Evaluation of the Success of Medical Management for Presumptive Cervical Intervertebral Disk Herniation in Dogs

Common Neurologic Diseases in Geriatric Dogs

The increase in the canine geriatric population means that veterinarians are more often confronted with diseases that are more prevalent in patients in this age group. As in other organ systems, degenerative, neoplastic, and vascular diseases are the most prevalent neurologic disorders in older dogs. A neurological disease in an older dog poses a challenge for the clinician due to the presence of concomitant diseases and age-related changes that make it difficult to interpret the neurological examination. In addition, given the age of the patients, some owners do not allow advanced imaging tests, and it is necessary to establish the most likely presumptive diagnosis to initiate treatment. Although many of these diseases can cause clinical signs that can be very upsetting, some of them can be managed with symptomatic therapy and have a good prognosis, such as idiopathic vestibular syndrome. Moreover, advances in and the greater availability of therapeutic options such as surgery and radiation therapy may increase survival and quality of life in diseases with a more serious prognosis, such as tumours. The aim of this review is to summarize the clinical presentation, diagnosis, and treatment of the more frequent diseases affecting the central nervous systems of geriatric dogs.

Case report: Double adjacent ventral slot in two medium-sized breed dogs

Two medium-sized, 7-year-old dogs, with no previous history of pain, presented with acute neurologic symptoms consistent with intervertebral disk disease. Both cases had CT, where cervical pathology was identified. In one dog, the diagnosis was singular extensive cervical disk herniation with possible epidural hemorrhage and in the other, the diagnosis was multiple-site cervical disk herniation. The first dog, a Shar-Pei, underwent treatment with two standard adjacent ventral slots between the C4-C5 and C5-C6 intervertebral disk spaces and a fenestration between the C3 and C4 intervertebral disk spaces. The second case, a beagle, underwent a double adjacent standard ventral slot between the C5-C6 and C6-C7 intervertebral disk spaces. Both dogs recovered uneventfully after the surgery and showed no signs of recurrence during a 2-year follow-up period. This is the first detailed report of the use of a double adjacent ventral slot as a treatment for spinal decompression in medium-sized dogs with multiple-site spinal cord compression.

Outcomes in Dogs with Multiple Sites of Cervical Intervertebral Disc Disease Treated with Single Ventral Slot Decompression

In dogs with acute myelopathy but showing multiple sites of spinal compression from intervertebral disc disease (IVDD) on imaging, one approach is surgical decompression of the single acute disc extrusion while ignoring other previously extruded or protruded discs. However, little is known regarding the outcomes of this approach. This study described the outcomes and investigated prognostic factors in 40 dogs with multiple sites of cervical disc extrusion or protrusion on MRI who underwent ventral slot decompression for the single acute disc. The overall recovery rate was 97.5%. The median recovery time was seven days. The number of affected discs (including disc extrusion and protrusion) and the presence and number of the affected discs causing severe spinal compression did not influence the 30-day outcome. Compared with 23 dogs with single disc extrusion treated surgically, the recovery time and outcomes were similar between the two groups. The total number of affected discs was not associated with recovery time or outcomes. In conclusion, if an acute disc could be identified, ventral slot decompression targeting the single acute disc is a viable management approach for dogs with an acute presentation but diagnosed with multiple sites of spinal cord compression from IVDD.

