Effects of acute hypoxia on auditory pathway of Wistar albino rats

Background/aim: Ischemia is insufficient blood flow to provide adequate oxygenation. In the present study, we aimed to show whether acute hypoxia has a critical oxygen value that may lead to the deterioration of cochlear function. Materials and methods: Under general anesthesia, prehypoxic signal-to-noise ratios were determined by distortion product otoacoustic emissions (DPOAE). The oxygen saturation (SaO2) values of rats were monitored with an oxygen saturation probe. Rats were injected with an extra dose of anesthetic agent, and SaO2 was reduced. DPOAE values in SaO2 100­90, 90­80, 80­70, and 70­60 posthypoxic values were measured and compared statistically with prehypoxic values. Results: At 3000 and 4000 Hz, SaO2 70­60 values measured after the hypoxia were observed to be statistically significantly lower than the values measured before the hypoxia. At 6000 and 8000 Hz, SaO2 80­70 and 70­60 values measured after the hypoxia were observed to be statistically significantly lower than the values measured before the hypoxia. At 10,000 Hz, all of the values measured after the hypoxia were observed to be statistically significantly lower than the values obtained before the hypoxia. Conclusion: Many studies have been conducted on the effects of hypoxia on the inner ear. It remains unclear how fluctuations in DPOAE levels affect hearing in clinical trials when the SaO2 starts to decrease. Although hypoxia has been implicated in the etiology of sudden hearing loss and tinnitus, the effects of acute hypoxia on the cochlea are still uncertain. Further studies are needed on this subject.

Effects of phenytoin injection on vocal cord healing after mechanical trauma: An experimental study

Background/aim: Phenytoin is an anticonvulsant drug which causes fibroblast proliferation, collagen synthesis, and an increase in epidermal growth factor. Therefore, the aim of the present study is to evaluate the effect of phenytoin injection on the wound healing process in rats with vocal cord injury by histopathological methods. Materials and methods: The vocal cords of 10 albino Wistar rats were damaged bilaterally; the left vocal cord was kept as the control group. Phenytoin was injected in the right vocal cord. Ten rats were sacrificed. The thickness of the lamina propria and density of the fibroblast and collagen were evaluated histopathologically. Results: Thickness of the lamina propria was 18.0 ± 7.1 µm in the control group, 65.5 ± 10.7 µm in the phenytoin group. The density of fibroblast and collagen were statistically lower in the control group compared the phenytoin group (P < 0.05). Conclusion: Phenytoin injection in rats after vocal cord injury significantly increased the thickness of the lamina propria and density of fibroblast and regular and mature collagen in the lamina propria. The findings in our study provide a feasible scientific view for adding phenytoin treatment to vocal cord surgeries in otolaryngology practice, but further studies are needed in order to evaluate the use of phenytoin in preventing the formation of scar tissue and possible effects on vocal cord vibration in humans after vocal cord injury.

Study of mouse induced pluripotent stem cell transplantation intoWistar albino rat cochleae after hair cell damage.

BACKGROUND/AIM: As the regeneration capacity of hair cells is limited, inner ear stem cell therapies hold promise. Effects of mouse induced pluripotent stem cells (IPSCs) on Wistar albino rats (WARs) with hearing impairment were investigated. MATERIALS AND METHODS: Thirty-five adult WARs with normal hearing were divided into 4 groups. Excluding the study group (n = 15), the other three groups served as control groups for ototoxicity and IPSC injection models. IPSC injections were performed via cochleostomy after a retroauricular approach. Auditory functions were evaluated with auditory brainstem responses (ABRs) before and after the injections. After a final hearing assessment the WARs were sacrificed and cochleae were extracted to see the biologic behavior of IPSCs in the inner ear by light microscopy and immunohistochemistry. RESULTS: There were no significant differences in the click-ABR thresholds in the study group after IPSC transplantation. The mean hearing threshold in the study group after ototoxic agent injection was 53.2 dB (10-90 dB). There was no significant difference between groups (P > 0.05) and no differentiated stem cells were observed immunohistochemically. CONCLUSION: Transplanted IPSCs did not show a therapeutic effect in this trial. We discuss potential pitfalls and factors affecting the therapeutic effect.

