Giant cell tumor of the accessory carpal bone in a dog

A 4-year-old Springer Spaniel was referred because of a 6-week history of progressive left forelimb lameness. A marked pain response was elicited by palpation over the left accessory carpal bone. Radiography revealed a lytic, markedly expansile lesion of the accessory carpal bone. The bone was excised, and pancarpal arthrodesis was performed. Histologic examination of the excised bone revealed giant cell tumor. At 14 months after surgery, the dog was using the limb normally. Radiography of the carpus revealed satisfactory progression of the arthrodesis, and thoracic radiographs were negative for metastases.     

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A 10‐YEAR‐OLD, male neurered golden retriever presented with a three‐month :history of intermittent left thoracic limb lameness. The owner reported that the lameness was worse on uneven ground and after exercise. At times, while resting, the dog held the left thoracic limb off the ground. The lameness had partially responded to non‐steroidal anti‐inflammatories and strict rest, bur had deteriorated again after the exercise level was increased. On examination, flexion of both carpiillicited pain responses in the animal. The dog was 3/10 lame on the left thoracic limb.     

Intraoperative use of ultrasonography during continuous dorsal laminectomy in two dogs with caudal cervical vertebral instability and malformation ("Wobbler syndrome")

OBJECTIVE: To describe an intraoperative ultrasound imaging technique during dorsal laminectomy in 2 dogs with caudal cervical vertebral instability and malformation (CCVIM, "Wobbler syndrome"). STUDY DESIGN: Clinical case report. SAMPLE POPULATION: Two dogs with CCVIM. RESULTS: On neurologic examination there was tetraparesis with upper motor neuron signs in the thoracic limbs and lower motor neuron signs in the pelvic limbs in dog 1, and hyperreflexia of the rear limbs, normoreflexia of the right front limb, and hyporeflexia of the left front limb of dog 2. Both dogs had signs of marked cervical pain and radiographic signs of cervical spinal cord compression. Intraoperative ultrasonography of the spinal cord revealed protruding intervertebral disc at C5-6 (dog 1) and C6-7 (dog 2), and the parallel borders of the spinal cord and central canal after decompression. Continuous dorsal laminectomy (CDL) resulted in improvement over 16 months (dog 1) and 20 months (dog 2). CONCLUSIONS: Intraoperative ultrasonographic imaging of the cervical spinal cord after CDL was helpful in determining adequate decompression (postlaminectomy) of the spinal cord in relation to the ventral and lateral compressive component(s) and to image the protruding intervertebral disc. CLINICAL RELEVANCE: Intraoperative ultrasonography can be used to provide valuable information on the spinal cord and surrounding soft tissues for the neurosurgeon.     

Spinal Root Origin of the Radial Nerve and Nerves Innervating Shoulder Muscles of the Dog

The ventral spinal root origin of the radial nerve, its muscle branches, and brachial plexus nerves which supply shoulder and thoracic musculature was determined in the dog. Electrophysiological signal averaging techniques measured evoked potential from specific ventral spinal roots to individual muscle nerves. The entire radial nerve received input from the sixth cervical (C6) through the second thoracic (T2) spinal roots. The most significant (p less than .05) input to triceps brachii came from C8 while the deep ramus of the radial nerve received its largest input from C7. The brachiocephalicus, suprascapular, and subscapular nerves all received their most significant (p less than .05) innervation from C6. Approximately 90% of the evoked potential to the axillary nerve originated from C7. The thoracodorsal nerve received most of its innervation from ventral roots C7 and C8. The lateral thoracic nerve which innervates the cutaneous trunci muscle was supplied by ventral roots C8-T2. Examination of innervation patterns suggests that only modest variation of spinal root input to specific nerves occurred between individual dogs.     

Hansen type I disk disease at T1-2 in a dachshund

A 7-year-old Dachshund was presented with chronic left thoracic limb lameness and acute neurological deficits to the hind limbs following trauma. A lesion was suspected between C7 and T2 on the basis of neurological examinations. Radiography and myelography identified a calcified intervertebral disk at C7-T1 and an extradural unilateral compressive lesion at T1-2. Computed tomography scans of the cranial thoracic spine revealed extrusion of disk material from the T1-2 intervertebral space resulting in marked spinal cord compression. Intervertebral disk disease is rarely reported at this location. The neurological condition deteriorated after a second myelogram, which was done to examine the thoracolumbar spine. A modified dorsal decompression of T1-2 was performed. The dog was euthanased due to further neurological deterioration 8 days after surgery.     

