Physiotherapy in the Recovery of Paraplegic Dogs without Nociception Due to Thoracolumbar Intervertebral Disc Extrusion Treated Surgically

Several authors have advocated for the role of physiotherapy in canine intervertebral disc extrusion, and it is routinely recommended by various veterinary neurologists. However, veterinary literature does not unanimously support the routine use of physiotherapy to ensure an increase in locomotor return in dogs with IVDE. The aim of the study was to investigate whether physiotherapy can influence the functional recovery of paraplegic dogs with loss of nociception (LN) affected by thoracolumbar IVDE (Hansen type I) and treated surgically. The animals were divided into two groups: the physiotherapy group (PG), which included those that underwent decompressive surgery and postoperative physiotherapy; and the control group (CG), which included dogs that did not undergo any physiotherapy after surgery. A total of 51 dogs were included, with 30 in the PG and 21 in the CG. The number of physiotherapy sessions ranged from 6 to 60. The rate of functional recovery in dogs within 21 days postoperatively (PO) was 10% (3/30) in the PG and 19% (4/21) in the CG. After 21 days PO, the recovery rate was 43.33% (13/30) in the PG and 61.9% (13/21) in the CG, with no significant difference observed between the groups (p = 0.258). Based on the findings of this study, it was concluded that physiotherapy in paraplegic dogs with LN due to thoracolumbar IVDE does not appear to influence functional recovery compared to the group without physiotherapy.

Recovery of ambulation in small, nonbrachycephalic dogs after conservative management of acute thoracolumbar disk extrusion

BACKGROUND

Currently, low-level evidence suggests loss of ambulation associated with acute thoracolumbar disk extrusion is best treated by decompressive spinal surgery. Conservative management can be successful, but the proportion of dogs that recover and the fate of herniated material are uncertain.

OBJECTIVES

Determine the proportion of nonambulatory dogs with conservatively treated acute thoracolumbar disk extrusion that recover ambulation and measure the change in spinal cord compression during the first 12 weeks after presentation.

ANIMALS

Seventy-two client-owned nonambulatory dogs with acute thoracolumbar intervertebral disk extrusion.

METHODS

This is a prospective cohort study. Enrolled dogs underwent magnetic resonance imaging at presentation and owners were provided with conservative management recommendations. Imaging was repeated after 12 weeks. Recovery of ambulation was defined as 10 consecutive steps without falling. Spinal cord compression was determined from the cross-sectional area of the vertebral canal and extradural compressive material at the lesion epicenter. The association between recovery and change in compression over the 12-week observational period was examined.

RESULTS

Forty-nine of fifty-one (96%; 95% confidence interval [CI], 87%-99%) of deep pain-positive and 10/21 (48%; 95% CI, 28%-68%) of deep pain-negative dogs recovered ambulation within the 12-week period. The median time to ambulation was 11 and 25 days for deep pain-positive and -negative dogs, respectively. Reduction in spinal cord compression varied among individuals from minimal to complete and apparently was unrelated to the recovery of ambulation.

CONCLUSIONS AND CLINICAL IMPORTANCE

A high proportion of conservatively treated dogs recovered ambulation after conservative management of acute thoracolumbar disk herniation. Recovery was not dependent on the resolution of compression.

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

OBJECTIVE

To investigate if weekend surgery is associated with poorer outcomes in dogs with acute thoracolumbar intervertebral disc extrusion (IVDE) undergoing decompressive thoracolumbar hemilaminectomy.

STUDY DESIGN

Retrospective observational cohort study.

SAMPLE POPULATION

A total of 460 consecutive cases were reviewed, with 401 dogs undergoing weekday surgery (Cohort WD), and 59 dogs undergoing weekend surgery (Cohort WE).

METHODS

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.

RESULTS

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.

CONCLUSION

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.

CLINICAL SIGNIFICANCE

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.

Outcome of the Use of Clinical Reasoning Alone in Dogs with Acute Thoracolumbar Myelopathy and/or Pain

Acute thoracolumbar myelopathy is a common neurological presentation in dogs. Although certain spinal conditions present with characteristic clinical pictures, managing such cases with clinical reasoning alone (i.e., without cross-sectional imaging) has never been explored. The aim of this study was to define the outcome of patients with suspected intervertebral disc extrusion (IVDE), ischaemic myelopathy (IM) or acute non-compressive nucleus pulposus extrusion (ANNPE) that were managed with clinical reasoning alone. The database of the Queen's Veterinary School Hospital (Cambridge) was searched for paraparetic or paraplegic dogs with suspected IVDE or IM/ANNPE that were initially managed medically without undergoing imaging. Clinical presentation and outcome were recorded. If cross-sectional imaging was subsequently performed, information about the final diagnosis was collected and compared with the initially suspected diagnosis. A total of 123 IVDE cases were collected: 81% had a successful outcome with no imaging performed; 16% had IVDE confirmed with imaging and successful outcome with surgery or medical management; and just 3% were found to have an alternative diagnosis or were euthanised without imaging. A total of 16 IM/ANNPE cases were collected: 94% had a successful outcome, and one dog was euthanised. Successful outcomes can be obtained by using clinical reasoning alone in most dogs with suspected IVDE or IM/ANNPE.

Thoracolumbar Intervertebral Disk Extrusion in Dogs: Do Onset of Clinical Signs, Time of Surgery, and Neurological Grade Matter?

OBJECTIVE

 The aim of this study was to determine the influence of time between the beginning of clinical signs, presentation and decompression, and combinations of several factors on the outcome and recovery of dogs undergoing surgery for thoracolumbar intervertebral disk extrusion (IVDE).

STUDY DESIGN

 In all, 433 client-owned dogs treated for IVDE between 2016 and 2020 were reviewed for signalment, neurological grade, rate of onset, duration of clinical signs, and surgical variables. Time from presentation to surgery was divided into three categories: S1 (0-12 hours), S2 (12-24 hours), and S3 (>24 hours). These variables were investigated to determine their influence on the return of pain sensation, urinary continence, ambulation and overall outcome.

RESULTS

 A significant association was found between an acute onset of clinical signs, worse neurological grade at presentation and poorer outcomes. There was a significant difference between S1, S2, and S3 in neurological grade at presentation (p < 0.001) and at discharge (p < 0.001); however, the latter was no longer significant when adjusted for the grade at presentation (p = 1,000). Disk fenestration was associated with a faster return to ambulation (p = 0.033). Duration of clinical signs and time of surgery did not correlate with the time to recovery and return of pain sensation, urinary continence, or ambulation.

CONCLUSION

 Dogs presented with severe neurological status and/or rapid onset of clinical signs were operated on more promptly, but their outcomes were also poorer. There was no significant evidence for a better outcome when surgery was not delayed.

Significance of intramedullary T2* signal voids in the magnetic resonance imaging of paraplegic deep pain-negative dogs following intervertebral disc extrusion at short-term follow-up

Introduction

Dogs presenting as paraplegic without nociception due to a thoracolumbar intervertebral disc extrusion provide a difficult decision to both the clinician and the owner. The prognosis when performing surgical decompression remains guarded. Aside from significant extradural compression, these dogs often have a significant secondary spinal cord injury, which has shown to be an important factor in determining both the likelihood of developing progressive myelomalacia and the return to ambulation.

Materials and methods

This is a retrospective, observational, single centre study including 82 dogs presenting as paraplegic with absent nociception diagnosed with an intervertebral disc extrusion. Patients underwent MRI of the thoracolumbar spine, including a gradient echo sequence which was evaluated for the presence of intramedullary signal void artefacts. Decompressive surgery was performed, and patients were evaluated for the presence of nociception at short term follow up (at least four weeks post-surgery).

Results

Overall, 59.8% of patients regained nociception within the study period. This number was significantly reduced to 33.3% when multiple gradient echo signal voids were present (compared to 67.3% of dogs without signal voids). There was no significant difference in the rate of developing progressive myelomalacia between groups.