Comparison of Etanercept, Etomidate and Erythropoietin and Their Combinations in Experimentally-Induced Spinal Cord Injury.

AIM: The aim of this study was to compare the preventive effects of Etanercept, Etomidate, Erythropoietin and their combination in experimentally induced spinal cord trauma by clinical, histopathological, electrophysiological parameters and biochemical examination. MATERIAL AND METHODS: 85 healthy female Wistar-Albino rats were used in this study. Rats were divided 8 trauma groups that consisted of 10 rats for each, and 5 rats for the sham group. Laminectomy was performed under general anesthesia and the spinal cord was exposed with intact dura mater, and injury was created by the clip compression model. After the spinal cord injury, drugs were administered immediately intraperitoneally or subcutaneously. Except the sham group, all groups received drugs and were observed 24 or 72 hours. At the 72nd hour each group was anesthesized and somatosensorial evoked potentials (SEP) were recorded from the interarcuate ligament from the 2 vertebra proximal to the injured spinal cord and spinal cord tissue samples were taken for histopathological and biochemical evaluation. RESULTS: Etomidate groups showed a lower effect on spinal cord injury than etanercept and erythropoietin in terms of clinical, SEP and TNF-α. Etanercept and erythropoietin's neuroprotective effectiveness was shown alone or in combination treatments. More meaningful results were achieved with the use of erythropoietin and etanercept combination after spinal cord injury (SCI) than using erythropoietin alone. After SCI, highest Basso, Beattie, and Bresnahan (BBB) scores were achieved in the group which Etanercept and Erythropoietin applied together. CONCLUSION: The neuroprotective activity of etomidate was suspect. The neuroprotective effect of etanercept and erythropoietin after SCI was shown in individual and combined applications in this study. However, more experimental studies are needed for clinical use.

The use of autologous neurogenically-induced bone marrow-derived mesenchymal stem cells for the treatment of paraplegic dogs without nociception due to spinal trauma.

The aim of this study was to investigate the effects of percutaneous transplanted autologous neurogenically-induced bone marrow-derived mesenchymal stem cells (NIBM-MSCs) in paraplegic dogs without deep pain perception (DPP) secondary to external spinal trauma. Thirteen client owned dogs that had failed in improvement neurologically at least 42 days after conservative management, decompression and decompression-stabilization were included in the study. Each dog received two doses of autologous 5.0 × 106 NIBM-MSCs suspension, which were positive to 2',3'-Cyclic-nucleotide-3'-phosphodiesterase (CNPase) and Microtubule-associated protein 2 (MAP-2), as well as to Glial fibrillary acidic protein (GFAP) and beta III tubulin. The cells were injected into the spinal cord through the hemilaminectomy or laminectomy defects percutaneously with 21 days interval for 2 times. The results were evaluated using Texas Spinal Cord Injury Scale (TSCIS), somatosensory evoked potentials (SEP) and motor evoked potentials (MEP) at the admission time, cell transplantation procedures and during 2, 5, 7 and 12th months after the second cell transplantation. Improvement after cell transplantation in gait, nociception, proprioception, SEP and MEP results was observed in just 2 cases, and only gait score improvement was seen in 6 cases, and no improvement was recorded in 5 cases. All progresses were observed until 2nd month after the second cell transplantation, however, there was no improvement after this period. In conclusion, percutaneous transplantation of autologous NIBM-MSCs is a promising candidate modality for cases with spinal cord injury after spinal trauma and poor prognosis.

Experimental Endoscopic Cordotomy in the Sheep Model.

