Acute Intervertebral Disc Extrusion Research Articles

Investigating the weekend effect in decompressive thoracolumbar hemilaminectomy for acute intervertebral disc extrusion: An observational cohort study of 460 cases (2018-2023).

To investigate if weekend surgery is associated with poorer outcomes in dogs with acute thoracolumbar intervertebral disc extrusion (IVDE) undergoing decompressive thoracolumbar hemilaminectomy. Retrospective observational cohort study. A total of 460 consecutive cases were reviewed, with 401 dogs undergoing weekday surgery (Cohort WD), and 59 dogs undergoing weekend surgery (Cohort WE). Medical records of a surgical referral center in the UK were reviewed. Preoperative patient demographic and clinical data, and postoperative outcome data were collected with a minimum 28-day follow-up period. Multivariable logistic regression analysis was used to model the odds of a negative outcome. Cohort WE had a higher preoperative proportion of nonambulatory dogs (p = .0115) but there were no significant differences between the nonambulatory (p = .3762) and deep-pain negative subgroups (p = .6199). Cohort WE had a higher risk of not recovering ambulation compared to Cohort WD [79.2% vs. 91.6% recovery; adjusted OR 3.010 (95% CI: 1.259-7.190); p = .0132] and had a higher risk of postoperative morbidity [32.2% vs. 17.2%; adjusted OR 2.015 (95% CI: 1.089-3.729); p = .0257]. There were no significant differences in other outcome measures between cohorts. Weekend surgery in canine decompressive thoracolumbar hemilaminectomy may be associated with poorer patient outcomes, specifically higher postoperative morbidity and a poorer rate of recovery of ambulation. This study demonstrates a weekend effect in veterinary surgery, which may be important in surgical decision-making in acute thoracolumbar IVDE. Further scrutiny of the patient's journey through the veterinary healthcare system is warranted.

Evaluation of different methods of environmental enrichment to control anxiety in dogs undergoing hemilaminectomy after acute intervertebral disc extrusion: a randomized double-blinded study.

The goal of this randomized, double-blinded, placebo-controlled study was to evaluate the effect of environmental enrichment (EE) on post-operative pain and anxiety in dogs following hemilaminectomy for acute intervertebral disc extrusion (IVDE). Twenty healthy client-owned dogs undergoing a hemilaminectomy for IVDE with the same immediate post-operative analgesia protocol were randomly assigned to either the EE or standard environment (SE) group post-operatively. Recovery was achieved in an intensive care room (SE) or a separate quiet room (EE) equipped with white noise and classical music. EE dogs were also exposed to dog-appeasing pheromones, essential oil scents, and positive human interactions and were provided meals through food toys. A blinded evaluator assessed all dogs using the modified Glasgow Composite Pain Scale (mGCPS) on presentation and at several time points post-operatively. A rescue injection of the opioid methadone was given to the dogs with an mGCPS score of ≥5/20. Dogs received the antidepressant trazodone when anxious behaviors (5 mg/kg) were observed. The mGCPS scores, the latencies to receive the first methadone and trazodone doses and to eat the first meal, the number of methadone and trazodone doses, and the number of meals ingested in the first 24 and 48 h post-surgery were compared using Wilcoxon tests, and Benjamini-Hochberg correction for false discovery rate was applied. Although median mGCPS scores did not differ between the groups, compared to SE dogs (n = 10), EE dogs (n = 6) received trazodone earlier (p = 0.019), were administered fewer methadone injections at 24 h (p = 0.043), and ate more at 48 h post-surgery (p = 0.007). Therefore, EE and anti-anxiety medications could be beneficial in improving the wellbeing of dogs post-operatively.

Comparison of Surgical Outcomes Associated With Compression Secondary to Hemorrhage and Intervertebral Disk Extrusions in Dogs.

