Neurology Networks tries to offer broad exposure to various topics that may be presented on the veterinary neurology board exam.

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Degenerative - IVDD type I



“Risk factors for recurrence of clinical signs associated with thoracolumbar intervertebral disk herniation in dogs: 229 cases (1994–2000).”

Mayhew et al.

JAVMA 2004.


Animals—229 dogs.

Procedure—Medical records of dogs that had decompressive laminectomy without prophylactic fenestration for a first episode of IVDD and were available for follow-up were reviewed. Information on 7 clinical and 8 radiographic potential risk factors were recorded.

Results—Clinical signs associated with recurrence of IVDD developed in 44 (19.2%) dogs. Ninety-six percent of recurrences developed within 3 years after surgery. Recurrence developed in 25% of Dachshunds and 15% of dogs of other breeds combined. Numberof opacified disks was a significant risk factor for recurrence. With each increase in the number of opacified disks in the region of the vertebral column from the T10-11 to the L3-4 space, the risk of recurrence increased by 1.4 times.Dogs with 5 or 6 opacified disks at the time of first surgery had a recurrence rate of 50%. The site of second or subsequent disk herniation was confirmed at surgery in 20 dogs that had 24 recurrences: 12 dogs had a second disk herniation at a space immediately adjacent to the site of first herniation. Seven dogs had a second thoracolumbar disk herniation at least 1 space away from the original site. In 3 dogs, the same space was affected and compression was caused either by residual disk material or scarring associated with the laminectomy.




“Recurrence of thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs after surgical decompression with or without prophylactic fenestration: 265 cases (1995–1999).”

Brisson et al.

JAVMA 2004.


Animals—265 dogs.

Procedures—Medical records of dogs that underwent spinal decompression between 1995 and 1999 were reviewed.

Results—13 (4.9%) dogs were euthanatized or died prior to discharge. Fenestration was performed in 252 dogs, including 37 (14.7%) at the site of decompression only, 48 (19%) at 3 to 4 disk spaces, and 167 (66%) at 5 to 7 disk spaces. There were 12 instances of recurrent disk extrusion confirmed by removal of disk at a second surgery 3.5 to 33 months after the first surgery. Recurrence was always at a new disk space, and rates did not significantly differ between dogs that underwent single or multiple fenestrations. Two recurrences were at a previously fenestrated disk space. Seven recurrences were at a site immediately adjacent to a fenestrated disk space, and 5 recurrences were at L4-5.

Conclusions and Clinical Relevance—Prophylactic fenestration is generally successful in preventing future disk extrusions at fenestrated disk spaces. Prospective evaluation is still required to determine whether fenestration decreases the overall rate of recurrence. Prophylactic fenestration could promote disk extrusion at adjacent, nonfenestrated disk spaces. This could have a substantial clinical impact if recurrence develops at L4-5. Two of 37 (5.4%) dogs in the single fenestration group and 9 of 215 (4.2%) dogs in the prophylactic fenestration group (4 to 6 disk spaces) received a second surgery for recurrent disk extrusion. Statistical comparison between the single fenestration and prophylactic fenestration groups did not reveal a significant difference in the rate of recurrence. Dachshunds were found to be approximately 10 times more likely to have recurrence than other breeds



“Prognostic value of magnetic resonance imaging in dogs with paraplegia caused by thoracolumbar intervertebral disk extrusion: 77 cases (2000–2003).”

Ito et al.

JAVMA 2005.


Result—33 (43%) dogs had areas of hyperintensity of the spinal cord greater than or equal to the length of the L2 vertebral body on T2-weighted magnetic resonance images. All 44 dogs without areas of hyperintensity on T2-weighted images had a successful outcome, but only 18 of the 33 (55%) dogs with an area of hyperintensity did. Only 5 of 16 dogs with an area of hyperintensity that had also lost deep pain perception had a successful outcome. The odds ratio for an unsuccessful outcome for a dog with an area of hyperintensity (29.87) was higher than the odds ratio for a dog that had lost deep pain perception (5.24). Duration and rate of onset of clinical signs were not associated with clinical outcome.

Conclusions and Clinical Relevance—Findings suggest that results of magnetic resonance imaging can be used to predict clinical outcome in dogs with paraplegia caused by intervertebral disk extrusion. The success rate for dogs with areas of hyperintensity that had also lost DPP was only 31% (5/16), and the success rate for dogs with an area of hyperintensity > 3 times the length of the L2 vertebral body that had lost DPP was only 10% (1/10).