AIM: Interventional pain therapies are usually based on destruction of the related pain-conducting pathways. Current procedures targeting pain have replaced conventional pain treatment modalities while being less invasive. In this study, we investigated the feasibility of the endoscopic percutaneous cordotomy process on the sheep cervical spinal cord. MATERIAL AND METHODS: Seven male sheep, Akkaraman® genus, were operated on in the study. The guide was introduced at C1 to C2 vertebrae. The interlaminar area was exposed by a dilator, the dura was identified, and then the working cannula was inserted into the subarachnoid space. The target point of cordotomy was defined by endoscopic visualization as the midpoint between the dentate ligament and ventral root entry zone. After determination of the target point, a carbon dioxide laser (CDL) probe was introduced through the cannula. Ablative lesioning was performed by CDL. Hindlimb withdrawal thresholds were measured using the "Sample Pain Scale". The lesion was demonstrated by magnetic resonance imaging and histopathological examination. RESULTS: Three sheep had ipsilateral hemiparesis and the response to firm pressure test was not performed on them. Among the remaining four sheep, the pain tolerance test showed that one sheep was at stage 0, two at stage 1, and the last one at stage 3. CONCLUSION: Cordotomy might be successfully performed with the endoscopic technique in the sheep model and this should encourage future studies regarding minimal invasive procedures for intractable pain.

Imaging and surgical outcomes of spinal tumors in 18 dogs and one cat.

Clinical and magnetic resonance imaging (MRI) findings, histological appearances and surgical outcomes of 18 dogs and one cat with spinal tumors are presented. Medical records of the cases admitted for spinal disorders were reviewed, and cases of spinal tumors that were diagnosed by MRI and confirmed by histological examination were included in this study. T1 weighted, T2 weighted and contrast enhanced T1 weighted images were taken and interpreted to evaluate the spinal tumors. The tumors were diagnosed as: meningioma (n = 6), ependymoma (n = 1), nerve sheath tumor (n = 4), metastatic spinal tumor (n = 3), osteosarcoma (n = 2), osteoma (n = 1), rhabdomyosarcoma (n = 1), and nephroblastoma (n = 1). Thirteen cases underwent surgical operation and the remaining six cases were euthanized at the request of the owners. The neurological status of the surgical cases did not deteriorate, except for one dog that showed ependymoma in the early period after the operation. These results indicate the potential for surgical gross total tumor removal of vertebral tumors to provide better quality of life and surgical collection of histological specimens for definitive diagnosis. For effective case management, dedicated MRI examination is important to accurate evaluation of the spinal tumors, and surgical treatment is useful for extradural and intradural-extramedullary spinal tumors.

Intraspinal Transplantation of Autologous Neurogenically-Induced Bone Marrow-Derived Mesenchymal Stem Cells in the Treatment of Paraplegic Dogs without Deep Pain Perception Secondary to Intervertebral Disk Disease.

AIM: To investigate the effects of neurogenically-induced autologous bone marrow-derived mesenchymal stem cells (NIBM-MSCs) in paraplegic dogs without deep pain perception (DPP) secondary to intervertebral disk disease (IVDD). MATERIAL AND METHODS: Seven dogs which could not be improved neurologically with conventional treatment modalities were included in the study. All dogs were diagnosed by magnetic resonance imaging and surgically treated. Each dog received two times a suspension of autologous 5.0x106 NIBM-MSCs, which were positive to CNPase and MAP-2, as well as to GFAP and beta III tubulin into the spinal cord through the hemilaminectomy defect percutaneously, with a 21-day interval. RESULTS: Two months after cell transplantation, there were no changes except for 1 gait score improvement for 1 of the cases. At the 4th month, gait score had improved 1 score in 5 cases, and one score progress was recorded in proprioception and nociception in 1 case. In eight months-followed up 4 cases were evaluated by the same parameter; gait score had improved in 3 cases, and propriception improved in 2 cases, and nociception improved in 3 cases. CONCLUSION: Our findings suggest that utility of autologous NIBM-MSCs for cases with poor prognosis after IVDD can be a promising approach.

Study the effects of zonisamide on fine structure of rabbit basilar artery and hippocampus in rabbit subarachnoid hemorrhage model.

