Vertebral Osteosarcoma in Two Cats-Diagnosis, Treatment, and Outcome.

In this case report, we describe the diagnosis, treatment, and outcome of two feline cases of vertebral osteosarcoma. Case 1: A 6-year-old female neutered domestic longhaired cat was presented with progressive paraparesis, ataxia, and spinal hyperesthesia. MRI of the thoracolumbar spinal cord and vertebral column revealed a strongly contrast-enhancing mass lesion originating from the dorsal lamina and spinous process of T13. The lesion caused extradural compression of the spinal cord. Surgical debulking was performed, and the histopathological evaluation of surgical biopsies was consistent with vertebral osteosarcoma. The cat was paraplegic with intact nociception post-surgery. Subsequently, the cat recovered ambulation while remaining mildly ataxic and paraparetic at long-term follow-up. Post-operative chemotherapy was started with doxorubicin. CT scans at 2, 4, 9, 13, and 20 months post-surgery showed no signs of local recurrence or metastasis. Case 2: A 15.5-year-old male neutered domestic shorthaired cat was presented with progressive paraparesis, tail paresis, and spinal hyperesthesia. Radiographs and CT scan of the lumbar vertebral column showed a large mass originating from the dorsal lamina and spinous process of L6, suggestive of neoplasia, with severe compression of the spinal cord. Surgical debulking was performed, and the histopathological evaluation was consistent with vertebral osteosarcoma. Post-operative chemotherapy was started with doxorubicin. Seven months post-surgery, the patient was neurologically normal with no signs of metastatic disease. This case report highlights the possibility of good outcomes after the surgical treatment of feline vertebral osteosarcoma supplemented with post-surgical chemotherapy.

Epidemiology of Modic changes in dogs: Prevalence, possible risk factors, and association with spinal phenotypes.

Background: Chronic low back pain, a leading contributor to disease burden worldwide, is often caused by intervertebral disc (IVD) degeneration. Modic changes (MCs) are MRI signal intensity changes due to lesions in vertebral bone marrow adjacent to degenerated IVDs. Only a few studies described the histopathological changes associated with MC to date. MC type 1 is suggested to be associated with bone marrow infiltration of fibrovascular tissue, type 2 with fatty infiltration, and type 3 with bone sclerosis in humans. Methods: This study investigated whether the dog can be a valuable animal model to research MCs, by examining the prevalence, imaging, and histological characteristics of lumbar MCs in dogs (340 dogs, 2496 spinal segments). Results: Logistic regression analysis indicated that the presence of lumbosacral MCs was associated with age and disc herniation (annulus fibrosis protrusion and/or nucleus pulposus extrusion). According to MRI analysis, MCs were mostly detected at the lumbosacral junction in dogs. Most signal intensity changes represented MC type 3, while previous spinal surgery seemed to predispose for the development of MC type 1 and 2. Histological analysis (16 dogs, 39 spinal segments) indicated that IVDs with MCs showed more histopathological abnormalities in the endplate and vertebral bone marrow than IVDs without MCs. Mostly chondroid proliferation in the bone marrow was encountered, while the histologic anomalies described in humans associated with MCs, such as fibrovascular or fatty infiltration, were scarcely detected. Conclusions: Dogs spontaneously develop MCs, but may exhibit other pathological processes or more chronic bone marrow pathologies than humans with MCs. Therefore, more research is needed to determine the translatability of the MCs encountered in dog low-back-pain patients.

Patient-specific 3D-printed shelf implant for the treatment of hip dysplasia tested in an experimental animal pilot in canines.

The concept of a novel patient-specific 3D-printed shelf implant should be evaluated in a relevant large animal model with hip dysplasia. Therefore, three dogs with radiographic bilateral hip dysplasia and a positive subluxation test underwent unilateral acetabular augmentation with a 3D-printed dog-specific titanium implant. The contralateral side served as control. The implants were designed on CT-based pelvic bone segmentations and extended the dysplastic acetabular rim to increase the weight bearing surface without impairing the range of motion. Outcome was assessed by clinical observation, manual subluxation testing, radiography, CT, and gait analysis from 6 weeks preoperatively until termination at 26 weeks postoperatively. Thereafter, all hip joints underwent histopathological examination. The implantation and recovery from surgery was uneventful. Clinical subluxation tests at the intervention side became negative. Imaging showed medialization of the femoral head at the intervention side and the mean (range) CE-angle increased from 94° (84°-99°) preoperative to 119° (117°-120°) postoperative. Gait analysis parameters returned to pre-operative levels after an average follow-up of 6 weeks. Histology showed a thickened synovial capsule between the implant and the femoral head without any evidence of additional damage to the articular cartilage compared to the control side. The surgical implantation of the 3D shelf was safe and feasible. The patient-specific 3D-printed shelf implants restored the femoral head coverage and stability of dysplastic hips without complications. The presented approach holds promise to treat residual hip dysplasia justifying future veterinary clinical trials to establish clinical effectiveness in a larger cohort to prepare for translation to human clinic.

