Intervertebral Disc Extrusion Research Articles

S100β Levels in CSF of Nonambulatory Dogs with Intervertebral Disk Disease Treated with Electroacupuncture.

The aim of the study was to investigate S100β levels in the cerebrospinal fluid of nonambulatory dogs with intervertebral disk disease treated with electroacupuncture: 10 dogs with thoracolumbar disk extrusion graded 3 to 5 (EA group) and 7 dogs without neurologic dysfunction (control group). All dogs regained ambulation. S100β was detected by Western blot analysis where EA group dogs were evaluated at two time points (M1 = before EA and M2 = when the dogs return ambulation) and at one time point from control group. In EA group dogs M1-S100β levels were significantly higher than in control group. EA group dogs were divided into subgroups A (n = 7—early motor recovery; 6.7 ± 7.8 days) and B (n = 3—late motor recovery; 76 ± 17.0 days). M1-S100β levels were similar between subgroups A and B. However, M2-S100β levels were significantly higher in subgroup B than in subgroup A. An elevated S100β levels were observed in dogs with late motor recovery. S100β may be associated with neuroplasticity following spinal cord injuries with intervertebral disk extrusion. Further studies with larger numbers of subjects and control group with affected dogs are necessary to investigate the relationship between neurotrophic factors and electroacupuncture stimulation.

Intervertebral Disc Protrusion in a Ferret with Triple Thoracic Block Vertebrae

Hind limb paresis or plegia in ferrets is a common sign of illness, which can be produced by intervertebral disc (IVD) extrusion or protrusion along with many other systemic diseases. This case report describes a ferret (Mustela putorius furo) with chronic onset paraplegia in which T7-T8, T8-T9, and T10-T11 IVD herniations and T9-T10 block vertebrae were diagnosed with the assistance of myelography. It is believed that the excessive stress on the adjacent annulus fibrosus and vertebral endplates resulting from block vertebrae could have been the cause of IVD disease in the atypical location described in this case.

How Long and Low Can You Go? Effect of Conformation on the Risk of Thoracolumbar Intervertebral Disc Extrusion in Domestic Dogs

Intervertebral disc extrusion (IVDE) is a common neurological disorder in certain dog breeds, resulting in spinal cord compression and injury that can cause pain and neurological deficits. Most disc extrusions are reported in chondrodystrophic breeds (e.g. Dachshunds, Basset Hounds, Pekingese), where selection for ‘long and low’ morphologies is linked with intervertebral discs abnormalities that predispose dogs to IVDE. The aim of this study was to quantify the relationship between relative thoracolumbar vertebral column length and IVDE risk in diverse breeds. A 14 month cross-sectional study of dogs entering a UK small animal referral hospital for diverse disorders including IVDE was carried out. Dogs were measured on breed-defining morphometrics, including back length (BL) and height at the withers (HW). Of 700 dogs recruited from this referral population, measured and clinically examined, 79 were diagnosed with thoracolumbar IVDE following diagnostic imaging ± surgery. The BL:HW ratio was positively associated with IVDE risk, indicating that relatively longer dogs were at increased risk, e.g. the probability of IVDE was 0.30 for Miniature Dachshunds when BL:HW ratio equalled 1.1, compared to 0.68 when BL:HW ratio equalled 1.5. Additionally, both being overweight and skeletally smaller significantly increased IVDE risk. Therefore, selection for longer backs and miniaturisation should be discouraged in high-risk breeds to reduce IVDE risk. In higher risk individuals, maintaining a lean body shape is particularly important to reduce the risk of IVDE. Results are reported as probabilities to aid decision-making regarding breed standards and screening programmes reflecting the degree of risk acceptable to stakeholders.