BACKGROUND: In this study, we investigated the effect of a novel antiepileptic drug, zonisamide (ZNS), on the basilar artery and hippocampus in a rabbit subarachnoid hemorrhage (SAH) model. METHODS: Three groups of New Zealand white rabbits were used: a sham (non-SAH) group, an SAH + saline group, and SAH + drug treatment group that received ZNS. In the treatment group, the subjects were given ZNS for 3 days after the SAH. Hippocampal sections were evaluated for neural tissue degeneration. Basilar artery lumen areas and arterial wall thickness were also measured in all groups. RESULTS: The mean luminal area of the SAH + ZNS was significantly greater than the SAH + saline group. In addition, the arterial wall thickness of SAH + ZNS group was significantly thinner than the SAH + saline group. The neuronal degeneration scores of the hippocampal CA1 regions in the SAH + ZNS group were significantly lower than the SAH + saline treatment animals. CONCLUSIONS: These results indicate that ZNS has a vasodilatatory effect on the basilar artery and a neuronal protective effect in the CA1 region of the hippocampus in a rabbit SAH model.

Protective effects of resveratrol on cisplatin-dependent inner-ear damage in rats.

Cisplatin is a common chemotherapeutic agent used in many solid and hematologic malignancies. The main unwanted effect of cisplatin is ototoxicity, for which no standard treatment has been reported. The present study examined the protective efficacy of resveratrol on cisplatin-dependent ototoxicity through an experimental model. Fifteen rats were randomized into three groups. Group 1 (control group) (n = 5) received intraperitoneal (i.p.) 15 mg/kg cisplatin; group 2 (resveratrol group) (n = 5) received i.p. 100 mg/kg resveratrol, followed by i.p. 15 mg/kg cisplatin; group 3 (n = 5) served as a vehicle group and received i.p. 1 ml dimethyl sulfoxide. All rats underwent the auditory brainstem response (ABR) test before and 72 h after the treatment. Pretreatment ABR values of the groups were not significantly different. The pretreatment hearing threshold values of the groups were 30 ± 6.60 and 28.5 ± 5.29 dB in groups 1 and 2, respectively (p > 0.05). The post-ABR-I and post-ABR-IV values were, respectively, 1.41 ± 0.18 and 5.83 ± 0.16 ms in the control subjects and 1.19 ± 0.22 and 4.58 ± 0.27 ms in the study group. The ABR-I and ABR-IV durations in rats treated with resveratrol were significantly shorter (p < 0.01). A comparison of threshold values shows that the resveratrol-treated rats had significantly lower values than the control rats. After cisplatin injection, ABR I-IV intervals were compared among the groups. The ABR I-IV interval duration was 4.42 ± 0.16 ms in the control group, while the resveratrol-treated rats showed a significantly shorter ABR I-IV interval duration of 3.49 ± 0.27 ms (p < 0.001). Resveratrol attenuated cisplatin-dependent inner-ear damage, as shown by the ABR-I, ABR-IV, ABR I-IV interval, and hearing threshold values. Our results suggest that this natural antioxidant may be effectively used in reducing the unwanted effects of cisplatin on the ear physiology of patients, particularly those undergoing chemotherapy.

Effect of curcumin on lipid peroxidation, early ultrastructural findings and neurological recovery after experimental spinal cord contusion injury in rats.

AIM: After acute spinal cord injury (SCI), a large number of axons are lost by a cascade of pathophysiological events known as a secondary injury. The main aim of the current study was to investigate the potential neuroprotective effects of curcumin on lipid peroxidation (LPO), neurological function, and ultrastructural findings after SCI. MATERIAL AND METHODS: Forty adult Wistar albino rats were randomized into five groups: control, SCI alone (50 g/cm weight drop), methylprednisolone sodium succinate (MPSS) (30 mg/kg), curcumin + dimethyl sulfoxide (DMSO) (300 mg/kg), and DMSO alone (0.1 mg/kg). RESULTS: Administration of curcumin significantly decreased LPO in first 24 hours. However, there were no differences in the neurological scores of injured rats between the medication groups and the control group. Curcumin was more effective than DMSO and MPSS in reducing LPO, whereas DMSO was more effective than curcumin and MPSS in minimizing ultrastuctural changes. The results of this study indicate that curcumin exerts a beneficial effect by decreasing LPO and may reduce tissue damage. CONCLUSION: Since ultrastructural and neurological findings does not support biochemical finding, our findings do not exclude the possibility that curcumin has a protective effect on the spinal cord ultrastructure and neurological recovery after SCI. A combination of curcumin with other vehicle may also have a considerable synergy in protecting spinal cord.