Structural, compositional, and functional effects of blunt and sharp cartilage damage on the joint: A 9-month equine groove model study.

This study aimed to quantify the long-term progression of blunt and sharp cartilage defects and their effect on joint homeostasis and function of the equine carpus. In nine adult Shetland ponies, the cartilage in the radiocarpal and middle carpal joint of one front limb was grooved (blunt or sharp randomized). The ponies were subjected to an 8-week exercise protocol and euthanized at 39 weeks. Structural and compositional alterations in joint tissues were evaluated in vivo using serial radiographs, synovial biopsies, and synovial fluid samples. Joint function was monitored by quantitative gait analysis. Macroscopic, microscopic, and biomechanical evaluation of the cartilage and assessment of subchondral bone parameters were performed ex vivo. Grooved cartilage showed higher OARSI microscopy scores than the contra-lateral sham-operated controls (p < 0.0001). Blunt-grooved cartilage scored higher than sharp-grooved cartilage (p = 0.007) and fixed charge density around these grooves was lower (p = 0.006). Equilibrium and instantaneous moduli trended lower in grooved cartilage than their controls (significant for radiocarpal joints). Changes in other tissues included a threefold to sevenfold change in interleukin-6 expression in synovium from grooved joints at week 23 (p = 0.042) and an increased CPII/C2C ratio in synovial fluid extracted from blunt-grooved joints at week 35 (p = 0.010). Gait analysis outcome revealed mild, gradually increasing lameness. In conclusion, blunt and, to a lesser extent, sharp grooves in combination with a period of moderate exercise, lead to mild degeneration in equine carpal cartilage over a 9-month period, but the effect on overall joint health remains limited.

Presumed cholesterinic granulomas detected on CT in horses are associated with increased lateral ventricle height and age.

Cholesterinic granulomas are mass-like lesions that form at the choroid plexus of the ventricular system. Large cholesterinic granulomas within the lateral ventricles have been reported to cause severe neurological signs. However, little data are available about their prevalence or appearance in the overall population. The objective was to report the prevalence of presumed cholesterinic granulomas on CT in a population of horses, and investigate associations between presumed cholesterinic granuloma presence, lateral ventricle size, age, and neurological signs. The study was cross sectional, CT scans of the head were assessed for presumed cholesterinic granuloma presence and size, and lateral ventricle height. Computed tomography findings and clinical information were compared using nonparametric testing. Computed tomography scans of 139 horses were included. Presumed cholesterinic granulomas were found in 22 horses (15.8%), nine were unilateral and 13 bilateral. A significant increase in prevalence was observed with age (P < .0001), with 38% of horses over 15 years old affected. The median volume of presumed cholesterinic granulomas was 242 mm3 with a range from 51 to 2420 mm3 . The mean lateral ventricle height was significantly increased in horses with presumed cholesterinic granulomas present (P = .004), with a median of 7.3 mm compared to 4.9 mm without. Neurological signs were not associated with presumed cholesterinic granuloma presence or lateral ventricle height. Fourth ventricle mineralizations were found in seven horses, which may represent cholesterinic granulomas. In conclusion, presumed cholesterinic granulomas occurred in a large proportion of the examined population and are associated with increased lateral ventricle dilation and advanced age.

Caudal lumbar spinal cysts in two French Bulldogs.

