Vertebrectomy, bone allograft fusion, and antitumor vaccination for the treatment of vertebral fibrosarcoma in a dog

OBJECTIVE: To describe the surgical technique of vertebrectomy with bone allograft fusion and the use of antitumor vaccine for the treatment of a primary vertebral neoplasm in a dog. STUDY DESIGN: Case Report. ANIMALS OR SAMPLE POPULATION: A 3 year old 32 kg female spayed mixed breed dog with progressive paraplegia. METHODS: Myelography was performed to identify an L5 lytic lesion with spinal cord compression. A dorsal laminectomy was performed to decompress the spinal cord and obtain biopsies. Pathologic fracture of the vertebral body two days later was treated with L5 vertebrectomy, cortical allograft implantation, and bilateral plating from L4 to L6. Tumor samples were used to create an autologous cytokine-gene-engineered tumor cell vaccine. Recheck radiographs and neurologic examinations were obtained 1, 2, 7, and 13 months after surgery. RESULTS: The histopathologic diagnosis was fibrosarcoma. Although slight osteopenia of the allograft was noted thirteen months after surgery, the allograft and plate fixation remained stable. The patient tolerated the antitumor vaccination protocol well. Two years after the procedures the dog was able to ambulate normally but remained urinary and fecal incontinent. CONCLUSIONS AND CLINICAL RELEVANCE: Vertebrectomy and cortical allograft implantation with plating permitted this patient to return to a functional lifestyle with its owners.     

Congenital kyphosis secondary to lumbar vertebral hypoplasia causing paraparesis in a Friesian foal

A 5‐day‐old Friesian colt was presented with a history of severe bilateral pelvic limb weakness since birth. Clinical examination revealed a painful dorsal deviation of the spinous processes of the lumbar vertebrae, pelvic limb paraparesis and grade 4/5 ataxia. Radiographic examination revealed kyphosis due to hypoplasia and malformation of the 5 lumbar vertebrae present. At myelography performed immediately after euthanasia, dorsal deviation of the myelographic contrast column was demonstrated at the level of T18–L4 with suspected spinal cord compression noticeable at L1. There was no lateral deviation of the spinal cord or scoliosis of the vertebrae visible.     

Postoperative complication of cervical fracture repair in a dog

Fracture and luxation of the second cervical vertebra of a dog were repaired with braided polyester sutures. After 28 months, the dog became ataxic. Compression of the spinal cord at C1-2 was seen on a myelogram. Surgical exploration of the area revealed a granuloma associated with the sutures and compressing the spinal cord. After the granuloma was removed, the dog recovered and has remained neurologically normal for 21 months. The abnormal tissue was determined histologically to be a pyogranuloma.     

Intraspinal synovial cyst in a dog

An eight-year-old, male Siberian husky cross was referred with a history of an acute onset of pelvic-limb ataxia and paraparesis. Radiography and subsequent myelography of the spine revealed an extradural compression of the spinal cord at the level of the 13th thoracic (T13) to first lumbar (L1) vertebrae. Hemilaminectomy resulted in the successful removal of an extradural cystic lesion. The morphological diagnosis based on histopathology was a synovial cyst with chondromatosis. There were no postoperative complications, and the dog's condition improved markedly. At two years postoperatively, the animal remains normal on both physical and neurological examination. To the authors' knowledge, this article is the first report of an intraspinal synovial cyst in a dog.     

Dorsal laminar elevation as a treatment for cervical vertebral canal stenosis in the dog

A five-month-old Great Dane was presented with marked ataxia and paraparesis. Dynamic radiographic studies showed instability between the fifth and sixth cervical vertebrae and a myelogram revealed spinal cord compression at the sixth cervical vertebral foramen. Dorsal laminar elevation was used in conjunction with articular facet fusion to decompress the spinal cord and stabilise the affected vertebrae. There were no postoperative complications and the dog improved to normality before dying of an unrelated condition seven months after surgery.     

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.     