Cystocele and rectal prolapse in a female dog.

A case of cystocele and prolapsed rectum is reported. The urinary bladder and rectum were repositioned and fixed by cystopexy, colposuspension, and colopexy concurrently. There was no recurrence after 3 months. This is the first report to describe cystocele in a young female dog never having been pregnant.

Cystocèle et prolapsus rectal chez une chienne. Un cas de cystocèle et de prolapsus rectal est signalé. La vessie urinaire et le rectum ont été repositionnés et réparés par cystopexie, par colposuspension et colopexie de manière concomitante. Il n'y a pas eu de récurrence après 3 mois. Il s'agit du premier rapport pour décrire la cystocèle chez une jeune chienne qui n'avait jamais eu de gestation.(Traduit par Isabelle Vallières).

Effect of granulocyte-colony stimulating factor on spinal cord tissue after experimental contusion injury.

The purpose of this study was to investigate the early effects of granulocyte-colony stimulating factor (G-CSF) on myeloperoxidase (MPO) activity, lipid peroxidation (LPO) and ultrastructural findings in rats after spinal cord injury (SCI). We also compared the effects of G-CSF and methylprednisolone sodium succinate (MPSS). Wistar rats were divided into four groups: control, SCI alone (50 g/cm weight drop trauma), SCI+MPSS (30 mg/kg), and SCI+G-CSF (50 µg/kg). Administration of G-CSF and MPSS significantly decreased LPO (p < 0.05) and MPO activity (p < 0.05) in the first 24 hours. MPSS was more effective than G-CSF in reducing LPO (p < 0.05) and in minimizing ultrastructure changes. The results of this study indicate that G-CSF exerts a beneficial effect by decreasing MPO activity and LPO and may reduce tissue damage in the first 24 hours after SCI. Our findings do not exclude the possibility that G-CSF has a protective effect on spinal cord ultrastructure after the first 24 hours following SCI.

Topiramate attenuates hippocampal injury after experimental subarachnoid hemorrhage in rabbits.

OBJECTIVE: The aim of this study was to investigate the ability of topiramate (TPM) to prevent neural injury in a rabbit model of subarachnoid hemorrhage (SAH). The effect of TPM on cerebral vasospasm was also evaluated. METHODS: Fifty-three New Zealand white rabbits were allocated into three groups randomly. SAH was induced by injecting autologous blood into the cisterna magna. The treatment groups were as follows: (1) sham operated (no SAH (n=18); (2) SAH only (n=17); (3) SAH + TPM (n=18). Hippocampal sections were evaluated for neural tissue degeneration, using the previously described neural degeneration scoring system. The ApopTag peroxidase in situ apoptosis detection kit (Serologicals Corp., former Intergen) was used to assess apoptosis in the hippocampal sections and the effect of TPM on the apoptotic response. Basilar artery lumen areas and arterial wall thickness were also measured in all groups. RESULTS: There was a statistically significant difference between the mean degeneration scores of the control and SAH only groups (p<0.05). The level of neural degeneration in TPM treated group was significantly lower compared with SAH only group (p<0.05), but not significantly higher than the control group (p>0.05). There were no statistically significant differences between arterial cross-sectional area and arterial wall thickness measurements of the SAH group and SAH + TPM group. CONCLUSION: These findings demonstrate that TPM has marked neuroprotective effect in an experimental model of SAH in rabbits. This observation may have clinical implications suggesting that this antiepileptic drug could be used as a possible neuroprotective agent in patients without major adverse effects.

