Spontaneous lumbar intervertebral disc protrusion in cats: literature review and case presentations

Reports on intervertebral disc disease in cats are rare in the veterinary literature. It has been postulated that intervertebral disc protrusion is a frequent finding during necropsy in cats, without having any clinical relevance (King and Smith 1958, King & Smith 1960a, King & Smith 1960b). However, a total of six cases with disc protrusions and clinically significant neurological deficits have been reported over the past decade. (Heavner 1971, Seim & Nafe 1981, Gilmore 1983, Littlewood et al 1984, Sparkes & Skerry 1990, Bagley et al 1995). As in dogs, there are also two types of intervertebral disc disease in cats: Hansen's type I (extrusion), and type II (herniation). Cervical spinal cord involvement was more commonly recognised in cats than the lumbar or the thoraco lumbar area. Cats over 15 years were mainly affected (King & Smith 1958, King & Smith 1960a, King & Smith 1960b). We describe two cats with lumbar intervertebral disc protrusions. Emphasis is placed on differential diagnoses, treatment and follow-up.     

Diagnosis of lumbosacral intervertebral disc disease and protrusion in a horse using ultrasonographic evaluation and computed tomography

This case report describes the clinical presentation, diagnostic imaging modalities, treatment and post mortem evaluation of lumbosacral intervertebral disc protrusion in a mature Quarter Horse gelding 10 days after initial signs were noted. Grade 3 hindlimb ataxia, conscious proprioceptive deficits, urinary and faecal incontinence were present, which did not improve with anti‐inflammatories, antimicrobial therapy, corticosteroids, antioxidant therapy, cold‐laser therapy or electroacupuncture. Imaging modalities utilised ante mortem were computed radiography, transcutaneous and transrectal ultrasonography. Transrectal ultrasonography yielded findings highly suggestive of lumbosacral intervertebral disc protrusion and due to the lack of improvement and a poor prognosis, the horse was humanely subjected to euthanasia. Post mortem computed tomography, necropsy and histopathological evaluation confirmed lumbosacral intervertebral disc disease and protrusion into the spinal canal with subsequent impingement of the spinal nerve roots. Lumbosacral intervertebral disc protrusion as a clinical disease in the horse has not been previously described and should be included as a differential diagnosis in cases with acute hindlimb ataxia, proprioceptive deficits, and urinary and faecal incontinence.     

Intervertebral disc protrusion in a cat

A case of prolapsed intervertebral disc at C_5–6 is described in an adult cat with a history of quadriparesis and two episodes of quadriplegia in a two year period. Plain radiographs showed no abnormality, there was no narrowing of the intervertebral space, but the protrusion was detected by myelography. Severe degeneration was found in the spinal cord.     

Cervical disc width index is a reliable parameter and consistent in young growing Dutch Warmblood horses

Intervertebral disc disease, as well as the associated alteration of the radiographic intervertebral disc space width, has been reported in horses. Disc height index (DHI) has proven to be an accurate and objective parameter in other species but data related to this parameter are lacking in horses. Therefore, the aims of this retrospective longitudinal diagnostic accuracy study were (a) to evaluate the reliability of measurements within and between observers of the equine Disc Width Index (EDWI) as a parameter for radiographic equine cervical intervertebral disc space width, and (b) to evaluate the sequential development of the EDWI over time. For this, EDWI from all intervertebral disc spaces between second cervical (C) to first thoracic (Th) vertebrae were obtained in a group of 39 Dutch Warmblood horses at 1, 5, and 18 months of age, by one European College of Veterinary Diagnostic Imaging (ECVDI) board‐certified veterinary radiologist (S.V.) and two veterinary students. Bland‐Altmann plots and intraclass Correlation Coefficient revealed a good intra‐ and interobserver agreement. A linear mixed‐effect model did reveal that mean EDWI increases significantly toward the caudal cervical spine, but did not differ significantly for a certain location over time or between sexes. Spearman's rank test did show a significant correlation between the vertebral alignment angle induced by different head‐neck positions and a normalized EDWI (ρ = 0.33, P < .0001). Student's t‐test revealed that the presence of C6‐C7 transposition of the transverse processes did not influence EDWI significantly. It was concluded that EDWI represents a reliable parameter for equine cervical radiographic intervertebral disc space width. Practical implementation of EDWI warrants monitoring in a group of adult horses while maintaining a standardized head‐neck position.     

