other terms, is a common multifactorial neurological disorder affecting mainly large/giant breed dogs. Cases of CSM have been broadly classified by their mechanism of spinal cord and/or nerve root compression as either disc-associated (DA-CSM) or osseous-associated (OA-CSM). This short communication describes dorsolateral compressive lesions of the spinal cord at the C2-C3 junction, similar to those described in giant breed dogs with OA-CSM, in two CKCS with concurrent CM, being evaluated with MRI for neck pain. To the author's knowledge, this is the first report of such MRI findings in this breed. In case 1, a 13.9 kg two-year-old male neutered CKCS presented with a three-month history of intermittent periods of apparent discomfort manifested as very abrupt rising from rest. Two weeks earlier, the owner had observed an isolated episode of ataxia during which the dog fell to the left, had a left-sided head tilt and facial twitching. The dog remained responsive to the owner throughout and returned to normal within 30 minutes. The owner also reported that the dog frequently scratched at one ear (the side unknown). Neurological and otoscopic examination revealed no abnormalities. Moderate to severe hyperaesthesia was evident upon manipulation of the cervical spine. ... It is notable that both dogs were considerably larger than the average CKCS, however, limited conclusions can be drawn from this with such a small number of cases. Identification and histopathological evaluation of further CKCS with dorsolateral myelocompression at C2-C3 and intraspinal cysts is essential to establish the full aetiopathogenesis and clinical effect of these abnormalities.

Intervertebral Disk Herniation. Jonathan M. Levine. NAVC Clinicians Brief. Feb 2012; 18-20. Quote: "Intervertebral disk herniation (IVDH) is abnormal displacement of the nucleus pulposus and/or annulus fibrosus into the vertebral canal or intervertebral foramen. IVDH is the most common cause of spinal cord injury in dogs; some breeds have a lifetime incidence that approaches 20%. ... Myelography, computed tomography (CT), and magnetic resonance imaging (MRI) are typically used to diagnose IVDH.All three imaging modalities can localize spinal cord compression. Many clinicians favor MRI because it is multiplanar and noninvasive, provides data associated with functional outcome, and is the only means of diagnosing certain vertebral column diseases that clinically resemble IVDH (eg, vascular myelopathies)."

Evolution of clinical signs and predictors of outcome after conservative medical treatment for disk-associated cervical spondylomyelopathy in dogs. Steven De Decker, Ingrid M. V. L. Gielen, Luc Duchateau, Anna Oevermann, Ingeborgh Polis, Iris Van Soens, Henri J. J. van Bree,Luc M. L. Van Ham. JAVMA April 2012; 240(7):848-857. Quote: "Objective—To evaluate the evolution of clinical signs and their correlation with results of magnetic resonance imaging (MRI) and transcranial magnetic stimulation (TMS) and to assess potential prognostic variables after conservative medical treatment for disk-associated cervical spondylomyelopathy (DA-CSM) in dogs. Design—Prospective cohort study. Animals—21 client-owned dogs with DA-CSM. Procedures—After neurologic grading, dogs underwent low-field MRI and TMS with measurement of onset latencies and peak-to-peak amplitudes from the extensor carpi radialis and cranial tibial muscles. Dimensions calculated from MRI images were remaining spinal cord area, spinal cord compression ratio, vertebral occupying ratio, vertebral canal height-to-body height ratio, vertebral canal height-to-body length ratio, and vertebral canal compromise ratio. Intraparenchymal signal intensity changes were graded. Dogs were reevaluated 1, 3, 6, 12, and 24 months after initial diagnosis. Results—Outcome was successful in 8 of 21 dogs. Negative outcomes were characterized by rapid progression of clinical signs. All dogs with more severe clinical signs of DA-CSM 1 month after diagnosis had unsuccessful outcomes. Outcome was associated with the remaining spinal cord area and vertebral canal compromise ratio. Prognosis was not associated with severity of clinical signs or results of TMS. There were no significant correlations among clinical signs, MRI findings, and TMS results. Conclusions and Clinical Relevance—Conservative medical treatment of DA-CSM was associated with a guarded prognosis. Selected MRI variables and clinical evolution 1 month after diagnosis can be considered prognostic indicators. The lack of correlation among clinical signs, results of diagnostic imaging, and results of electrophysiologic evaluation in dogs with DA-CSM warrants further investigation."

Incidence of intervertebral disk degeneration–related diseases and associated mortality rates in dogs. Niklas Bergknut, Agneta Egenvall, Ragnvi Hagman, Pia Gustås, Herman A. W. Hazewinkel, Björn P. Meij, Anne-Sofie Lagerstedt. J.Amer.Vet.Med.Assn. June 2012; 2240(11):1300-1309. Quote: "Objective — To determine the incidence and distribution of intervertebral disk (IVD) degeneration–related diseases in a large population of dogs of various breeds, ages, and sexes and to determine mortality rates among dogs with these diseases. ... Because a comprehensive categorization of breeds was not available, the following breeds were classified as chondrodystrophic on the basis of previously published information1,4,7,12,23– 31: Basset Hound, Beagle, Standard Dachshund, Miniature Dachshund, English Bulldog, French Bulldog, American Cocker Spaniel, English Cocker Spaniel, Bichon Frisé, Jack Russell Terrier, Drever, Pug, Miniature Poodle, Cavalier King Charles Spaniel, Shih Tzu, Papillion, and Tibetan Spaniel.  ... Design — Epidemiological study. Sample — Insurance data for dogs with veterinary health-care and life insurance coverage (n = 665,249 and 552,120, respectively)[cavalier King Charles spaniels included]. Procedures — Insurance claim records of 1 company in Sweden were searched to identify dogs with IVD degeneration–related diseases; incidence and mortality rates were determined for affected dogs < 12 years old and < 10 years old, respectively. Only the first paid IVD degeneration–related claim for a dog was included in incidence rate calculations. Results — The incidence rate of IVD degeneration–related diseases was 27.8 (95% confidence interval [CI], 27.2 to 28.4) occurrences/10,000 dog-years at risk (DYAR), indicating that approximately 0.3% of dogs/y in this population were affected. Miniature Dachshund was the most highly represented breed, followed by Standard Dachshund and Doberman Pinscher (237.1 [95% CI, 212.9 to 261.4], 141.5 [95% CI, 135.5 to 147.4], and 88.6 [95% CI, 72.1 to 105.2] occurrences/10,000 DYAR, respectively). The incidence rate of IVD degeneration–related disease was greater in male than in female dogs and increased with age. Overall mortality rate attributed to IVD degeneration–related diseases was 9.4 (95% CI, 8.9 to 9.8) deaths/10,000 DYAR and was greater in males than in females. Conclusions and Clinical Relevance — Differences in incidence rates among various breeds suggested a genetic involvement. Knowledge of the distribution of IVD degeneration–related diseases among dogs of various breeds and ages may facilitate early diagnosis and preemptive treatments in patients at risk for developing these diseases."

Intervertebral disc disease in dogs – Part 1: A new histological grading scheme for classification of intervertebral disc degeneration in dogs.  N. Bergknut, B.P. Meij, R. Hagman, K.S. de Nies, J.P. Rutges, L.A. Smolders, L.B. Creemers, A.S. Lagerstedt, H.A.W. Hazewinkel, G.C.M. Grinwis. Vet.J. July 2012. Quote: "Intervertebral disc (IVD) degeneration is common in dogs and can lead to serious disorders. Current treatments can relieve clinical signs of disease, but do not restore IVD function. The development of regenerative strategies for IVD dysfunction requires detailed knowledge of the pathogenesis of IVD degeneration and its underlying mechanisms. Histological examination of IVDs at different stages of degeneration might provide this knowledge, but as there is currently no histological grading scheme for canine IVD degeneration, the aim of this study, which is the first of a two-part series, was to design and validate an appropriate scheme. Three independent observers evaluated 35 IVDs at different stages of degeneration using the scheme. Glycosaminoglycan contents of the nucleus pulposus and macroscopic grading according to Thompson, which are considered ‘gold standards’ for IVD degeneration, were used to validate the scheme. Reproducibility was assessed by analysing the inter-observer reliability of all individual variables of the grading scheme, using a weighted κ analysis. Significant correlations were found between Thompson grading and total histological score (r = 0.94; P < 0.01) and between glycosaminoglycan content and total histological score (r = −0.72; P < 0.01). Most individual histological variables showed ‘moderate’ to ‘almost perfect’ inter-observer reliability. The high correlation with the gold standards in combination with the high reproducibility indicates that the proposed histological grading scheme is reliable and objective for classification of IVD degeneration in both chondrodystrophic and non-chondrodystrophic dog breeds."