Effects of raloxifene on cerebral vasospasm after experimental Subarachnoid Hemorrhage in rabbits.

BACKGROUND: The aim of this study was to investigate the ability of a SERM, RLX, to prevent vasospasm in a rabbit model of SAH. METHODS: Thirty-four New Zealand white rabbits were allocated into 3 groups randomly. Subarachnoid hemorrhage was induced by injecting autologous blood into the cisterna magna. The treatment groups were as follows: (1) sham operated (no SAH [n = 12]), (2) SAH only (n = 12), and (3) SAH plus RLX (n = 10). Basilar artery lumen areas and arterial wall thickness were measured to assess vasospams in all groups. RESULTS: There was a statistically significant difference between the mean basilar artery cross-sectional areas and the mean arterial wall thickness measurements of the control and SAH-only groups (P < .05). The difference between the mean basilar artery cross-sectional areas and the mean arterial wall thickness measurements in the RLX-treated group was statistically significant (P < .05). The difference between the SAH group and the SAH + RLX group was also statistically significant (P < .05). CONCLUSIONS: These findings demonstrate that RLX has marked vasodilatatory effect in an experimental model of SAH in rabbits. This observation may have clinical implications suggesting that this SERM drug could be used as possible anti-vasospastic agent in patients without major adverse effects.

Effects of carbamazepine on spinal cord ischemia.

BACKGROUND: Prophylactic treatment with carbamazepine has been shown to reduce the cerebral damage and neurologic deficit in ischemic conditions. A randomized controlled study based on a rabbit model was designed to study the effect of carbamazepine on a spinal cord ischemic reperfusion injury. METHODS: Thirty New Zealand rabbits were randomly assigned to 1 of the 2 groups (n = 15 per group): group I (control group) and group II (carbamazepine group). Spinal cord ischemia was induced by infrarenal aortic crossclamp for 25 minutes in both groups. Functional evaluation with the Tarlov score during a 2-day observation period and histopathologic assessment of the lumbar spinal cord were performed. Changes in spinal cord morphology were observed with hematoxylin-eosin staining and electron microscopy. Gray matter damage was assessed on the basis of the number of normal neurons in the ventral horn. RESULTS: Diffuse destruction of gray matter with moderate to severe vacuolization and essentially no normal ganglion cells was observed in the spinal cord of rabbits in the control group, whereas specimens of rabbits assigned to the carbamazepine group showed ganglion cells with normal nuclei and cytoplasm (P < .0001). Neurologic impairment was significantly attenuated in the carbamazepine group compared with the Tarlov scores of the control group (P < .0001 at day 2). CONCLUSION: Carbamazepine may protect the spinal cord from ischemic reperfusion injury that is associated with ameliorated neurologic and histopathologic results.

Lamotrigine attenuates cerebral vasospasm after experimental subarachnoid hemorrhage in rabbits.

BACKGROUND: Increasing evidence implicates voltage-dependent sodium and potassium channels, in addition to calcium channels of various types, in the pathophysiological development of cerebral vasospasm. This study investigated the ability of LTG, an antiepileptic drug with multi-ion channel inhibition properties, to prevent cerebral vasospasm and subsequent neural ischemia in a rabbit model of SAH. METHODS: Thirty-five New Zealand white rabbits were assigned to 1 of 3 groups: (1) control (no SAH, saline injection); (2) SAH alone; (3) SAH + LTG, 20 mg/kg daily. Animals were killed 72 hours after SAH, then basilar artery lumen areas and arterial wall thickness were measured in all groups. The histological sections of the CA1 and CA3 regions and dentate gyri of the hippocampi were evaluated semiquantitatively for neural tissue degeneration. RESULTS: In the SAH group, the mean luminal cross-sectional area of the basilar artery was reduced by 62% after SAH as compared with the non-SAH controls (P < .0001). After SAH, the vasospastic response was attenuated by 36% in animals treated with 20 mg/kg of LTG compared with the SAH group (P < .005). The mean luminal cross-sectional areas of the basilar artery were 279000 +/- 27000 microm(2) in the control group, 173000 +/- 17600 microm(2) in the SAH group, and 236000 +/- 10000 microm(2) in the SAH + LTG group. The differences between the SAH group and the LTG-treated group were statistically significant (P < .0001). Histological examination was done in 12 control, 12 SAH, and 9 SAH + LTG-treated animals. The mean degeneration score for the control group and SAH + LTG group was statistically significant (P = .012). The difference between the SAH group and SAH+ LTG group was also statistically significant (P = .006). CONCLUSIONS: These findings demonstrate that oral administration of LTG has marked neuroprotective effect and significantly attenuates cerebral vasospasm after SAH, thus providing additional support for the role of non-L-type calcium channels and voltage-dependent sodium channels in vasospasm.