Acute intervertebral disk extrusion (IVDE) is one of the most commonly reported neurologic disorders seen in veterinary practice. There is a recognized subset of IVDE cases that have a hemorrhagic inflammatory reaction within the epidural space that causes compression in addition to compression from herniated disk material. Previous reports have been conflicting in the outcomes of these cases. The goals of this retrospective case-control cross-sectional study are to (1) compare the success rate of routine surgical decompression in dogs with DEEH compression compared to Modified Frankel Score (MFS) matched dogs with non-hemorrhagic disk extrusions; (2) evaluate the extent of spinal cord compression on MRI compared to final patient outcomes in DEEH compression and (3) determine the surgical compression to decompression ratio and its relation to patient outcomes in cases of DEEH compression. A total of 143 dogs were included in this study and divided into two groups: DEEH compression dogs (n = 78) and non-hemorrhagic IVDE dogs (n = 65). Outcomes were assigned for each patient [0 = deceased, 1 = alive and non-ambulatory (MFS 0–3), 2 = alive and ambulatory (MFS 4 or 5)] in both groups. Outcomes of DEEH and non-hemorrhagic IVDE did not differ when taken to surgery with comparable success rates when stratified by MFS. Similarly, outcomes did not differ between DEEH and non-hemorrhagic IVDE dogs when assessed by compression to decompression ratio. Dogs with DEEH compression had more compressed sites than dogs with non-hemorrhagic IVDE (P = 0.001) and had more sites decompressed surgically than dogs with non-hemorrhagic IVDE (P < 0.001). Consequently, the compression to decompression ratio did not differ between the two groups (P = 0.52). Our results support the finding that when a similar level of surgical decompression is achieved, dogs with DEEH compression have similar outcomes to dogs with non-hemorrhagic IVDE for similar degrees of neurological dysfunction.

Focal spinal hyperesthesia as a prognostic factor in paraplegic dogs without deep pain perception

ABSTRACT: Intervertebral disc extrusion (IVDE) is the most common cause of spinal cord compression in dogs, whose prognosis is variable and depends on several factors, with deep pain perception (DPP) being the main parameter used. Investigations of new prognostic factors are studied to assist in the estimation of functional recovery. Thus, this study aimed to evaluate whether spinal hyperesthesia (SH) at the compression site can be used as a prognostic factor for the functional recovery of dogs with acute IVDE (Hansen type I), without DPP being subjected to thoracolumbar hemilaminectomy. Decompression surgery was performed on the same day or the day after admission. The duration of the loss of DPP until surgery performance ranged from 1 to 60 days, with a median of 4.5 days for the group of dogs with SH and 5.5 days for those without SH. Among the 68 dogs included in this retrospective study, 73.5% (50/68) showed SH, and 26.5% (18/68) were not identified. Recovery was satisfactory in 60% (30/50) of dogs with SH and in 27.7% (5/18) of dogs without SH, demonstrating that paraplegic dogs without DPP but with SH were 3.9 times more likely to recover when compared to dogs in the same condition, but with no SH. No studies have evaluated SH by palpation of the spine as a prognostic factor, which reinforces the relevance of the present study. The results of this study imply that SH in paraplegic dogs affected by thoracolumbar IVDE, without the presence of DPP, can be used as a possible prognostic indicator of functional recovery.

A Controlled Clinical Study of Intensive Neurorehabilitation in Post-Surgical Dogs with Severe Acute Intervertebral Disc Extrusion.