Intervertebral disc disease in dogs – Part 2: Comparison of clinical, magnetic resonance imaging, and histological findings in 74 surgically treated dogs.  Hendrik-Jan C. Kranenburg, Guy C.M. Grinwis, Niklas Bergknut, Ninke Gahrmann, George Voorhout, Herman A.W. Hazewinkel, Björn P. Meij. Vet.J. July 2012. Quote: "The relationship between intervertebral disc (IVD) disease and IVD degeneration remains unclear. The aim of the present study was to compare the clinical severity of IVD herniation (IVDH), determined with a neurological grading system, with findings of magnetic resonance imaging (MRI) and histology using grading systems for IVD degeneration in chondrodystrophic (CD; n = 37) and non-chondrodystrophic (NCD; n = 37) dogs. This study is the second part of a two-part investigation, where the first part involved the development and validation of a histological grading scheme for classification of canine IVD degeneration. IVD degeneration graded on MRI correlated significantly with IVD degeneration graded on histology, but not with pre-operative clinical signs. Hansen type 1 hernias were more common in the cervical and thoracolumbar segments and Hansen type 2 hernias were more common in the lumbosacral segment. Type 1 hernias occurred more often in CD dogs than in NCD dogs, and CD dogs were clinically more severely affected than NCD dogs. The grade of IVD degeneration on MRI was higher in CD dogs than in NCD dogs, but there was no difference between dogs with type 1 and type 2 hernias. No significant differences in histological grade were found between CD and NCD dogs or between type 1 and type 2 hernias. It was possible to conclude that IVD degeneration did not correlate with the neurological severity of IVDH. The extent of degeneration identified on MRI correlated with degeneration seen histologically. Although the MRI grading system reflected the severity of IVD degenerative changes as confirmed by histopathology, it appeared less useful in predicting the clinical implications."

Assessment of the effects of adjunctive gabapentin on postoperative pain after intervertebral disc surgery in dogs. Sonja A. Aghighi, Andrea Tipold, Marion Piechotta, Piotr Lewczuk, Sabine B.R. Kästne. Veterinary Anaesthesia and Analgesia. Nov. 2012; 39(6):636–646. Quote: "Objective: To assess the effect of adjunctive gabapentin (GBP) on pain after thoracolumbar intervertebral disc surgery in dogs. Study design  Prospective, randomized, controlled, clinical, ‘blinded’ trial. Animals: Sixty-three client owned dogs undergoing hemilaminectomy. Methods: Dogs were assigned to two treatment groups. The GBP group received gabapentin 10 mg kg−1 orally every 12 hours starting before anaesthesia; the placebo (P) group received empty gelatin capsules. Background analgesia was initiated with intravenous levomethadone 0.6 mg kg−1 (as the combination ‘L-Polamivet) at anaesthesia induction, followed by a fentanyl patch and levomethadone 0.2 mg kg−1 subcutaneously every 8 hours for 24 hours. Pain was assessed by the short form of the Glasgow Composite Measure Pain Score (CMPS-SF) without the gait category, and by a Visual Analogue Scale (VAS). Serum GBP concentrations and cortisol concentrations were measured. Statistical analyses utilized chi square test, Kolmogorov-Smirnov test, two-way analysis of variances for repeated measurements, Wilcoxon test and Friedmann test as relevant. Correlations were tested by Spearman’s and Pearson’s correlation coefficient. p < 0.05 was considered significant. Results: Median CMPS-SF was lower in group GBP than in group P on days 0.5, 1, 4 and 5. However, CMPS-SF and VAS were not significantly different between groups. Both pain scores decreased significantly over time. Cortisol concentrations were not significantly different between groups. Minimum serum concentrations of GBP fell below the detection limit of 1 μg mL−1 in 6 of 29 and 7 of 28 dogs at 24 and 72 hours, respectively. Conclusions and clinical relevance: 10 mg kg−1 GBP orally twice a day did not result in a detectable reduction in pain behaviour compared to background opioid analgesia alone, although a trend to lower pain levels (p < 0.1) was present. Further studies are needed to determine if this is related to effective background analgesia or an ineffective dose of GBP."

Intervertebral disc degeneration in the dog. Part 2: Chondrodystrophic and non-chondrodystrophic breeds. Lucas A. Smolders, Niklas Bergknut, Guy C.M. Grinwis, Ragnvi Hagman, Anne-Sofie Lagerstedt, Herman A.W. Hazewinkel, Marianna A. Tryfonidou, Björn P. Meij. Vety.J. March 2013;195(3):292-299. Quote: Dogs can be grouped into two distinct types of breed based on the predisposition to chondrodystrophy, namely, non-chondrodystrophic (NCD) and chondrodystrophic (CD). ... IVD degeneration is more common in CD breeds, which are characterized by a disturbed endochondral ossification, primarily of the long bones, such that CD dogs have disproportionally short limbs. Popular CD breeds include, among others, the (miniature) Dachshund, Basset Hound, French and English Bulldog, Shi Tzu, miniature Schnauzer, Pekingese, Beagle, Lhasa Apso, Bichon Frisé, Tibetan Spaniel, Cavalier King Charles Spaniel, Welsh Corgi, and the American Cocker Spaniel. ...  In addition to a different process of endochondral ossification, NCD and CD breeds have different characteristics of intravertebral disc (IVD) degeneration and IVD degenerative diseases. The anatomy, physiology, histopathology, and biochemical and biomechanical characteristics of the healthy and degenerated IVD are discussed in the first part of this two-part review. This second part describes the similarities and differences in the histopathological and biochemical characteristics of IVD degeneration in CD and NCD canine breeds and discusses relevant aetiological factors of IVD degeneration.

Intervertebral Disk Degeneration in Dogs: Consequences, Diagnosis, Treatment, and Future Directions. N.D. Jeffery, J.M. Levine, N.J. Olby and V.M. Stein. J.Vet.Int.Med. Nov. 2013;27(6):1318–1333. Quote: "Evidence of intervertebral disk degeneration (IVDD) is extremely common in dogs, and its prevalence increases with age. It has many important consequences because degeneration of the intervertebral disks often is a prelude to disk herniation, which can injure the spinal cord, spinal nerves, or both. This review summarizes the advances in diagnosis and treatment of IVDD that have been made since the 1950s when the first detailed description of the degenerative changes was published. It also discusses new approaches to treatment of the associated spinal cord injury and new methods by which to classify injury severity that are currently under development."

Influence of duration of clinical signs on surgical treatment results of 16 dogs with intervertebral disc disease (IVDD). Marcin Wrzosek, Zdzisław Kiełbowicz, Elżbieta Giza, Marta Płonek, Józef Nicpoń. Bull Vet Inst Pulawy. 2014:58:277-281. Quote: "The purpose of this study was to evaluate the outcome of surgical treatment in 16 dogs, depending on the animal’s age, body weight, deep pain perception, and time from the onset of neurological symptoms to the consultation with a veterinary neurologist and successive surgery. Sixteen dogs diagnosed with cervical (n = 11) [including a cavalier King Charles spaniel] or thoracolumbar (n = 5) disc extrusions underwent spinal surgeries (eleven ventral slots and five hemilaminectomies). The success rate of surgical treatment was 64.3% in dogs with preserved nociception. No association between the animal’s age or body weight and the result of surgical treatment was found. A successful surgical outcome was more likely when the symptom-to-surgery time was shorter."