Lesão iatrogênica meningomedular em um cão submetido à espondilectomia ventral para tratamento de extrusão crônica de disco intervertebral cervical

Objetivou-se descrever a ocorrência de lesão iatrogênica meningomedular em um cão da raça Dachshund, macho, oito anos de idade, apresentando tetraparesia flácida há dois meses, que foi submetido à espondilectomia ventral para tratamento de extrusão crônica de disco intervertebral cervical. Durante remoção do material de disco herniado com removedores de tártaro e pinça hemostática, observou-se severa hemorragia dos seios venosos, descolamento meníngeo com laceração medular e imediata queda dos parâmetros cardiovasculorrespiratório, com evolução para a morte ante a ausência de respostas às medidas de ressuscitação cardiopulmonar.

Clinical and Pathological Analysis of Epidural Inflammation in Intervertebral Disk Extrusion in Dogs

Little is known about the pathologic changes in the epidural space after intervertebral disk (IVD) extrusion in the dog. To analyze the pathology of the epidural inflammatory response, and to search for correlations between this process and clinical findings. Clinical data from 105 chondrodystrophic (CD) and nonchondrodystrophic (NCD) dogs with IVD extrusion were recorded. Epidural material from these dogs was examined histopathologically and immunohistochemically. Using statistical analysis, we searched for correlations between severity of epidural inflammation and various clinical and pathologic variables. Most dogs exhibited an epidural inflammatory response, ranging from acute invasion of neutrophils to formation of chronic granulation tissue. The mononuclear inflammatory infiltrates consisted mostly of monocytes and macrophages and only few T and B cells. Surprisingly, chronic inflammatory patterns also were found in animals with an acute clinical history. Severity of the epidural inflammation correlated with degree of the epidural hemorrhage and nucleus pulposus calcification (P = .003 and .040), but not with age, chondrodystrophic phenotype, neurologic grade, back pain, pretreatment, or duration. The degree of inflammation was statistically (P = .021) inversely correlated with the ability to regain ambulation. Epidural inflammation occurs in the majority of dogs with IVD extrusion and may develop long before the onset of clinical signs. Presence of calcified IVD material and hemorrhage in the epidural space may be the triggers of this lesion rather than an adaptive immune response to the nucleus pulposus as suggested in previous studies. Because epidural inflammation may affect outcome, further research is warranted.

Como a Ressonância Magnética Pode Contribuir Para a Caracterização Medular De Pacientes Com Suspeita De Lesão Hansen Tipo III?

To assess the magnetic resonance imaging (MRI) contribution to patients with presumptive diagnostic of Type III Hansen, acute high velocity non compressive intervertebral disc extrusions. Eight dogs, medium age and medium size were attempted to the MRI service with clinical history of acute neurological sign characterized by hind limbs paralysis and thoracic and lumbar pain. MRI demonstrated intramedullary hyperintensity on T2-weighted images, variable dimensions and no disc compression were characterized. Although MRI does not provide Type III Hansen definitive diagnostic, the association of clinical history with MRI findings can help predict outcome in dogs with acute non compressive nucleus pulposus extrusions, a non surgical lesion.