Cervical chondroid chordoma in a standard dachshund: a case report

A ten-year-old male standard dachshund was presented with a history of neck pain and progressive gait disturbances. Following a neurological examination and diagnostic imaging, including CT, a neoplastic lesion involving the third and fourth cervical vertebrae was suspected. The lesion included an extradural mass on the right side of the spinal canal causing a local compression of the cervical cord. Surgery, using a modified dorsal laminectomy procedure, was performed in order to decompress the cervical spinal cord. Histopathological examination of the extradural mass indicated that the tumour was a chondroid chordoma. Following discharge, the quality of life for the dog was very good for a sustained period, but clinical signs recurred at 22 months. The dog was euthanased 25 months post-surgery. On post-mortem examination, a regrowth of neoplastic tissue was found to have infiltrated the bone and spinal cord at C3-C4. This is the first report to show that palliative surgery can offer successful long-lasting treatment of chondroid chordoma of the cervical spine in the dog.     

Vertebral stabilisation and selective decompression for the management of triple thoracolumbar disc protrusions

Triple adjacent thoracolumbar disc protrusions causing moderate to severe spinal cord compression were diagnosed by magnetic resonance imaging in two German shepherd dogs with marked paraparesis and pelvic limb ataxia. Both cases were managed by selective hemilaminectomy, partial annulectomy and bilateral quadruple vertebral body stabilisation using novel canine locking fixation plates (SOP). The stabilisation of multiple vertebrae in the thoracolumbar spine was possible because the plates could be contoured with six degrees of freedom. Spinal pain resolved and neurological function improved in both dogs. Screw breakage was evident in one dog five months following surgery.     

Paraparesis as initial manifestation of a Prototheca zopfii infection in a dog

A case of protothecosis causing non‐ambulatory paraparesis in a dog without clinical evidence of disseminated infection is described. A five‐year‐old female Labrador retriever was referred with a 10‐day history of progressive non‐ambulatory paraparesis and lumbar pain as the only physical and neurological abnormalities. Lumbar myelography revealed severe extradural spinal cord compression extending from L4 to L7 vertebrae, and a right hemilaminectomy was performed. Surgical findings included an adherent whitish hard ill‐defined mass. Cytology and biopsy results disclosed the presence of algae enclosed in a matrix of chronic inflammatory infiltrate. Culture confirmed the presence of Prototheca species. Neurological improvement occurred within a month, and the dog received antifungal treatment without evidence of clinical disseminated disease for 6 months, but died after a generalised tonic–clonic seizure. Post‐mortem examination revealed multiple foci of inflammatory granulomatous infiltrate and algae‐like structures in the brain, lumbar intumescence and cauda equina. Prototheca zopfii was identified using molecular biology methods.     

Acute basophilic leukaemia in a three-month-old calf

A three-month-old female Holstein–Friesian calf was presented with acute tetraparesis. After neurological examination a multifocal lesion in the central nervous system was suspected with the most pronounced lesions between the third thoracic and the third lumbar vertebrae. Haematological examination revealed moderate anaemia as well as severe thrombocytopenia, neutropenia and leucocytosis. A blood smear and bone marrow aspirate exhibited predominantly blasts with basophilic granulation leading to a diagnosis of acute (myeloid) leukaemia with involvement of the basophilic lineage or an acute basophilic leukaemia. Magnetic resonance imaging revealed spinal cord compression; at necropsy, extensive localised haemorrhages extending into the thoracic vertebral canal were found. Histopathology revealed a large population of blast cells in several tissues including the meninges. Due to multifocal detection of neoplastic cells in the vascular system, neoplasia of the haematopoietic system was assumed in agreement with haematological findings. Signs of paresis could be explained by intramedullary spinal cord haemorrhage and myeloid infiltrations of meningeal vessels. In conclusion, despite its rarity, acute myeloid leukaemia with involvement of the basophilic lineage may be considered in diagnosing calves with progressive deteriorating general condition, paresis, leucocytosis with moderate basophilic differentiation or haemorrhagic disorders.     