Spinal cord injury resulting from incorrect microchip placement in a cat

A 2-year-old, male neutered domestic shorthair cat was presented for investigation of an acute onset of tetraparesis immediately following the implantation of a pet identification microchip. A left-sided C6-T2 spinal segment localisation was suspected from the neurological examination, with spinal cord trauma being the primary differential diagnosis. Myelography demonstrated obliteration of the contrast columns by the microchip at the C5-C6 intervertebral disc space. A dorsal laminectomy was undertaken and the microchip was successfully removed. Eleven months after the surgery, the cat was able to weight bear in all limbs but with mild residual paresis in the left thoracic limb.     

Surgical treatment of an intramedullary spinal cord hamartoma in a dog

A 9-year-old spayed female Golden Retriever was examined because of progressive hind limb lameness. Magnetic resonance imaging of the thoracic and lumbar portions of the vertebral column revealed a focal, contrast-enhancing, intramedullary spinal cord mass. The history, signalment, and magnetic resonance findings were suggestive of spinal cord neoplasia. A hemilaminectomy, durotomy, and longitudinal myelotomy were performed, and a 1 X 1-cm mass that contained numerous blood vessels was removed with blunt dissection. Results of histologic examination and immunohistochemical staining of the mass suggested that it was a hamartoma. The dog improved after surgery, with no evidence of a recurrence of clinical signs 14 months after surgery. Vascular malformations of the CNS in dogs include hamartomas, hemangiomas, angiomas, hemangioblastomas, meningocerebral hemangiomatosis, and arteriovenous malformations. A hamartoma is a non-neoplastic overgrowth of cells or an improper proportion of cells that are normally in the involved tissue. Although magnetic resonance imaging may be helpful in determining the extent of the lesion in dogs with vascular malforrmations, it cannot be used to distinguish neoplastic from non-neoplastic formations. Excision may result in a good outcome for dogs with an intramedullary spinal cord hamartoma.     

Evaluation of a Midhumeral Block of the Radial,Ulnar, Musculocutaneous and Median (RUMM Block) Nerves for Analgesia of the Distal Aspect of the Thoracic Limb in Dogs

Objective: To evaluate a technique for midhumeral peripheral nerve blockade in the dog. Study Design: Cadaveric technique development; in vivo placebo‐controlled, prospective crossover study. Animals: Canine cadavers (n=38) and 8 clinically healthy, adult hound dogs. Methods: A technique for peripheral block of the radial, ulnar, musculocutaneous, and median nerves (RUMM block) was evaluated using cadaver limbs. Eight purpose‐bred, research dogs were anesthetized; a RUMM block was performed on each thoracic limb. One limb from each dog randomly received 0.5% bupivacaine and the opposite limb was assigned to receive sterile saline solution as a control. After recovery from anesthesia, skin sensation at selected dermatomes was evaluated for 24 hours using a mechanical stimulus. Weight‐bearing, conscious proprioception, and withdrawal reflex were also evaluated. One month after initial testing, each dog was reanesthetized and each limb received the opposite treatment. Results: Sensory thresholds were significantly increased over baseline measurements when compared with control limbs for all nerves. Complete sensory block was achieved in radial (15/16), ulnar (3/16), musculocutaneous (8/16), and median (11/16) nerves, using a mechanical stimulus of analgesia. Complete simultaneous block of all nerves was only obtained in 1 of 16 limbs. Conclusion: RUMM block resulted in desensitization of the skin in the associated dermatomes for 4–10 hours. Complete sensory block of the dermatomes supplied by the radial nerve was most consistent. Clinical Relevance: RUMM block may be an effective technique to provide adjunctive analgesia for dogs undergoing surgery of the distal aspect of the thoracic limb.     

Extradural spinal liposarcoma in a dog.

An 8-year-old female Doberman Pinscher was examined because of progressive, asymmetric, ambulatory caudal paraparesis. Myelography revealed extradural left ventrolateral spinal cord compression over the first and second lumbar vertebral bodies. A left hemilaminectomy, extending from the thirteenth thoracic to the second lumbar vertebrae, was done, and an extradural mass was removed. The tumor was identified histologically as myxoid liposarcoma. The dog's neurologic function improved gradually after surgery; however, at 7 months after surgery, hind limb neurologic function deteriorated rapidly over a 5-week period, presumably because of local recurrence of the tumor. The dog was euthanatized; necropsy was not permitted.     