Conclusions

This paper adds to the existing literature and suggests that the gradient echo sequence may be of use when assessing acute spinal cord injury in the context of intervertebral disc extrusion and how it relates to prognosis.

Randomized single-blinded prospective comparison between ozone therapy and electroacupuncture for canine thoracolumbar disk disease

Ozone therapy has been used to control pain in animals. Moreover, electroacupuncture (EA) has been effective in neurological recovery and pain control in dogs with thoracolumbar discopathy. EA was compared with Ozone applied at acupuncture points in dogs with signs of thoracolumbar disk disease. Chondrodystrophic mongrel dogs, with lesion scores between 1 and 4, were randomly divided into groups: EA (n = 13) - electroacupuncture at BL20, BL23, ST36, KID3 and BL60 and dry needle in lumbar Bai Hui, and OZO (n = 15) - paravertebral application of 3 mL ozone (20 μg / mL) at BL20, BL23, lumbar Bai Hui, ST36, and KID3/BL60, both groups with weekly applications. No significant differences were observed between groups in weekly blind pain assessments using a dynamic interactive visual analog scale, and neurological assessments using a numerical-functional scale. Both groups showed a progressive improvement in pain control and neurological condition, which was observed when comparing the group's EA and OZO in dogs with all lesion scores. The time of return to locomotion (days) of dogs scored 3 and 4, between groups EA (10.6 ± 5.4) and OZO (14.5 ± 15.7), had no significant differences. Ozone therapy was effective to control pain and motor rehabilitation and sensory functions of dogs with thoracolumbar discopathy signs, just as electroacupuncture. Ozone application was a quick and easy-to-handle treatment. Paravertebral and subcutaneous routes did not require anesthesia or other advanced imaging technology, besides being safe and effective.

A case series of 37 surgically managed, paraplegic, deep pain negative French bulldogs, with thoracolumbar intervertebral disc extrusion, from two English referral centres

Background

Thoracolumbar intervertebral disc extrusions (TL-IVDEs) are a common spinal disorder in dogs, especially within chondrodystrophic breeds. Loss of deep pain perception is a well-documented negative prognostic indicator in dogs with TL-IVDE. The objectives of this study were to report the rate of return of deep pain perception and independent ambulation in surgically treated, paraplegic, deep pain perception negative French bulldogs with TL-IVDEs.

Methods

A retrospective case series of deep pain perception negative dogs with TL-IVDE presenting to two referral centres between 2015 and 2020 was conducted. Medical and MRI records were reviewed, including the following quantitative MRI changes: lesion length, extent of spinal cord swelling and severity of spinal cord compression.

Results

Thirty-seven French bulldogs met the inclusion criteria, with 14 of 37 (38%) regaining deep pain perception by the time of discharge (median hospitalisation 10.0 days [interquartile range 7.0-15.5 days]) with two dogs independently ambulatory (6%). Ten of the 37 dogs were euthanased during hospitalisation. Significantly fewer dogs (3/16, 19%) with L4-S3 lesions regained deep pain perception compared to 11 of 21 (52%) of dogs with T3-L3 lesions (p = 0.048). Quantitative MRI changes were not associated with the return of deep pain perception. After discharge, with a median 1-month follow-up period, an additional three dogs regained deep pain perception and five dogs became independently ambulatory (17/37 [46%] and 7/37 [19%], respectively).

Conclusions and clinical importance

This study adds support to the contention that the recovery of French bulldogs with TL-IVDE from surgery is poor compared with other breeds; further prospective, breed-controlled studies are indicated.

MRI features can help to confirm a diagnosis of progressive myelomalacia, but may not be accurate in dogs lacking characteristic clinical signs at the time of imaging

Progressive myelomalacia (PMM) is a fatal sequela of acute thoracolumbar intervertebral disc extrusion in dogs, with unpredictable onset in the days after the inciting injury. No single reliable diagnostic test is currently available. Magnetic resonance imaging (MRI) features such as T2-weighted spinal cord hyperintensity and loss of subarachnoid signal in a half-Fourier single-shot turbo spin echo (HASTE) sequence have been associated with PMM, but are sometimes present in other dogs with severe deficits. Magnetic resonance imaging findings in 22 dogs with a clinical or histopathologic diagnosis of PMM and 38 deep pain-negative paraplegic dogs were compared in a retrospective case-control study. Length of T2-weighted hyperintense spinal cord change and HASTE signal loss were significantly associated with clinically evident PMM (P = .0019 and P = .0085), however, there were no significant differences between groups when analysis was restricted to dogs not yet showing clinical signs of PMM. The PMM group also had significantly shorter compressive lesions than the control group (P = 0.026), suggesting a possible role of more severe focal pressure at the extrusion site. A segment of total loss of contrast enhancement in the venous sinuses and meninges, a feature not previously described, was more common in the PMM group and the difference approached significance (P = 0.054). Findings show that MRI features can support the diagnosis in dogs with clinical evidence of PMM, and absence of these features supports absence of PMM at time of imaging. However, their absence does not reliably differentiate dogs with imminent progressive myelomalacia from other dogs with severe deficits following intervertebral disc extrusion.

HASTE MRI sequence findings correlate with loss of deep pain perception in dogs with thoracolumbar disc extrusion

BACKGROUND

Thoracolumbar intervertebral disc extrusion (TL IVDE) is a common reason for the veterinary hospital admission. Various imaging factors including degree and length of compression have been tested for correlation with clinical severity, but no reliable correlation has been found. Half-Fourier acquisition single-shot turbo spin echo (HASTE) magnetic resonance imaging (MRI) sequences highlight the dorsal and ventral cerebrospinal fluid (CSF) columns and have been used to demonstrate spinal cord swelling in dogs with TL IVDE. This has been used as a predictor of progressive ascending-descending myelomalacia but has not been correlated with neurological grade.

OBJECTIVE

This study aims to investigate the correlation between the attenuation of CSF HASTE signal and clinical severity in dogs suffering from TL disc extrusions.

METHODS

Dogs less than 15 kg who were non-ambulatory due to suspected TL IVDE were prospectively recruited for a study into conservative management. MRI studies were undertaken under sedation including HASTE sequences. The ratio of the length of CSF attenuation to the length of the L2 vertebra was calculated and correlated with clinical severity.

RESULTS

Twenty dogs met the inclusion criteria. No statistically significant difference was demonstrated between the mean CSF attenuation and neurological grade (p = 0.17 but there was a significant difference in the mean CSF attenuation in those who retained deep pain perception and those who did not (p = 0.02). Time to loss of ambulation was also found to not be correlated with CSF attenuation (p = 0.95).

CONCLUSION

In conclusion, the length of CSF attenuation of HASTE MRI sequences in dogs less than 15 kg suffering from IVDEs may be correlated with a loss of deep pain perception.

Does surgical timing affect the rapidity of recovery in deep pain-entire non-ambulatory dogs with thoracolumbar intervertebral disk extrusion?

OBJECTIVE

To investigate whether the delay between onset of neurological signs and spinal cord decompression affects the time to recovery in non-ambulatory paraparetic/paraplegic dogs with deep pain perception affected by thoracolumbar intervertebral disc extrusion.

MATERIALS AND METHODS

Data on non-ambulatory dogs with preserved deep pain perception in both hindlimbs and surgically treated for thoracolumbar intervertebral disc extrusion were prospectively collected from three referral hospitals. Cox proportional hazards regression was used to explore the relationship of time until restoration of independent ambulation with age, weight, preoperative use of anti-inflammatory drugs, delay between onset of inability to walk and arrival at the clinic, time between presentation and spinal surgery and surgery time.

RESULTS

One hundred and fifty-one dogs were included. Median time from admission to surgery, including imaging, was 180 (interquartile range, 65.4 to 240) minutes. All dogs were operated within 72 hours. Follow-up was available for all 151 dogs and ranged from 1 to 21 months. All but three dogs, which were all grade IV at presentation, recovered the ability to ambulate. In both univariable and multivariable models, only duration of surgery and neurological (Frankel) grade at presentation were significantly associated with the rapidity of recovery of ambulation.