Mielomalácia hemorrágica progressiva em 14 cães

A mielomalácia hemorrágica progressiva (MHP) é uma afecção rara e fatal, em que ocorre necrose aguda isquêmica e progressiva do parênquima da medula espinhal, levando à liquefação da mesma. Pode ocorrer após extrusão do disco intervertebral, trauma medular ou embolismo fibrocartilaginoso. Este estudo teve como objetivo avaliar casos de mielomalácia hemorrágica progressiva em cães atendidos no Hospital Veterinário da Universidade Estadual de Londrina entre os anos 2000 e 2011, realizando-se a análise dos prontuários de atendimento e acompanhamento dos casos. Os animais do presente estudo atendiam a alguns critérios de inclusão, como histórico de paraplegia com sinais de neurônio motor superior, piora dos sinais progredindo para tetraplegia flácida, alterações clínicas progressivas e/ou alterações nos exames complementares. Foram analisados os aspectos epidemiológicos (raça, idade e sexo), clínicos (evolução dos sinais clínicos e neurológicos), laboratoriais (análise do líquido cefalorraquidiano), radiográficos (radiografias simples e contrastadas) e o tempo decorrido desde o início dos sinais clínicos até óbito ou eutanásia. A raça Teckel foi a mais acometida (43%), a média de idade foi de 5,04 anos e no atendimento inicial a síndrome toracolombar grau V foi a alteração mais encontrada, além de hiperpatia e progressão cranial da diminuição do reflexo cutâneo do tronco. Em sete cães a causa da MHP foi a doença do disco intervertebral toracolombar, em um cão a causa foi o trauma medular, em dois cães a MHP foi decorrente de linfoma e em quatro cães a causa provável foi doença de disco intervertebral. Alterações na análise do líquido cerebroespinhal, na mielografia e na evolução dos sinais clínicos e neurológicos foram extremamente importantes para diagnosticar a MHP. Seis animais progrediram para tetraplegia e quatro cães já apresentavam tetraplegia flácida no atendimento inicial. Em outros quatro pacientes, a identificação de sinais sugestivos de MHP antes desta progressão levou à indicação de eutanásia. Como o prognóstico é ruim e ocasiona sofrimento ao animal, o clínico deve estar atento ao histórico de paraplegia com posterior mudança da síndrome de neurônio motor superior para neurônio motor inferior, diminuição do reflexo cutâneo do tronco cranialmente e presença de respiração abdominal, sendo que algumas alterações em exames complementares encontradas neste trabalho também podem auxiliar no diagnóstico precoce da MHP, como o líquido cerebroespinhal xantocrômico com aumento de proteínas, hemácias e pleocitose. Na mielografia o edema medular e a presença de contraste no interior do tecido nervoso, frente às alterações clínicas e liquóricas, são sugestivas de MHP.

Magnetic resonance imaging findings in dogs with traumatic intervertebral disk extrusion with or without spinal cord compression: 31 cases (2006–2010)

To determine the prevalence of spinal cord compression subsequent to traumatic intervertebral disk (IVD) extrusion in dogs, characterize factors associated with spinal cord compression in dogs with traumatic IVD extrusion, and evaluate the outcomes of dogs with traumatic IVD extrusion with or without spinal cord compression. Retrospective case series. 31 dogs with traumatic IVD extrusion. Medical records and MRI findings were reviewed for dogs with a history of trauma to the spinal region. Dogs were included in the study if a neurologic examination and MRI were performed and there was a description of clinical signs and MRI findings including identification of the spinal cord segment affected by IVD extrusion, presence or absence of spinal cord compression, treatment, and outcome available for review. 31 of 50 (62%) dogs had traumatic IVD extrusions without any other detectable vertebral lesions; 9 (29%) and 22 (71%) of those 31 dogs did and did not have spinal cord compression, respectively. Dogs with spinal cord compression were significantly older and more likely to be chondrodystrophic and have evidence of generalized IVD degeneration, compared with dogs without spinal cord compression. The outcome for dogs with spinal cord compression was similar to that for dogs without spinal cord compression. Results indicated traumatic IVD extrusion was common and should be considered as a differential diagnosis for dogs with trauma to the spinal region, and spinal cord compression should be evaluated, especially in older or chondrodystrophic dogs.

Coexistence of expanding abdominal aortic aneurysm and aggravated intervertebral disc extrusion -a case report-

Abdominal aortic aneurysm is included in the differential diagnosis of lower back pain. Although rare, this important disease can cause potentially lethal complications. In this case, expanding abdominal aortic aneurysm coexisted with intervertebral disc extrusion. The diagnosis of abdominal aortic aneurysm was delayed, putting the patient at risk of aneurysmal rupture. In the management of patients with degenerative spinal diseases, we should not overlook the possibility of comorbidities such as an abdominal aortic aneurysm. We also suggest the importance of interpreting images more carefully, especially for elderly male patients.