Medical Infrared Imaging (Thermography) of Type I Thoracolumbar Disk Disease in Chondrodystrophic Dogs. Brian P. Grossbard, Catherine A. Loughin, Dominic J. Marino, Leonard J. Marino, Joseph Sackman, Scott E. Umbaugh, Patrick S. Solt, Jakia Afruz, Peter Leando, Martin L. Lesser, Meredith Akerman. Vet. Surgery. Oct. 2014;43(7):869-876. Quote: "Objective: to: (1) determine the success of medical infrared imaging (MII) in identifying dogs with TLIVDD, (2) compare MII localization with magnetic resonance imaging (MRI) results and surgical findings, and (3) determine if the MII pattern returns to that of normal dogs 10 weeks after decompression surgery. Study Design: Prospective case series. Animals: Chondrodystrophic dogs (n=58) with Type I TLIVDD and 14 chondrodystrophic dogs with no evidence of TLIVDD. Methods: Complete neurologic examination, MII, and MRI studies were performed on all dogs. Dogs with type I TLIVDD had decompressive surgery and follow-up MII was performed at 10 weeks. Pattern analysis software was used to differentiate between clinical and control dogs, and statistical analysis using anatomic regions of interest on the dorsal views were used to determine lesion location. Recheck MII results were compared with control and pre-surgical images. Results: Computer recognition pattern analysis was 90% successful in differentiating normal dogs from dogs affected by TLIVDD and 97% successful in identifying the abnormal intervertebral disc space in dogs with TLIVDD. Statistical comparisons of the ROI mean temperature were unable to determine the location of the disc herniation. Recheck MII patterns did not normalize and more closely resembled the clinical group. Conclusions: MII was 90% successful differentiating between normal dogs and 97% successful in identifying the abnormal intervertebral disc space in dogs with TLIVDD. Abnormal intervertebral disc space localization using ROI mean temperature analysis was not successful. MII patterns 10 weeks after surgery do not normalize."

Disc Prostheses: Cervical Disc Arthroplasty. Filippo Adamo. ACVS. October 2014.

Modulation of the proteoglycan receptor PTPσ promotes recovery after spinal cord injury. Bradley T. Lang, Jared M. Cregg, Marc A. DePaul, Amanda P. Tran, Kui Xu, Scott M. Dyck, Kathryn M. Madalena, Benjamin P. Brown, Yi-Lan Weng, Shuxin Li, Soheila Karimi-Abdolrezaee, Sarah A. Busch, Yingjie Shen, Jerry Silver. Nature. December 2014. Quote: "Contusive spinal cord injury leads to a variety of disabilities owing to limited neuronal regeneration and functional plasticity. It is well established that an upregulation of glial-derived chondroitin sulphate proteoglycans (CSPGs) within the glial scar and perineuronal net creates a barrier to axonal regrowth and sprouting. Protein tyrosine phosphatase σ (PTPσ), along with its sister phosphatase leukocyte common antigen-related (LAR) and the nogo receptors 1 and 3 (NgR), have recently been identified as receptors for the inhibitory glycosylated side chains of CSPGs. Here we find in rats that PTPσ has a critical role in converting growth cones into a dystrophic state by tightly stabilizing them within CSPG-rich substrates. We generated a membrane-permeable peptide mimetic of the PTPσ wedge domain that binds to PTPσ and relieves CSPG-mediated inhibition. Systemic delivery of this peptide over weeks restored substantial serotonergic innervation to the spinal cord below the level of injury and facilitated functional recovery of both locomotor and urinary systems. Our results add a new layer of understanding to the critical role of PTPσ in mediating the growth-inhibited state of neurons due to CSPGs within the injured adult spinal cord."

Potassium Channel Antagonists 4-Aminopyridine and the T-Butyl Carbamate Derivative of 4-Aminopyridine Improve Hind Limb Function in Chronically Non-Ambulatory Dogs; A Blinded, Placebo-Controlled Trial. Ji-Hey Lim, Audrey C. Muguet-Chanoit, Daniel T. Smith, Eric Laber, Natasha J. Olby. PLOS One. December 2014. Quote: "4-Aminopyridine (4-AP) blocks voltage gated potassium channels, restoring conduction to demyelinated axons and improving function in demyelinating conditions, but its use is associated with adverse effects and benefit in spinal cord injury is limited. Derivatives of 4-AP have been developed to improve clinical efficacy while reducing toxicity. We compared the therapeutic effects of orally administered 4-AP and its t-butyl carbamate derivative (t-butyl) with placebo in dogs that had suffered an acute spinal cord injury that left them chronically paralyzed. Nineteen dogs were entered into the trial, conducted in two-week treatment blocks starting with placebo, followed by random assignment to 4-AP or t-butyl, a washout and then the opposite medication followed by placebo. Investigators and owners were blinded to treatment group. Primary outcome measures included open field gait score (OFS), and treadmill based stepping score and regularity index, with additional secondary measures also considered. Thirteen of 19 dogs completed the protocol. Two were euthanized due to unrelated heath problems, two developed side effects and two were unable to complete for unrelated reasons. Dogs showed significant improvement in supported stepping score (from 17.39 to 37.24% with 4-AP; 16.85 to 29.18% with t-butyl p<0.0001) and OFS (from 3.63 to 4.73 with 4-AP; 3.78 to 4.45 with t-butyl, p = 0.005). Response was individually variable and most dramatic in three dogs that were able to walk without support with treatment. No significant difference was found between 4-AP and t-butyl. No adverse effects were reported with t-butyl but gastrointestinal upset and seizures were observed in two dogs with 4-AP. In conclusion, both 4-AP and t-butyl significantly improved supported stepping ability in dogs with chronic spinal cord injury with no adverse effects noted with t-butyl. Drug response varied widely between individuals, highlighting the need to understand the factors that influence canine and human patients' response to therapy."

Will There be a Role for Disc Prostheses in Small Animals? Filippo Adamo and Franck Forterre. In, Advances in Intervertebral Disc Disease in Dogs and Cats, First Edition. Edited by James M. Fingeroth and William B. Thomas. John Wiley & Sons, Inc. February 2015.

Canine chondrodystrophic intervertebral disc disease (Hansen type I disc disease). Clare Rusbridge. BMC Musculoskeletal Disorders. December 2015; 16(Suppl 1):S11. Quote: "Intervertebral disc disease (IVDD) is the most common spinal disease in dogs. Chondrodystrophic dogs, which have disproportionably short and curved limbs, are predisposed to Hansen type I IVDD and of these the miniature Dachshund is over represented, is more likely to be presented at an earlier age and is at greater risk of a severe spinal cord injury. The tendency for IVDD in Dachshunds is inherited and a major locus on chromosome 12 harbours genetic variations affecting the development of intervertebral disc calcification. Hansen type I disc degeneration is thought to occur because of loss of notochordal cells which produce proteoglycans which “hold water” in the disc. Chondrodystrophic dogs have a primary deficiency of notochordal cells, a study found that large notochordal cells in the nucleus pulposus of chondrodystrophoid dogs formed 13% of the cell population in young dogs and fell to 0.4% in adults, whereas they were the predominant cell type in the nonchondrodystrophoid dogs at all ages. Thus chondrodystrophoid dogs suffer early degenerative changes in the disc and a concomitant reduction in proteoglycan content, increased collagen, and loss of water content making the discs likely to herniate. Certain lifestyle factors may increase or decrease risk of IVDD and this is currently under investigation. There is a suggestion that exercise (including stair climbing) reduces the incidence of disc calcification. By contrast it has been hypothesized that obesity/lack of postural muscle strength may increase risk. Dachshunds with intervertebral disc extrusion had significantly smaller cross sectional area and greater fat infiltration in the epaxial muscles (muscles which lie dorsal to the horizontal septum of the vertebrae which mobilize and globally stabilize the trunk) compared to dogs presenting with fibrocartilagenous embolism (another acute onset intervertebral disc related spinal disease). In addition chondrodystrophic dogs may have increased risk of IVVD if they have a more extreme conformation e.g. Dachshunds that have a longer back and shorter limbs are more at risk and breeds with a comparatively heavy head such as the Bassett Hound may be more at risk of cervical disc disease. Breeds with a tendency for kyphoscoliosis such as the French Bulldog may be more at risk of IVDD in the IVDs adjacent to a vertebral malformation. This presentation details the pathogeneis, clinical presentation, diagnosis and treatment of IVDD in chondrodystrophic dogs."

