Magnetic resonance imaging and neurological findings in dogs with disc-associated cervical spondylomyelopathy: a case series

Treatment of Canine Disc-Associated Cervical Spondylomyelopathy with a Cervical Distraction-Stabilization Technique (C-LOX Combined with LCP Plate) and Clinical Outcomes

Canine disc-associated cervical spondylomyelopathy (DA-CSM) is a form of caudal CSM, characterized by the compression of the spinal cord and nerve roots due to an intervertebral disc protrusion. It is more frequent in large canine breeds. A variety of surgical techniques has been proposed for DA-CSM. The aim of the study was to evaluate the outcomes of a cervical distraction-stabilization technique using an intervertebral anchored fusion device (C-LOX) combined with a locking compression plate (LCP plate) for the treatment of DA-CSM in dogs, based on clinical and radiographical follow-up data. Thirteen dogs affected by DA-CSM were included in the study. After the surgical procedure, an improvement in neurological status was documented in 9/13 cases. This cervical distraction-stabilization technique seems to be a valuable surgical alternative to treat this canine pathology.

Magnetic resonance imaging and neurologic characterization of combined osseous- and disc-associated cervical spondylomyelopathy in dogs

BACKGROUND

Although both disc- or osseous-associated forms of cervical spondylomyelopathy (CSM) are observed in the same dogs, this combined form has not been thoroughly evaluated.

OBJECTIVES

To describe imaging characteristics of dogs with concurrent disc- and osseous CSM and investigate an association between findings on neurological examination and imaging.

ANIMALS

Sixty dogs with disc and osseous-associated CSM from 232 CSM-affected dogs.

METHODS

Retrospective study. Dogs diagnosed via high-field MRI with a combination of intervertebral disc (IVD) protrusion and osseous proliferation of articular processes, dorsal lamina, or both were identified. Large and giant breed dogs were grouped according to whether combined compressions were at the same site or different sites. Statistical methods were used to investigate the association and relationship between variables.

RESULTS

Thirty-five out of 60 (58%) were large breeds and 22/60 (37%) were giant breeds. Mean and median age was 6.6 and 7 years respectively (range, 0.75-11 years). Forty of the 60 dogs (67%) had concurrent osseous and disc-associated spinal cord compression in the same location. This was considered the main compression site in 32/40 (80%) dogs. Dogs with osseous- and disc-associated compressions at the same site were more likely to have a higher neurologic grade (P = .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

A substantial percentage of dogs with CSM present with concomitant IVD protrusion and osseous proliferations, most at the same site. Characterizing this combined form is important in the management of dogs with CSM because it could affect treatment choices.

The volume of extruded materials is correlated with neurologic severity in small-breed dogs with type I thoracolumbar intervertebral disk herniation

OBJECTIVE

To assess whether the volume of extruded materials is correlated with neurologic severity in dogs with type I thoracolumbar intervertebral disk herniation (TL-IVDH).

ANIMALS

70 client-owned small-breed dogs with type I TL-IVDH diagnosed between July 1, 2016, and June 30, 2018.

PROCEDURES

For this retrospective cohort study, the medical records of 70 dogs with surgically confirmed type I TL-IVDH were reviewed. The volume and height of the intervertebral disk and the area of the maximal transverse compressed spinal cord were measured using CT myelographic images. For each dog, the volume of the disk immediately cranial to the herniated disk was an internal control. Dogs were grouped on the basis of grade of neurologic severity.

RESULTS

Preoperative grades of neurologic severity were grade 2 in 7 (10%) dogs, grade 3 in 16 (23%) dogs, grade 4 in 28 (40%) dogs, and grade 5 in 19 (27%) dogs. The total volume of the affected intervertebral disks was significantly larger than the internal control. Weak positive correlation was found between the volume of the extruded materials into the vertebral canal and the grade of neurologic severity.

CLINICAL RELEVANCE

Our findings indicated that the total volume of the affected intervertebral disks is larger in dogs with type I TL-IVDH, and the volume of the extruded materials into the vertebral canal is weakly correlated with the neurologic severity.