CLINICAL SIGNIFICANCE

Delay between onset of clinical signs and presentation and time between presentation and spinal surgery was not associated with the rapidity of recovery of ambulation in dogs surgically treated for thoracolumbar intervertebral disc extrusion. These results should be evaluated in the context of a limited range of delay since only 14.5% dogs had a delay ≥6.5 hours. Duration of surgery and neurological grade at presentation were significantly associated with rapidity of recovery of ambulation.

Functional outcome in dogs undergoing hemilaminectomy for thoracolumbar disc extrusion but without nociception > 96 h: A prospective study

This prospective study investigated the functional recovery of surgically treated dogs with thoracolumbar intervertebral disc extrusion (IVDE) without deep pain perception (DPP) for > 96 h. Dogs (n = 36) with paraplegia secondary to thoracolumbar intervertebral disc extrusion with loss of deep pain perception ranging from 4 to 60 days were enrolled. All dogs underwent hemilaminectomy and fenestration of the affected intervertebral disc and postoperative follow-up was provided for a maximum of 180 days. Recovery of motor function was satisfactory (based on the owner's assessment) in 22 dogs, 61.1% (47.2% with DPP, and 13.9% without DPP) and unsatisfactory in 38.9% of cases (n = 14). Postoperative physiotherapy, preoperative anti-inflammatory drugs, and age had no effect on recovery. In this study, the longer the time taken to regain pain perception, the longer the recovery time. The median time to recovery was 30 days. A total of 47.2% of dogs with paraplegia and absence of DPP secondary to thoracolumbar IVDE lasting > 96 h, recovered functional ambulation after decompressive surgery.

A 50-step walking test for analysis of recovery after decompressive surgery for thoracolumbar disc herniation in dogs

BACKGROUND

Despite its importance, there is no agreed definition of recovery of ambulation in dogs with spinal cord injury.

OBJECTIVES

To validate a new walking test in dogs recovering from thoracolumbar spinal cord injury.

ANIMALS

Two hundred twenty-four dogs weighing <20 kg: 120 normally ambulatory dogs, plus 104 dogs undergoing decompressive surgery for acute thoracolumbar intervertebral disc herniation.

METHODS

Prospective cohort studies. The distance each freely-ambulatory dog walked during 50 step cycles was regressed on ulna length. For each postsurgical dog, we recorded when the calculated 50-step distance was completed without falling, or their inability to complete this distance by 4 months or more after surgery. Bayesian analysis compared outcomes for presurgical neurologic categories; association of recovery with several preoperative variables was explored using logistic and time-to-event regression.

RESULTS

For control dogs, 50-step distance (m) = 1.384 × ulnar length (cm) + 2.773. In postsurgical dogs, the 50-step test provided decisive evidence that deep pain-negative dogs were less likely to recover ambulation than dogs with intact pain perception (12/29 recovered vs 71/75; Bayes factor [BF] = 5.9 × 106 ) and, if they did recover, it took much longer (median 91 days vs median 14 days; BF = 1.5 × 103 ). Exploratory analysis suggested that presurgical neurologic status (subhazard ratio [SHR] = 0.022; P < .001) and duration of presurgical anesthesia (SHR = 0.740; P = .04) were associated with rapidity of recovery.

CONCLUSIONS AND CLINICAL IMPORTANCE

This straightforward 50-step walking test provides robust data on ambulatory recovery well-suited to large scale pragmatic trials on treatment of thoracolumbar spinal cord injury in dogs.

Intervertebral Disc Disease in Dogs – The Relationship Between Recovery and Timing of Surgery

The aim of this study was to evaluate the relationship between functional recovery and timing of surgery in dogs diagnosed with intervertebral disc disease treated surgically. Intervertebral disc disease is the most common spinal disease in dogs; it plays a significant role in the scientific field by its high prevalence. There is also an existing hypothesis that the faster the surgery is performed, the better the outcome will be. The data were collected during two years at one institution. The patients were neurologically assessed using the modified Frankel score when they were first diagnosed with intervertebral disc disease at the clinic and later after the surgery and during the following weeks. A total of 36 dogs were included in this study, represented by 13 different dog breeds and crossbreeds. In total 17 were females and 19 males. The mean age of the patients was 6.9 ± 2.97 years (range 2—15 years) and the mean body condition score was 3.5 within a scale of 1—5. Out of the 36 evaluated dogs, surgery was performed on 25 of them. The mean time of duration of clinical signs before surgery was 9 ± 13 days. The main limitation of this study was the small group of investigated dogs. Although the study was based on a small number of participants, the findings suggested that the timing of the surgery and recovery had a positive Pearson correlation coefficient of 0.39; implying that the timing of the surgery may have affected the recovery.

ACVIM consensus statement on diagnosis and management of acute canine thoracolumbar intervertebral disc extrusion

Background

Thoracolumbar intervertebral disc extrusion (TL‐IVDE) is the most common cause of acute paraparesis and paraplegia in dogs; however, guidelines on management of the condition are lacking.

Objectives

To summarize the current literature as it relates to diagnosis and management of acute TL‐IVDE in dogs, and to formulate clinically relevant evidence‐based recommendations.

Animals

None.

Methods

A panel of 8 experts was convened to assess and summarize evidence from the peer‐reviewed literature in order to develop consensus clinical recommendations. Level of evidence available to support each recommendation was assessed and reported.

Results

The majority of available literature described observational studies. Most recommendations made by the panel were supported by a low or moderate level of evidence, and several areas of high need for further study were identified. These include better understanding of the ideal timing for surgical decompression, expected surgical vs medical outcomes for more mildly affected dogs, impact of durotomy on locomotor outcome and development of progressive myelomalacia, and refining of postoperative care, and genetic and preventative care studies.

Conclusions and Clinical Importance

Future efforts should build on current recommendations by conducting prospective studies and randomized controlled trials, where possible, to address identified gaps in knowledge and to develop cost effectiveness and number needed to treat studies supporting various aspects of diagnosis and treatment of TL‐IVDE.

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 &lt; 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.

Postoperative outcome of ambulatory dogs with intervertebral disc extrusion causing incontinence and/or tail dysfunction: 18 cases (2010-2020)

Objectives

To assess the recovery of urinary continence, faecal continence and tail function in ambulatory dogs with caudal lumbar intervertebral disc extrusion and to explore clinical factors that may be associated with recovery.

Materials and Methods

Medical records from January 2010 to December 2020 were searched to identify ambulatory dogs undergoing surgical treatment for a caudal lumbar intervertebral disc extrusion causing urinary incontinence, faecal incontinence and/or tail dysfunction. Signalment, history, presenting clinical signs, neurological examination findings, diagnostic test results, treatment and outcome were recorded for all dogs.

Results

Eighteen dogs with caudal lumbar intervertebral disc extrusion causing tail dysfunction, urinary and/or faecal incontinence were included. Urinary continence was recovered in 12 (86%) of 14 affected dogs, faecal continence recovered in nine (90%) of 10 affected dogs and tail function recovered in 13 (87%) of 15 affected dogs. Loss of tail nociception was recorded in three dogs on presentation; two made a full recovery and one showed mild persistent tail paresis.

Clinical Significance

The prognosis for functional recovery of urinary continence, faecal continence and tail function in ambulatory dogs with caudal lumbar intervertebral disc extrusion following surgical treatment is good. Larger studies are needed to identify prognostic factors associated with failure of recovery.

Intramuscular tetanus neurotoxin reverses muscle atrophy: a randomized controlled trial in dogs with spinal cord injury

BACKGROUND

Motor symptoms of spinal cord injury (SCI) considerably impair quality of life and are associated with a high risk of secondary diseases. So far, no pharmacological treatment is available for these symptoms. Therefore, we conducted a randomized, double-blinded, placebo-controlled study in dogs with spontaneous SCI due to disc herniation to test whether a reduction of spinal inhibitory activity by intramuscular injections of tetanus neurotoxin (TeNT) alleviates motor symptoms such as muscle atrophy or gait function.