“Partial percutaneous discectomy for treatment of thoracolumbar disc protrusion: retrospective study of 331 dogs.”

Kinsel et al.

JSAP 2005.


METHODS: Three hundred and thirty-one dogs presenting with symptoms of thoracolumbar intervertebral disc disease from 1998 to 2003 were treated with PPD. Diagnosis and location of intervertebral disc disease was confirmed by clinical examination, radiography, myelography and magnetic resonance imaging. PPD was performed via fluoroscopy-guided removal of a 5 mm bore cylinder out of the central intervertebral space.

RESULTS: Clinical success after surgery was achieved in 159 (88·8 per cent) grade II to IV patients and 58 (38·2 per cent) grade V patients. The mean (sd) time from percutaneous discectomy to first improvement was 8·3 (13·2) days.

CLINICAL SIGNIFICANCE: The PPD approach to the thoracolumbar spine involves minor trauma (yielding rapid recovery) and less pain, and produces results comparable with open fenestration. Consequently, this simple minimal invasive technique can be recommended as an alternative to the technique of fenestration and can be easily performed in addition to open surgical decompression techniques or prophylactically. However, it is not a replacement for surgical treatment in dogs with thoracolumbar disc disease that require removal of disc.  In 162 patients (48·9 per cent) discectomy was performed at one intervertebral space, in 121 patients (36·6 per cent) at two, in 35 patients (10·6 per cent) at three and in 13 patients (3·9 per cent) at four intervertebral spaces. The number of discectomies did not have a significant influence on the clinical improvement of the patients (P=0·5765). Clinical success after surgery was achieved in 159 of 179 patients (88·8 per cent) with deep pain present (grade II to IV) and in 58 of 152 patients (38·2 per cent) with deep pain absent (grade V) before surgery. The mean (sd) time from percutaneous discectomy to first improvement was 8·3 (13·2) days. In 20 of the grade II to IV patients (11·2 per cent) and in 94 of the grade V patients (61·8 per cent), there was no improvement at all. A worsening of neurological symptoms after treatment was not detected in any patient. All of these follow-up radiographs showed an osseous fusion of the adjacent vertebrae. Disco in one dog.


“Thoracolumbar disc extrusion associated with extensive epidural haemorrhage: a retrospective study of 23 dogs.”

Tartarelli et al.

JSAP 2005.


METHODS: The records of 23 dogs with surgically confirmed DEEH were reviewed retrospectively.

RESULTS: All cases were characterised by rapid progression to severe neurological dysfunction (grade III, V and VI). Myelography was performed in 21 cases and showed an absence (16 cases) or attenuation (five cases) of contrast medium column along three to seven vertebrae. In two dogs, magnetic resonance imaging was accurate in confirming extradural compression due to disc material and haemorrhage, determining the extent of compression and side of the lesion. All cases were treated surgically with extensive hemilaminectomy involving all the compressed spinal segments. Twenty-one dogs (91 per cent) recovered and regained ambulatory function. Two dogs, without deep pain perception before surgery, did not improve. A two-year follow-up history was available for 15 dogs. Disc extrusion recurred in two dogs (9 per cent), two and 20 months after surgery.


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

Besalti et al.

Can Vet Jour 2005.


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).




“Concentrations of 15F2t isoprostane in urine of dogs with intervertebral disk disease.”

McMichael et al.

AJVR 2006.


Results—Urinary isoprostane-to-creatinine ratios were significantly higher in dogs with IVDD than in control dogs before and after surgery. There was no significant difference between values before and after surgery for either group. There was a significant correlation of neurologic score and urinary isoprostaneto-creatinine ratio because dogs that had higher neurologic scores (ie, less severely affected) generally had higher isoprostane-to-creatinine ratios.

Conclusions and Clinical Relevance—Urinary isoprostane-to-creatinine ratios were higher in dogs with IVDD before and after surgery. Analysis of these data suggests that dogs with IVDD are in a state of oxidative stress and that preemptive treatment with antioxidants warrants further investigation.


“Matrix metalloproteinase-9 activity in the cerebrospinal fluid and serum of dogs with acute spinal cord trauma from intervertebral disk disease.”

Levine et al.

AJVR 2006.


Procedure—CSF and serum were collected from affected and control dogs. Zymography was used to detect MMP-9.

