A modified ventral fixation for surgical management of atlantoaxial subluxation in 19 dogs

OBJECTIVE: To describe a modified ventral stabilization technique for surgical management of atlantoaxial subluxation in dogs and to evaluate the outcome. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Nineteen client-owned dogs. METHODS: Medical records of 19 dogs with a radiographic diagnosis of atlantoaxial subluxation surgically managed by a modified ventral fixation technique (cortical screws, Kirschner wires, polymethylmethacrylate) were reviewed. Data on pre- and post-operative neurologic status, surgical technique, and complications were retrieved. Follow-up evaluation was performed at approximately 1 month. Telephone interview of the owner was used for long-term assessment (median follow-up for 17 surviving dogs was 10.5 months). RESULTS: Adequate reduction and stabilization was achieved in all dogs based on radiographic assessment immediately after surgery. Improved neurologic outcome occurred in 16 dogs at 1 month and in 15 dogs at follow-up; 2 dogs died of post-operative complications within 24 hours of surgery. One dog was euthanatized at the owners' request because of recurrent neck pain associated with implant failure after 1 month. Two dogs required surgery to remove broken and migrated implants, but further stabilization was not necessary. CONCLUSIONS: Adequate stabilization and improved neurologic outcome was achieved in most dogs. However, on account of the small size of the study and the variable neurologic signs of the dogs on admission, the surgical technique described could not be compared to those previously reported. CLINICAL RELEVANCE: The surgical technique described is an effective means of surgical treatment for atlantoaxial subluxation.     

Magnetic resonance imaging characteristics of suspected vertebral instability associated with fracture or subluxation in eleven dogs

The purpose of this study was to describe the magnetic resonance imaging (MRI) characteristics of suspected instability in dogs with vertebral fractures or subluxations. Eleven dogs that had MRI examinations of the spine prior to surgical stabilization of vertebral fractures and/or subluxations were included in the study. Nine dogs also had survey radiographs. Four dogs had cervical fracture or fracture-subluxation and presented with tetraplegia with intact nociception (n = 2) or nonambulatory tetraparesis (n = 2). Seven dogs had thoracolumbar fracture-subluxation or subluxation and presented with paraplegia with intact nociception (n = 5) or nonambulatory paraparesis (n = 2). A three-compartment model was applied to the interpretation of both the radiographic and MRI studies. Radiography identified compartmental disruption consistent with spinal instability in seven out of the nine cases radiographed. In MRI studies, rupture of the supportive soft tissue structures and/or fracture in at least two compartments could be visualized. Nine cases had spinal cord changes on MRI including signal intensity changes, swelling, compression, and intramedullary hemorrhage. Paravertebral muscle intensity changes were also visible at each trauma site. Magnetic resonance imaging provided helpful information on the location and extent of damage to supportive soft tissue structures and enabled assessment of spinal cord injury in this group of dogs with surgically confirmed vertebral fractures and subluxations.     

Disc extrusion in a Rottweiler dog with caudal cervical spondylomyelopathy after failure of intervertebral distraction/stabilisation

A Rottweiler dog was presented with an 8 week history of hindlimb ataxia. Neurological examination localised the lesion to the cervical spinal cord. Myelography demonstrated dynamic compressive lesions at C5-6 and C6-7 consistent with a diagnosis of caudal cervical spondylomyelopathy. Distraction/stabilisation of both discs was performed using interbody polymethyl methacrylate. Both implants subsequently failed leading to extrusion of the remaining dorsal annulus fibrosus of the C5-6 intervertebral disc and nonambulatory tetraparesis. A ventral slot combined with distraction/stabilisation using screws and polymethyl methacrylate was performed and resulted in nearly full neurological recovery.     

Multi‐modality diagnostic imaging of a cervical articular process fracture in a Thoroughbred horse including a novel C‐Arm imaging technique

Interpretation of cervical radiographs can be challenging due to the complex anatomy and superimposition of osseous structures on either side of the vertebrae. This report describes the investigation of neck pain in a Thoroughbred gelding following a traumatic fall. Several imaging modalities were used to demonstrate the presence of a fracture of the left cranial articular process of the fourth cervical vertebra (C4), including nuclear scintigraphy, ultrasonography, oblique radiographic projections and a novel cineradiographic technique. Oblique radiographs were superior to standard lateral‐lateral radiographs in both the diagnosis and for monitoring the progression of healing of the articular process fracture in this case.     

Conservative treatment of a comminuted cervical fracture in a racehorse

The 'classical' or 'Hangman' neck fracture involves the odontoid peg (process) of the second cervical vertebra (C2), and is described as an axial, dens or odontoid peg fracture in both the veterinary and human literature. Possible surgical treatment in both foals and adult horses requires a technique that allows decompression, anatomical alignment and stabilisation of the odontoid fracture. A limited number of surgical cases in foals have been reported in literature, but never in an adult horse. A mature Irish Thoroughbred racehorse was diagnosed with a type 2a odontoid peg fracture. Clinical signs included reluctance to move the head and neck, a left hind limb lameness and a neurological status of grade 2. The horse was treated conservatively and raced successfully five months after the diagnosed injury.     