METHODS

To this end, 25 dogs were treated with injections of either TeNT or placebo into their paretic hindlimb muscles. Effects of TeNT on muscle thickness were assessed by ultrasound, while effects on gait function were measured using the modified functional scoring system in dogs.

RESULTS

Four weeks after the TeNT injections, muscle thickness of the gluteus medius muscle (before median 1.56 cm [inter-quartile range {IQR} 1.34-1.71 cm] and after median 1.56 cm [IQR 1.37-1.85 cm], P-value 0.0133) as well as of the rectus femoris muscle (before median 0.76 cm [IQR 0.60-0.98 cm] and after median 0.93 cm [IQR 0.65-1.05 cm], P-value 0.0033) significantly increased in the TeNT group. However, there was no difference in gait function between the TeNT and placebo groups. The treatment was well tolerated by all dogs without any signs of generalized tetanus symptoms or any spreading of effects beyond the lumbar level of the injected hindlimbs.

CONCLUSIONS

With regard to the beneficial effects on muscle thickness, intramuscular injections of TeNT represent the first pharmacological approach that focally reverses muscle atrophy in SCI. Moreover, the study data support the safety of this treatment when TeNT is used at low dose.

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

Simple Summary

This 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.

Abstract

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.

Evaluation of the involvement of Th17-cells in the pathogenesis of canine spinal cord injury

Intervertebral disc herniation (IVDH) is a frequently occurring neurological disease of dogs and the most common reason for spinal cord injury (SCI). Clinical signs are variable thus a reliable prognosis is crucial for further treatment decisions. Currently, the prognosis of IVDH primarily depends on presence or absence of deep pain perception. The purpose of this study was to investigate if Th17-cells could serve as a potential, prognostic biomarker for IVDH. We investigated a possible role of the adaptive immune system in the pathophysiology of IVDH in dogs. The investigation was performed by analyzing the influence of Th17-cells in blood and cerebrospinal fluid (CSF) of sixty-two dogs suffering from IVDH. In addition, we examined if Th17-cells might influence the course of this disease. As controls, paired blood and CSF samples of ten healthy clinic-owned dogs were examined and the values were compared to those of the IVDH group. Isolated lymphocytes were analyzed after stimulation by using multicolour flow cytometry to measure the number of Th17-cells. IL-17 levels were measured in paired serum and CSF samples by Enzyme‐linked Immunosorbent Assays (ELISA). Highly significant differences of stimulated Th17-cells in EDTA-blood samples could be determined between Th17-cell levels of dogs suffering from IVDH and the healthy control group and also between three sampling time points: preoperative, after clinical improvement and after six months. Preoperatively, Th17-cell levels were strongly decreased in contrast to the healthy controls. The decreased amount of Th17-cell levels recovered postoperatively so that Th17-cell levels of the last follow-up examinations were comparable to the control group after six months. At the same time IL-17 measured in serum preoperatively was significantly higher in dogs with IVDH than in healthy controls. However, there was no considerable difference of IL-17 measured in CSF between the groups. In conclusion, a high activity and consequent consumption of IL-17-producing Th17-cells is suspected in acute IVDH. These findings may indicate an involvement of Th17-cells in the pathogenesis of IVDH and emphasize that these cells might be involved in the interaction of pain, stress and immune reaction. However, based on the findings of this study the development of Th17-cells as a biomarker cannot be recommended, yet.

Effect of a Corset on the Gait of Healthy Beagle Dogs

Simple Summary

In recent years, corsets have been used in the prevention of nerve diseases in dogs and in their rehabilitation following surgery. The Anifull Dog’s Corset Pro, made by Daiya Industry Co., Ltd., is manufactured and sold for this purpose, but no studies have yet been conducted to verify its effectiveness. To evaluate the effects of the corset, we analyzed the gait of healthy beagle dogs that were or were not wearing the Anifull Dog’s Corset Pro. We found no difference in the walking speed of the dogs, but wearing the corset reduced the horizontal sway of the back. In conclusion, this corset does not affect the gait of dogs and may help body stability. Therefore, the Anifull Dog’s Corset Pro may be useful for the treatment of dog nerve conditions.

Abstract

The prognosis for intervertebral disc disease (IVDD), a common neurologic disease in dogs, varies, with some cases requiring long-term rehabilitation. Corsets are used as part of the physical rehabilitation of dogs, and one of these, the Anifull Dog’s Corset Pro, is manufactured and sold by Daiya Industry Co., Ltd. This corset is used to relieve pain caused by spinal cord and vertebral diseases, and to prevent neurological conditions from worsening, by limiting spinal movement. However, the effect of the Anifull Dog’s Corset Pro on gait has not yet been clarified. Therefore, we aimed to evaluate the effects of this corset on the gait of dogs using kinematic and kinetic analyses. Five healthy beagle dogs wearing corsets were trotted, kinematic and kinetic parameters were measured using motion capture and force plates, and the results were compared to those obtained when the dogs were not wearing a corset. The range of motion of the angle formed by the 13th thoracic vertebra and the 7th lumbar vertebra at the apex of the 7th cervical vertebra was significantly reduced in the corset-wearing dogs. Thus, the Anifull Dog’s Corset Pro may improve trunk stability without affecting gait.

Serum phosphorylated neurofilament heavy chain as a diagnostic biomarker for progressive myelomalacia in dogs with thoracolumbar intervertebral disc herniation

Background

Serum phosphorylated neurofilament‐heavy chain (pNF‐H) has not been longitudinally evaluated in dogs that develop progressive myelomalacia (PMM) after Type I intervertebral disc herniation (IVDH).

Objectives

To determine if serum pNF‐H concentrations would predict outcome of neuroligical disease in dogs with acute, severe thoracolumbar myelopathy secondary to Type I IVDH.

Animals

Thirty‐nine client‐owned dogs with thoracolumbar myelopathy secondary to IVDH.

Methods

Prospective controlled cohort study. Serum was collected from dogs undergoing hemilaminectomy at multiple timepoints. Final neurological status was established at 12 months and groups were stratified accordingly. Comparisons between outcome and pNF‐H concentration at each timepoint was examined using Kruskal‐Wallis analysis of variance on ranks and receiver operator characteristics curve analysis.

Results

Median serum pNF‐H concentrations were not significantly different between deep pain negative dogs that did or did not recover at any timepoint (baseline: 0.37 ng/mL [0‐0.9 ng/mL] vs 0 ng/mL [0‐0.9 ng/mL], P > 1; 24 hours: 1.25 ng/mL [0.35‐7.23 ng/mL] vs 1.53 ng/mL [0‐11.94 ng/mL], P > 1; 48 hours: 1.22 ng/mL [0.63‐6.62 ng/mL] vs 2.12 ng/mL [0‐20.72 ng/mL], P >  1; 72 hours: 2.77 ng/mL [1.33‐6.62 ng/mL] vs 16.69 ng/mL [4.02‐40.12 ng/mL], P >  1). Dogs that developed PMM had significantly higher serum pNF‐H concentrations after surgery compared to all other cohorts at 24 hours: 39.88 ng/mL (25.74‐50.68 ng/mL); P < .05 and 72 hours: 223.9 ng/mL (155.4‐263.7 ng/mL); P < .05. A serum pNF‐H concentration ≥31.39 ng/mL was 83.33% sensitive and 100% specific for identifying PMM in this cohort.

Conclusions and Clinical Importance

Serum pNF‐H is a promising biomarker for antemortem diagnosis of PMM in dogs with acute, severe thoracolumbar myelopathy secondary to Type I IVDH.