Results—Activity of MMP-9 in CSF was detected in 6 of 35 dogs with IVDD; activity was significantly more common in dogs with duration of signs < 24 hours.  Paraplegic dogs were more likely to have MMP-9 activity in the CSF than non-paraplegic dogs. No significant difference in hospitalization time was detected in dogs with IVDD between those with and without activity of MMP-9 in the CSF. Serum MMP-9 was detected more frequently in dogs with IVDD than in control dogs.

Conclusions and Clinical Relevance—Data were consistent with results of experimental rodent spinal cord injury studies that indicate that MMP-9 is expressed early during secondary injury. Expression of MMP-9 has been associated with processes involved in early secondary injury, such as blood-spinal cord barrier permeability and neutrophil migration.8,12 Results obtained with a mouse open spinal cord injury model suggest that inhibition of MMP-9 expression improves locomotor outcome and reduces blood-spinal cord barrier disruption


“Prevalence and Characterization of Urinary Tract Infections in Dogs with Surgically Treated Type 1 Thoracolumbar Intervertebral Disc Extrusion.”

Stiffler et al.

Vet Surg 2006.


Sample Population—Dogs (n1/492) that were surgically treated for a thoracolumbar extradural compressive spinal cord lesion that was consistent with type 1 IVD extrusion.

Methods—Dogs were evaluated for bacterial lower UTI when possible by cystocentesis and urine culture before surgery, and 48–72, 96–120 hours, and 7 days after surgery while hospitalized. Paraparesis, confirmation of thoracolumbar extruded nucleus pulposus, and informed owner consent were required for study inclusion. Urine specimens (n1/4297) were cultured and both objective and subjective clinical data were obtained.

Results—Prevalence of UTI in dogs with surgically treated type 1 thoracolumbar IVD extrusion was 27%(25 dogs). Temporal prevalence of UTI was 15% (13/89) before surgery, 12%(11/91) at 2– 3 days, 16% (12/76) at 4–5 days, and 20% (8/41) at 7 days after surgery. Statistically significant factors affecting UTI prevalence included neurologic and urinary status, sex, administration of perioperative antibiotics, and amount of time body temperature was o351C during anesthesia.

Conclusion—UTI are common in dogs with surgically treated type 1 thoracolumbar IVD extrusion. Females, dogs that cannot ambulate or voluntarily urinate, dogs not administered perioperative cefazolin, and dogs whose body temperature falls o351C during anesthesia have a higher incidence of UTI. Dogs that were administered corticosteroids were 3 times as likely to have UTI.


“Association between various physical factors and acute thoracolumbar intervertebral disk extrusion or protrusion in Dachshunds.”

Levine et al.

JAVMA 2006.


Results—Mean T1-S1 distance and median tuber calcaneus– to–patellar tendon (TC-PT) distance were significantly shorter in affected than in unaffected dogs. A 1-cm decrease in T1-S1 distance was associated with a 2.1-times greater odds of being affected, and a 1-cm decrease in TC-PT distance was associated with an 11.1-times greater odds of being affected.  Results of multivariable logistic regression also indicated that affected dogs were taller at the withers and had a larger pelvic circumference than unaffected dogs, after adjusting for other body measurements. Results of ordinal logistic regression indicated that longer T1-S1 distance, taller height at the withers, and smaller pelvic circumference were associated with more severe spinal cord injury. We speculate that these particular variables were associated with acute thoracolumbar disk extrusion or protrusion in the present study either because they were associated with alterations in vertebral column biomechanics or serve as markers for the degree of chondrodystrophia


“Magnetic resonance imaging findings in dogs with thoracolumbar intervertebral

disk disease: 69 cases (1997–2005).”

Besalti et al.

JAVMA 2006.


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 presence of increased signal intensity was significantly associated with neurologic status score.


“Fecal incontinence associated with epidural spinal hematoma and intervertebral disk extrusion in a dog.”

Cerda-Gonzalez et al.

JAVMA 2006.


Case Description—A 7-year-old castrated male Great Dane was evaluated because of a 2-month history of fecal incontinence.

Clinical Findings—On the basis of the presence of paraparesis and apparently normal spinal reflexes, the neurologic signs were localized in the region of the third thoracic to the third lumbar spinal cord segments. On the basis of the findings of magnetic resonance imaging, a presumptive diagnosis of a compressive intervertebral disk extrusion with secondary hemorrhage and epidural hematoma formation was made.