Determination of the Accuracy of Neurological Data, Survey Radiography, Computed Tomography (CT), Myelography and CT Myelography for Detection of the Seat of Intervertebral Disc Herniation in Dogs. Mohammed Abdel-Hakiem, Masaaki Katayama, Ahmed Saleh, Haroun Youssef, Yasuhiko Okamura, Yuji Uzuka. J. Advanced Vet. Research. January 2016;6(1):44-52. Quote: "The present study was carried out to determine the accuracy of different tools for detection of the seat of intervertebral disc (IVD) herniation in dogs. Forty-six dogs of different breeds were included in this study. [46 miniature Dachshunds, 5 Chhihuahuas, 3 toy poodles, 3 Yorkshire terriers, and 2 cavalier King Charles spaniels, among others]. The neurological examination and plain radiography were performed for all dogs. Computed tomography (CT), myelography and CT myelography were performed for 38, 33 and 31 dogs respectively. The results showed that the Miniature Dachshund is the most common breed suffering IVDD (39.13%), ... then the Cavalier King Charles Spaniel (12.5%) [with a combined total of 11 lesions]. ... C2-3 was the most affected site in the cervical region (13.37%), while L2-3 is considered the highly affected thoracolumbar site (11.4%) followed by T13-L1 and L1-2 (10.23% for each). The accuracy of neurological examination, plain radiography, CT, myelography and CT myelography for determining the site of the lesion was calculated as 54.3, 30.4, 65.8, 84.85 and 100%, respectively. Moreover, the accuracy of CT, myelography and CT myelography for detection of the side of the lesion was 44.74, 54.54 and 93.9% respectively. ... The results of this study suggested that the neurological examination and survey radiography are not reliable for detection of the site of IVD herniation. The accuracy of the CT increases in the chondrodystrophic breeds, which have chronic lesions due to the mineralization of the extruded disc materials. The myelography is considered a valuable tool in the detection of the lesion, especially in the smaller sized dogs. The CT myelography is considered the bset tool in this study for determining the site of IVD herniation and its laterality in dogs."

Clinical characterization of thoracolumbar and lumbar intervertebral disk extrusions in English Cocker Spaniels. Thomas J.A. Cardy, Caitlin E. Tzounos, Holger A. Volk, Steven De Decker. JAVMA. February 2016;248(4):405-412. Quote: Oojective: To assess the anatomic distribution of thoracolumbar and lumbar intervertebral disk extrusions (IVDEs) in English Cocker Spaniels as compared with findings in Dachshunds and to characterize clinical findings in English Cocker Spaniels with thoracolumbar or lumbar IVDEs affecting various regions of the vertebral column. Design: Retrospective observational study. Animals: 81 English Cocker Spaniels and 81 Dachshunds with IVDEs. Procedures: Signalment, clinical signs, neurologic examination findings, and affected intervertebral disk spaces (IVDSs) were recorded for both breeds. Management methods and outcomes were recorded for English Cocker Spaniels. Lesions were categorized as thoracolumbar (IVDSs T9–10 through L1–2), midlumbar (L2–3 through L4–5), or caudal lumbar (L5–6 through L7–S1). Results: Midlumbar and caudal lumbar IVDEs were significantly more common in English Cocker Spaniels than in Dachshunds. English Cocker Spaniels with caudal lumbar IVDEs had a longer median duration of clinical signs before evaluation and more commonly had unilateral pelvic limb lameness or spinal hyperesthesia as the predominant clinical sign than did those with IVDEs at other sites. Those with caudal lumbar IVDEs less commonly had neurologic deficits and had a higher median neurologic grade (indicating lesser severity), shorter mean postoperative hospitalization time, and faster mean time to ambulation after surgery than those with other sites affected. These variables did not differ between English Cocker Spaniels with thoracolumbar and midlumbar IVDEs. Conclusions and Clinical Relevance: Caudal and midlumbar IVDEs were more common in English Cocker Spaniels than in Dachshunds. English Cocker Spaniels with caudal lumbar IVDE had clinical signs and posttreatment responses that differed from those in dogs with midlumbar or thoracolumbar IVDE.

Recognition and Breed Specificity of Canine Spondyloarthropathy. Bruce M. Rothschild, Sabine M. Breit. J. Spine. March 2016;5(2):293. Quote: Human diseases sometimes represented across phylogenetic lines. Their recognition is at times compromised by differential (between human and veterinary medicine) use of diagnostic terms. A major impetus to such change is recognition of additional treatment options that would not be considered for the replaced diagnosis/ category. Canine syndesmophytes are recognized as identifier for spondyloarthropathy. This study examines the breed-specificity of those changes. The axial skeletons and peripheral joints (when available) of 1323 dogs, identified to breed [including 26 cavalier King Charles spaniels], were examined for evidence of syndesmophytes and sacroiliac joint disease. Syndesmophytes were found in 315 of 1323 axial skeletons examined, extremely common in Boxer and German Shephard; rare, in Beagle, Chihauahua, Dachshund, Maltese and Pug. First noted at 2 years of age, its prevalence increased geometrically over the next 13 years. All affected individuals weighed more than 2 kilograms and prevalence increased geometrically through 39.9 kilograms. Spondyloarthropathy was present in 17.3% of brachycephalic, contrasted with 35.0% of mesticephalic dogs [Chi square = 16.972, p < 0.0001]. Presence of syndesmophytes identified the underlying arthritis as spondyloarthropathy, not osteoarthritis. Recognition of the vertebral findings as characteristic of this inflammatory arthritis affords an opportunity for controlling the disease process and improving quality of life of the afflicted dog.

Differential diagnosis of vertebral spinous process deviations in archaeological and modern domestic dogs. Dennis F. Lawler, Chris Widga, David A. Rubin, Jennifer A. Reetz, Richard H. Evans, Basil P. Tangredi, Richard M. Thomas, Terrence J. Martin, Charles Hildebolt, Kirk Smith, Daniel Leib, Jill E. Sackman, James G. Avery, Gail K. Smith. J. Archaeological Science: Reports. July 2016. Quote: Paleopathological study of domestic animal remains can elucidate human-domesticate relationships, when all reasonable differential diagnoses are considered. Deviated spinous processes found on ancient domesticated dog vertebrae have been assumed to result from pack burdens, although consideration of diagnostic alternatives has been unclear. To more thoroughly assess the potential significance of these features, we first generated an extensive differential diagnosis of potential causes. Broad causal categories included: (i) morphological; (ii) infectious; (iii) taphonomic; (iv) life history (in utero to death), with numerous subcategories that sometimes overlap. We then evaluated these possibilities through an observational and radiology study of 15 ancient deliberate domestic dog burials (191 vertebrae) from the midwestern USA, dating between 10,130 and 200 years ago. Archaeological specimens from the UK were included to evaluate for geographic uniqueness of our observations. We characterized deviations of spinous processes of cervical (n = 74), thoracic (n = 51), lumbar (n = 60), and sacral (n = 6) vertebrae. Affected spinous processes were found in 34% of cervical vertebrae, 63% of thoracic vertebrae, 78% of lumbar vertebrae, and 50% of sacral vertebrae. Four types of spinous process deviations were observed: (a) lateral leaning from the base but not otherwise deviated; (b) lateral curving at some point above the base; (c) bowing because of multiple curves; and (d) torsion along the vertical axis. Computed tomography and micro-computed tomography were essential tools for establishing differential diagnoses. Highlights: Deviated vertebral spinous processes in dogs have been attributed historically to use as pack animals. A differential diagnosis for deviated spinous processes in domesticated dogs is presented. Observational and imaging studies indicate that deviated vertebral spinous processes have complex origins. Computed tomography and micro-computed tomography were essential tools for establishing differential diagnoses.