Agreement between magnetic resonance imaging, myelography, and surgery for detecting recurrent, thoracolumbar intervertebral disc extrusion in dogs

Although magnetic resonance imaging (MRI) is reported to be superior to myelography to determine the location and site of first time disc herniation, comparison of these diagnostic methods in cases of recurrent intervertebral disc disease (IVD) herniation after a first surgery has not been evaluated. The objective was to compare the diagnostic accuracy of MRI and myelography in a series of dogs undergoing repeat surgical decompression for recurrent IVD extrusion when compared to the gold standard of surgery. Ten dogs with recurrent IVD herniation underwent MRI and myelography followed by surgical decompression. Three observers reviewed the images to determine the site and side of the first surgery and the recurrent lesion. Agreement was determined by calculating a kappa (κ) score. Substantial interobserver agreement was noted for recurrent lesion site using MRI and myelography (κ = 0.77 vs. 0.73) and when comparing MRI and myelography to the reported surgical site (κ = 0.73 vs. 0.67). Interobserver agreement was greater with MRI for circumferential location compared to myelography (κ = 0.76 vs. 0.43), similar to what was found when comparing to surgical side (κ = 0.82 vs. 0.49). The previous surgical site in this study had no effect on ability to identify the new lesion. Despite the limitations of MRI, there was greater agreement between observers using MRI for both the recurrent and first lesion.

The use of an electronic von Frey device for evaluation of sensory threshold in neurologically normal dogs and those with acute spinal cord injury

The utility and inter-session repeatability of sensory threshold measurements using an electronic von Frey anesthesiometer (VFA) were assessed in a group of six neurologically normal dogs. Sensory threshold values obtained in neurologically normal dogs were compared to those of dogs with acute spinal cord injury (SCI) caused by intervertebral disc extrusion (n=6) and to a group of neurologically normal dogs with cranial cruciate ligament rupture (CCLR; n=6).Sensory threshold values in neurologically normal dogs were 155.8±37.7g and 154.7±67.2g for the left and right pelvic limbs, respectively. The difference in mean sensory threshold values obtained for the group when two distinct testing sessions were compared was not statistically significant (P>0.05). Mean sensory threshold values for the group with SCI were significantly higher than those for neurologically normal dogs at 351.1±116.5g and 420.3±157.7g for the left and right pelvic limbs, respectively (P=0.01). A comparison of sensory threshold values for the group with CCLR and neurologically normal dogs was not statistically significant (P>0.05). The modified dorsal technique for VFA described here represents a reliable method to assess sensory threshold in neurologically normal dogs and in those with SCI.

Permanent monoparesis in a dog after intramedullary injection of iohexol into the lumbar spinal cord

CASE HISTORY: An 8-year-old, spayed, Doberman Pinscher bitch presented for assessment of acute hindlimb paresis. CLINICAL FINDINGS: During a lumbar myelographic contrast study a small volume of iohexol contrast agent was inadvertently injected into the cord parenchyma. After surgical hemilaminectomy for an intervertebral disc extrusion at L1–2 the dog recovered use of one hindlimb, but had ongoing extensor weakness of the left hindlimb. Left femoral nerve function had not returned after 14 months. DIAGNOSIS: EMG findings 14 months after the incident indicated persistent femoral neuropathy consistent with the intramedullary contrast injection at L3–4. CLINICAL RELEVANCE: Inadvertent deposition of iohexol into spinal cord parenchyma may be rare, but if it occurs it can have long-lasting consequences.