Treatment and Outcome—A right-sided hemilaminectomy was performed (centered at the T13-L1 intervertebral space) to further characterize the lesion and decompress the spinal cord. The histopathologic diagnosis was extruded intervertebral disk material with chronic hemorrhage and inflammation. Three weeks after surgery, there was complete resolution of the dog’s fecal incontinence and moderate improvements in its hind limb function.

Clinical Relevance—Thoracolumbar spinal cord injuries can result in upper motor neuron fecal incontinence in ambulatory dogs


“Evaluation of the association between spondylosis deformans and clinical signs of intervertebral disk disease in dogs: 172 cases (1999–2000).”

Levine et al.

JAVMA 2006.


Results—Dogs with IVDD had significantly fewer sites of involvement and lower grades of spondylosis deformans, compared with those in the non-IVDD group. When groups were adjusted for age and weight via multivariate linear regression, there were no differences in severity of osteophytosis or number of affected sites. Dogs with type II disk disease had higher numbers of affected sites and more severe changes, compared with dogs with type I disk herniation. There was no difference between groups in the rate at which IVDD was diagnosed at sites of spondylosis, compared with the rate at which IVDD was diagnosed in unaffected disk spaces. Areas of spondylosis were closer to sites of IVDD that elicited clinical signs than to randomly chosen intervertebral spaces, and distances between sites of spondylosis and sites of IVDD had a bimodal appearance.

Conclusions and Clinical Relevance—An association may exist between radiographically apparent spondylosis and type II disk disease; type I disk disease was not associated with spondylosis. Spondylosis in radiographs of dogs with suspected type I disk disease is not clinically important. Spatial associations among sites of spondylosis and sites of IVDD may be coincidental or associated with vertebral column biomechanics. The German Shepherd Dog, Boxer, Cocker Spaniel, and Airedale Terrier are breeds suspected of having a predisposition for developing spondylosis deformans. Cross-sectional comparative analysis of dogs in England, Sweden, and the United States revealed that joints at L2-3 and L7-S1 were most frequently affected, with other areas of high incidence centered around the midthoracic portion of the vertebral column (ie, T4 through T6), at the T9-10 disk space, and in the midlumbar portion of the vertebral column. 2 In a study7of female Beagles, the L1 through L6 disk spaces and C6-7 disk space had the highest frequency of spondylosis. Weakened disk-to-endplate attachments lead to annular tears and result in small ventral or ventrolateral disk herniations. The combination of annular tearing and small-volume disk herniation is likely the cause of spondylosis The combined group values for incidence and grade of severity were highest at T13-L1, L1-2, L2-3, and L7-S1. Disk spaces in the cervical portion of the vertebral column and in the thoracic portion of the vertebral column cranial to T11-12 had fewer affected sites and lower grades of severity, with the exception of the T4-5 and T5-6 articulations. Dogs with spondylosis immediately adjacent to or at the site of IVDD did not differ in duration of clinical signs, type of disk herniation, or breed type, compared with other dogs with IVDD and spondylosis.



“Association of spinal cord compression seen on magnetic resonance imaging with clinical outcome in 67 dogs with thoracolumbar intervertebral disc extrusion.”

Penning et al.

JSAP 2006.


RESULTS: Eighty-five per cent (57 of 67) of dogs were chondrodystrophoid. Mean spinal cord compression was 53 per cent (sd5219_7, range 14_3 to 84_9 per cent). There was no association between the degree of spinal cord compression and the neurological grade at presentation, rate of onset of disease, duration of clinical signs or postsurgical outcome, with no difference between chondrodystrophoid and non-chondrodystrophoid dogs.

CLINICAL SIGNIFICANCE: The degree of spinal cord compression documented with magnetic resonance imaging in dogs with thoracolumbar Hansen type 1 intervertebral disc disease was not associated with the severity of neurological signs and was not a prognostic indicator in this study.



“Functional outcome following hemilaminectomy without methylprednisolone sodium succinate for acute thoracolumbar disk disease in 51 non-ambulatory dogs.”

Bush et al.

JVECCS 2006.