BACKGROUND: Spinal cysts are rare findings in veterinary medicine, but they are increasingly recognized due to the availability of advanced imaging techniques. Extradural meningeal cysts in French Bulldogs have not been reported previously and arachnoid cysts (diverticula) have not been reported at the caudal lumbar (L6-L7) region in dogs. CASE PRESENTATION: Two French Bulldogs, aged 5 and 8 years, were referred for evaluation of lower back pain and bilateral hind limb neurological deficits. Neurologic examination revealed ataxia and postural deficits in both dogs. Magnetic resonance imaging (MRI) showed cauda equina compression due to a cyst-like lesion at the level of L6-L7 in both cases. The dogs underwent dorsal laminectomy and the meningeal cyst was completely removed in one dog and in the other dog the spinal arachnoid diverticula was marsupialized. In Case 1, histopathology of the cysts was performed and MRI was repeated. Both dogs were pain free during follow-up evaluations. CONCLUSIONS: Based on radiological, intra-operative and histopathological findings, the first case was diagnosed as a meningocele connected by a pedicle to the caudal tip of the dural sac forming a dural diverticulum categorized as an extradural spinal cyst type Ib, and Case 2 as a type III intradural arachnoid diverticula. It is concluded that spinal cysts should be included in the differential diagnosis of cauda equina syndrome and lower back pain in French Bulldogs. Results of these cases may be useful for diagnostic and treatment management.

Intradiscal application of a PCLA-PEG-PCLA hydrogel loaded with celecoxib for the treatment of back pain in canines: What's in it for humans?

Chronic low back pain is a common clinical problem in both the human and canine population. Current pharmaceutical treatment often consists of oral anti-inflammatory drugs to alleviate pain. Novel treatments for degenerative disc disease focus on local application of sustained released drug formulations. The aim of this study was to determine safety and feasibility of intradiscal application of a poly(ε-caprolactone-co-lactide)-b-poly(ethylene glycol)-bpoly(ε-caprolactone-co-lactide) PCLA-PEG-PCLA hydrogel releasing celecoxib, a COX-2 inhibitor. Biocompatibility was evaluated after subcutaneous injection in mice, and safety of intradiscal injection of the hydrogel was evaluated in experimental dogs with early spontaneous intervertebral disc (IVD) degeneration. COX-2 expression was increased in IVD samples surgically obtained from canine patients, indicating a role of COX-2 in clinical IVD disease. Ten client-owned dogs with chronic low back pain related to IVD degeneration received an intradiscal injection with the celecoxib-loaded hydrogel. None of the dogs showed adverse reactions after intradiscal injection. The hydrogel did not influence magnetic resonance imaging signal at long-term follow-up. Clinical improvement was achieved by reduction of back pain in 9 of 10 dogs, as was shown by clinical examination and owner questionnaires. In 3 of 10 dogs, back pain recurred after 3 months. This study showed the safety and effectiveness of intradiscal injections in vivo with a thermoresponsive PCLA-PEG-PCLA hydrogel loaded with celecoxib. In this set-up, the dog can be used as a model for the development of novel treatment modalities in both canine and human patients with chronic low back pain.

Computed tomographic characteristics of presumed normal canine abdominal lymph nodes.

Though identification of lymph nodes is essential in staging cancer patients, little has been reported about the CT features of canine abdominal lymph nodes. The purpose of this retrospective study was to describe the visibility, location, and characteristics of abdominal lymph nodes in abdominal CT studies of dogs considered unlikely to have lymphadenopathy. The relationship between the number of identified lymph nodes and intraabdominal fat ranking, body weight, and slice thickness was also investigated. A total of 19 dogs were included. At least two jejunal lymph nodes and both left and right medial iliac lymph nodes were identified in all dogs. Colic lymph nodes were not identified in any of the dogs. Visualization of all other lymph nodes varied. There were significantly more lymph nodes visible in dogs with more intraabdominal fat (P < 0.0001). No correlation between the number of identified lymph nodes and body weight (P = 0.64) or slice thickness (P = 0.76) was found. Though most of all identified lymph nodes had an elongated shape, a rounded shape was most common in splenic, pancreaticoduodenal, renal, ileocolic and caudal mesenteric lymph nodes. Most lymph nodes had a homogeneous structure before and following the intravenous administration of contrast medium. Some lymph nodes had a slightly irregular structure or were relatively more hyper attenuating in the periphery than centrally before and/or after contrast administration. Mean attenuation before contrast was 37 Hounsfield Units (HU) (range 20-52 HU), and 109 HU after contrast (range 36-223 HU). Findings indicated that the CT visibility, characteristics of different abdominal lymph nodes may be variable in dogs.