Prevalence of spinous process impingement in thoracic vertebrae on radiographs of clinically-unaffected dogs.  F. Thierry, K. Bradley, C. Warren-Smith. J. Small Anim. Pract. October 2016. Quote: Objectives: To assess the prevalence of impinged spinous processes in asymptomatic dogs. Methods: One hundred and ninety lateral thoracic radiographs of asymptomatic dogs [including cavalier King Charles spaniels] radiographed for reasons other than spinal pain, were retrospectively reviewed by two board-certified radiologists. Images were assessed for impinged spinous processes and graded for narrowing, sclerosis or remodelling of the spinous processes. Results: The prevalence of impinged spinous processes in unaffected dogs was 33·2%. Seventy-five of 79 (95%) lesions were located between T8 and T11. Impingement of the spinous processes was more common in older dogs and larger dogs displayed more frequent and more severe impingement of the spinous processes compared with smaller breeds. Clinical Significance: Spinous process impingement is common in animals with no history of spinal pain, indicating that this radiographic finding should be interpreted with caution.

Recurrence of disk herniation following percutaneous laser disk ablation in dogs with a history of thoracolumbar intervertebral disk herniation: 303 cases (1994–2011). Danielle R. Dugat, Kenneth E. Bartels, Mark E. Payton. J.A.V.M.A. December 2016; doi: 10.2460/javma.249.12.1393. Quote: Objectdive: To determine rate of recurrence of disk herniation in dogs that underwent percutaneous laser disk ablation (PLDA) because of a previous episode of suspected or confirmed thoracolumbar intervertebral disk herniation (IVDH). Design: Retrospective case series. Animals: 303 dogs that underwent PLDA and for which a minimum of 3 years of follow-up information was available (n = 294) or for which recurrence was documented within 3 years after the procedure [including one cavalier King Charles spaniel]. Procedures: Information on signalment, previous episodes of IVDH, specifics of the PLDA procedure, and recurrence was obtained from the medical records. Owners were contacted to complete a questionnaire regarding outcome and recurrence. Results: 60 of the 303 (19.8%) dogs had an episode of suspected or confirmed IVDH after undergoing PLDA, but only 11 of the 303 (3.6%) dogs had a recurrence of IVDH confirmed by means of CT or MRI and hemilaminectomy. Recurrence rate following PLDA was not significantly different between dogs that had been treated medically for previous episodes of IVDH and dogs that had been treated surgically. Overall, 270 of 286 (94.4%) owners reported that their dog was the same (109 [38.1%]) or improved (161 [56.3%]) immediately after PLDA, and 265 (92.7%) owners rated their satisfaction with the procedure as ≥ 9 on a scale from 1 (completely dissatisfied) to 10 (completely satisfied). Conclusion and Clinical Relevance: Results suggested that PLDA was a relatively safe, minimally invasive procedure associated with a low rate of recurrence of disk herniation when performed in dogs with a history of previous episodes of suspected or confirmed IVDH.

Proportion recovery and times to ambulation for non-ambulatory dogs with thoracolumbar disc extrusions treated with hemilaminectomy or conservative treatment: A systematic review and meta-analysis of case-series studies. L. Langerhuusa, J. Milesb. Vet. J. February 2017;220:7-16. Quote: Thoracolumbar intervertebral disc extrusion is a common cause of spinal cord dysfunction in dogs. Peer-reviewed studies reporting treatment of predominantly chondrodystrophic dogs with disc extrusion with loss of ambulation with either hemilaminectomy or conservative treatment (rest, analgesics and anti-inflammatories) were evaluated in a systematic review of the literature. Generally, the level of evidence available was low with no controlled studies and only case series available. In the meta-analysis, there was a clear trend to a greater proportion of dogs recovering and returning faster to ambulation for dogs treated with hemilaminectomy than for conservatively treated dogs. The mean proportions that recovered for neurological grades 3, 4 and 5 were 93, 93 and 61% for those treated with hemilaminectomy, and 79, 62 and 10% for those treated conservatively (Grade 3 – non-ambulatory paraparetic dogs; grade 4 – paraplegic dogs with intact deep pain perception; grade 5 – paraplegic dogs without intact deep pain perception). Due to the use of case series, these results represent between-study comparisons, thereby increasing the risk of selection bias and other biases. Data presented in this review support the current recommendations for surgical management of non-ambulatory dogs with disc-extrusion, but controlled clinical studies comparing outcomes are necessary to confirm these findings.

Evaluation of T2-weighted versus short-tau inversion recovery sagittal sequences in the identification and localization of canine intervertebral disc extrusion with low-field magnetic resonance imaging. Daniel Housley, Abby Caine, Giunio Cherubini, Olivier Taeymans. Vet. Rad. & Ultra. April 2017. Quote: Sagittal T2-weighted sequences (T2-SAG) are the foundation of spinal protocols when screening for the presence of intervertebral disc extrusion. We often utilize sagittal short-tau inversion recovery sequences (STIR-SAG) as an adjunctive screening series, and experience suggests that this combined approach provides superior detection rates. We hypothesized that STIR-SAG would provide higher sensitivity than T2-SAG in the identification and localization of intervertebral disc extrusion. We further hypothesized that the parallel evaluation of paired T2-SAG and STIR-SAG series would provide a higher sensitivity than could be achieved with either independent sagittal series when viewed in isolation. This retrospective diagnostic accuracy study blindly reviewed T2-SAG and STIR-SAG sequences from dogs (n = 110) with surgically confirmed intervertebral disc extrusion [including 6 cavalier King Charles spaniels]. A consensus between two radiologists found no significant difference in sensitivity between T2-SAG and STIR-SAG during the identification of intervertebral disc extrusion (T2-SAG: 92.7%, STIR-SAG: 94.5%, P = 0.752). Nevertheless, STIR-SAG accurately identified intervertebral disc extrusion in 66.7% of cases where the evaluation of T2-SAG in isolation had provided a false negative diagnosis. Additionally, one radiologist found that the parallel evaluation of paired T2-SAG and STIR-SAG series provided a significantly higher sensitivity than T2-SAG in isolation, during the identification of intervertebral disc extrusion (T2-SAG: 78.2%, paired T2-SAG, and STIR-SAG: 90.9%, P = 0.017). A similar nonsignificant trend was observed when the consensus of both radiologists was taken into consideration (T2-SAG: 92.7%, paired T2-SAG, and STIR-SAG = 97.3%, P = 0.392). We therefore conclude that STIR-SAG is capable of identifying intervertebral disc extrusion that is inconspicuous in T2-SAG, and that STIR-SAG should be considered a useful adjunctive sequence during preliminary sagittal screening for intervertebral disc extrusion in low-field magnetic resonance.

FGF4 retrogene on CFA12 is responsible for chondrodystrophy and intervertebral disc disease in dogs. Emily A. Brown, Peter J. Dickinson, Tamer Mansour, Beverly K. Sturges, Miriam Aguilar, Amy E. Young, Courtney Korff, Jenna Linda, Cassandra L. Ettinger, Samuel Varon, Rachel Pollard, C. Titus Brown, Terje Raudsepp, Danika L. Bannasch. PNAS. October 2017; doi: 10.1073/pnas.17090821. Quote: Chondrodystrophy in dogs is defined by dysplastic, shortened long bones and premature degeneration and calcification of intervertebral discs. Independent genome-wide association analyses for skeletal dysplasia (short limbs) within a single breed (PBonferroni = 0.01) and intervertebral disc disease (IVDD) across breeds (PBonferroni = 4.0 × 10−10) both identified a significant association to the same region on CFA12. Whole genome sequencing identified a highly expressed FGF4 retrogene within this shared region. The FGF4 retrogene segregated with limb length and had an odds ratio of 51.23 (95% CI = 46.69, 56.20) for IVDD. Long bone length in dogs is a unique example of multiple disease-causing retrocopies of the same parental gene in a mammalian species. FGF signaling abnormalities have been associated with skeletal dysplasia in humans, and our findings present opportunities for both selective elimination of a medically and financially devastating disease in dogs and further understanding of the ever-growing complexity of retrogene biology.

