Pathological changes in the lumbar spine of pigs: gross findings.

The lumbar vertebral columns from 60 sows and 30 slaughter weight pigs were examined grossly for pathological changes. Asymmetry of lumbar articular facets and minor periarticular osteophytes were seen in the slaughter weight group. Degeneration of intervertebral discs or vertebral osteophytes were not present. In contrast, 38% of 60 sows had vertebral osteophytes and 40% had degeneration of intervertebral discs. Extensive ankylosing spondylosis was present in two sows. Other vertebral lesions observed in sows include asymmetry and arthrosis of articular facets, fissures and areas of cavitation in the annulus fibrosus and vertebral end plate, and vertebral osteomyelitis and/or vertebral fracture. Extravertebral skeletal lesions, some of which could be related to a clinical history of lameness or posterior paralysis, include sacroiliac arthrosis, pelvic deformity, polyarthritis, femoral osteomyelitis, sacroiliac dislocation and epiphyseolysis involving the femoral head or tuber ischii.     

Pathological changes in the lumbar spine of boars.

Lumbar vertebral columns from 73 boars were examined for pathological changes. While pathological changes were minimal at five months of age, several animals aged seven to 18 months of age had facet asymmetry and large osteophytes surrounding lumbar facets. In the adult group 36% had degeneration of intervertebral discs and 28% had ventrolateral vertebral osteophytes. Lesions characterized by irregular areas of cavitation in the annulus and adjacent vertebral epiphyses were also observed. Of animals submitted for necropsy with a history of clinical lameness. lesions included nonsuppurative polyarthritis, fracture of the sacrum and femoral head, osteochondrosis involving articular cartilage of the distal humerus and distal femur, vertebral osteomyelitis, meningeal abscess and ulnar osteomyelitis.     

Tibiotarsal fracture repair in a bald eagle (Haliaeetus leucocephalus) using an interlocking nail.

A 14-yr-old, 5.13-kg bald eagle (Haliaeetus leucocephalus) was hit by a car and presented to the Michigan State University Small Animal Clinic with an open, grade II, transverse, midshaft, Winquist-Hansen type-II-comminuted left tibiotarsal fracture. The fracture was reduced and fixation established with a 4.7-mm-diameter, 112-mm-long, four-hole veterinary intramedullary interlocking nail maintained in position by single 2-mm transcortical screws placed in the main proximal and distal fragments. The bird was weight bearing on the bandaged limb 48 hr postoperatively. Radiographs obtained 4 wk postoperatively revealed bridging callus over three of four cortices. The bird was released after 5 mo of rehabilitation.     

Fractures and luxations of the vertebral column.

External fixation of the vertebral column is indicated to treat fractures of the caudal lumbar spine, open fractures where vertebral osteomyelitis is present or likely to occur, and vertebral fractures not easily stabilized by internal fixation alone (e.g., compression fractures, fractures including spinous processes, and articular facets). Advantages of external fixation of caudal lumbar fractures, especially in combination with dorsal fixation devices, include the following: Fracture fixation does not preclude dorsal decompression; fixation devices need not be applied directly to the fractured vertebrae; and the combined technique provides dorsal and ventral vertebral fixation, which is more stable than dorsal fixation alone. Although external fixation is not applicable to all vertebral fracture/luxations in small animals, it provides additional points of fixation for rigid stability. Animals with vertebral fracture/luxations treated with an external fixation device have tolerated the external portion well. Development of additional applications for this method of vertebral fracture repair seems warranted.     

MRI has limited agreement with CT in the evaluation of vertebral fractures of the canine trauma patient

Complete assessment of vertebral trauma in dogs currently requires CT and MRI for evaluation of the osseous and soft tissue structures that contribute to vertebral stability. Some studies in people have suggested that MRI may be sensitive and specific at detecting vertebral fractures making this potentially a single modality that could be used in spinal trauma evaluation. This study aimed to assess the ability for observers to evaluate vertebral fractures using MRI when compared to CT, which was used as the reference standard. Twenty‐nine dogs with previously diagnosed acute vertebral fractures and four dogs with no vertebral fracture that had undergone sequential CT and MRI were included into the study. One hundred twenty‐eight vertebrae were evaluated for the presence of fractures. Imaging studies were read by two observers blinded to the history. While both observers had similarly high sensitivity and specificity for simple detection of any fractured vertebrae, interobserver agreement was only moderate (κ = 0.584). When evaluations were specifically limited to detection of structurally unstable fractured vertebrae both observers showed improved specificity and interobserver agreement became substantial (κ = 0.650). Complete agreement for exact fracture location between MRI and CT results was only achieved in 14.3‐32.6% of fractured vertebra with up to 79% of fractures being missed in some vertebral structures. This suggests that although MRI may be able to detect the presence of fractured vertebrae, it is not able to replace CT for the complete evaluation of the traumatized spine and documentation of fracture morphology.     