Simple SummaryThis study explores the potential intensive neurorehabilitation plasticity effects in post-surgical paraplegic dogs with severe acute intervertebral disc extrusion aiming to achieve ambulatory status. The intensive neurorehabilitation protocol translated in 99.4% (167/168) of recovery in deep pain perception-positive dogs and 58.5% (55/94) in deep pain perception-negative dogs. There was 37.3% (22/59) spinal reflex locomotion, obtained within a maximum period of 3 months. Thus, intensive neurorehabilitation may be a useful approach for this population of dogs, avoiding future euthanasia and promoting an estimated time window of 3 months to recover.This retrospective controlled clinical study aimed to verify if intensive neurorehabilitation (INR) could improve ambulation faster than spontaneous recovery or conventional physiotherapy and provide a possible therapeutic approach in post-surgical paraplegic deep pain perception-positive (DPP+) (with absent/decreased flexor reflex) and DPP-negative (DDP−) dogs, with acute intervertebral disc extrusion. A large cohort of T10-L3 Spinal Cord Injury (SCI) dogs (n = 367) were divided into a study group (SG) (n = 262) and a control group (CG) (n = 105). The SG was based on prospective clinical cases, and the CG was created by retrospective medical records. All SG dogs performed an INR protocol by the hospitalization regime based on locomotor training, electrical stimulation, and, for DPP−, a combination with pharmacological management. All were monitored throughout the process, and measuring the outcome for DPP+ was performed by OFS and, for the DPP−, by the new Functional Neurorehabilitation Scale (FNRS-DPP−). In the SG, DPP+ dogs had an ambulation rate of 99.4% (n = 167) and, in DPP−, of 58.5% (n = 55). Moreover, in DPP+, there was a strong statistically significant difference between groups regarding ambulation (p < 0.001). The same significant difference was verified in the DPP– dogs (p = 0.007). Furthermore, a tendency toward a significant statistical difference (p = 0.058) regarding DPP recovery was demonstrated between groups. Of the 59 dogs that did not recover DPP, 22 dogs achieved spinal reflex locomotion (SRL), 37.2% within a maximum of 3 months. The progressive myelomalacia cases were 14.9% (14/94). Therefore, although it is difficult to assess the contribution of INR for recovery, the results suggested that ambulation success may be improved, mainly regarding time.

Serum C-reactive protein in dogs with paraplegia secondary to acute intervertebral disc extrusion.

BackgroundApart from the absence of nociception, there is no readily available prognostic test for dogs presenting with paraplegia secondary to acute intervertebral disc extrusion (IVDE).ObjectiveTo assess if serum C‐reactive protein (CRP) can predict the postoperative outcome in paraplegic dogs undergoing surgery for IVDE and to assess the association between serum CRP and presence/absence of nociception on admission, and serum CRP and presence/absence of intramedullary changes seen on magnetic resonance imaging (MRI).AnimalsOne hundred dogs that underwent surgery at our hospital between 2018 and 2020 because of acute paraplegia secondary to IVDE and in which serum CRP was measured.MethodsRetrospective observational cohort study. Dogs were classified as 4 or 5 according to the modified Frankel score (MFS) depending on presence/absence of nociception, respectively. MRI images were reviewed and the T2‐weighted hyperintensity: L2 vertebral body length was measured. Postoperative outcome was defined as positive if nociception, ambulation or both returned after decompressive surgery.ResultsThe median (95% CI) serum CRP was 4 (4‐5) and 6 (4‐7) mg/L in MSF4 and MSF5, respectively (P = .03). A weak linear relationship (R 2 = 0.049, P = .03) was found between CRP and the T2‐weighted hyperintensity: L2 vertebral length. Outcome data was available for 85 dogs: CRP was 4 (4‐5) and 5 (4‐10) mg/L in positive and negative outcome dogs, respectively (P = .32).Conclusion and Clinical ImportanceSerum CRP did not predict outcome after surgery in dogs with paraplegia secondary to IVDE.

Prognostic Factors in Canine Acute Intervertebral Disc Disease.

Knowledge of the prognosis of acute spinal cord injury is critical to provide appropriate information for clients and make the best treatment choices. Acute intervertebral disc extrusions (IVDE) are a common cause of pain and paralysis in dogs with several types of IVDE occurring. Important prognostic considerations are recovery of ambulation, return of urinary and fecal continence, resolution of pain and, on the negative side, development of progressive myelomalacia. Initial injury severity affects prognosis as does type of IVDE, particularly when considering recovery of continence. Overall, loss of deep pain perception signals a worse outcome. When considering Hansen type 1 IVDE, the prognosis is altered by the choice of surgical vs. medical therapy. Concentration of structural proteins in the plasma, as well as inflammatory mediators, creatine kinase, and myelin basic protein in the cerebrospinal fluid (CSF) can provide additional prognostic information. Finally, cross-sectional area and length of T2 hyperintensity and loss of HASTE signal on MRI have been associated with outcome. Future developments in plasma and imaging biomarkers will assist in accurate prognostication and optimization of patient management.

Extended durotomy to treat severe spinal cord injury after acute thoracolumbar disc herniation in dogs.