The Effect of Electromagnetic Fields on Post-Operative Pain and Locomotor Recovery in Dogs with Acute, Severe Thoracolumbar Intervertebral Disc Extrusion: A Randomized Placebo-Controlled, Prospective Clinical Trial. Natalia Zidan, Joe Fenn, Emily Griffith, Peter J. Early, Chris L. Mariani, Karen R. Muñana, Julien Guevar, Natasha J. Olby. J. Neurotrauma. August 2018;35:1726-1736. Quote: Spinal cord injury (SCI) attributed to acute intervertebral disc extrusions (IVDEs) is common in dogs and is treated by surgical decompression. Dogs with sensorimotor complete injuries have an incomplete recovery. Pulsed electromagnetic fields (PEMFs) reduce post-operative pain through anti-inflammatory effects and there is growing evidence for neuroprotective effects. This randomized, controlled clinical trial evaluated the effect of PEMF on post-operative pain and neurological recovery in dogs with surgically treated sensorimotor complete SCI attributed to acute IVDE. Sixteen dogs with surgically treated complete thoracolumbar SCI were randomized to receive PEMF (15 min every 2 h for 2 weeks then twice-daily for 4 weeks) or placebo starting immediately after diagnosis. The primary outcome was gait score at 2 weeks. Secondary measures of gait, pain perception, and proprioceptive function were evaluated at 2 and 6 weeks. Plasma glial fibrillary acidic protein (GFAP) concentration was measured as an SCI biomarker. Post-operative pain was quantified by measuring mechanical sensory thresholds (MSTs) at control and surgical sites. There was no significant difference in demographics or GFAP concentration between the two groups at trial entry. There was no difference in primary outcome or in secondary measures of gait, but proprioceptive placing was significantly better at 6 weeks and GFAP concentrations were significantly lower at 2 weeks in the PEMF group. MSTs were significantly higher in the PEMF-treated group. We conclude that PEMF reduced incision-associated pain in dogs post-surgery for IVDE and may reduce extent of SCI and enhance proprioceptive placing. Larger clinical trials are warranted.

Effect of Targeted Pulsed Electromagnetic Field Therapy on Canine Postoperative Hemilaminectomy: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial. Leilani X. Alvarez, John McCue, Nathaniel K. Lam, Gulce Askin, Philip R. Fox. J. Amer. Anim. Hosp. Assn. March 2019;55(2):83-91. Quote: Intervertebral disc disease is one of the leading causes of paralysis in dogs. Pulsed electromagnetic field (PEMF) therapy has been advocated for improving wound healing and pain reduction; however, robust clinical trials are lacking. The present prospective, double-blind, placebo-controlled trial evaluated targeted PEMF therapy administered to 53 client-owned dogs who underwent hemilaminectomy for naturally occurring disk extrusion intervertebral disc disease. The dogs were randomized to receive either targeted PEMF (n = 27) or placebo treatment (n = 28). Wound healing, evaluated by visual analog score and wound evaluation scale, was significantly improved at 6 wk postoperatively in the treatment compared with the control group (P = .010 and .023, respectively). Pain medications were administered less frequently in dogs receiving PEMF treatment during the 7 day postoperative period compared with the control treatment group (P = .010) with codeine administered 1.8 times more frequently in the control group. No untoward effects were recorded in either treatment group. More frequent evaluation of outcome measures with larger patient numbers, as well as histologic samples, may be useful in future studies. Dogs receiving PEMF therapy following postoperative hemilaminectomy demonstrated improved wound scores at 6 wk and reduced mean number of owner-administered pain medications compared with the control group therapy.

Phenotypic Effects of FGF4 Retrogenes on Intervertebral Disc Disease in Dogs. Kevin Batcher, Peter Dickinson, Michelle Giu rida, Beverly Sturges, Karen Vernau, Marguerite Knipe, Sheida Hadji Rasouliha, Cord Drögemüller, Tosso Leeb, Kimberly Maciejczyk, Christopher A. Jenkins, Cathryn Mellersh, Danika Bannasch. Genes. June 2019; doi: 10.3390/genes10060435. Quote: Two FGF4 retrogenes on chromosomes 12 (12-FGF4RG) and 18 (18-FGF4RG) contribute to short-limbed phenotypes in dogs. 12-FGF4RG has also been associated with intervertebral disc disease (IVDD). Both of these retrogenes were found to be widespread among dog breeds with allele frequencies ranging from 0.02 to 1; however, their additive contribution to disease is unknown. Surgical cases of IVDD (n = 569) were evaluated for age of onset, disc calcification, and genotypes for the FGF4 retrogenes. Multivariable linear regression analysis identified the presence of one or two copies of 12-FGF4RG associated with significantly younger age at first surgery in a dominant manner. 18-FGF4RG had only a minor effect in dogs with one copy. Multivariable logistic regression showed that 12-FGF4RG had an additive effect on radiographic disc calcification, while 18-FGF4RG had no effect. Multivariable logistic regression using mixed breed cases and controls identified only 12-FGF4RG as highly associated with disc herniation in a dominant manner (Odds Ratio, OR, 18.42, 95% Confidence Interval (CI) 7.44 to 50.26; p < 0.001). The relative risk for disc surgery associated with 12-FGF4RG varied from 5.5 to 15.1 within segregating breeds and mixed breeds. The FGF4 retrogene on CFA12 acts in a dominant manner to decrease the age of onset and increase the overall risk of disc disease in dogs. Other modifiers of risk may be present within certain breeds, including the FGF4 retrogene on CFA18.

Clinical, diagnostic imaging, surgical findings and long-term outcome in a Cavalier King Charles Spaniel with thoracolumbar vertebral articular process hyperplasia. Fabio Stabile, Robert Brash, Luisa De Risio. Vet. REc. Case Repts. October 2019;7(4):e000932. Quote: A 2-year-old female spayed Cavalier King Charles Spaniel presented with 10-day history of progressive painful T3–L3 myelopathy. MRI of the spine revealed an extradural dorsal spinal cord compression at the level of T12–T13 vertebrae caused by hyperplasia of the caudal vertebral articular process (CVAP) of T12 vertebra. Similar changes were noticed at the level of the T13–L1 vertebrae, not causing spinal cord compression. In order to plan surgical decompression, CT of the spine was performed. This revealed thickened T12 dorsal lamina, hyperplastic T12 CVAP, and narrowed and elongated T13 VAP. The patient underwent T12–T13 dorsal laminectomy and spinal cord decompression by removal of the hyperplastic CVAP of T12. Postoperative 6-year follow-up revealed a normal neurological examination. A combination of MRI and CT allowed optimal treatment selection and surgical planning for CVAP hyperplasia. Surgical treatment by dorsal laminectomy provided successful long-term outcome. ... The day after surgery, the patient showed pelvic limb proprioceptive ataxia and ambulatory paraparesis. On discharge 3 days after surgery, the degree of ataxia and paresis were mildly improved compared with preoperative examination. After 4 weeks of strict restriction in exercise and postsurgical analgesia with meloxicam 0.1 mg/kg/24 h and gabapentin 10 mg/kg/8 h, the patient had a normal posture and a mild degree of roprioceptive ataxia. Paw positioning and hopping were mildly delayed on the pelvic limbs. At 2-month postoperative follow-up, the patient’s postural reactions were normal and the gait was slightly ataxic in the pelvic limbs. Follow-up at 1 year, 3 years and 6 years after surgery revealed normal posture, normal gait and normal proprioception on both pelvic limbs. The patient remained comfortable, exercising without restrictions. ... This is the first report of a successful outcome after surgical treatment for focal T3–L3 myelopathy caused by thoracic CVAP hyperplasia in a young CKCS with a 6-year long-term follow-up. ... In our patient, a CKCS of 10 kg of body weight, no changes compatible with DJD [degenerative joint disease] were identified supporting the hypothesis that this patient was more likely affected by a primary form of CVAP hyperplasia. The authors consider that this is also supported by the fact that the similar changes seen at T13–L1 did not cause any clinical signs over the long-term follow-up.