Surgical treatment of a vertebral fracture associated with a haematogenous osteomyelitis in a dog.

A seven-month-old Rottweiler was referred for a diagnosed femoral neck fracture and a suspected vertebral fracture. The simplified neurological examination revealed an acute paraplegia. A discospondyilitis associated with a pathologic fracture of Th11 and a spinal compression, and a haematogenous epiphysitis of the femoral neck were diagnosed based on radiographic and computed tomographic examinations. The vertebral fracture was stabilised using screws and polymethylmetacrylate with gentamycin by a lateral intercostal approach. The dog was able to walk seven days later. A femoral head and neck ostectomy was performed two weeks later. Staphylococcus intermedius was isolated from both sites, which confirmed the diagnosis. The dog was treated with cephalexin (30 mg/kg/d) for six weeks. A telephone interview with owners indicated that no more clinical signs were present four months after the second surgery. Discospondylitis associated with haematogenous osteomyelitis has only been reported in two cases. Paraplegia is an unusual clinical presentation for discospondylitis. The lateral approach (which allowed a direct access to the infected site) and the technique (screws associated with antibiotic-impregnated cement) are unique for surgical treatment of discospondylitis. Although applying cement to an infected area may pose a risk, antibiotic-loaded cement is successfully used in the treatment of chronic osteomyelitis in humans.     

Fracture healing after stabilization with intramedullary xenograft cortical bone pins: a study in pigeons

OBJECTIVE: To investigate the effectiveness of intramedullary xenograft cortical bone pins compared with stainless steel Kirschner wire for the repair of a standardized avian humeral fracture. STUDY DESIGN: Prospective randomized study. SAMPLE POPULATION: Thirty mature pigeons (Columba livia). METHODS: Birds were randomly assigned to 3 groups. Transverse mid-diaphyseal humeral fractures were created in 1 humerus in each bird. Fractures were stabilized with intramedullary ostrich or canine xenograft cortical bone pins or Kirschner wire. Radiographic, histological, and biomechanical assessments were used to compare fracture healing 6 weeks after fracture stabilization. The contralateral humerus of each bird was used as a control. RESULTS: All fractures healed regardless of intramedullary pin type. There were no statistically significant biomechanical differences among groups or within groups. Xenograft cortical bone pins induced a mononuclear inflammatory reaction that did not impair bone healing. Bones stabilized with intramedullary cortical bone pins had more periosteal callus and inflammation at the fracture site than bones stabilized with stainless steel Kirschner wires. CONCLUSIONS: Intramedullary xenograft cortical bone pins, derived from mammalian or avian sources, appear to represent an alternative for the repair of avian humeral fractures. CLINICAL RELEVANCE: Intramedullary xenograft cortical bone pins are biodegradable and may reduce the need for additional surgery to remove implants after fracture healing.     

Video-assisted thoracoscopic surgery for pneumothorax induced by migration of a K-wire to the chest

A 2 yr old female English setter dog was admitted for acute dyspnea. The dog underwent treatment of a T9T10 thoracic vertebral fracture subluxation at the authors' institution 15 mo earlier. Upon admission, a chest X-ray revealed a pneumothorax and a metallic foreign body in the left hemithorax. An emergency video-assisted thoracoscopic surgery was successfully performed to remove a 4.6-mm long Kirschner wire that migrated from the thoracic vertebral column to the thoracic cavity. The operating time was 27 min. The dog made an uneventful recovery and was discharged on the third day after surgery. Pneumothorax should be considered in patients that develop acute dyspnea and have a history of wire fixation in the thoracic vertebral column. Video-assisted thoracoscopic surgery is a safe and effective treatment of this condition.     