To report recovery of ambulation of dogs treated with extended thoracolumbar durotomy for severe spinal cord injury caused by intervertebral disc herniation. Descriptive cohort. Twenty-six consecutive paraplegic dogs presented with loss of deep pain sensation after acute thoracolumbar intervertebral disc herniation. Each dog underwent routine diagnostic assessment and surgery for removal of extradural herniated intervertebral disc, followed by a four-vertebral body length durotomy centered on the herniated disc. Each dog was followed up until it was able to walk 10 steps without assistance or until 6 months after surgery. Sixteen of 26 dogs recovered to walk unaided (all but one also recovered fecal and urinary continence), and six dogs did not; four dogs were lost to follow-up. One dog was euthanized because of signs consistent with progressive myelomalacia. There was no evidence of detrimental effects of durotomy within the period of study. Using Bayesian analysis, we found a point estimate of successful outcome of 71% with 95% credible interval from 52% to 87%. Extended durotomy seemed to improve the outcome of dogs in our case series without increase in morbidity. Extended durotomy appears safe and may improve the outcome of dogs with severe thoracolumbar mixed contusion and compressive injuries associated with acute intervertebral disc extrusion.

Risk factors associated with progressive myelomalacia in dogs with complete sensorimotor loss following intervertebral disc extrusion: a retrospective case-control study

BackgroundProgressive myelomalacia (PMM) is a usually fatal complication of acute intervertebral disc extrusion (IVDE) in dogs but its risk factors are poorly understood. The objective of this retrospective case-control study was to identify risk factors for PMM by comparing dogs with complete sensorimotor loss following IVDE that did and did not develop the disease after surgery. We also investigated whether any risk factors for PMM influenced return of ambulation. Medical records of client-owned dogs with paraplegia and loss of pain perception that underwent surgery for IVDE from 1998 to 2016, were reviewed. Dogs were categorized as PMM yes or no based on clinical progression or histopathology. Walking outcome at 6 months was established. Signalment, onset and duration of signs (categorized), steroids, non-steroidal anti-inflammatory drugs (yes or no), site of IVDE (lumbar intumescence or thoracolumbar) and longitudinal extent of IVDE were retrieved and their associations with PMM and walking outcome were examined using logistic regression.ResultsOne hundred and ninety seven dogs were included, 45 with and 152 without PMM. A 6-month-outcome was available in 178 dogs (all 45 PMM dogs and 133 control dogs); 86 recovered walking (all in the control group). Disc extrusions at the lumbar intumescence were associated with PMM (p = 0.01, OR: 3.02, CI: 1.3–7.2). Surgery performed more than 12 h after loss of ambulation was associated with PMM (OR = 3.4; CI = 1.1–10.5, p = 0.03 for 12-24 h and OR = 4.6; CI = 1.3–16.6, p = 0.02 for the > 24 h categories when compared with the ≤12 h category). Treatment with corticosteroids was negatively associated with PMM (OR: 3.1; CI: 1.3–7.6, p = 0.01). The only variable to affect walking outcome was longitudinal extent of IVDE (OR = 2.6; CI = 1.3–5.3, p = 0.006).ConclusionDogs with lumbar intumescence IVDE are at increased risk of PMM. Timing of surgery and corticosteroid use warrant further investigations. PMM and recovery of walking are influenced by different factors.

Low-field magnetic resonance changes in the paravertebral musculature of dogs with acute intervertebral disc extrusion.

To describe the MRI features and prevalence of paravertebral muscle signal intensity changes in dogs with acute intervertebral disc extrusion and to search for associations between the signal changes and clinical history, signalment, neurological examination, serum creatine kinase activity and MRI characteristics of the disc herniation. Medical records and MRI examinations from 688 dogs with surgically confirmed acute intervertebral disc extrusion were reviewed retrospectively. T2-weighted and STIR MRI sequences were available for 276 cases and were examined for paravertebral muscle signal intensity changes. When present, extension, lateralisation and signal characteristics of these changes were recorded. Exclusion criteria were muscle injections 24 hours before MRI scan, trauma and previous spinal surgery. Nineteen dogs met the inclusion criteria. There were signal changes in the multifidus muscle, mostly in the thoracolumbar region and often extending caudally from the level of the intervertebral disc herniation. Two cases had paravertebral muscle signal intensity changes in the cervical region. MRI signal changes were seen more frequently in the muscles of non-ambulatory dogs. Clinical history and neuro-examination did not allow differentiation between dogs with and without paravertebral muscle signal intensity changes. Paravertebral muscle signal intensity changes were observed infrequently in the epaxial musculature of 6.9% dogs with acute intervertebral disc extrusion in both the thoracolumbar and cervical regions. The pathophysiological processes responsible for these MRI changes remain unknown.