Intervertebral disc disease in Dachshunds radiographically screened for intervertebral disc calcifications

Background

Intervertebral disc disease (IDD) is a very common neurological disease, Dachshunds being the breed most often affected. In this breed, IDD has a hereditary background and is associated with intervertebral disc calcification (IDC), an indicator of severe intervertebral disc degeneration. In Finland, spinal radiography is used, when screening for IDC before breeding Dachshunds. We evaluated the association between IDC and IDD in Finnish Dachshunds radiographically screened for IDC.A questionnaire was sent to owners of 193 radiographically screened Dachshunds aged at least ten years. Clinical signs indicative of IDD were compared with IDC grade (grade 0 = no calcifications, grade 1 = 1 – 2 calcifications, grade 2 = 3 – 4 calcifications and grade 3 = 5 or more calcifications) and with age at the time of the radiographic examination. The diagnosis of IDD was confirmed by a veterinarian.

Results

IDD was common in the study population with 31% of dogs being affected. IDD and IDC were clearly connected (P < 0.001); IDD was rare in dogs with no calcifications (grade 0) and common in dogs with severe IDC (grade 3). The IDC grade was strongly positively associated with frequency of back pain periods (P < 0.001), and dogs with IDC grade 3 had frequent periods of pain. Reluctance to jump onto a sofa had a strong positive association with back pain. No association existed between age of the dog at the time of the radiographic examination and clinical signs indicative of IDD.

Conclusions

Radiographically detected IDC and IDD are common in Finnish Dachshunds and are strongly associated with one another. Spinal radiography is an appropriate screening tool for breeders attempting to diminish IDC and IDD in Dachshunds. A breeding program that screens dogs and selects against IDC can be expected to reduce the occurrence of IDD in future. Twenty-four to 48 months of age is a suitable age for screening.

Electronic supplementary material

The online version of this article (doi:10.1186/s13028-014-0089-4) contains supplementary material, which is available to authorized users.     

Results of surgical treatment for thoracolumbar disc protrusion

Ninety-nine dogs were treated by hemilaminectomy for thoracolumbar intervertebral disc protrusion. Most animals were 4–7 years old and chondrodystrophoid. The incidence of protrusion was higher at the thoracolumbar junction. Animals with paresis, pain, or pain and paresis had a greater recovery rate than dogs with paralysis. Résumé. La protrusion du disque intervertébral thoracolombaire a été traitée par hémi-laminectomie chez 99 chiens, la plupart âgés de 4 à 7 ans et atteints de chondrodystrophie. Les protrusions étaient plus fréquentes à la jonction thoraco-lombaire. Les animaux qui manifes-taient de la parésie ou de la douleur, ou de la parésie et de la douleur, se rétablissaient plus vite et mieux que les animaux paralysés. Zusammenfassung. Neunundneunzig Hunde wurden mit Hemilaminektomie bei thoraco-lumbaren Zwischenwirbelscheibenvorfall behandelt. Die meisten Tiere waren 4–7 Jahre alt und chondrodystrophoid. Die Häufigkeit von Diskushernien war höher am thoracolumbarem Über-gangsabschnitt. Tiere mit Parese, Schmerzen oder Schmerzen und Parese wurden häufiger wiederhergestellt als Hunde mit Paralyse.     

Intervertebral disc degeneration in the dog. Part 1: Anatomy and physiology of the intervertebral disc and characteristics of intervertebral disc degeneration

Intervertebral disc (IVD) degeneration is common in dogs and can give rise to a number of diseases, such as IVD herniation, cervical spondylomyelopathy, and degenerative lumbosacral stenosis. Although there have been many reports and reviews on the clinical aspects of canine IVD disease, few reports have discussed and reviewed the process of IVD degeneration. In this first part of a two-part review, the anatomy, physiology, histopathology, and biochemical and biomechanical characteristics of the healthy and degenerated IVD are described. In Part 2, the aspects of IVD degeneration in chondrodystrophic and non-chondrodystrophic dog breeds are discussed in depth.     