Effect of extradurally administered morphine on postoperative analgesia in dogs undergoing surgery for thoracolumbar intervertebral disk extrusion

To investigate the effect of intraoperative extradural morphine administration on postoperative analgesia in dogs undergoing thoracolumbar spinal surgery to treat disk extrusion. Prospective clinical trial. 26 client-owned dogs undergoing thoracolumbar spinal surgery. Animals were randomly allocated to receive morphine (0.1 mg/kg [0.045 mg/lb], extradurally) or no treatment (control group). Following preanesthetic medication with methadone (0.25 mg/kg [0.11 mg/lb], IM), anesthesia was induced with propofol and maintained with isoflurane or sevoflurane in oxygen. Lidocaine and fentanyl were administered during surgery in both groups at fixed rates. In the morphine administration group, morphine was splashed over the dura mater immediately prior to wound closure. Postoperative analgesia was assessed for 48 hours by assessors unaware of group allocation, and methadone was administered as rescue analgesic. Demographic characteristics, urinary output, days of hospitalization, and perioperative use of analgesics were compared via a Mann-Whitney U test. Demographic data were similar between groups. In the morphine administration group, 2 of 13 dogs required postoperative methadone, and in the control group, methadone was administered to 11 of 13 dogs. The total number of doses of methadone administered in the 48 hours after surgery was 28 in the control group and 3 in the morphine administration group. No adverse effects were recorded in any group. Intraoperative extradural morphine administration was effective in reducing postoperative analgesic requirement. Dogs undergoing thoracolumbar spinal surgery benefited from topical administration of preservative-free morphine administered directly on the dura mater as part of analgesic management.

Percutaneous intradiscal high-pressure injection of saline and lidocaine in patients with lumbar intervertebral disc extrusion

The intradiscal high-pressure injection of saline and lidocaine (IDHP) is a minimally invasive percutaneous procedure for a lumbar intervertebral disc extrusion. The purpose of this study was to investigate the clinical outcomes of IDHP in terms of pain relief, reduction of disability, and risk of complications. Thirty patients with primarily radicular pain due to an extrusion-type disc herniation who underwent IDHP were enrolled in the study. A visual analogue pain scale (VAS) and the Japanese Orthopedic Association (JOA) scoring system for the treatment of low back disorders were used at pre-treatment, 2 weeks post-treatment, and 3 months post-treatment. The mean VAS decreased significantly (p < 0.01) from 64.3 mm at pre-treatment to 26.3 mm at 2 weeks post-treatment and 15.5 at 3 months post-treatment. The mean JOA score improved significantly (p < 0.01) from 14.7 to 21.3 at 2 weeks post-treatment and 24.6 at 3 months post-treatment. IDHP appeared to produce significant effects in patients with radicular pain, leading to the improvement of VAS and JOA scores. IDHP appears to be a safe, minimally invasive treatment option for a lumbar intervertebral disc extrusion.

The Results of Percutaneous Intradiscal High-Pressure Injection of Saline in Patients with Extruded Lumbar Herniated Disc: Comparison with Microendoscopic Discectomy

Intradiscal high-pressure injection of saline (IDHP) is a noninvasive procedure for a lumbar intervertebral disc extrusion and an alternative treatment to surgery, such as microendoscopic discectomy (MED). The purpose of this study was to compare the representative outcomes of IDHP with MED in terms of pain relief, reduction of disability, and risk of complications. Forty-five patients with primarily radicular pain due to an extrusion type disc herniation who underwent either IDHP (N = 24) or MED (N = 21) were enrolled in the study. The visual analog pain scale (VAS) and the Japanese Orthopedic Association (JOA) scoring system for the treatment of low-back disorders were assessed at pretreatment, 2 weeks posttreatment, and JOA was again taken 3 months posttreatment. Patients were asked to choose their satisfaction from four alternatives, "excellent,""good,""fair," and "poor," 3 months after treatment. Mean VAS decreased from 65.1 to 18.8 mm in the IDHP group, and from 80.6 to 16.5 in the MED group. Mean JOA recovery rates at 3 months posttreatment were 67.2 and 75.2, and patients with "excellent" or "good" results were 73.7% and 78.6% in the IDHP and in MED, respectively. IDHP produced significant effects on patients with radicular pain, leading to the improvement of VAS and JOA. Although IDHP displayed slightly less efficacy than MED, IDHP appears to be an alternative as a nonoperative treatment for a lumbar intervertebral disc extrusion.