Spinal Cord Injuries in Dogs Part I: A Review of Basic Knowledge

Abstract Spinal cord injuries (SCI) in dogs are not frequent, but they are serious pathological conditions accompanied with high morbidity and mortality. The pathophysiology of SCI involves a primary insult, disrupting axons, blood vessels, and cell membranes by mechanical force, or causes tissue necrosis by ischemia and reperfusion. The primary injury is followed by a cascade of secondary events, involving vascular dysfunction, edema formation, continuing ischemia, excitotoxicity, electrolyte shifts, free radical production, inflammation, and delayed apoptotic cell death. The most frequent cause of SCI in dogs is an acute intervertebral disc extrusion, exogenous trauma or ischemia. Neurological symptomatology depends on the location, size and the type of spinal cord lesions. It is characterized by transient or permanent, incomplete or complete loss of motor, sensory, autonomic, and reflex functions caudal to the site of the lesion. In a case of partial spinal cord (SC) damage, one of the typical syndromes develops (e. g. Brown-Séquard syndrome, central SC syndrome, ventral SC syndrome, dorsal SC syndrome, conus medullaris syndrome, or traumatic cauda equina syndrome). The severe transversal spinal cord lesion in the cervical region causes paresis or plegia of all four extremities (tetraparesis, tetraplegia); in thoracic or lumbosacral region, paresis or plegia of the pelvic extremities (paraparesis, paraplegia), i. e. sensory-motor deficit, urinary and foecal incontinence and sexual incompetence. The central nervous system in mammals does not regenerate, so the neurological deficit in dogs following severe SCI persists for the rest of their lives and animals display an image of permanent suffering. The research strategy presented here involved a PubMed, Medline (Ovid) and ISI Web of Science literature search from Januray 2001 to December 2017 using the term “canine spinal cord injury” in the English language; also references from selected papers were scanned and relevant articles included.

Clinical Characteristics of Dogs with Progressive Myelomalacia Following Acute Intervertebral Disc Extrusion.

BackgroundProgressive myelomalacia (PMM) is a catastrophic disease associated with acute intervertebral disc extrusion (IVDE). Published data on the clinical characteristics of this disease are limited.ObjectiveTo describe the onset and progression of clinical signs of PMM in a large case cohort.AnimalsFifty‐one dogs, 18 with histopathologically confirmed PMM, 33 presumptively diagnosed based on clinical signs and diagnostic imaging.MethodsRetrospective study. Dogs with confirmed IVDE and either a histopathologic diagnosis of PMM or a high clinical suspicion were identified by medical record search. Data on nature and progression of signs were extracted.ResultsTwenty‐four of 51 dogs were Dachshunds. T12–T13 was the most common site of disc extrusion (12 of 56), and 18 of 55 of mid‐to‐caudal lumbar discs (between L3 and L6) were affected. Onset of PMM signs ranged from present at first evaluation (17/51) to 5 days after presentation, with 25 of 51 cases developing signs within 48 hours. Progression of signs from onset of PMM to euthanasia or death, excluding 7 cases euthanized at presentation, ranged from 1 to 13 days with 23 being euthanized within 3 days. Nonspecific systemic signs were documented in 30 of 51 dogs.Conclusion and Clinical ImportanceThe majority of dogs developed PMM within 2 days of presentation and was euthanized within another 3 days. However, onset can be delayed up to 5 days after presentation with progression to euthanasia taking as long as 2 weeks. Mid‐to‐caudal lumbar discs might be associated with an increased risk of PMM.

Residual Spinal Cord Compression Following Hemilaminectomy and Mini-Hemilaminectomy in Dogs: A Prospective Randomized Study.