Atypical Radiologic Appearance of a Second Cervical Vertebral Fracture in a Horse

This report presents the case of a 21-year-old Warmblood mare referred to the clinic with neurological dysfunctions and considerable signs of discomfort. A fracture of the caudal vertebral body of C2 with a very unusual radiographic appearance was diagnosed, and the mare was euthanized due to deterioration in neurological status. Histology revealed no evidence of neoplasia or pathological fracture.     

Traumatic odontoid process synchondrosis fracture with atlantoaxial instability in a calf: clinical presentation and imaging findings

A 6-week-old female Simmental calf was evaluated for acute non-ambulatory tetraparesis. Physical and laboratory examinations revealed no clinically relevant abnormalities. Neurological findings were consistent with acute, progressive and painful cervical myelopathy. Radiographs displayed a fractured odontoid process (dens axis) and vertebral step misalignment at the fracture site. A traumatic origin was suspected. Advanced diagnostic imaging was considered to allow better planning of potential surgical stabilisation and to exclude any additional lesions of the cervical vertebral column. However, during trailer transportation to the advanced diagnostic imaging and surgery site, the calf deteriorated neurologically and was humanely euthanised. Magnetic resonance imaging (MRI) and computed tomography (CT) were performed immediately post-mortem for scientific reasons. The MRI examination reflected the radiographic findings and confirmed severe spinal cord compression at the fracture site. In addition, a T2W-hyperintense signal change within the paravertebral soft tissue dorsal to the fracture site was indicative of a traumatic event. CT identified the fracture site at the synchondrosis between the odontoid process and the body of the axis, and this finding was confirmed by post-mortem examination. Advanced diagnostic imaging and post-mortem examination did not identify any other cervical lesion. In summary, this calf was diagnosed with a traumatic odontoid process synchondrosis fracture, which has not been reported previously in calves but presents a challenging and well-known fracture type in young children. This case report indicates that the odontoid process synchondrosis is a potential predisposed injury site and that traumatic odontoid process synchondrosis fractures should be considered as a potential differential in calves with acute cervical pain and/or signs of a cervical myelopathy.     

Malignant melanoma in a seagull (Larus fuscus): morphological and immunohistochemical approach

A common seagull (Larus fuscus) was found near the southern coast of Italy by the veterinarians of the local wild animal rescue center. Physical examination of the bird revealed an ulcerated mass involving a majority of the oral cavity; the mass did not allow for normal feeding. After the bird died necropsy was performed and the mass was histologically and immunohistochemically examined. The morphology and the immunoreactivity for Melan-A and S-100 antigens led to a diagnosis of malignant melanoma. This is the first case of malignant melanoma described in a seagull, and herein we compare the characteristics of the present case with malignant melanoma already described in domestic animals.     

Use of pins and methyl-methacrylate in stabilisation of spinal fractures and luxations

Fracture/luxation of the vertebral column commonly results from automobile accidents. Various surgical techniques have been described to stabilise the traumatised vertebral column. This paper describes the use of pins and methyl-methacrylate to maintain fixation of vertebral fracture/luxation at different locations along the spine in four patients of differing bodyweights.     

Lightning injury in an outdoor swine herd.

Three pigs, weighing 63 kg-70 kg each, from a group of 8 pigs in an outdoor pen that was struck by lightning were necropsied. All 3 pigs presented with hind limb paralysis. The only lesions identified were multiple fractures of the last (seventh) lumbar vertebral body and first sacral vertebral segment, with dorsal displacement of the sacrum and transection of the distal spinal cord and spinal nerves. Hemorrhages extended from the fracture sites into muscles immediately surrounding the lumbosacral junction and retroperitoneally into the pelvic cavity. These hemorrhages were not clearly visible until the pelvic region was dissected. Lesions commonly found in human lightning-strike victims were not present in these pigs. Because vertebral fractures may be the only lesions and may be grossly subtle in heavily muscled pigs, careful pelvic and vertebral dissection is recommended in cases of suspected lightning strike and electrocution.     

