Methylprednisolone sodium succinate reduces spinal cord swelling but does not affect recovery of dogs with surgically treated thoracolumbar intervertebral disk herniation.

The effect of methylprednisolone sodium succinate (MPSS) therapy was studied in 50 dogs with surgically treated Hansen type I thoracolumbar intervertebral disk herniation (TL-IVDH). Administration of MPSS significantly reduced the swelling of the spinal cord. The sensitivity of localization of disk extrusion using myelography in the MPSS group was 92.3%, and in the non-administration group was 83.3%. No significant difference in recovery rate or length of recovery time was found between the two groups. Administration of MPSS reduced spinal cord swelling, but has no effect on recovery in dogs after surgery for TL-IVDH.

Clinical features of early recurrence of type I thoracolumbar intervertebral disk herniation in Miniature Dachshunds.

Some reports have been published on clinical features in dogs with early recurrence of type I thoracolumbar intervertebral disk herniation (TL-IVDH), but there is little understanding of the changes involved. This retrospective study describes the clinical features, including radiographic image results at the time of recurrence, of dogs with type I TL-IVDH that had undergone hemilaminectomy but then suffered early recurrence. Our medical records were searched between June 2007 and December 2022. Nine dogs showed deterioration in neurological signs within 4 to 6 weeks after surgery. All nine were Miniature Dachshunds. Radiographic images at initial onset showed calcification at the affected intervertebral disk space in all 9 dogs. Disk herniations at the initial onset were located between T11-12 and L1-2. After the first surgery, neurological function improved in all dogs. Recurrence occurred at the same site as at initial onset in all dogs. No calcification was observed at the affected intervertebral disk space on images at the time of recurrence. The extruded disk materials were surgically removed, and neurological function improved after the second surgery. In conclusion, calcification at the affected disk space at the time of initial onset is indicative of residual nucleus materials not yet fully extruded, and is a risk factor for early recurrence of type I TL-IVDH.

The volume of extruded materials is correlated with neurologic severity in small-breed dogs with type I thoracolumbar intervertebral disk herniation.

OBJECTIVE: To assess whether the volume of extruded materials is correlated with neurologic severity in dogs with type I thoracolumbar intervertebral disk herniation (TL-IVDH). ANIMALS: 70 client-owned small-breed dogs with type I TL-IVDH diagnosed between July 1, 2016, and June 30, 2018. PROCEDURES: For this retrospective cohort study, the medical records of 70 dogs with surgically confirmed type I TL-IVDH were reviewed. The volume and height of the intervertebral disk and the area of the maximal transverse compressed spinal cord were measured using CT myelographic images. For each dog, the volume of the disk immediately cranial to the herniated disk was an internal control. Dogs were grouped on the basis of grade of neurologic severity. RESULTS: Preoperative grades of neurologic severity were grade 2 in 7 (10%) dogs, grade 3 in 16 (23%) dogs, grade 4 in 28 (40%) dogs, and grade 5 in 19 (27%) dogs. The total volume of the affected intervertebral disks was significantly larger than the internal control. Weak positive correlation was found between the volume of the extruded materials into the vertebral canal and the grade of neurologic severity. CLINICAL RELEVANCE: Our findings indicated that the total volume of the affected intervertebral disks is larger in dogs with type I TL-IVDH, and the volume of the extruded materials into the vertebral canal is weakly correlated with the neurologic severity.

Safety of autologous bone marrow stromal cell transplantation in dogs with acute spinal cord injury.

OBJECTIVE: To assess the feasibility and safety of transplantation of autologous bone marrow stromal cell (BMSC) in dogs with acute spinal cord injury (SCI). STUDY DESIGN: An open-label single-arm trial. ANIMALS: Dogs (n = 7) with severe SCI from T6 to L5, caused by vertebral fracture and luxation. METHODS: Decompressive and stabilization surgery was performed on dogs with severe SCI caused by vertebral fracture and luxation. Autologous BMSCs were obtained from each dog's femur, cultured, and then injected into the lesion in the acute stage. Adverse events and motor and sensory function were observed for >1 year after SCI. RESULTS: Follow-up was 29-62 months after SCI. No complications (eg, infection, neuropathic pain, worsening of neurologic function) were observed. Two dogs walked without support, but none of the 7 dogs had any change in sensory function. CONCLUSIONS: Autologous BMSC transplantation is feasible and safe in dogs with acute SCI. Further studies are needed to determine the efficacy of this therapy.