Early Locomotor Training in Tetraplegic Post-Surgical Dogs with Cervical Intervertebral Disc Disease

Locomotor training (LT) is task-specific repetitive training, with sensorimotor stimulation and intensive exercises that promote neuromuscular reorganization. This study aimed to observe if LT could be initiated safely in the first 3−15 days after surgery in tetraplegic C1−C5 IVDD—Hansen type I dogs. This prospective blinded clinical study was conducted at two rehabilitation centers in Portugal, with 114 grade 1 (MFS/OFS) dogs, divided by the presence of spinal hyperesthesia into the SHG (spinal hyperesthesia group) (n = 74) and the NSHG (non-spinal hyperesthesia group) (n = 40), evaluated in each time point for two weeks according to a neurorehabilitation checklist by three observers for inter-agreement relation. LT was safely applied with 62.3% of the OFS ≥ 11 within 15 days and of these, 32.4% achieved a OFS ≥ 13. There were no new cases of hyperesthesia in the NSHG and from the SHG all recovered. Comparing groups, a significant difference was observed in their ability to achieve ambulatory status (p < 0.001), between the presence of hyperesthesia and days until ambulation (p < 0.006) and in each time point (p < 0.001; R2 = 0.809). Early LT may be a safe treatment to be applied in the first 3 days on these dogs and spinal hyperesthesia should be important to the rehabilitation team. This study should be continued.

Comparative clinical and morphometric investigations of cervical stenosis of the spinal canal in humans and dogs

Acquired stenosis of the spinal canal is a common problem in human and animal pathology. It is defined as a pathological condition that mainly develops as degeneration of the spine with cervical myelopathy development, which is a characteristic manifestation of this pathology. Pain both in the neck and upper back is the leading syndrome of this pathology. 65 human patients aged 20–65 years and 19 dogs weighing more than 20 kg were examined with the aim of comparative clinical and morphometric analysis of stenosis of the spinal canal. The age of the dogs was maximally converted to the age of a person. Computed tomography using the Pavlov-Torg index and the reserve space evaluation supplemented diagnosis of stenosis of the spinal canal. The mass proportion of stenotic changes of the spinal canal against the background of the degenerative-dystrophic process was 21 in males (n = 25) 84.0%, females – 28 persons (n = 40) 70.0%. Pain syndrome was the main complaint in all patients. Cervicalgia prevailed in 60 (92.3%), pain in the upper back was registered in 32 (49.2%) patients. The intensity of pain syndrome was equal to 3.1 ± 0.4 points. Motor deficiency in the form of paresis, mainly of the distal parts of the hands, was registered in 48 patients (73.8%), pyramidal symptoms were noted in the legs in 32 (49.2%) patients, pelvic reservoir dysfunction (7.0–10.8%), and sensory disorders were also found (24.0–36.9%). Such manifestations of cervical myelopathy progressed slowly. Pyramidal symptoms were more frequent and more pronounced in men. According to the computed tomography scan, degenerative changes of the spine were maximal at the level of the C6 vertebra with the maximum clinical correlation (neurological deficit, pain syndrome, etc.). In the course of the research, probable stenosis of the spinal canal was found in people on computed tomography images. In the 19 dogs observed weighing 20 kg or more the presence of pain syndrome was evaluated in all the animals (100.0%) as well as behaviour change (100.0%). During the examination, gait disorder was detected (18.0–94.7%); reaction to palpation of the neck area (15.0–78.9%); the habitus of animals experiencing pain, especially during neck movements (14.0–73.7%), body tension (12.0–63.1%), etc. Bony outgrowths of the edges of the vertebrae and intervertebral joints were found in almost all dogs of 18 (94.7%) large breeds compared to others. Narrowing of the intervertebral openings, deformation and sclerotic changes of the locking plates, thickening of the yellow and elongated ligaments occurred three to four times more in large breeds compared to dogs weighing less than 20 kg, and were absent in cats. Stenosis of the spinal canal was detected in 15 (78.9%) dogs. Therefore, acquired stenosis of the spinal canal probably develops after degenerative-dystrophic changes in the neck in 87.7% of people and in 78.9% of dogs with clinical manifestations of cervical myelopathy and with persistent pain syndrome (equal to 3.1 ± 0.3 points in humans and 2.6 ± 0.4 points in animals according to visual analog scale). This kind of pathological process in the investigated groups developed mainly at the level of the C6 vertebra. Similar clinical and morphometric indexes were obtained in humans (87.7%). It was found that the maximum similarity of pathological processes with stenosis of the spinal canal formation was characteristic in dogs of exclusively large breeds. Therefore, we consider it promising to study the development mechanisms of stenosis of the spinal canal and peculiarities primarily in young generations of humans and animals, to implement modern non-invasive neuroimaging methods, in particular for animals with investigation of morphometric indexes. This will prevent the occurrence of most comorbid syndromes, including chronic pain, neurological deficits as well as help find new opportunities for correction of stenosis of the spinal canal, to suppress the aging processes not only of the muscle-skeletal system but also of the body as a whole. The importance of this work, we suppose, lies in the further identification of adequate models in animals of different breeds and weight categories with stenosis of the spinal canal pathology in which it develops significantly faster, for extrapolation to humans to predict the development of pathological events.