Fifty-one dogs met the inclusion criteria. Before surgery, all dogs were nonambulatory (26 paraplegic, 25 paraparetic), and 98% were painful. Preoperative incontinence was not assessed or unknown in most cases. Ten days following surgery, 90% were ambulatory, 98% were pain free, and 82% were fully continent. By 6 weeks, 100% were ambulatory, 94% were pain free, and 86% were fully continent. By 16 weeks, 96% were pain free, and 88% were fully continent.

Conclusion: Hemilaminectomy is highly successful in returning non-ambulatory, small breed dogs to full function and in these dogs MPSS may not be a necessary adjunct to surgery.




Use of the ventrodorsal myelographic view to predict lateralization of extruded disk material in small-breed dogs with thoracolumbar intervertebral disk extrusion: 104 cases (2004–2005).

Bos et al.

JAVMA 2007.


ResultsAgreement regarding myelographic pattern and location of extruded disk material was moderate (κ = 0.74 and 0.80, respectively) among the 4 observers. Ninety-three (89%) dogs had myelographic evidence of lateralized extrusion, and in 83 of the 93 (89%), predicted location of extruded disk material matched the surgically confirmed location. In 33 of the 40 (83%) dogs with bilateral contrast column gaps of unequal length, disk material was found to be located on the side with the shorter, rather than the longer, contrast gap, a phenomenon described as PCO (paradoxical contrast obstruction).


“Influence of surgical approach on the efficacy of the intervertebral disk fenestration: a cadaveric study.”

Morelius et al.

JSAP 2007.


METHODS: Twenty cadavers of beagle dogs were randomly divided into four groups: a control group and three treatment groups in which intervertebral fenestration was performed using either a dorsal, dorsolateral or lateral approach between the 12th thoracic and second lumbar spaces. The volume of nucleus pulposus, the weight of the residual nucleus pulposus and the angle of the working sector were measured. The ratio of the residual nucleus pulposus weight to the nucleus pulposus volume was used to evaluate the efficacy of the performed fenestration. Data were analysed with Kruskal-Wallis analysis of variance between groups on ranks with correction for ties and Bonferroni correction for multiple comparisons. Correlation between ratio and working angle was calculated using a Spearman’s rank test (P<0_05).

RESULTS: The calculated ratio of nuclear weight to volume was significantly less in the lateral approach group than that in the other groups. The working sector was widest in the dorsolateral approach group, but this did not correlate with efficient fenestration.

CLINICAL SIGNIFICANCE: Using the lateral approach for intervertebral disc fenestration may increase the efficiency of the fenestration procedure. The dorsal and lateral fenestrations created a narrower working sector than the dorsolateral approach (P,0_007). The weights of the remaining nuclear material after fenestration decreased significantly with lateralisation of the surgical approach (P,0_001). The more lateral the approach, the greater the depth of the fenestration into the nucleus pulposus and the bigger amount of the nucleus pulposus is retrieved. Dorsolateral and lateral treatment groups had significantly lower residual nuclear weight-to-volume ratio values when compared with that of the control group The dorsolateral approach creates the largest working sector (median 31_).


“Magnetic resonance imaging of traumatic intervertebral disc extension in dogs.”

Chang et al.

Vet Rec 2007.


This retrospective study evaluated the magnetic resonance (MR) images of traumatic disc extrusions in 11 dogs. The findings included a reduction in the volume and signal intensity of the nucleus pulposus, focal hyperintensity within the overlying spinal cord on T 2-weighted MR images, and subtle spinal cord compression, extraneous material or signal change within the vertebral canal. The largest area of hyperintensity in the spinal cord was directly over or close to the affected disc space, appeared asymmetrical and in the majority of cases was less than one vertebra in length. Parenchymal spinal cord haemorrhage was identified in four of the dogs. Vacuum phenomena, evident as a signal void in the centre of the disc, were identified in two of the dogs.


“Recurrence rate of presumed thoracolumbar intervertebral disc disease in ambulatory dogs with spinal hyperpathia treated with anti-inflammatory drugs: 78 cases (1997-2000). “

Mann et al.

JVECCS 2007.