Accuracy, intermethod agreement, and inter-reviewer agreement for use of magnetic resonance imaging and myelography in small-breed dogs with naturally occurring first-time intervertebral disk extrusion

To determine accuracy, intermethod agreement, and inter-reviewer agreement for multisequence magnetic resonance imaging (MRI) and 2-view orthogonal myelography in small-breed dogs with first-time intervertebral disk (IVD) extrusion. Prospective evaluation study. 24 dogs with thoracolumbar IVD extrusion. Each dog underwent MRI and myelography. Images obtained with each modality were independently evaluated and assigned standardized scores in a blinded manner by 3 reviewers. Results were compared with surgical findings. Inter-reviewer and intermethod agreements were assessed via κ statistics. Accuracy was assessed as the percentage of dogs for which ≥ 2 of 3 reviewers recorded findings identical to those determined surgically. Inter-reviewer agreement was substantial for site (κ = 0.70) and side of IVD extrusion (κ = 0.62) in T2-weighted magnetic resonance images and was substantial for site (κ = 0.72) and fair for side of extrusion (κ = 0.37) in myelographic images. Agreement for site between each modality and surgical findings was near perfect (κ = 0.94 and 0.88 for MRI and myelography, respectively). Intermethod agreement was substantial for site (κ = 0.71) and moderate for side of extrusion (κ = 0.40). Accuracy of MRI for site and side was 100% when results for T1-weighted, T2-weighted, and contrast-enhanced T1-weighted sequences were combined. Accuracy of myelography was 90.9% and 54.5% for site and side, respectively. Agreement between imaging results and surgical findings for identification of IVD extrusion sites in small-breed dogs was similar for MRI and myelography. However, MRI appeared to be more accurate than myelography and allowed evaluation of extradural compressive mass composition.

Recurrent Thoracolumbar Intervertebral Disc Extrusion after Hemilaminectomy and Concomitant Prophylactic Fenestration in 662 Chondrodystrophic Dogs

To determine the prevalence and location of recurrent thoracolumbar intervertebral disc extrusion (T-L IVDE) after hemilaminectomy with prophylactic fenestration (PF) and to document PF-related complications. Retrospective case series. Chondrodystrophic dogs (n = 793). In 662 successfully recovered dogs (>1 year follow-up), the prevalence of dogs with recurrent T-L IVDE that required a 2nd surgery and dogs with clinical signs that improved without surgery was evaluated. Prevalence of second disc extrusions (SDEs) within T11-L4 intervertebral discs was compared between PF discs and non-PF discs. T-L SDEs were intraoperatively confirmed in 15 dogs (2.3%), 2-61 months after initial surgery and 66 dogs (10.0%) had signs of T-L IVDE recurrence that improved without surgery (mean follow-up, 44.7 months). No dog had further extrusion at the initial T-L site. SDE occurred at a PF disc (n = 1), adjacent to PF discs (8), or at distant discs (6). Prevalence of SDE in non-PF discs was 26.2 times higher than PF discs (95% CI: 3.4, 203.4; P < .001). Major PF-related complications included iatrogenic introduction of the disc material into the spinal canal (n = 1), and vertebral subluxation/instability (3) at 1-88 months postoperatively. SDE is more likely to occur at non-PF discs than PF discs when PF is performed at spaces predisposed to disc extrusion. PF is a safe and effective treatment to prevent SDE in chondrodystrophic dogs.

Application of evidence-based medicine to recurrence of Hansen’s type I intervertebral disc disease in dogs: A justification for continuation of study into percutaneous laser disc ablation?