Retrospective Study of 240 Dogs Receiving Gabapentin for Chronic Pain Relief. Lily V Davis, Peter W Hellyer, Robin A Downing, Lori R Kogan. J. Vet.Med. & Research. August 2020;7(4):1194-1197. Quote: Our goal was to assess gabapentin dosage and tolerability in dogs taking it for chronic pain. ... All patients in this study were on gabapentin due to an inability to fully control their pain with NSAIDs or nutraceuticals alone. ... The majority (217 patients; 90.42%) had pain localized to their back. The other anatomic locations of pain included stifle (33; 13.8%), elbow/shoulder (21; 8.8%) and hip (11; 4.6%). Some patients’ pain was localized to multiple areas and is counted in all categories. The most common diagnosis of pain was osteoarthritis (203; 84.6%), followed by generalized, nonspecific back pain (22;9.2%), intervertebral disk disease (18; 7.5%), and degenerative myelopathy (11; 4.6%). Some patients experienced two different kinds of pain and are embodied in both categories. One hundred and thirty-six (56.67%) patients did not have definitive anatomic cause for their pain, such as cruciate tears or intervertebral disc disease, as seen in Table 2. ... We retrospectively analyzed the medical records of 240 dogs taking gabapentin for chronic pain and systematically assessed: patient signalment, definitive diagnosis, location and description of pain, VAS scores immediately preceding and following the patient’s maximum gabapentin dose, maximum gabapentin dosage, presence or absence of side effects related to gabapentin use, use of NSAID/immunomodulator drugs and nutraceuticals, presence or absence of levothyroxine supplementation, surgical procedures, and physical medicine. The range of tolerated gabapentin doses was 6.9 - 500 mg/kg/day [3.1- 227.3 mg/lb], PO, q12 hr (every 12 hrs) and only 10% of patients experienced the most common side effect of sedation. ... The results from this case series suggest that gabapentin is well-tolerated at much higher doses than what is typically prescribed. Side effects were uncommon, with no clear pattern based on dose, or dog size or age. Therefore, like many other analgesic medications, the efficacy of gabapentin appears patient-specific and should be dosed to effect until side effects are noted or analgesia is achieved.

Classification of Intervertebral Disc Disease. Joe Fenn, Natasha J. Olby, the Canine Spinal Cord Injury Consortium. Front. Vet. Sci. October 2020; doi: 10.3389/fvets.2020.579025. Quote: Intervertebral disc disease (IVDD) is a broad term that is widely used in veterinary medicine and encompasses a range of lesions affecting the intervertebral disc. ... Whilst there are still many controversies in the categorization of types of disc-associated lesions in veterinary medicine, in this article we aim to review the relevant literature and to outline a consensus where possible. We will provide an up to date overview of reported types of IVDD, highlighting important features, and aiming to explain the theories behind their classification.

Diagnostic Imaging in Intervertebral Disc Disease. Ronaldo C. da Costa, Steven De Decker, Melissa J. Lewis, Holger Volk, the Canine Spinal Cord Injury Consortium (CANSORT-SCI). Front. Vet. Sci. October 2020; 7:588338. Quote: Imaging is integral in the diagnosis of canine intervertebral disc disease (IVDD) and in differentiating subtypes of intervertebral disc herniation (IVDH). These include intervertebral disc extrusion (IVDE), intervertebral disc protrusion (IVDP) and more recently recognized forms such as acute non-compressive nucleus pulposus extrusion (ANNPE), hydrated nucleus pulposus extrusion (HNPE), and intradural/intramedullary intervertebral disc extrusion (IIVDE). Many imaging techniques have been described in dogs with roles for survey radiographs, myelography, computed tomography (CT), and magnetic resonance imaging (MRI). Given how common IVDH is in dogs, a thorough understanding of the indications and limitations for each imaging modality to aid in diagnosis, treatment planning and prognosis is essential to successful case management. While radiographs can provide useful information, especially for identifying intervertebral disc degeneration or calcification, there are notable limitations. Myelography addresses some of the constraints of survey radiographs but has largely been supplanted by cross-sectional imaging. Computed tomography with or without myelography and MRI is currently utilized most widely and have become the focus of most contemporary studies on this subject. Novel advanced imaging applications are being explored in dogs but are not yet routinely performed in clinical patients. The following review will provide a comprehensive overview on common imaging modalities reported to aid in the diagnosis of IVDH including IVDE, IVDP, ANNPE, HNPE, and IIVDE. The review focuses primarily on canine IVDH due to its frequency and vast literature as opposed to feline IVDH.

Lumbosacral intervertebral disk extrusions in 13 dogs. Luca Bresciani, Raquel Trevai,, Stephen Clarke, Rodrigo Gutierrez-Quintana, Sebastien Behr, Kali Lazzerini, Josep Brocal, Bill Oxley, Jonathan Pink, Roberto José-López. Vet. Surgery. March 2021; doi: 10.1111/vsu.13624. Quote: 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 [including one cavalier King Charles spaniel]. 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 [including the CKCS]. 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 the CKCS], including one case of epidural steatitis. On reexamination 4–6 weeks postsurgery, outcome was judged as excellent in 11 dogs [including the CKCS] 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.

The Effects of FGF4 Retrogenes on Canine Morphology. Danika Bannasch, Kevin Batcher, Fabienne Leuthard, Michael Bannasch, Petra Hug, Denis J. Marcellin-Little, Peter J. Dickinson, Michaela Drögemüller, Cord Drögemüller, Tosso Leeb. Genes. February 2022; doi: 10.3390/genes13020325. Quote: Two FGF4 retrogenes (FGF4L1 on chromosome 18 and FGF4L2 on chromosome 12) have been identified to cause dwarfism across many dog breeds. Some breeds are nearly homozygous for both retrogenes (e.g., Dachshunds) and others are homozygous for just one (e.g., Beagles and Scottish Terriers). Since most breeds do not segregate both of these retrogenes, it is challenging to evaluate their individual effects on long bone length and body size. We identified two dog breeds selected for hunting ability, the Alpine Dachsbracke and the Schweizer Niederlaufhund, that segregate both of these retrogenes. Using individual measurements of height at the shoulder, back length, head width, thorax depth and width, and thoracic limb measurements, we evaluated the combined effects of FGF4 retrogenes within these breeds. We applied multivariable linear regression analysis to determine the effects of retrogene copy numbers on the measurements. Copy numbers of both retrogenes had significant effects reducing height at the shoulders and antebrachial length, with FGF4L1 having a much greater effect than FGF4L2. FGF4L1 alone influenced the degree of carpal valgus and FGF4L2 alone increased head width. Neither retrogene had an effect on thorax width or depth. Selectively breeding dogs with FGF4L1 and without FGF4L2 would likely lead to a reduction in the FGF4L2-related risk of intervertebral disc herniation while maintaining the reduction in leg length resulting from FGF4L1.