Main results: All dogs recovered from the initial episode; 39 experienced recurrence and 39 did not. There was no statistically significant relationship between gender, age, or severity score and recurrence rate. Dogs treated with NSAIDs or methylprednisolone sodium succinate (MPSS) were less likely to experience recurrence than dogs treated with corticosteroids other than MPSS. Conclusion: A 50% recurrence of presumed IVDD occurred in this population of dogs after treatment with NSAIDs or corticosteroids. Those treated with NSAIDs or MPSS were less likely to experience a recurrence. There were recurrences in 21 of 37 (57%) cases with severity score 1, 12 of 27 (44%) cases with severity score 2, and 5 of 13 (38%) cases with severity score 3. 12/36 NSAIDs, 4/12 MPSS, 23/30 steroids recurred 11 recurred in first 1-6 months, 14 in  6 mo to 1 year




“Influence of Intervertebral Disc Fenestration at the Herniation Site in Association with Hemilaminectomy on Recurrence in Chondrodystrophic Dogs with Thoracolumbar Disc Disease: A Prospective MRI Study.”

Forterre et al.

Vet Surg 2008


Methods—Dogs were divided into 2 groups: group 1 (9 dogs) had thoracolumbar disc extrusion (Hansen type I) treated by hemilaminectomy and concomitant fenestration of the affected intervertebral disc and group 2 (10 dogs) had hemilaminectomy without fenestration. All dogs had 3 magnetic resonance imaging (MRI) examinations: preoperatively, immediately postoperatively to assess removal of herniated disc material, and again 6 weeks after surgery.

Results—There were 13 male and 6 female dogs; mean age, 7.1 years. Thoracolumbar disc herniation was confirmed with MRI. Immediate post surgical MRI revealed that the herniated disc removal was complete in all but 1 dog and that fenestration did not lead to complete removal of nucleus pulposus within the intervertebral disc space. On the 3rd MRI examination, none of the group 1 dogs had further disc material herniation at the fenestrated site. Six of the 10 group 2 dogs had a recurrence of herniation leading to clinical signs in 3 dogs (pain in 2 dogs, paresis in 1 dog).

Conclusion—In thoracolumbar disc herniation, fenestration of the affected intervertebral disc space prevents further extrusion of disc material.

Clinical Relevance—Fenestration reduces the risk of early recurrence of disc herniation and associated postoperative complications.


“Quantification of the association between intervertebral disk calcification and disk herniation in Dachshunds.”

Jensen et al.

JAVMA 2008.


Animals—61 Dachshunds that had been radiographically screened for calcification of intervertebral disks at 2 years of age in other studies. Thirty-seven of the dogs had survived to the time of the present study and were ≥ 8 years of age; 24 others had not survived.

Procedures—Radiographic examination of 36 surviving dogs was performed, and information on occurrence of disk calcification at 2 years of age were obtained from records of all 61 Dachshunds. Information on occurrence of disk herniation between 2 and 8 years of age was obtained from owners via questionnaire. Associations between numbers of calcified disks and disk herniation were analyzed via maximum likelihood logistic regression.

Results—Disk calcification at 2 years of age was a significant predictor of clinical disk herniations (odds ratio per calcified disk, 1.42; 95% confidence interval, 1.19 to 1.81). Number of calcified disks in the full vertebral column was a better predictor than number of calcified disks between vertebrae T10 and L3. Numbers of calcified disks at ≥ 8 years of age and at 2 years of age were significantly correlated.

Conclusions and Clinical Relevance—Number of calcified disks at 2 years of age was a good predictor of clinical disk herniation in Dachshunds. Because of the high heritability of disk calcification, it is possible that an effective reduction in occurrence of severe disk herniation in Dachshunds could be obtained by selective breeding against high numbers of calcified disks at 2 years of age.


“Adverse effects and outcome associated with dexamethasone administration in dogs

with acute thoracolumbar intervertebral disk herniation: 161 cases (2000–2006).”

Levine et al.

JAVMA 2008.


Animals—161 dogs with surgically confirmed thoracolumbar disk herniation.

Procedures—Medical records from 2 hospitals were used to identify dogs that had received dexamethasone < 48 hours prior to admission (dexamethasone group dogs), dogs that received glucocorticoids other than dexamethasone < 48 hours prior to admission (other-glucocorticoid group dogs), and dogs that received no glucocorticoids (nontreatment group dogs). Signalment, neurologic injury grade, laboratory data, and complications were extracted from medical records.

Results—Dexamethasone group dogs were 3.4 times as likely to have a complication, compared with other-glucocorticoid or nontreatment group dogs. Dexamethasone group dogs were 11.4 times as likely to have a urinary tract infection and 3.5 times as likely to have diarrhea, compared with other-glucocorticoid or nontreatment group dogs. No differences in neurologic function at discharge or recheck evaluation were detected among groups.