The aim of this study was to compare the reduction of spinal cord compression after surgical treatment of dogs with acute thoracolumbar intervertebral disc (IVD) extrusion achieved using hemilaminectomy versus mini-hemilaminectomy techniques. This was a prospective randomized study with client-owned dogs presented with acute IVD extrusion that were allocated to surgical treatment using hemilaminectomy (n = 15) or mini-hemilaminectomy (n = 15) techniques. Plain and intravenous-contrast computed tomography was performed pre- and postoperatively. The preoperative minimal cross-sectional dimension of the spinal cord (MDSCpre) and the postoperative minimal cross-sectional dimension of the spinal cord (MDSCpost) were measured at the level of greatest compression. The minimal diameter of the uncompressed spinal cord was measured in a similar way both pre- (MDUSCpre) and postoperatively (MDUSCpost). Dogs in the mini-hemilaminectomy group had significantly greater reduction of compression (RC) (p < 0.01) after surgery compared to dogs in the hemilaminectomy group. The mean RC in the hemilaminectomy group was 34.6% and in the mini-hemilaminectomy group 62.6%. Our results showed a significantly greater reduction of spinal cord compression for mini-hemilaminectomy compared to hemilaminectomy. Additionally, mini-hemilaminectomy could be a preferred method due to its minimal invasiveness and easier access to lateral fenestration.

Postoperative pain in dogs undergoing hemilaminectomy: Comparison of the analgesic activity of buprenorphine and tramadol

Abstract The objective of this study was to compare the analgesic activity of buprenorphine and tramadol for the management of postoperative pain after hemilaminectomy because of acute intervertebral disc extrusion in dogs. This is a randomized, blinded, and prospective clinical trial. The study was carried out on 50 dogs undergoing hemilaminectomy. After diagnosis, the dogs were divided randomly into 2 groups: group A (n = 25 dogs) received 3 mg/kg −1 of tramadol intramuscularly and group B (n = 25 dogs) received 0.02 mg/kg −1 of buprenorphine intramuscularly 10-15 minutes before the end of surgery and, then, every 8 and 6 hours, respectively, for 48 hours. Using the short form of the Glasgow Composite Pain Scale at 4 time points (before and 2, 12, and 24 hours after surgery), the dogs were clinically monitored and scored by the same operator who was blinded to the treatment. Data were analyzed using Mann-Whitney U tests. Significance was set at P

Risk factors for early post-operative neurological deterioration in dogs undergoing a cervical dorsal laminectomy or hemilaminectomy: 100 cases (2002–2014)

Early post-operative neurological deterioration is a well-known complication following dorsal cervical laminectomies and hemilaminectomies in dogs. This study aimed to evaluate potential risk factors for early post-operative neurological deterioration following these surgical procedures. Medical records of 100 dogs that had undergone a cervical dorsal laminectomy or hemilaminectomy between 2002 and 2014 were assessed retrospectively. Assessed variables included signalment, bodyweight, duration of clinical signs, neurological status before surgery, diagnosis, surgical site, type and extent of surgery and duration of procedure. Outcome measures were neurological status immediately following surgery and duration of hospitalisation. Univariate statistical analysis was performed to identify variables to be included in a multivariate model.Diagnoses included osseous associated cervical spondylomyelopathy (OACSM; n = 41), acute intervertebral disk extrusion (IVDE; 31), meningioma (11), spinal arachnoid diverticulum (10) and vertebral arch anomalies (7). Overall 54% (95% CI 45.25–64.75) of dogs were neurologically worse 48 h post-operatively. Multivariate statistical analysis identified four factors significantly related to early post-operative neurological outcome. Diagnoses of OACSM or meningioma were considered the strongest variables to predict early post-operative neurological deterioration, followed by higher (more severely affected) neurological grade before surgery and longer surgery time. This information can aid in the management of expectations of clinical staff and owners with dogs undergoing these surgical procedures.