Treatment of a prolapsed lumbar intervertebral disc in a ferret

A seven-month-old, male ferret had acute paraplegia and radiographs showed signs of disc prolapse between the second and third lumbar vertebrae (L2/3). Hemilaminectomy was performed to decompress the spinal cord. Histological examination revealed that the extradural material was consistent with annulus fibrosus and the L2/3 articular facets were enlarged as a result of bone remodelling. The ferret became ambulatory one month postoperatively. Five months postoperatively, the ferret had normal posture with mild proprioceptive deficits in the pelvic limbs, and fusion of the L2 and L3 vertebral bodies.     

Spinal nephroblastoma in a crossbreed dog

A three-year-old, male crossbreed dog presented with progressive hindlimb paresis. Magnetic resonance imaging revealed an intramedullary spinal cord lesion of 1.5 cm diameter at the levels of the first and second lumbar vertebrae. Following surgical excision of the mass, there was resolution of the neurological signs. Twelve months later, hindlimb paresis was again evident. A second surgical procedure restored ambulatory status for a further five months before signs recurred and the dog was euthanased. A diagnosis of spinal nephroblastoma was made on the basis of signalment, lesion location and histopathological analysis of biopsy specimens.     

Spinal dural ossification causing neurological signs in a cat

A six-year-old Ragdoll cat underwent examination due to a six-month history of slowly progressive gait abnormalities. The cat presented with an ambulatory tetraparesis with a neurological examination indicating a C1-T2 myelopathy. Radiographs of the spine showed a radiopaque irregular line ventrally in the vertebral canal dorsal to vertebral bodies C3-C5. In this area, magnetic resonance imaging revealed an intradural extramedullary/extradural lesion compressing the spinal cord. The spinal cord was surgically decompressed. The cause of the spinal cord compression was dural ossification, a diagnosis confirmed by histopathological examination of the surgically dissected sample of dura mater. The cat gradually improved after the procedure and was ambulating better than prior to the surgery. The cat’s locomotion later worsened again due to ossified plaques in the dura causing spinal cord compression on the same cervical area as before. Oral prednisolone treatment provided temporary remission. Ten months after surgery, the cat was euthanized due to severe worsening of gait abnormalities, non-ambulatory tetraparesis. Necropsy confirmed spinal cord compression and secondary degenerative changes in the spinal cord on cervical and lumbar areas caused by dural ossification. To our knowledge, this is the first report of spinal dural ossification in a cat. The reported cat showed neurological signs associated with these dural changes. Dural ossification should be considered in the differential diagnosis of compressive spinal cord disorders in cats.     

MRI of a split cord malformation in a german shepherd dog

A 9 yr old spayed female German shepherd dog was referred for MRI of the thoracic and lumbar spine because she had clinical signs of chronic neurogenic bladder dysfunction of an unknown cause. Transverse T2-weighted images identified a type II split cord malformation (i.e., diastematomyelia) in the thoracic spine. Split cord malformations are forms of spinal dysraphism where the abnormal development of spinal cord results in sagittal splitting of a portion of the cord into two hemicords. The location of the lesion in the thoracic spine was consistent with the dog's clinical signs of an upper motor neuron bladder. Split cord malformations that occur in humans have similar MRI characteristics and can result in similar clinical signs as those identified in the dog described in this report.     

Osteosarcoma in adjacent lumbar vertebrae in a dog

An 8-year-old male Belgian Malinois was referred for evaluation of progressive caudal paresis of 2 to 3 weeks' duration. Radiography revealed a mottled appearance to the body of L4 and misshapen intervertebral foramen at L4-L5. Myelography revealed that the dye column terminated within the body of L4. Computed tomography revealed a soft tissue mass adjacent to or involving the spinal cord and L4, with complete destruction of a portion of the floor of the vertebral foramen. Small circular lesions were also noticed within the body of L3 and L5. A left-sided hemilaminectomy was performed. Histologic examination of a biopsy specimen revealed a high-grade sarcoma. Because of the poor prognosis, the dog was euthanatized. Necropsy examination revealed osteosarcoma, with lesions in L3 to L7, the sacrum, and the lungs. Metastatic lesions in adjacent bones have been termed skip metastases and the primary tumor is typically in long bones. Prognosis associated with skip metastases is similar to or even graver than that associated with pulmonary metastases. In the dog of the present report, the unusual finding of distinct foci of osteosarcoma within 5 adjacent lumbar vertebrae and the sacrum was consistent with skip metastases, potentially spread via the vertebral venous plexus.     