“Association of preoperative magnetic resonance imaging findings with surgical features

in Dachshunds with thoracolumbar intervertebral disk extrusion.”

Naude et al.

JAVMA 2008.


Objective—To evaluate the accuracy of specific magnetic resonance imaging (MRI) sequences in determining the site, lateralization, and extent of extruded intervertebral disk material (EIDM), compared with surgical findings, in Dachshunds with thoracolumbar intervertebral disk extrusion (TLIDE).

Sample Population—16 Dachshunds with clinical signs of intervertebral disk disease.

Procedures—Preoperative T1-weighted, T2-weighted, and short tau inversion recovery (STIR) MRI measurements and description of the location of EIDM were compared with intraoperative measurements and determination of the EIDM position.

Results—The T12-13 intervertebral disk space was the most frequent site of EIDM (6/16 dogs). The EIDM lateralized with equal frequency to the left and right sides; no central extrusions were seen. There was moderate to substantial agreement (kappa, 0.59) between MRI and surgical findings for evaluation of the craniocaudal distribution of the EIDM. For measurement of the length of EIDM, the T1-weighted, T2-weighted, and STIR sequences had a mean error of –1.15, –0.38, and –1.93 mm, respectively; concordance correlation coefficients were 0.666, 0.904, and 0.458, respectively. Mean absolute errors were 2.54, 1.35, and 2.90 mm, respectively; these values did not differ significantly.

Conclusions and Clinical Relevance—In the thoracolumbar vertebral column of Dachshunds with clinical signs of intervertebral disk disease, MRI is a valuable technique for determining location and craniocaudal length of EIDM. T2-weighted images appeared to be more accurate and precise and are potentially more reliable for determination of the length of EIDM in those dogs.






“Intramedullary intervertebral disc extrusion in a cat.”

McConnell et al.

VRU 2004.


Radiographically, there was mineralized disk material within the vertebral canal. On magnetic resonance images, the disk material was found to be within the spinal cord. A linear disk trail extending from the disk space into the spinal cord may be specific for intramedullary disk extrusion.




“Acute non-ambulatory tetraparesis attributable to cranial cervical intervertebral disc disease in a cat.”

Maritato et al.

JFMS 2007.


A 10-year-old domestic longhair cat was presented for acute non-ambulatory tetraparesis. Clinicopathologic diagnostics revealed no abnormalities. Cervical myelogram revealed an extradural compressive lesion consistent with intervertebral disc disease of the C2eC3 intervertebral disc space. Ventral slot decompression confirmed the presence of extruded intervertebral disc material into the vertebral canal of the C2eC3 intervertebral space. The patient succumbed to cardiorespiratory arrest 3 days postoperatively.




“Lumbosacral Intervertebral Disk Disease in Six Cats.”

Harris et al.

JAAHA 2008.


Each of the six cats underwent dorsal decompressive laminectomy at the L7 to S1 interspace. Postoperative clinical follow-up lasted 3 to 35 months, with most cats having excellent outcomes. Of 32 total previously reported cases, 7 were T13-L1 and 7 were L4-5




“Partial lateral corpectomy for ventral extradural thoracic spinal cord compression in a cat.”

Bottcher et al.

JFMS 2008.


Compression at the level of Th3eTh4 intervertebral disc space was considered responsible for the paraparesis. The lesion was approached via a right-sided lateral partial corpectomy as described for dogs. Complete spinal decompression was achieved, as documented intraoperatively by visual inspection and palpation of the spinal canal. No surgery related complications were encountered and the cat improved gradually within 8 weeks after the procedure. At 1 year follow-up only a slight proprioceptive deficit in the right hind limb could be noted. This is the first report of partial lateral corpectomy in a cat and should encourage the use of this technique even in small patients.




Exotics, etc


“Treatment of a prolapsed lumbar intervertebral disc in a ferret.”

Lu et al.

JSAP 2004.


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. Primary neurological disorders that may cause paraparesis in ferrets include congenital malformation, trauma, intervertebral disc disease, Aleutian disease and neoplasms, such as plasma cell myeloma, chordoma or lymphoma. Subsequent subluxation and development of large exostoses around L2/3, and eventual fusion of affected vertebrae, were compatible with healing local inflammation and thus also supported the diagnosis of discospondylitis. The progression of radiographic signs was analogous to that seen in some dogs with discospondylitis.