Prevalence of Urinary Tract Infection in Dogs after Surgery for Thoracolumbar Intervertebral Disc Extrusion

Urinary tract infection (UTI) is a common complication in people with spinal cord injury (SCI). Dogs with acute intervertebral disc extrusion (IVDE) have similar risk factors for UTI when compared with human SCI patients and have a high perioperative prevalence of UTI. Determine the prevalence of UTI in dogs for 3 months after surgery for thoracolumbar IVDE and identify risk factors for development of UTI. Twenty-five dogs treated surgically for 26 acute disc extrusions. Prospective study. Urinalysis and urine culture were performed perioperatively. At home, owners monitored urine with dipsticks every 48 hours for 1 month then once a week until 3 months. Dogs returned for assessment of motor function, urinalysis, and urine culture at 1 and 3 months after surgery. Presence of UTI over the 3-month period was correlated to potential risk factors. Ten dogs (38%) developed 12 UTIs over the 3-month period, with the majority occurring between weeks 1 and 6; 60% of the UTIs were occult. Hematuria in the absence of pyuria or UTI was a common finding in the perioperative period. Sex, breed, and ambulatory status influenced the risk of developing a UTI. There is a high prevalence of UTIs, many of which are occult, in the 3 months after surgery for thoracolumbar IVDE. These dogs should be routinely monitored for UTI with urine culture regardless of urinalysis results.

MYELOGRAPHY VS. COMPUTED TOMOGRAPHY IN THE EVALUATION OF ACUTE THORACOLUMBAR INTERVERTEBRAL DISK EXTRUSION IN CHONDRODYSTROPHIC DOGS

Myelography and/or computed tomography (CT) are commonly used to evaluate acute intervertebral disk extrusion in chondrodystrophic dogs. The purpose of this study was to evaluate the sensitivity of myelography and two different CT protocols in determining level and lateralization of acute thoracolumbar intervertebral disk extrusion in comparison with surgical findings, investigate interobserver variability, and determine examination duration times. Results of conventional CT, helical CT, and myelography were compared with surgical findings in 19 chondrodystrophic dogs with acute thoracolumbar intervertebral disk extrusion. Agreement among investigators was determined for different imaging modalities, and examination times were recorded. In the diagnosis of level of disk extrusion there was agreement of myelography, conventional CT, and helical CT with surgical findings in 94.7%, 100%, and 94.7% of dogs, respectively (P = 0.144). In the diagnosis of level and lateralization of disk extrusion there was agreement of myelography, conventional CT, and helical CT with surgical findings in 78.9%, 87.4%, and 85.3% of dogs, respectively (P = 0.328). Interobserver agreement was very good for all imaging modalities (myelography K = 0.87; conventional CT K = 0.86; helical CT K = 0.95). There were significant differences in median examination duration times between helical CT (4 min), conventional CT (8 min), and myelography (32 min) (P < 0.001). Both helical and conventional CT appear to be accurate for evaluation of acute thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs and are faster to perform than myelography.

Acute intervertebral disc extrusion in a cat: clinical and MRI findings

A 5 year old, neutered male, domestic shorthaired cat had acute left hemiparesis and Horner's syndrome. Magnetic resonance imaging (MRI) revealed a loss of the normal signal from the nucleus pulposus of the intervertebral disc at C3/4, narrowing of the ventral subarachnoid space and slight dorsal displacement of the spinal cord and a focal hyperintense lesion affecting the left side of the spinal cord at the same level. The presumptive diagnosis was focal spinal cord oedema associated with intervertebral disc extrusion. A traumatic aetiology was suspected. The cat was treated conservatively and improved gradually over a period of 6months.

Intervertebral disc extrusion in six cats

Existing reports concerning intervertebral disc disease (IVDD) have focused almost exclusively on dogs, although a small number of individual case reports of IVDD of cats has been published. The medical records of six cats with IVDD were reviewed. Radiographic studies confirmed narrowed intervertebral disc spaces, mineralised intervertebral discs, and one or more extradural compressive lesions of the spinal cord in each cat. All disc extrusions were located in the thoracolumbar region. Surgical decompression of the spinal cord was achieved in all cats by means of hemilaminectomy and removal of compressive extradural material confirmed to be degenerative disc material. Good to excellent neurological recovery was noted in five of the six cats included in this report. Based on this review, it appears that IVDD of cats has many similarities to IVDD of dogs, and that healthy cats with acute intervertebral disc extrusion(s) respond favourably to surgical decompression of the spinal cord.