Atlantoaxial subluxation with absence of the dens in a rottweiler

Atlantoaxial subluxation was diagnosed in a five-month-old male rottweiler. Surgical treatment was performed by lag screw fixation via a ventral approach. Treatment resulted in complete resolution of the neurological signs.     

Intertarsal and tarso-metatarsal subluxation in the dog

Forty-four cases of intertarsal subluxation and eight cases of tarso-metatarsal subluxation in the dog are reported. The anatomical features of the hock related to these conditions are briefly considered. There was evidence that the Shetland Sheepdog is predisposed to intertarsal subluxation and in this breed minimal trauma was associated with the occurrence of the condition. The history, clinical and radiographic features are reported for each condition and the methods and results of treatment described.     

Diagnosis and treatment of a chronic atlanto-occipital subluxation in a dog

A 6-year-old Labrador retriever-cross was evaluated for an abnormal gait and head carriage 6 weeks after suffering trauma. The dog was presented with an ambulatory tetraparesis and was reluctant to move his head. Myelography and computed tomography demonstrated a subluxation of the atlanto-occipital joint with compression of the spinomedullary junction and the brain stem by the occipital bone. Removal of the compressive part of the occipital bone resulted in improvement of the clinical signs within 6 weeks, and resolution of clinical signs occurred 8 months after surgery.     

X-ray and CT morphology of atlas variants in the dog

To investigate variations in atlas shape in dogs the image archives of the Department for Small Animals and Horses, University of Vienna, and The Royal Veterinary College, University of London were searched for radiographs and CT images of the canine atlas. 32 radiographic and 78 CT studies, including 51 toy and 54 large breed dogs, were retrieved and analysed. Five dogs had both radiographs and CT scans. Patients with pathologic alterations, such as fractures and incomplete ossification of the atlas, as well as oblique projections were excluded. Compared to large breed dogs (body weight more than 30 kg) the atlas of toy breed dogs (body weight less than 10 kg) had a reduced craniocaudal and an increased dorsoventral diameter. The vertebral longitudinal axis appeared to be dorsorotated, resulting in a steeper rise of the atlas wings and a more dorsally located lateral vertebral foramen. When comparing the atlas of toy and large breed dogs, the distribution of three morphologic parameters was statistically different: Ratio length to height (toy breeds > 1, large breeds < or = 1), shape of the vertebral chanal (toy breeds: vertically oval, large breeds: round resp. cross-oval, or vertically oval) and trabecular bone of the dorsal arch (toy breeds: absent, large breeds: present). There was no significant difference in the morphology of the ventral arch. Differences in atlas morphology could contribute to the predisposition of toy breed dogs to atlanto-axial instability; however, further studies are necessary to test this hypothesis.     

Temporomandibular subluxation in the dog: A case report

Temporomandibular subluxation was diagnosed in a 2-year old Irish Setter dog. The presenting sign was frequent bouts of open jaw-locking. Tomographic evidence suggested that temporomandibular dysplasia was a factor in the aetiology of the condition. Surgical excision of rostral segments of the zygomatic arches effectively alleviated the clinical condition.     

Vertebral subluxation following ventral cervical decompression in the dog

Cervical intervertebral disk disease is commonly treated surgically by ventral decompression through a ventral slot. Nine dogs with documented vertebral subluxation following surgical creation of a ventral slot are reported. The location of the subluxation was at the fourth cervical (C4) to fifth cervical (C5) intervertebral space in two dogs, C5 to sixth cervical (C6) intervertebral space in four dogs, and C6 to seventh cervical (C7) intervertebral space in three dogs. The ventral slot width to vertebral body width ratio ranged from 0.39 to 0.80, with the ratio being 0.50 or greater in seven of eight cases evaluated radiographically. Surgical reduction and stabilization were performed in seven of nine dogs.     