Functional Neurorehabilitation in Dogs with an Incomplete Recovery 3 Months following Intervertebral Disc Surgery: A Case Series

Simple Summary

A non-invasive neurorehabilitation multimodal protocol (NRMP) may be applicable to chronic T3-L3 dogs 3 months after undergoing surgery for acute Intervertebral Disc Disease (IVDD) Hansen type I; this protocol has been shown to be safe, feasible, and potentially effective at improving ambulation in both open field score (OFS) 0 and OFS 1 dogs. The specific sample population criteria limit the number of dogs included, mainly due to owners withdrawing over time. Thus, the present case series study aimed to demonstrate that an NRMP could contribute to a functional treatment possibly based on synaptic and anatomic reorganization of the spinal cord.

Abstract

This case series study aimed to evaluate the safety, feasibility, and positive outcome of the neurorehabilitation multimodal protocol (NRMP) in 16 chronic post-surgical IVDD Hansen type I dogs, with OFS 0/DPP− (n = 9) and OFS 1/DPP+ (n = 7). All were enrolled in the NRMP for a maximum of 90 days and were clinically discharged after achieving ambulation. The NRMP was based on locomotor training, functional electrical stimulation, transcutaneous electrical spinal cord stimulation, and 4-aminopyridine (4-AP) pharmacological management. In the Deep Pain Perception (DPP)+ dogs, 100% recovered ambulation within a mean period of 47 days, reaching OFS ≥11, which suggests that a longer period of time is needed for recovery. At follow-up, all dogs presented a positive evolution with voluntary micturition. Of the DPP− dogs admitted, all achieved a flexion/extension locomotor pattern within 30 days, and after starting the 4-AP, two dogs were discharged at outcome day 45, with 78% obtaining Spinal Reflex Locomotion (SRL) and automatic micturition within a mean period of 62 days. At follow-up, all dogs maintained their neurological status. After the NRMP, ambulatory status was achieved in 88% (14/16) of dogs, without concurrent events. Thus, an NRMP may be an important therapeutic option to reduce the need for euthanasia in the clinical setting.

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

BACKGROUND

Apart from the absence of nociception, there is no readily available prognostic test for dogs presenting with paraplegia secondary to acute intervertebral disc extrusion (IVDE).

OBJECTIVE

To 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).

ANIMALS

One 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.

METHODS

Retrospective 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.

RESULTS

The 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 (R²  = 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 IMPORTANCE

Serum CRP did not predict outcome after surgery in dogs with paraplegia secondary to IVDE.

Nervous system modulation through electrical stimulation in companion animals

Domestic animals with severe spontaneous spinal cord injury (SCI), including dogs and cats that are deep pain perception negative (DPP-), can benefit from specific evaluations involving neurorehabilitation integrative protocols. In human medicine, patients without deep pain sensation, classified as grade A on the American Spinal Injury Association (ASIA) impairment scale, can recover after multidisciplinary approaches that include rehabilitation modalities, such as functional electrical stimulation (FES), transcutaneous electrical spinal cord stimulation (TESCS) and transcranial direct current stimulation (TDCS). This review intends to explore the history, biophysics, neurophysiology, neuroanatomy and the parameters of FES, TESCS, and TDCS, as safe and noninvasive rehabilitation modalities applied in the veterinary field. Additional studies need to be conducted in clinical settings to successfully implement these guidelines in dogs and cats.

Poliomyelomalacia in three dogs that underwent hemilaminectomy for intervertebral disk herniation

CASE DESCRIPTION

3 dogs were examined because of a sudden onset of signs of pain (1 dog) or paraparesis (2 dogs).

CLINICAL FINDINGS

Neurologic findings consisted of myelopathy affecting the lumbar intumescence (1 dog) and T3-L3 myelopathy (2 dogs). In all dogs, MRI revealed spinal cord compression caused by L3-4 disk herniation. All dogs underwent routine surgical decompression of the intervertebral disk herniation. During MRI and decompressive surgery, physiologic variables were monitored. Immediately after surgery, all dogs were paraplegic with pelvic limb neurologic dysfunction consistent with myelopathy affecting the L4 through caudal spinal cord segments.

TREATMENT AND OUTCOME

Within 24 hours after surgery, repeated MRI in all dogs revealed hyperintensity in the spinal cord gray matter of the lumbar intumescence on T2-weighted images. In the absence of neurologic improvement, dogs were euthanized at 3, 91, and 34 days after surgery. Postmortem microscopic examination of each dog's spinal cord at the lumbar intumescence revealed necrosis of the gray matter with relative white matter preservation suggestive of an ischemic injury.

CLINICAL RELEVANCE

Dramatic neurologic deterioration following decompressive surgery for intervertebral disk herniation in dogs may be associated with the development of poliomyelomalacia secondary to ischemia. In these 3 dogs, ischemia developed despite probable maintenance of normal spinal cord blood flow and perfusion during anesthesia. To exclude other causes, such as compression or hemorrhage, MRI was repeated and revealed hyperintensity of the spinal cord gray matter on T2-weighted images, which microscopically corresponded with ischemic neurons and neuronal loss.

Outcomes and prognostic indicators in 59 paraplegic medium to large breed dogs with extensive epidural hemorrhage secondary to thoracolumbar disc extrusion

OBJECTIVE

To evaluate outcomes and prognostic factors after decompressive hemilaminectomy in paraplegic medium to large breed dogs with extensive epidural hemorrhage (DEEH) and thoracolumbar intervertebral disc extrusion (TL-IVDE).

STUDY DESIGN

Retrospective, cohort, descriptive study.

ANIMALS

Fifty-nine client-owned dogs.

METHODS

Medical records and advanced imaging were reviewed for paraplegic dogs with DEEH. Ambulatory status 6 months after surgery and postoperative complications were recorded. Multiple logistic regression models were constructed to explore prognostic factors.

RESULTS

Records of 22 dogs with and 37 dogs without pelvic limb pain perception at presentation were included. Median age of dogs was 5 years (interquartile range, 4-7), and mean weight was 26.9 kg (SD, ±9.71). Labradors and Labrador mixes were most common (17/59 [28.8%]). Recovery of ambulation occurred in 17 of 22 (77.3%) dogs with and in 14 of 37 (37.8%) dogs without pain perception prior to surgery. Progressive myelomalacia was recorded in three of 59 (5.1%) dogs, one with pain perception and two without pain perception at presentation. Postoperative complications (14/59 [23.7%]) were common. Factors independently associated with outcome included clinical severity (odds ratio [OR] 0.179, P = .005), number of vertebrae with signal interruption in half Fourier single-shot turbo spin-echo sequences (HASTEi; OR, 0.738; P = .035), and ratio of vertebral sites decompressed to HASTEi (OR, 53.79; P = .03).

CONCLUSION

Paraplegic medium to large breed dogs with DEEH have a less favorable outcome after surgical decompression than paraplegic dogs with TL-IVDE.

CLINICAL SIGNIFICANCE

Dogs with DEEH can have severe postoperative complications. Loss of pain perception and increased HASTEi are associated with a poor outcome, while more extensive decompression improves outcome.

Outcome in Cats with Acute Onset of Severe Thoracolumbar Spinal Cord Injury Following Physical Rehabilitation

The literature is lacking data concerning the prognosis in cats suffering from naturally occurring acute onset of thoracolumbar (TL) spinal cord injury that are undergoing rehabilitation therapy. Therefore, we investigated the effect of physical rehabilitation in cats suffering from naturally occurring TL spinal cord injury. The medical records of 36 cats with acute onset of TL spinal cord injury that were selected for rehabilitation treatment were reviewed. Twenty-nine cats underwent an intensive physical rehabilitation protocol in the clinic (group 1), whereas the owners of seven cats declined physical rehabilitation (group 2). In group 1, seven cats had pelvic limb deep pain perception (DPP), which was significantly associated with the functional recovery of voluntary ambulatory status (p = 0.010) and voluntary micturition (p < 0.001). Spinal walking was achieved in 10/22 (45%) of the cats without DPP, and none regained voluntary micturition. In group 2, no cats regained ambulatory status or voluntary micturition, although pelvic limb DPP was present in three patients. Treatment with a clinic-based rehabilitation program and the presence of a crossed extensor reflex were significantly associated with a higher possibility of regaining functional ambulatory status (p < 0.010), but there was no difference in the recovery of voluntary micturition between the groups. Thus, cats with severe, naturally occurring, acute onset of TL spinal cord injury may benefit from physical rehabilitation. In the case of the loss of DPP, the acquisition of spinal walking is possible, despite the high possibility of a persistent neurologically dysfunctional bladder.