AbstractTo review and evaluate the literature reporting results of prophylactic surgical procedures for Hansen’s type I intervertebral disc disease.Systematic literature review.Online bibliographic searches of abstracts through PubMed and the Veterinary Information Network (VIN) were performed using the searchable term “canine intervertebral disc disease and recurrence”. The resources were evaluated in regard to the ability of the retrieved references to directly address the clinical question as follows: which prophylactic technique when considered with or without surgery will consistently reduce or eliminate the recurrence of clinical signs associated with Hansen’s type I intervertebral disc disease. All studies were compared and evaluated with regard to study design, technique utilized, short and long-term outcome, and evidence classification.An online bibliographical search was performed in PubMed using the full search term of “canine intervertebral disc disease and recurrence” resulted in 20 total sources, and of those sources 13 contained information pertaining to the clinical question. The same search term when used in the VIN search engine under the classification of journal abstracts resulted in 43 total results with 18 applicable resources. In review of both searches, 13 resources were listed in both searches. Of the 18 obtained by the VIN search 14 were available in the English language. No resources were included in class I level of evidence, and only one was considered as class II level of evidence. As for the remaining studies, three results were classified as class III studies, and the remaining reports were classified as class IV level of evidence.Although direct extrapolation of the evidence provided by the search to the clinical scenario is not possible, this review will hopefully provide the basis for development of a randomized controlled study to provide for a clear need in evidence for prevention of intervertebral disc extrusion in dogs.

The Cutaneous Trunci Muscle Reflex: A Predictor of Recovery in Dogs with Acute Thoracolumbar Myelopathies Caused by Intervertebral Disc Extrusions

To determine whether changes in the cutaneous trunci muscle (CTM) reflex are an early predictor of outcome in dogs with severe acute thoracolumbar intervertebral disc extrusion (IVDE). Multicenter prospective cohort study. Dogs (n = 36) with acute IVDE causing paraplegia, loss of nociception in pelvic limbs and tail, and an abnormal CTM reflex postoperatively. The caudal border of the CTM reflex was established 24 hours after surgery and at discharge, and was reported as moving cranially, caudally, or staying static. Dogs were re-evaluated at 12-20 weeks and at 7-36 months postoperatively. Outcome was classified as improved or unimproved, successful or unsuccessful, and ascending myelomalacia or not, and compared with early movement of the CTM reflex by construction of contingency tables and performing a Fisher's exact test. By discharge (mean, 4.7 days; SD = 2.10), CTM reflex progression was caudal in 19 dogs, static in 11, and cranial in 6. Five of 6 dogs with cranial movement developed ascending myelomalacia (P < .0001). Seventeen of 19 dogs with caudal movement showed an improvement by 12-20 weeks (P = .0046) and none developed ascending myelomalacia (P = .0013). Postoperative changes of the caudal border of the CTM reflex are an early indicator of outcome in dogs with severe acute IVDE. Cranial movement of the CTM reflex is significantly associated with the development of ascending myelomalacia. Caudal movement is significantly associated with improvement, but not associated with a long-term successful outcome.

Early Reherniation of Disk Material in Eleven Dogs with Surgically Treated Thoracolumbar Intervertebral Disk Extrusion

To report findings and outcomes of dogs with reherniation of nuclear material within 7 days of hemilaminectomy for acute thoracolumbar (TL) intervertebral disk extrusion. Retrospective case series. Chondrodystrophic dogs (n = 11). Dogs with acute neurologic decline within 1 week of surgical decompression for TL disk extrusion were identified. Advanced imaging was used to document extradural spinal cord compression at the previous surgery site. Ten dogs had a 2nd decompressive surgery to remove extruded nuclear material. All dogs had acute neurologic deterioration (average, 2 neurologic grades) 2-7 days after initial hemilaminectomy. Computed tomography (CT; n = 10) or myelography (n = 1) documented extradural spinal cord compression compatible with extruded disk material at the previous hemilaminectomy site. Dogs that had a 2nd surgical decompression improved neurologically within 24 hours and were paraparetic at discharge. The single dog that did not have decompressive surgery did not regain deep nociception during 185-day follow-up. Early reherniation at the site of previous hemilaminectomy can produce acute deterioration of neurologic function and should be investigated with diagnostic imaging. Repeat decompressive surgery can lead to functional recovery.