Severe seizures associated with traumatic brain injury managed by controlled hypothermia,pharmacologic coma,and mechanical ventilation in a dog

Objective – To describe the management and outcome of a dog presenting with intractable seizures associated with traumatic brain injury. Case Summary – A spayed female Wheaten Terrier was presented to an emergency clinic with neurologic deficits (modified Glasgow coma scale of 10) shortly after a road traffic accident. Seizures were uncontrolled despite aggressive pharmacologic intervention. Controlled hypothermia to achieve a rectal temperature of 33–35°C (91.4–95°F) was initiated as a protective measure to reduce intracranial pressure and cerebral metabolic rate, and to assist with seizure control. Intubation and mechanical ventilation were required to protect the airway and manage hypercapnia associated with hypoventilation. The patient went on to make a full recovery, although behavioral changes were noted by the owners for an 8‐week period following injury. New or Unique Information Provided – To the author's knowledge, this is the first instance of therapeutic hypothermia reported in the veterinary literature. A short review of this treatment modality is provided.     

Conservative management of comminuted central tarsal bone fracture and joint instability in a horse

A comminuted fracture of the central tarsal bone, fragmentation of the fourth tarsal bone and associated joint instability was diagnosed in a 14‐year‐old Sport Horse mare who presented for investigation of acute nonweightbearing hindlimb lameness. The mare responded well to conservative management and, unlike previously reported cases of similar injuries, returned to a similar level of athletic activity.     

A modified ab externo approach for suture fixation of an intraocular lens implant in the dog

The goals of canine cataract and lens instability surgery should be to ensure a small incision, minimal tissue trauma, shortened surgical time, maintenance of the anterior chamber, and restoration of emmetropia through the use of a stable intraocular lens specifically designed for the canine eye. While this is usually the case with routine phacoemulsification and in-the-bag intraocular lens implantation, it is often not the case with lens instability, lens luxation or large posterior capsular ruptures. In such cases the incisions are often larger, surgical time and tissue trauma are excessive, and the patient is often left aphakic. The goal of this paper is to present a modified ab externo technique designed to allow removal of the lens and placement of a ciliary sulcus sutured IOL through a small incision, with minimal trauma and shortened surgical time. Use of this technique may allow more canine patients to be emmetropic postoperatively. In addition, the ease of this procedure may encourage earlier removal of an unstable lens and decrease the risk of secondary glaucoma and retinal detachment that occur in association with lens luxation.     

CT diagnosis of occipital condyle fracture in a dog presented for severe cervical hyperesthesia

A 9-month-old male entire Doberman Pinscher presented with acute onset of severe cervical hyperesthesia after a fall. Neurological examination revealed a normal gait with low head carriage and severe cervical hyperesthesia. A CT scan of the cervical vertebral column revealed the presence of a comminuted fracture at the dorsomedial aspect of the right occipital condyle and sclerosis of the underlying bone. Medical management was initiated consisting of an external bandage, strict rest, and pain medication. Due to the lack of clinical improvement, the dog was euthanized 2 months after diagnosis. Histopathology of the lesion was compatible with a healing fracture.     

Bilateral traumatic optic nerve avulsion in a Thoroughbred gelding

This report describes an unusual case of acute blindness following traumatic head injury in a mature horse. The horse fell over backwards and subsequently presented with bilateral blindness and epistaxis. Vision did not return following medical supportive therapy and euthanasia was elected. Post mortem findings revealed a basisphenoid fracture and bilateral optic nerve avulsion rostral to the optic chiasm, an uncommon presentation of traumatic blindness not previously reported in the horse.     

Palliative radiation therapy in a dog with malignant trichoepithelioma

An 11-year-old male Bearded Collie was brought to the Gifu University Animal Medical Centre with a skin mass on the lateral right thigh. Physical examination revealed a 30 × 65-mm oval mass with an alopecic and ulcerated surface. Histopathology of the surgically excised sample confirmed malignant trichoepithelioma. Five months after the surgery, the dog experienced lumbar pain resulting from metastasis to the lumbar vertebrae. Radiation therapy (RT) was performed and it alleviated the lumbar pain. Nine months after the surgery, multiple skin metastases were identified. RT was performed at each occurrence, which reduced the size of each tumour and resulted in a partial response; however, systemic metastasis occurred and the dog died 17 months after the initial surgery. Canine malignant trichoepithelioma is a rare tumour, so an effective treatment has not been determined. Data from our case study indicate that RT has potential for pain control of primary and metastatic malignant trichoepithelioma.