Postoperative outcome of ambulatory dogs with intervertebral disc extrusion causing incontinence and/or tail dysfunction: 18 cases (2010-2020). R. Pfund, A. K. Forward, R. Fentem, A. Nagendran, A. R. Fraser, A. H. Crawford. J. Sm. Anim. Pract. July 2022; doi: 10.1111/jsap.13497. Quote: Objectives: To assess the recovery of urinary continence, faecal continence and tail function in ambulatory dogs with caudal lumbar intervertebral disc extrusion and to explore clinical factors that may be associated with recovery. Materials and Methods: Medical records from January 2010 to December 2020 were searched to identify ambulatory dogs undergoing surgical treatment for a caudal lumbar intervertebral disc extrusion causing urinary incontinence, faecal incontinence and/or tail dysfunction. Signalment, history, presenting clinical signs, neurological examination findings, diagnostic test results, treatment and outcome were recorded for all dogs. Results: Eighteen dogs with caudal lumbar intervertebral disc extrusion causing tail dysfunction, urinary and/or faecal incontinence were included. ... Affected breeds were four (22%) Cavalier King Charles Spaniels, four (22%) cocker spaniels, three (17%) dachshunds, two (11%) crossbreeds, one (6%) French bulldog, Belgian Laekenois, Pug, German shepherd dog and Pomeranian. ... Cocker spaniels and Cavalier King Charles spaniels appeared to be over-represented, accounting for eight of 18 (44%) dogs in this case series. ... Urinary continence was recovered in 12 (86%) of 14 affected dogs [including 2 of the CKCS], faecal continence recovered in nine (90%) of 10 affected dogs [including 2 of the CKCS] and tail function recovered in 13 (87%) of 15 affected dogs [including 1 CKCS]. Loss of tail nociception was recorded in three dogs on presentation; two made a full recovery and one showed mild persistent tail paresis. Clinical Significance: The prognosis for functional recovery of urinary continence, faecal continence and tail function in ambulatory dogs with caudal lumbar intervertebral disc extrusion following surgical treatment is good. Larger studies are needed to identify prognostic factors associated with failure of recovery.

ACVIM consensus statement on diagnosis and management of acute canine thoracolumbar intervertebral disc extrusion. Sarah A. Moore, Natasha J. Olby, Brigitte Brisson, Joe Fenn, Thomas Flegel, Gregg Kortz, Melissa Lewis, Andrea Tipold. J. Vet. Intern. Med. July 2022; doi: 10.1111/jvim.16480. Quote: Background: Thoracolumbar intervertebral disc extrusion (TL-IVDE) is the most common cause of acute paraparesis and paraplegia in dogs; however, guidelines on management of the condition are lacking. Objectives: To summarize the current literature as it relates to diagnosis and management of acute TL-IVDE in dogs, and to formulate clinically relevant evidence-based recommendations. Methods: A panel of 8 experts was convened to assess and summarize evidence from the peer-reviewed literature in order to develop consensus clinical recommendations. Level of evidence available to support each recommendation was assessed and reported. Results: The majority of available literature described observational studies. Most recommendations made by the panel were supported by a low or moderate level of evidence, and several areas of high need for further study were identified. These include better understanding of the ideal timing for surgical decompression, expected surgical vs medical outcomes for more mildly affected dogs, impact of durotomy on locomotor outcome and development of progressive myelomalacia, and refining of postoperative care, and genetic and preventative care studies. Conclusions and Clinical Importance: Future efforts should build on current recommendations by conducting prospective studies and randomized controlled trials, where possible, to address identified gaps in knowledge and to develop cost effectiveness and number needed to treat studies supporting various aspects of diagnosis and treatment of TL-IVDE.

Spontaneous vocalization in dogs presenting for neurological evaluation between 2016 and 2022: A descriptive study.  A. Spencer-Taylor, P. Freeman, L. Alves, A. Vanhaesebrouck, S. Khan, G. Harris. 34th Symposium ESVN-SCVN; QB10. J. Vet. Intern. Med. September 2022; doi: 10.1111/jvim.17218. Quote: Introduction Spontaneous vocalization has been anecdotally associated with cervical disc disease and more robustly associated with Chiari-like malformation and syringomyelia. This study describes the signalment, localisation and diagnoses in a cohort of dogs presenting with spontaneous vocalization. Methods The records of dogs presenting to the neurology department between 2016 and 2022 with spontaneous vocalization as a presenting sign were reviewed and analyzed. Spontaneous vocalization was defined as a sudden, highpitched sound when moving or at rest without an obvious inciting cause. Dogs were excluded if vocalization was an isolated episode, initiated by palpation or was associated with strenuous activity. Results 59 dogs met the inclusion criteria, 44 were male, 40 were neutered and the median age at presentation was 63 months (4–348). French Bulldog (n = 10), crossbreed (n = 8), and Cavalier King Charles Spaniel (n = 7) were the three commonest breeds. The most prevalent localisation was C1–C5 (n = 17). The most frequent diagnoses were intervertebral disc herniation (n = 26), syringomyelia (n = 6), neoplasia (n = 5), and atlantoaxial instability (n = 4). Of the 33 dogs localized to the cervical spine, intervertebral disc herniation was found in 18 of them. DiscussionIn this cohort of dogs, spontaneous vocalization was most frequently associated with a localisation of the cervical spine (more specifically C1-C5) and a diagnosis of intervertebral disc herniation. Of those dogs that localized to the cervical spine an intervertebral disc herniation was the most likely diagnosis (18/33). Incorporating this information into a clinical reasoning framework may aid in clinical decision making especially when advanced imaging is unavailable.

Retrospective study of acupuncture treatment for canine thoracolumbar intervertebral disc herniation. Qianyu Jia, Yu Wang, Haidong Pang, Kai Fan, Huisheng Xie, Jiahao Lin. One Health Advances. September 2023; doi: 10.1186/s44280-023-00022-y. Quote: Thoracolumbar interverbal disk herniation (TL-IVDH) is a common neurological disorder in dogs, which often affects the life quality of patients and their caregivers. Acupuncture is increasingly accepted by veterinarians and animal owners, and has been used in the treatment of neurologic disorders. This study aims to evaluate the effects of acupuncture treatment for canine TL-IVDH. Clinical cases from 2016 to 2021 were collected. According to the inclusion and exclusion criteria, 94 TL-IVDH cases that received acupuncture treatment were selected. Clinical classification and efficacy criteria were formulated based on the Frankel Score. For each case, clinical presentation, improvement, recovery and recurrence were recorded. Male dogs with TL-IVDH accounted for 64% of all cases. The average age was 7.49 years old, the predominant breed was poodle, and the incidence site was concentrated from T11 to L1. The overall recovery rate after receiving acupuncture treatment was 79.78%, which was comparable when considering only cases with grade 2, 3, or 4 spinal cord lesions (83.33% ~ 85.19%). In conclusion, canine with grade 2, 3, and 4 spinal cord lesions due to TL-IVDH receiving acupuncture had a high recovery rate, suggesting acupuncture could be a viable treatment options for canine with TL-IVDH. ... In conclusion, the total recovery rate of acupuncture treatments in this study was 79.78%, which is significantly higher than that of conservative treatment recovery rates reported in previous studies. Deep pain perception is the most important factor for the efficacy of acupuncture on IVDH functional recovery. Additionally, the age of patients, those with recurrent disease, and the frequency of acupuncture treatments also affected the recovery outcome.

Clinical and imaging findings in dogs with nerve root signature associated with cervical intervertebral disc herniation. Jordan Schachar, Alan Bocage, Nathan C. Nelson, Peter J. Early, Christopher L. Mariani, Natasha J. Olby, Karen R. Muñana. J. Vet. Intern. Med. January 2024; doi: 10.1111/jvim.16982. Quote: 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 [incluidng one cavalier King Charles spaniel]. 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, 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, and to be associated with compression of the nerve root at the level of the intervertebral foramen. 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.

Spontaneous resorption of a C7–T1 intervertebral disc extrusion in a Cavalier King Charles spaniel confirmed via low-field MRI. Michelle du Toit, Neringa Alisauskaite. Vet. Rec. February 2024; doi: 10.1002/vrc2.812. Quote: A 4-year-old, male, neutered Cavalier King Charles spaniel was referred to the neurology service with a 10-day history of cervical hyperaesthesia. A low-field magnetic resonance imaging scan of the cervical spine identified a large C7–T1 intervertebral disc extrusion, resulting in severe spinal cord compression.The patient was treated with conservative therapy (exercise restriction and analgesia for 4 weeks). Repeat magnetic resonance imaging of the cervical spine was performed 4 months after initial presentation, and identified spontaneous resorption of the extruded C7–T1 disc material. There are very few documented cases of spontaneously resorbed cervical intervertebral disc extrusions in canine patients following successful conservative therapy. To the authors’ knowledge, this is the first report of spontaneous resorption of an intervertebral disc extrusion at an unusual C7–T1 location confirmed via follow-up low-field magnetic resonance imaging following conservative therapy.