Acute myelomonocytic leukemia (AML-M4) in a dog with the extradural lesion.

A two-year-old dog having presented with neurological signs showed marked leukocytosis and appearance of blast cells in the peripheral blood. Hematological and bone marrow examination showed an increase in blasts having both myeloid and monocytic cells characteristics. The dog was diagnosed with acute myelomonocytic leukemia (AML-M4) on the basis of bone marrow findings. Although the dog was treated with a multi-combination chemotherapy, the neurological abnormalities progressed and the dog was euthanized. Myelographic examination and necropsy revealed the extradural lesion formed by AML-M4 around the cervical spinal cord and this lesion was considered as a cause of the neurological signs.

Inflammatory reaction in the herniated degenerative disc materials in miniature dachshunds.

Histological and immunohistochemical studies were conducted using herniated intervertebral disc materials obtained surgically from 39 miniature dachshunds. Infiltration of inflammatory cells, such as macrophages, neutrophils, T or B lymphocytes, and multinucleated giant cells, were identified in intervertebral disc materials in 23 cases. Furthermore, proliferations of connective tissue, including neovascularization, were also observed in 17 cases. These results suggest that spontaneous regression of herniated intervertebral disc material could occur in affected dogs.

Effects of structural flexibility of wings in flapping flight of butterfly.

The objective of this paper is to clarify the effects of structural flexibility of wings of a butterfly in flapping flight. For this purpose, a dynamics model of a butterfly is derived by Lagrange's method, where the butterfly is considered as a rigid multi-body system. The panel method is employed to simulate the flow field and the aerodynamic forces acting on the wings. The mathematical model is validated by the agreement of the numerical result with the experimentally measured data. Then, periodic orbits of flapping-of-wings flights are parametrically searched in order to fly the butterfly models. Almost periodic orbits are found, but they are unstable. Deformation of the wings is modeled in two ways. One is bending and its effect on the aerodynamic forces is discussed. The other is passive wing torsion caused by structural flexibility. Numerical simulations demonstrate that flexible torsion reduces the flight instability.

Three cases of idiopathic sterile pyogranulomatous inflammation of epidural fat in Miniature Dachshunds.

Progressive ataxia and paralysis in three Miniature Dachshunds were found to be caused by idiopathic sterile pyogranulomatous inflammation of epidural fat between T5 and L4. All dogs were managed by hemilaminectomy and removal of epidural compressive material. Surgical findings and histopathological evaluation were necessary to diagnose epidural pyogranulomatous inflammation. A dog did not regain motor and sensor function after the surgery. Two dogs had exhibited improved neurological function after the surgery, but they recurred. Oral cyclosporine treatment was useful for their long remission. Idiopathic sterile pyogranulomatous inflammation of epidural fat can be considered to be a cause of thoracolumbar myelopathy in dogs.

Evaluation of transplantation of autologous bone marrow stromal cells into the cerebrospinal fluid for treatment of chronic spinal cord injury in dogs.

OBJECTIVE: To evaluate effects of transplantation of bone marrow stromal cells (BMSCs) into the CSF for the treatment of chronic spinal cord injury in dogs that had not responded by 1 month after decompressive surgery. ANIMALS: 23 dogs. PROCEDURES: Dogs with paraplegia and loss of nociception in the pelvic limbs for at least 1 month after decompressive surgery were assigned to transplantation or control groups. Dogs in the transplantation group received BMSCs injected into the CSF 1 to 3 months after decompressive surgery. Dogs in the control group did not receive additional treatments. Improvements in gait, proprioceptive positioning, and nociception were evaluated by use of the Texas Spinal Cord Injury Scale for ≥ 6 months after BMSC transplantation. RESULTS: 6 of 10 dogs in the transplantation group regained the ability to walk, whereas only 2 of 13 dogs in the control group regained the ability to walk. Scores for the Texas Spinal Cord Injury Scale in the transplantation group were significantly higher than scores in the control group at the endpoint of the study (6 months after BMSC transplantation or after decompressive surgery for the transplantation and control groups, respectively). Only 1 dog (transplantation group) recovered nociception. All dogs from both groups had fecal and urinary incontinence. No complications were observed in relation to BMSC transplantation. CONCLUSIONS AND CLINICAL RELEVANCE: Injection of BMSCs into the CSF caused no complications and could have beneficial effects on pelvic limb locomotion in dogs with chronic spinal cord injuries.