Magnetic resonance imaging findings in dogs with thoracolumbar intervertebral disk disease: 69 cases (1997-2005).

OBJECTIVE: To determine magnetic resonance imaging (MRI) abnormalities in dogs with intervertebral disk disease (IVDD) and develop a classification scheme for IVDD in dogs based on MRI findings. DESIGN: Retrospective case series. ANIMALS: 69 dogs. PROCEDURE: Medical records of dogs admitted because of thoracolumbar IVDD in which MRI of T9 through L7 had been performed were reviewed. RESULTS: A total of 759 intervertebral disk spaces were examined. Of these, 342 (45.1%) were classified as having a normal MRI appearance; the remaining 417 (54.9%) had various types of IVDD. Disk degeneration was identified in 276 disk spaces in 56 dogs, bulging of the intervertebral disk was identified in 37 disk spaces in 24 dogs, disk protrusion was identified in 54 disk spaces in 32 dogs, and disk extrusion was identified in 50 disk spaces in 48 dogs. Cartilage endplate changes were identified in 35 vertebrae in 17 dogs, and increased signal intensity of the spinal cord was identified in 21 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Four types of IVDD (disk degeneration, bulging of the intervertebral disk, disk protrusion, and disk extrusion) were identified on the basis of MRI findings in dogs with thoracolumbar IVDD. We recommend that a standardized nomenclature be adopted for the various types of thoracolumbar IVDD in dogs.

The role of extruded disk material in thoracolumbar intervertebral disk disease: a retrospective study in 40 dogs.

The objective of the study was to determine the effect of the dispersed or nondispersed form of the extruded disk material (EDM) on the neurological status and surgical outcomes in Hansen thoracolumbar intervertebral disk disease Type I (IVDD-I). Medical records of 40 dogs with IVDD-I were reviewed, including neurologic status on admission, findings on magnetic resonance imaging (MRI), intraoperative findings, and surgical outcomes. In MRI evaluations, EDM was on the right in 16, on the left in 18, and centrally in 6 cases; in all cases, findings were confirmed by surgery. Extruded disk material was localized and classified as dispersed disk (DD) or nondispersed disk (NDD) according to its dispersion in the epidural space on MRI. Twenty-five dogs had DD and 15 had NDD on both MRI and surgery. There was no significant difference between DD and NDD in preoperative neurological status and surgical outcomes (P > 0.05).

Nasca classification of hemivertebra in five dogs.

: Five dogs, four small mixed breed and a Doberman Pinscher, presented in our clinic with hemivertebra. Complete physical, radiological and neurological examinations were done and the spinal deformities were characterized in accord with the Nasca classification used in human medicine. Two dogs had multiple hemivertebrae (round, oval or wedge-shaped: Type 3) in the thoracic region; one dog had an individual surplus half vertebral body (Type 1) plus a wedge-shaped hemivertebra (Type 2b) in the lumbar region; one dog had multiple hemivertebrae which were fused on one side (Type 4a) in the thoracic region; and one dog had a wedge-shaped hemivertebra (Type 2a) in the cervical region.