Imaging diagnosis--cervical spine chondroma in a dog

An extradural chondroma originating in the cervical spine was diagnosed in an 8-year-old, intact male Chow-Chow that presented acute cervical pain and chronic right thoracic limb lameness. Myelographic images were within normal limits. With magnetic resonance (MR) imaging, an extradural mass was identified at the level of the C4-C5 vertebrae. This mass was excised, and the histologic diagnosis was chondroma. Fifteen months after surgery, the dog was clinically normal, and no regrowth of the mass was identified on follow-up MR images. Spinal chondromas are rare tumors in the dog, but should be considered as a rule out for contrast-enhancing extradural vertebral masses.     

Surgical and radiotherapy treatment of a spinal cord ependymoma in a dog

A 4-year-old Beagle dog was presented for investigation of a left pelvic limb gait abnormality. Neurolocalisation indicated a lumbar (L2 to L5) spinal cord lesion. On magnetic resonance imaging (MRI), an intramedullary mass was demonstrated at L3. The mass was partially removed under general anaesthesia and a diagnosis of ependymoma was made on histological examination. The dog was treated with postoperative orthovoltage x-ray radiation (total dose; 44 Gy given in 11 fractions over a 4 week period) combined with low dose carboplatin (25 mg/m2). The dog was alive 16 months after surgery without further neurological deficits. No further tumour growth was detected on subsequent MRI evaluations.     

Primary osteosarcoma of the synovium in a dog

An eight-year-old, spayed female Labrador retriever was presented for evaluation of left thoracic limb lameness. Radiographs of the left elbow revealed mineralization of the soft tissues surrounding the joint, with no evidence of periarticular bony lysis. Biopsy of the synovial tissues of the left radiohumeral joint yielded a diagnosis of osteosarcoma (OSA). The dog was treated with palliative radiotherapy, piroxicam, and carboplatin chemotherapy, which resulted in excellent pain control for approximately eight months. Amputation of the affected limb was then performed. Six months later, the dog developed multiple subcutaneous OSA metastases, and the dog was euthanized 15 months after diagnosis due to refractory vomiting. This report documents the first known case of primary OSA of the synovium in any species.     

Pneumorrhachis in a rottweiler

An 8·5-year-old, female, neutered, Rottweiler was presented for investigation of progressive ataxia of one week duration. Proprioception was absent in the left pelvic limb and reduced on the right, thoracolumbar hyperalgesia was evident and pelvic limb segmental spinal reflexes were normal. Magnetic resonance imaging (MRI) demonstrated a spherical region of signal void compressing the spinal cord between the fifth and sixth thoracic vertebrae and several non-compressive degenerate intervertebral discs. Computed tomography (CT) of the region confirmed the findings and identified the lesion as gas. A dorsolateral hemilaminectomy was performed to decompress the spinal cord and achieved complete resolution of the clinical signs on examination after 3 months. This is the first known reported case of spontaneous pneumorrhachis in a veterinary patient.     

Spinal cord injury secondary to electrocution in a dog

A 13‐year‐old, female spayed, crossbreed dog of 32 kg was presented for evaluation of peracute onset of non‐ambulatory tetraparesis after chewing an electrical wire. Neurological examination was consistent with a C1‐C5 myelopathy. Magnetic resonance imaging revealed a focal intramedullary lesion over the C2‐C3 vertebral bodies, which was confirmed to be an acute focal necrotising poliomyelopathy with subarachnoid and subdural haemorrhages on postmortem examination. This report describes the clinical, imaging and histopathological findings of this unusual type of spinal cord injury, and the effects of electrocution in the central nervous system of dogs.     

Neurological signs in a horse due to metastases of an intestinal adenocarcinoma

A 22-year-old Dutch Warmblood mare was referred to Utrecht University with progressive left hind limb paresis and hyporeflexia. The preliminary clinical diagnosis was the neurological form of equine herpes virus (EHV-1) infection. Within 1 day of admission, the mare became recumbent and deteriorated rapidly. Postmortem examination revealed an adenocarcinoma of the caecum, with metastases in all regional lymph nodes and extending from the lumbar nodes into the vertebral canal, causing spinal cord compression and destruction of the left 4th and 5th lumbar nerves.     