Decompressive laminectomy in thoraco-lumbar disc protrusion with paraplegia in the dog

Early decompressive laminectomy according to the method previously described (Funkquist, 1962b) has been performed during the period 1963-66 on a large number of cases of thoraco-lumbar disc protrusion with paraplegia at the Department of Surgery of the Royal Veterinary College, Stockholm, Sweden. In the author's own cases, twenty-six of the twenty-seven dogs operated on (96%) regained their ability to walk. Corresponding figures for the total number of cases operated on (including those of the author) by specially trained surgeons are seventy-three of eighty-two or 89%. In control cases treated conservatively twenty-one of forty-one dogs (51%) regained walking ability. In the cases operated on as emergencies by operators with mainly a general surgical training, operation results are conspicuously worse (thirty-one of forty-nine dogs or 63% regained walking ability). Relapse incidence was at least as high after laminectomy as conservative treatment, the former, as a rule, should be followed by a prophylactic disc evacuation in a subsequent operation. Zusammenfassung. Frühzeitige dekompressive Laminektomie nach der früher beschriebenen Methode (Funkquist, 1962) wurde wahrend der Periode 1963–1966 an einer grossen Zahl Fälle von thoracolumbarem Bandscheibenvorfall mit Paraplegie in der Chirurgischen Abteilung der Königlichen Tierärztlichen Akademie in Stockholm, Schweden, durchgeführt. In den Fällen des Autors erlangten 26 der 27 operierten Hunde (96%) ihre Gehfähigkeit wieder. Die entsprechenden Zahlen (einschliesslich der des Autors) für die Gesamtzahl der von Chirurgen mit Spezialausbildung durchgeführten Operationen sind 73 von 82 oder 89%. In den konservativ behandelten Kontrollfällen erhielten 21 von 41 Hunden (51%) ihre Gehfähigkeit zurück. Bei solchen Fällen, die als Notoperationen von Chirurgen hauptsächlich mit allgemeiner chirurgischer Ausbildung behandelt wurden, waren die Operationsergebnisse auffallig schlechter (31 von 49 Hunden oder 63% erhielten die Gehfähigkeit zurück). Da die Rückfallhäufigkeit nach Laminektomie mindestens so hoch ist wie nach konservativer Behandlung, sollte sich an die erstere in der Regel eine prophylaktische Bandscheibenevakuation in einrr späteren Operation anschliessen. Résumé. Une laminectomie précoce de décompression d'après la technique décrite antérieurement (Funkquist, 1962b), a été effectuée au cows de la période de 1963 à 1966 dans un grand nombre de cas de protrusion des disques thoraco-lombaires avec paraplégie au Département de Chirurgie, Veterinary College de Stockholm (Suède). Parmi les cas personnels de l'auteur 26 chiens sur 27 (soit 96%) ont pu remarcher. Le nombre correspondant pour la totalité des cas opérés (y compris ceux de l'auteur) par des chirurgiens entraînés était de 73 sur 82 chiens, soit 89% des cas. Pour les cas témoins la proportion des animaux traités conservativement et ayant pu remarcher, était de 21 sur 41 (51%). Dans les cas opérés en urgence par des opérateurs entraînés surtout en chirurgie générale, les résultats de l'opération étaient nettement moins favorables (31 chiens sur 49 seulement on pu remarcher, soit 63%). La fréquence des rechutes étant au moins aussi forte après laminectomie qu'après le traitement conservateur, on devrait procéder à une ablation du disque à titre prophylactique au cours d'une intervention ultérieure.     

Surgical treatments for intervertebral disc disease.

Surgical treatments for intervertebral disc disease are useful for animals with gradually progressive, severely acute, or recurrent lesions. Surgical patients require a diligent neuroradiographic evaluation to confirm location and severity of the discopathy and rule out conditions unrelated to disc disease. Although controversial, some surgeons advocate fenestration for recurrent pain or mild ataxia associated with a noncompressive lesion. Decompressive procedures are recommended for treatment and prognostication of compressive disc-associated myelopathy. Foraminotomy is reserved for patients with lateralizing extrusions confirmed with myelography or newer imaging modalities (CT, MRI). Future treatments for animals may include chemonucleolysis or various discectomy procedures currently performed in humans with symptomatic disc disease.     

Modified lateral spinal decompression in 61 dogs with thoracolurnbar disc protrusion

A modified lateral spinal decompression technique was performed in 61 dogs with thoracolumbar disc protrusion. Myelography combined with plain radiography and neurological examination determined the side of greatest compression in 93 per cent of the dogs. Disc material was retrieved in 98 per cent of the cases. Of the 35 non-ambulatory dogs, 95 per cent regained the ability to walk. The recovery time was three weeks.