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.     

RADIOGRAPHIC DIAGNOSIS: CARTILAGINOUS EXOSTOSES IN A DOG

A 6 month-old dog was examined for progressive paraparesis. On physical examination bony malformations were palpated over the cranial lumbar vertebral bodies and on the left metatarsal bone. Neuroanatomic lesion localization for the paraparesis was a T3-L3 spinal cord lesion. Radiographs confirmed bony masses at L1-L2 and on the left 3rd metatarsal bone. Magnetic resonance imaging was performed from T3-L3. Severe spinal cord compression was identified at L1-L2. Surgical decompression and biopsy confirmed the mass to be cartilaginous exostoses. This paper is an example of cartilaginous exostoses imaged with MR.     

Suspected Spinal Epidural Empyema and Associated Vertebral Osteomyelitis (Physitis)in a Dog

A 1 year old female Aurstralian Heeler dog was presented for fever and paraplegia of recent onset. Radiography and myelography revealed osteolysis of the first lumber (L₁) vertebra and extensive epidural spinal cord compression from the level of the thirteenth thoracic (T₁₃) to the fourth lumbar (L4) vertebra. A decompressive hemilaminectomy was performed; purulent-appearing fluid and inflamed epidural fat were present in the vertebral canal. The neurologic recovery of the dog was satisfactory 6 months following surgery.     

Methyl-methacrylate and bone screw repair of seventh lumbar vertebral fracture-luxations in dogs

Fracture-luxations of the seventh lumbar vertebrae in two large dogs were stabilised with bone screws and methylmethacrylate. Screws inserted bilaterally into the bodies of the lumbar vertebrae and ilial wings were left protruding by about 2 cm, and embedded in methylmethacrylate bone cement. Implant failure occurred in one dog six days after surgery, necessitating a revision of the fixation. Fracture healing and return of normal ambulation ocurred in both dogs. Implants were removed in one dog because of screw loosening and discomfort.     

Treatment of traumatic cervical myelopathy with surgery, prolonged positive-pressure ventilation, and physical therapy in a dog

CASE DESCRIPTION: A 9-year-old dog was evaluated for traumatic cervical myelopathy after a surgical attempt to realign and stabilize the C2 and C3 vertebrae. CLINICAL FINDINGS: The dog could not ventilate spontaneously and was tetraplegic; positive-pressure ventilation (PPV) was maintained. Myelography and computed tomography revealed spinal cord compression with subluxation of the C2 and C3 vertebrae and extrusion of the C2-3 intervertebral disk. TREATMENT AND OUTCOME: Surgically, the protruding disk material was removed and the vertebrae were realigned with screws and wire. For PPV, assist control ventilation in volume control mode and then in pressure control mode was used in the first 6 days; this was followed by synchronized intermittent mandatory ventilation until 33 days after the injury; then only continuous positive airway pressure was provided until the dog could breathe unassisted, 37 days after the injury. Physical therapy that included passive range of motion exercises, neuromuscular electrical stimulation, and functional weight-bearing positions was administered until the dog was discharged 46 days after injury; the dog was severely ataxic and tetraparetic but could walk. Therapy was continued at home, and 1 year later, the dog could run and had moderate ataxia and tetraparesis. CLINICAL RELEVANCE: Hypoventilation with tetraparesis in traumatic spinal cord injury can be successfully treated with PPV exceeding 30 days, surgery, and physical therapy.