Outcomes of extensive hemilaminectomy with durotomy on dogs with presumptive progressive myelomalacia: a retrospective study on 34 cases

Background

Progressive myelomalacia (PMM) is a fatal complication of progressive ascending and descending necrosis of the spinal cord after acute spinal cord injury. A recent study suggested that extensive hemilaminectomy with durotomy (EHLD) at the intramedullary T2-hyperintense region which performed immediately after magnetic resonance imaging (MRI) improved the survival rate in dogs with presumptive PMM. The objective of this retrospective study was to evaluate the effects of EHLD on halting the progression of PMM in dogs presumptively diagnosed with PMM which had the interval between MRI and surgery.

Results

Thirty-four dogs with presumptive PMM which had undergone EHLD with the delay following MRI examination (range, 0 to 3 days) were included. The cranial side of EHLD was set depending on the delay time after MRI, MRI findings, neurological examination and intraoperative macroscopic appearance. Two weeks after surgery, the perioperative survival rate was 97% (33/34). During follow-up with a median time period of 82.5 weeks (range, 0-290 weeks), the postoperative survival rate was 91% (31/34). At the end of the follow-up period, 31 out of 34 dogs were alive without severe postoperative complications while the remaining 2 dogs died from causes not directly attributable to the surgery. There was no improvement in the pelvic limb function of all dogs.

Conclusions

EHLD appears to be effective in halting the progression of presumptive PMM and preventing morbidity even in dogs which had the interval between MRI and EHLD. Our algorithm of determining the range of EHLD may enable to set the appropriate ranges of EHLD in the cases which develop signs consistent with PMM after MRI examination.

Relationship between Machine-Learning Image Classification of T2-Weighted Intramedullary Hypointensity on 3 Tesla Magnetic Resonance Imaging and Clinical Outcome in Dogs with Severe Spinal Cord Injury

Early prognostic information in cases of severe spinal cord injury can aid treatment planning and stratification for clinical trials. Analysis of intraparenchymal signal change on magnetic resonance imaging has been suggested to inform outcome prediction in traumatic spinal cord injury. We hypothesized that intraparenchymal T₂-weighted hypointensity would be associated with a lower potential for functional recovery and a higher risk of progressive neurological deterioration in dogs with acute, severe, naturally occurring spinal cord injury. Our objectives were to: 1) demonstrate capacity for machine-learning criteria to identify clinically relevant regions of hypointensity and 2) compare clinical outcomes for cases with and without such regions. A total of 95 dogs with complete spinal cord injury were evaluated. An image classification system, based on Speeded-Up Robust Features (SURF), was trained to recognize individual axial T₂-weighted slices that contained hypointensity. The presence of such slices in a given transverse series was correlated with a lower chance of functional recovery (odds ratio [OR], 0.08; confidence interval [CI], 0.02-0.38; p < 10^-3) and with a higher risk of neurological deterioration (OR, 0.14; 95% CI, 0.05-0.42; p < 10^-3). Identification of intraparenchymal T₂-weighted hypointensity in severe, naturally occurring spinal cord injury may be assisted by an image classification tool and is correlated with functional recovery.

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.

Case Report: Intramedullary Intervertebral Disk Extrusion in a Cat: Clinical, Computed Tomographic, High-Field Magnetic Resonance Imaging, and Outcome Findings

Background: Intramedullary disk extrusions has rarely been described in veterinary medicine, more especially in cats, with only two cases are reported in the veterinary literature. Diagnosis may be difficult, even though clinical presentation and imaging studies, such as MRI or CT, can present specific features. Treatment and prognosis are not clearly described. Case presentation: A 10-year-old domestic shorthair female cat was evaluated for a 12 h-history of peracute-onset of paraparesis with flaccid tail and urinary and fecal incontinence. The patellar reflexes were normal, the pelvic flexor reflexes were decreased (more markedly on the right limb) and the perianal reflex was absent. The tail was flaccid, without nociception. Abdominal palpation revealed a small urinary bladder, easily expressed. Manipulation of the lumbar vertebral column elicited marked pain. Neurological examination was consistent with a L7-caudal segments lesion. A lumbosacral MRI and CT evaluations were performed and revealed a focal intramedullary hemorrhagic lesion, with an associated vertical linear tract communicating with the L5-L6 intervertebral disk space, and a suspected intramedullary focus of mineralization. These imaging findings were highly suggestive of an L5-L6 intramedullary disk extrusion. A dorsal L5-L6 laminectomy confirmed the presence of intramedullary degenerative nucleus pulposus fragments, which were surgically removed. Rapid and progressive neurological improvement was observed post-surgery. At the 1-year follow-up, right plantigrade stance and mild paraparesis were still noticed, but jumps and voluntary tail movements were observed. Occasional urinary and fecal incontinence episodes remained. Conclusions: This is the first feline case report of an intramedullary disk herniation with long-term follow-up available. Clinical description, CT and High-Field MRI findings, surgical procedure and histological results are reported, and help describing the characteristics of this rare non-compressive category of peracute intervertebral disk extrusion. Surgical management may be considered in feline cases of intramedullary disk herniation and may be associated with a good outcome.

Classification of Intervertebral Disc Disease

Intervertebral disc disease (IVDD) has been recognized in dogs since the 1800s, when the first descriptions of extruded disc material within the vertebral canal were published. In the intervening time our understanding of intervertebral disc pathology in dogs and cats has increased dramatically, with many variations of IVDD described. Whilst the volume of literature and collective understanding of IVDD has expanded, there has also been scope for confusion as the definition of intervertebral disc disease, with its myriad different manifestations, becomes more complicated. A large volume of literature has aimed to combine the use of histopathology, diagnostic imaging and clinical findings to better understand the various ways in which IVDD can be classified. Much of this research has focused on the classification of mechanisms of intervertebral disc degeneration, centering around the differences between, and overlaps in, IVDD in chondrodystrophic and non-chondrodystrophic dog breeds. However, with the increasing availability of advanced imaging modalities allowing more accurate antemortem diagnosis, the concept of IVDD has expanded to include other clinical presentations that may not fit into traditional models of classification of IVDD. This review aims to provide an up to date overview of both historical and current systems of IVDD classification, highlighting the important findings and controversies underpinning them.

Magnetization transfer and diffusion tensor imaging in dogs with intervertebral disk herniation

Background

Quantitative magnetic resonance imaging (QMRI) techniques of magnetization transfer ratio (MTR) and diffusion tensor imaging (DTI) provide microstructural information about the spinal cord.

Objective

Compare neurologic grades using the modified Frankel scale with MTR and DTI measurements in dogs with thoracolumbar intervertebral disk herniation (IVDH).

Animals

Fifty‐one dogs with thoracolumbar IVDH.

Methods

Prospective cohort study. Quantitative MRI measurements of the spinal cord were obtained at the region of compression. A linear regression generalized estimating equations model was used to compare QMRI measurements between different neurological grades after adjusting for age, weight, duration of clinical signs, and lesion location.