FRACTURED SCLERAL OSSICLES IN A RED TAIL HAWK

Following head trauma, the left globe of a Red Tail Hawk showed demonstrable indentation on palpation. Recurrent anterior chamber collapse and reformation dependent on head position was the most significant clinical finding. A fracture of the scleral ossicles in the caudal portion of the scleral ring was identified in the rostrocaudal radiograph of the skull. Conservative management of the fracture resulted in phthisis bulbi. Fractured scleral ossicles have been shown radiographically in the enucleated globe but have not been previously demonstrated in the eye of the living bird.     

Lumbar fractures in a 5-year-old Warmblood cross gelding

This case report describes multiple lumbar vertebral fractures in a 5-year-old Warmblood cross gelding used for low-level exercise, with no known history of trauma. Clinical signs included intermittent severe pain, distress and unwillingness to move. When the horse was in less severe pain, he tilted the pelvis to one side when walking and also when trotting. Fracture of the 6th lumbar vertebral body was diagnosed by transrectal ultrasonography and confirmed by post-mortem computed tomography. Post-mortem examination also revealed a complete fracture of the 3rd lumbar vertebral body. Previously, lumbar fractures have only been reported in racing breeds and ante mortem diagnosis has been limited to scintigraphy.     

Internal Skeletal Fixation Using a Kirschner Apparatus for Stabilization of Fracture/Luxations of the Lumbosacral Joint in Six Dogs: A Modification of the Transilial Pin Technique

A technique using a modification of the transilial pin technique for stabilization of fracture/ luxations of the lumbosacral joint was performed in six dogs. This technique used an internal skeletal fixator composed of two transilial pins secured with two double fixator clamps. Collapse (shortening) of the seventh lumbar vertebra (L7) was observed in five dogs without compromise of the vertebral canal. Kirschner wires placed across the articular facets as supplemental fixation devices migrated to the subcutaneous tissues in two dogs and were easily removed. Migration of the internal fixators was not observed during healing; vertebral canal dimensions were maintained in all cases, and the internal fixators were not removed after resolution of fracture healing. All fractures were healed within 6 to 12 weeks of surgery without evidence of pain, neurologic impairment, or long-term complications.     

Metastatic Tumor in Pregnancy: Placental Germ Cell Tumor With Metastasis to the Foal

A placental mass was observed in an otherwise-healthy Quarter Horse mare; subsequently, the mare's 52-day-old foal was examined because of hind limb ataxia, urinary incontinence, and raised lesions of the distal limbs. Clinical and biochemical findings were supportive of liver disease and lumbosacral injury. Ultrasonographic evaluation of the abdomen suggested a liver mass, which was confirmed with computed tomography (CT) and determined to be neoplastic via histopathologic evaluation of a liver biopsy sample. Initial histopathology suggested a germ cell tumor. Regions of lysis affecting both femurs and third metacarpal bones and a complete oblique sagittal fracture through the body of the first sacral vertebra were present on CT. Supportive care was provided until CT confirmation of diffuse hepatic neoplasia and vertebral fracture. Necropsy revealed a large multinodular mass within the liver and a pathologic fracture of the first sacral vertebral body. Histopathologic comparison between neoplastic cells examined from the placenta and foal confirmed metastases of a germ cell tumor. Placental tumors are rare in all species; however, when noted in horses, clinicians should be aware of the possibility of metastatic spread to the foal.     

Dysplasia of the caudal vertebral articular facets in four dogs: results of radiographic, myelographic and magnetic resonance imaging investigations

Congenital anomalies of the vertebral column associated with aberrations of one of the primary vertebral ossification centres have been frequently described in the veterinary literature, but clinically significant abnormalities of secondary vertebral ossification centres, particularly involving the caudal articular processes, are much less frequently reported. This paper describes three dogs with aplasia and one dog with hypoplasia of the caudal vertebral articular processes. Thoracolumbar spinal cord compression and ataxia was evident in the three dogs with aplasia but no clinical signs were evident in the dog with hypoplasia. The radiographic appearance was similar in all four cases, with aplasia or hypoplasia of the caudal articular facets at one or more intervertebral joints in the thoracolumbar region. Bone proliferation was evident secondary to an associated degenerative joint disease. Compensatory hyperplasia of the adjacent cranial articular facets and ligamentum flavum protruded into the vertebral canal, resulting in a compressive myelopathy observed by myelography and magnetic resonance imaging.