Stabilisation of atlantoaxial subluxation in the dog through ventral arthrodesis

Ten miniature breed dogs with atlantoaxial subluxation underwent ventral lag screw stabilisation. The procedure did not include bone graft packing into the atlantoaxial articulation. Four dogs showed continuous improvement after surgery. Three dogs developed complications due to external trauma and postoperative implant failure but improved with conservative therapy. Three patients died or were euthanized in early perioperative or postoperative period. The long-term outcome was good or favourable in all surviving patients. Suspected fibrous tissue proliferation and stabilisation without permanent bone fusion was found to be clinically satisfactory when the atlantoaxial joint has been subjected to limited stress during a long-term monitoring period.     

Bilateral maxillary periodontal ligament hamartoma in a dog

A 12.5-year-old dog was presented for severe periodontal disease and bilateral maxillary enlargement. Radiographs of the maxilla showedgeneralized root resorption, ankylosis, and rarefaction of bone with focal radiodense areas. Surgical tooth extraction of multiple maxillary teeth and bilateral incisional biopsies of the periodontal tissue and maxilla in the region of the maxillary fourth premolars were performed. Histopathologic examination showed features typical of fully differentiated periodontal ligament with abundant cementum/alveolar lining bone and sparce odontogenic epithelial cell rests. Histopathology in conjunction with radiographic and clinical signs suggested a diagnosis of bilateral periodontal ligament hamartoma. Examination 3-months postoperatively indicated uncomplicated healing of the extraction and biopsy sites with no resolution of the maxillary enlargement.     

Atlantoaxial cartilaginous exostosis causing spinal cord compression in a mature Bernese mountain dog

Cartilaginous exostosis developed in the atlantoaxial region of a three-and-a-half-year-old Bernese mountain dog. The dog exhibited ataxia in the hindlimbs and flailing movements in the forelimbs. On survey radiographs of the cervical spine there was a focal calcified mass between the dorsal arch of the atlas and the spinous process of the axis. Lumbar myelography revealed severe dorsal spinal cord compression. The mass was removed surgically and the dog made a complete recovery. Histopathology of the excised mass was consistent with a diagnosis of cartilaginous exostosis.     

Chronic desmitis and enthesiophytosis of the radio-ulnar interosseous ligament in a dog

A 10-year-old golden retriever dog was presented for chronic right forelimb lameness associated with a painful swelling at the lateral aspect of the proximal ulna. Proximal ulnar ostectomy and stabilization resulted in a good clinical outcome. The proposed diagnosis is chronic desmitis and enthesiophytosis of the radio-ulnar interosseous ligament.     

Collateral ligament prosthesis for the repair of subluxation of the metatarsophalangeal joint in a jersey cow

A two-and-a-half-year-old Jersey cow had been moderately lame in its right hindlimb for one month. Clinical and radiographic examinations revealed an incomplete lateral luxation of the metatarsophalangeal joint. The medial condyle of the metatarsal bone was locked in the condylar groove of the medial first phalanx. The subluxation was reduced, the joint carefully debrided and irrigated, and the torn ligament was replaced with a synthetic prosthesis which was fixed with titanium alloy staples. One year after surgery, the joint was slightly swollen but the cow was not lame.     

Laparoscopic-assisted extirpation of falciform ligament hemangiosarcoma in a dog

An 8-year-old, spayed female, bichon frisé dog had incidental nodules within its falciform ligament identified on routine abdominal ultrasonography. A laparoscopic-assisted technique provided both a diagnostic and a therapeutic treatment option. A histopathological diagnosis of hemangiosarcoma was made. This is the second case reporting hemangiosarcoma of the falciform fat.     

Torsion and volvulus of the transverse and descending colon in a German shepherd dog

A German shepherd dog was presented two months after surgery for correction of acute gastric dilatation volvulus. The dog had been diagnosed with exocrine pancreatic insufficiency. Radiographs revealed marked gaseous distension of one loop of intestine with a generalised increase in intestinal gas content. A 360 degrees anticlockwise rotation of the descending and transverse colon, around the longitudinal axis of the mesocolon, was diagnosed at exploratory coeliotomy. The transverse and descending colon appeared uniformly necrotic and an end-to-end colo-colic resection and anastomosis was performed. The dog initially made satisfactory postoperative progress but was euthanased on the third postoperative day after it developed an intestinal intussusception.