Gross morphological features of plexus brachialis in the chinchilla (Chinchilla lanigera)

This study documents the detailed features of the morphological structure and the innervation areas of the plexus brachialis in the chinchilla (Chinchilla lanigera). The animals (5 female and 5 male) were euthanased with ketamine hydrocloride and xylazine hydrocloride combination, 60 mg/kg and 6 mg/kg, respectively. Skin, muscles and nerves were dissected under a stereo-microscope. The brachial plexus of the chinchilla is formed by rami ventrales of C5-C8, T1 and T2, and possesses a single truncus. The subscapular nerve is formed by the rami of the spinal nerves originating from C6 (one thin ramus) and C7 (one thick and 2 thin rami). These nerves innervate the subscapular and teres minor muscles. The long thoracic nerve, before joining with the brachial plexus, obtains branches from C6 and C7 in 5 cadavers (3 male, 2 female), from C7 in 4 cadavers (2 male, 2 female) and from C6-C8 in only 1 female cadaver. These nerves disperse in variable combinations to form the extrinsic and intrinstic named, nerves of the thoracic limb. An undefined nerve branch originates from the rami ventrales of C7, C8 and T1 spinal nerves enter the coracobrachial muscle.     

IMAGING DIAGNOSIS: CRANIAL CERVICAL INTRASPINAL SCHWANNOMA IN A DOG

A 3‐year‐old, intact female Golden Retriever was presented with acute tetraplegia. Neurologic examination was consistent with a C1–C5 myelopathy. On magnetic resonance (MR) imaging a well‐defined, extradural mass was detected within the spinal canal at the level of C1–C2. The mass was isointense to normal spinal cord gray matter on T1‐weighted (T1W) images, hyperintense on T2‐weighted (T2W), and gradient‐echo (GE) images, and enhanced homogeneously after intravenous contrast administration. MR imaging features were mainly consistent with a meningioma. Surgical treatment was refused by the owners, and the dog was euthanized. Postmortem examination demonstrated that the intraspinal mass was a schwannoma.     

Epidural myelolipoma in a Husky-cross: a case report

Epidural spinal myelolipoma was diagnosed in an 11.5-year-old castrated male Husky-cross that was evaluated at the veterinary teaching hospital due to progressive thoracolumbar spinal hyperaesthesia and mild proprioceptive pelvic limb ataxia. A focal, ill-defined mildly inhomogenous extradural mass lesion was detected by MRI. The dog was euthanized. At necropsy an extradurally located reddish mass of about 2.5 cm in diameter was present in the vertebral canal. The mass was identified histopathologically as an epidural myelolipoma.     

Suspected disseminated histiocytic sarcoma in a 3-year-old Perro de Presa Canario dog

A 3-year-old intact male Perro de Presa Canario dog was presented with acutely inflamed and edematous right hind limb, scrotum, prepuce, and an enlarged left carpus. Two weeks later the dog returned with weight loss, draining tracts in the right hind limb, dermal nodules, a palpable abdominal mass, and uveitis in the left eye. The dog succumbed to his illness 2 days later and a widely disseminated round cell tumor compatible with histiocytic sarcoma was diagnosed following postmortem examination.     

Abdominal aortic aneurysm associated with systemic fungal infection in a German shepherd dog

A 2 yr old spayed female German shepherd presented with a chief complaint of acute onset paraparesis and weight loss. At presentation, the dog was pyrexic, nonambulatory, and had generalized muscle wasting. Neurolocalization was consistent with a thoracolumbar spinal cord lesion. An abdominal ultrasound was performed and revealed a focal dilation (4 cm) of the terminal aorta with evidence of blood stasis consistent with an aortic aneurysm. The dog was euthanized shortly after admission to the hospital and a post mortem examination was performed. Fungal organisms were identified in the aortic aneurysm as well as from the thoracic vertebrae, mesenteric lymph nodes, axillary lymph nodes, spleen, kidneys, liver, lungs, and heart. Although the morphology was consistent with Candida spp., immunohistochemistry and PCR could not definitively identify the causative organism. Mycotic aortic aneurysms are a rare finding in humans and have not been previously reported in the dog. To the authors' knowledge, this is the first known report of an aortic aneurysm associated with systemic fungal infection in a dog.