Results

Grade 5 (.79  ×  10⁻³ mm²/s [median], .43−.91 [range]) and axial (1.47 × 10⁻³ mm²/s, .58−1.8) diffusivity were lower compared to grades 2 (1.003, .68−1.36; P = .02 and 1.81 × 10⁻³ mm²/s, 1.36−2.12; P < .001, respectively) and 3 (1.07 × 10⁻³ mm²/s, .77−1.5; P = .04 and 1.92 × 10⁻³ mm²/s, 1.83−2.37;P < .001, respectively). Compared to dogs with acute myelopathy, chronic myelopathy was associated with higher mean (1.02 × 10⁻³ mm²/s, .77−1.36 vs. .83 × 10⁻³ mm²/s, .64−1.5; P = .03) and radial diffusivity (.75 × 10⁻³ mm²/s, .38−1.04 vs. .44 × 10⁻³ mm²/s, .22−1.01; P = .008) and lower MTR (46.76, 31.8−56.43 vs. 54.4, 45.2−62.27; P = .004) and fractional anisotropy (.58, .4−0.75 vs. .7, .46−.85; P = .02). Fractional anisotropy was lower in dogs with a T2‐weighted intramedullary hyperintensity compared to those without (.7, .45−.85 vs. .54, .4−.8; P = .01).

Conclusion and Clinical Relevance

Mean diffusivity and AD could serve as surrogates of severity of spinal cord injury and are complementary to the clinical exam in dogs with thoracolumbar IVDH.

Current Approaches to the Management of Acute Thoracolumbar Disc Extrusion in Dogs

Intervertebral disc extrusion (IVDE) is one of the most common neurologic problems encountered in veterinary clinical practice. The purpose of this manuscript is to provide an overview of the literature related to treatment of acute canine thoracolumbar IVDE to help construct a framework for standard care of acute canine thoracolumbar IVDE where sufficient evidence exists and to highlight opportunities for future prospective veterinary clinical research useful to strengthen care recommendations in areas where evidence is low or non-existent. While there exist a number of gaps in the veterinary literature with respect to standards of care for dogs with acute thoracolumbar IVDE, recommendations for standard care can be made in some areas, particularly with respect to surgical decompression where the currently available evidence supports that surgery should be recommended for dogs with nonambulatory paraparesis or worse. While additional information is needed about the influence on timing of decompression on outcome in dogs that are deep pain negative for longer than 48 h duration, there is no evidence to support treatment of the 48 h time point as a cut off beyond which it becomes impossible for dogs to achieve locomotor recovery. Surgical decompression is best accomplished by either hemilaminectomy or mini-hemilaminectomy and fenestration of, at a minimum, the acutely ruptured disc. Adjacent discs easily accessed by way of the same approach should be considered for fenestration given the evidence that this substantially reduces future herniation at fenestrated sites. Currently available neuroprotective strategies such as high does MPSS and PEG are not recommended due to lack of demonstrated treatment effect in randomized controlled trials, although the role of anti-inflammatory steroids as a protective strategy against progressive myelomalacia and the question of whether anti-inflammatory steroids or NSAIDs provide superior medical therapy require further evaluation.

Clinical Trial Design-A Review-With Emphasis on Acute Intervertebral Disc Herniation

There is a clear need for new methods of treatment of acute disc herniation in dogs, most obviously to address the permanent loss of function that can arise because of the associated spinal cord injury. Clinical trials form the optimal method to introduce new therapies into everyday clinical practice because they are a reliable source of unbiased evidence of effectiveness. Although many designs are available, parallel cohort trials are most widely applicable to acute disc herniation in dogs. In this review another key trial design decision—that between pragmatic and explanatory approaches—is highlighted and used as a theme to illustrate the close relationship between trial objective and design. Acute disc herniation, and acute spinal cord injury, is common in dogs and there is a multitude of candidate interventions that could be trialed. Most current obstacles to large-scale clinical trials in dogs can be overcome by collaboration and cooperation amongst interested veterinarians.

Comparison of Gait Assessment Scales in Dogs with Spinal Cord Injury from Intervertebral Disc Herniation

Naturally occurring thoracolumbar spinal cord injury (SCI) is common in dogs, and multi-center veterinary clinical studies can serve as translational tools to identify potentially effective therapies for human clinical trials. Assessment of gait is a key outcome, and several scales are used in dogs. The purpose of this study was to determine whether an international group of researchers could score gait reliably, to compare and contrast the performance of gait scales and to describe appropriate data analysis techniques. A training module was developed for a binary scale, modified Frankel Scale (MFS), Texas SCI Scale (TSCIS), and Open Field Scale (OFS). Raters viewed the training module, scored five training video clips to achieve proficiency, then scored 30 video clips from 10 dogs recovering from SCI. Interrater reliability was calculated, and correlation between scales was examined. Ceiling effect was described. Twenty raters with differing experience participated. The training module took 16 min to view. Raters chose identical binary outcomes in 597 of 600 observations. Intraclass correlation for MFS, TSCIS, and OFS was excellent at 0.85, 0.96, and 0.96, respectively, regardless of rater expertise. Ceiling effect occurred in all dogs that recovered ambulation, particularly using MFS and binary outcome. The TSCIS and OFS captured recovery of ambulatory dogs better, and addition of scores on hopping and proprioception mitigated ceiling effect. We conclude that gait in dogs with SCI can be scored reliably after training. A variety of different gait scales can be used in multi-center trials to capture outcome in different ways.

Same-day surgery may reduce the risk of losing pain perception in dogs with thoracolumbar disc extrusion

OBJECTIVES

To compare the proportions of dogs with thoracolumbar disc extrusion that lose pelvic limb pain perception if surgery is performed on the day of admission or delayed overnight. To describe the outcome of those dogs that deteriorate to lose pain perception.

MATERIALS AND METHODS

Retrospective, single centre study on 273 client-owned dogs with thoracolumbar disc extrusion and intact pain perception, but inability to walk unaided on their pelvic limbs. Dogs were subdivided into two groups: early surgery (spinal decompression between their examination at day of admission and the following morning), and delayed surgery (did not undergo surgery between admission and the following morning). The proportion of dogs that lost pelvic limb pain perception overnight was compared between the early and delayed surgery groups.

RESULTS

Seven of 151 dogs in the early surgery group lost pain perception overnight compared to 15 of 122 in the delayed surgery group (Fisher's exact test, P = 0.025). Number-needed-to-treat analysis suggested that 14 dogs (95% confidence interval: 7-106 dogs) need early surgery to prevent one losing pain perception overnight. Five of the seven dogs that lost pain perception in the early surgery group recovered pain perception by 3 weeks post-operatively, compared to eight of 14 in the delayed group.

CLINICAL SIGNIFICANCE

This study suggests that an overnight delay before spinal decompression increases the risk of clinically meaningful deterioration in dogs unable to walk following thoracolumbar disc extrusion.

Association between anesthesia duration and outcome in dogs with surgically treated acute severe spinal cord injury caused by thoracolumbar intervertebral disk herniation

Background

Retrospective research recently identified a possible relationship between duration of surgery and outcome in severely affected dogs treated surgically for acute thoracolumbar intervertebral disk herniation (TL‐IVDH).

Hypothesis

That increased duration of surgery is associated with poorer outcome in dogs with absent pain perception treated surgically for TL‐IVDH.

Animals

Two hundred ninety‐seven paraplegic dogs with absent pain perception surgically treated for acute TL‐IVDH.

Methods

Retrospective cohort study. Medical records of 5 institutions were reviewed. Inclusion criteria were paraplegia with absence of pain perception, surgical treatment of TL‐IVDH, and 1‐year postoperative outcome (ambulatory: yes or no). Canine data, outcome, and surgery and total anesthesia duration were retrieved.

Results

In this study, 183/297 (61.6%) dogs were ambulatory within 1 year, 114 (38.4%) dogs failed to recover, including 74 dogs (24.9%) euthanized because of progressive myelomalacia. Median anesthesia duration in dogs that regained ambulation within 1 year of surgery (4.0 hours, interquartile range [IQR] 3.2‐5.1) was significantly shorter than those that did not (4.5 hours, IQR 3.7‐5.6, P = .01). Multivariable logistic regression demonstrated a significant negative association between both duration of surgery and total anesthesia time and ambulation at 1 year when controlling for body weight and number of disk spaces operated on.

Conclusions and Clinical Importance

Findings support a negative association between increased duration of anesthesia and outcome in this group of dogs. However, the retrospective nature of the data does not imply a causal relationship.

Perilesional photobiomodulation therapy and physical rehabilitation in post-operative recovery of dogs surgically treated for thoracolumbar disk extrusion

BACKGROUND

Recent studies have reported contrasting results of the effects of laser therapy on post-operative intervertebral disk herniation, with a lack of evidence-based advantages of this modality within a rehabilitation protocol. The aim of this study was to report the clinical effects of photobiomodulation therapy within a post-operative rehabilitation protocol in dogs submitted to surgery for thoracolumbar disk extrusion. Twenty-four dogs were included in the study (12 dogs treated with laser therapy and rehabilitation protocol and 12 dogs treated with same rehabilitation protocol but without laser therapy).

RESULTS

All dogs treated with laser therapy showed improved neurological status (Modified Frankel Score more than 3 within 30 days of physiotherapy starting) if deep nociception on admission was maintained (P = 0.04). However, Kaplan-Meier analysis did not show any statistical difference in time to regain ambulatory ability, although there was a tendency for a shorter mean time of 14.2 ± 8.55 days in the laser group versus 24 ± 18.49 days in the no laser group.

CONCLUSIONS

The use of laser therapy in the post-operative rehabilitation of dogs affected by intervertebral disc extrusion and submitted to surgery for spinal decompression could help improve their neurological status.

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

OBJECTIVE

To report recovery of ambulation of dogs treated with extended thoracolumbar durotomy for severe spinal cord injury caused by intervertebral disc herniation.

STUDY DESIGN

Descriptive cohort.

ANIMALS

Twenty-six consecutive paraplegic dogs presented with loss of deep pain sensation after acute thoracolumbar intervertebral disc herniation.

METHODS

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.

RESULTS

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%.

CONCLUSION

Extended durotomy seemed to improve the outcome of dogs in our case series without increase in morbidity.

CLINICAL SIGNIFICANCE

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.

Effect of durotomy in dogs with thoracolumbar disc herniation and without deep pain perception in the hind limbs

OBJECTIVE

To determine the effectiveness of durotomy as an adjunct to surgical decompression in dogs with thoracolumbar intervertebral disc herniation (TL-IVDH) and loss of deep pain perception (DPP) in the hind limbs.

STUDY DESIGN

Retrospective study.

ANIMALS

Dogs (n = 116) with TL-IVDH and loss of DPP treated with hemilaminectomy.

METHODS

Signalment, surgical site, recovery rate, incidence of progressive myelomalacia (PMM), time elapsed from onset of paraplegia of the hind limbs to surgery (TPS), and the length of area of hyperintensity of the spinal cord on magnetic resonance T2-weighted images compared with L2 vertebral body length (LHT2) were compared between dogs treated with hemilaminectomy alone and those treated with adjunct durotomy. Multivariate logistic regression analyses were used to test the association between outcomes and the external view of the spinal cord parenchyma after durotomy.

RESULTS

The percentage of dogs regaining ambulation was greater when durotomy was performed (56.9%) than when dogs were treated with hemilaminectomy alone (38.5%; P = .04). In the hemilaminectomy group, 14 dogs died of suspected PMM, while no PMM was detected in the durotomy group. Durotomy, breed, surgical site, and LHT2 influenced recovery. No association was detected between age, sex, body weight, and TPS and recovery.

CONCLUSION

Performing a durotomy in combination with decompression improved the return to function and prevented PMM in our clinical setting.

CLINICAL SIGNIFICANCE

Surgeons should consider durotomy in dogs with TL-IVDH and loss of DPP in hind limbs to improve surgical outcome.

Therapeutic effects of Tetanus neurotoxin in spinal cord injury: a case series on four dogs

STUDY DESIGN

Case series on four dogs.

OBJECTIVES

To determine the alleviation of motor symptoms in spinal cord injury (SCI) by tetanus neurotoxin (TeNT).

SETTING

Different Berlin veterinary clinics, Germany.

METHODS

We report on the effect of intramuscular injections of low-dose TeNT into paretic hind limb muscles 2-157 weeks after SCI due to lumbar disc herniation in a clinical case series on four dogs. All dogs underwent unsuccessful or incomplete surgical decompression prior to TeNT treatment. TeNT was injected on a compassionate basis. Stance, gait ability and the diameter of the rectus femoris muscle were assessed as parameters.

RESULTS

All four dogs improved their stance and three of these dogs improved in gait at 4 and 6 weeks after TeNT injections without evidence of side effects or spreading of TeNT effects. At the same time, the size of the rectus femoris muscle diameter increased considerably as compared with baseline (baseline: 100%; 4 weeks: 148.7% ± 10.9%; 6 weeks: 137.1% ± 7.9%).

CONCLUSIONS

Facilitation of α-motor neurons by TeNT injections into paretic hind limb muscles of four dogs improved standing and/or gait abilities and partly reversed muscle atrophy after SCI. The absence of generalized or painful muscle spasms supports the safety of low-dose TeNT. Therefore, TeNT might evolve as a promising therapeutic option for muscle paresis of central origin, e.g. in individuals with SCI, stroke or multiple sclerosis.

Clinical management of dogs with presumptive diagnosis of thoracolumbar intervertebral disc disease: 164 cases (2006-2017)

ABSTRACT: This study aimed to identify dogs with presumptive diagnosis of cervical intervertebral disc disease (IVDD) submitted to clinical management and to evaluate the outcomes. Data were obtained from the medical records of patients with neurological dysfunction assisted at a University Veterinary Hospital from 2006 to 2017. In addition to the patients’ records, dog owners responded to a questionnaire on the success of therapy. Four hundred and thirteen neurological records were evaluated, and 164 met the inclusion criteria of the study. The most common breed was Dachshund, followed by mongrels. Classification of neurological dysfunction in the study sample was as follows: 15.9% with grade I, 25.6% with grade II, 26.8% with grade III, 8.5% with grade IV, and 23.2% with grade V. Outcome was satisfactory in 71.6% of the dogs and unsatisfactory in 28.4% of them. Recurrence was observed in 27.7% of those with satisfactory outcomes. The clinical treatment of dogs with thoracolumbar IVDD is satisfactory, particularly for animals with milder disease grades (I, II, and III). There is possibility of recurrence with conservative therapy and clinical signs may be more severe.

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

BACKGROUND

Progressive 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.

RESULTS

One 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).

CONCLUSION

Dogs 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.

Relationship of preoperative neurologic score with intervals to regaining micturition and ambulation following surgical treatment of thoracolumbar disk herniation in dogs

OBJECTIVE To estimate the times required for dogs to regain micturition and ambulation following surgical treatment for thoracolumbar Hansen type I intervertebral disk extrusion (IVDE) and determine whether these variables were associated with preoperative modified Frankel score (MFS). DESIGN Retrospective case series with nested cohort study. ANIMALS 54 dogs weighing < 20 kg (44 lb) that were surgically treated for Hansen type I IVDE at a referral hospital between January and December 2015. PROCEDURES Medical records and CT and MRI data were reviewed. Information was collected regarding dog signalment, type and duration of clinical signs, preoperative MFS, degree of spinal cord compression, type of medical and surgical treatment provided, and intervals from surgery to regaining micturition and ambulation (outcomes). Collected data were evaluated for correlations with outcomes. RESULTS Mean ± SD interval from surgery to regaining micturition was 4.1 ± 4.4 days, and mean interval from surgery to regaining ambulation was 13.8 ± 25.1 days. These intervals differed significantly. Significant negative correlations with MFS were identified for interval to regaining micturition (r = -0.63) and interval to regaining ambulation (r = -0.64). No other correlations with outcome were identified. CONCLUSIONS AND CLINICAL RELEVANCE The amount of time required for dogs to regain micturition and ambulation following surgery for thoracolumbar IVDE was correlated with preoperative severity of clinical signs, as reflected by preoperative MFSs. This information should be useful for pre- and postoperative decision-making and setting of expectations for owners of and clinicians treating affected dogs.