Cervical intervertebral disc disease in 60 Yorkshire terriers

Intervertebral disc extrusion (IVDE) is a common neurological condition in many dog breeds. This study aimed to describe this condition in Yorkshire terriers (YT) and calculate the prevalence of this condition amongst the YTs with neurological diseases. This is a double-centre retrospective study which was conducted in two arms. The first part of the study, describing the clinical features and prognosis of cervical (C) IVDE in YTs, is based on data from 2005 to 2021. The second part of the study calculated the prevalence of C IVDE amongst the YTs with neurological diseases based on data from 2016 to 2021. A retrospective search through the medical records was conducted. YTs with C IVDE diagnosed with MRI and confirmed surgically were eligible for inclusion in this study. Sixty YTs were included in the first part of the study. There were 48 (80%) dogs with acute onset and 12 (20%) with chronic onset with acute deterioration. Ambulation was preserved in 31 (51.7%) dogs on admission, and the remaining 29 (48.3%) dogs were non-ambulatory. No significant association was found between ambulation on admission and recovery status (p = 0.547). Seventy-three intervertebral spaces were treated during the surgical intervention. Relapses were seen in seven (11.7%) dogs. Forty-nine (81.7%) dogs were ambulatory at discharge. A complete recovery was observed in 46 (76.7%) dogs; the remaining dogs (14, 23.3%) were classified as incomplete recovery. A significant difference was found in time to ambulation (p = 0.0238) and time to discharge (p = 0.0139) between the on-admission ambulatory and non-ambulatory dogs. Three hundred and eight YTs were diagnosed with neurological diseases between 2016 and 2021 in one referral centre. C IVDE was diagnosed in 31 (10.06%) dogs. This is the first study explicitly describing the C IVDE in YTs and establishing the prevalence of this condition amongst YTs with other neurological disorders.

Recurrence rate of intervertebral disc disease in surgically treated French Bulldogs: a retrospective study (2009-2019)

BACKGROUND

Intervertebral disc disease (IVDD) is a common diagnosis and well-investigated pathological condition in French Bulldogs with neurological deficiencies. However there is currently only one recently published retrospective descriptive study looking for recurrence rates of IVDD in French Bulldogs. Medical reports of French Bulldogs with a first episode of IVDD and surgical treatment were evaluated and reviewed for clinical signs of recurrence. Risk factors for Total-Recurrence, Cervical- and Thoracolumbar-Recurrence were evaluated by means of logistic regression models. The aim of this study was to assess frequency and risk factors associated with the recurrence of IVDD in French Bulldogs.

RESULTS

One hundred twenty-seven French Bulldogs with a first episode of IVDD and surgical treatment were evaluated. 52.7% (67/127) of these patients showed signs of recurrence. The recurrence rate in the cervical spine was slightly lower (47%) compared to the thoracolumbar spine (56.6%). A significant association with recurrence could be found for the factor age: French Bulldogs with a first episode of IVDD ≤ 3 years seem to be prone for Total-Recurrence (P = 0.002) and Cervical-Recurrence (with ORs ranging from 0.02 to 0.03 for patients older than 3 years). 50% of the recurrences (median) occurred within the first 12 month after the first episode of IVDD.

CONCLUSIONS

Recurrence of IVDD can be expected in more than half of French Bulldogs affected by IVDD. Especially young French Bulldogs are prone for recurrence in cervical spine. Almost every fourth patient with IVDD suffers from a recurrence within 12 months. Future dog owners should be informed about the risk of IVDD and the early onset of recurrences in French Bulldogs.

Recurrence of signs consistent with cervical intervertebral disc extrusion in dogs

OBJECTIVES

Report the rate of recurrent clinical signs following successful treatment of cervical intervertebral disc extrusion, and explore the association between treatment method and recurrence.

MATERIALS AND METHODS

Medical records of dogs with MRI- or CT-confirmed cervical intervertebral disc extrusion were reviewed to verify that they recovered. Type of treatment, site of initial extrusion and whether dogs re-presented with recurrent clinical signs were recorded. Recurrence was considered presumed if based on clinical signs or confirmed if based on repeat cross-sectional imaging.

RESULTS

Complete recovery was documented following medical (36/119, 30.3%) or surgical (83/119, 69.7%) management of initial cervical disc extrusion. There was a recurrence of consistent clinical signs in 40 of 119 (34%) cases, of which 27 of 83 (33%) were initially managed surgically and 13 of 36 (36%) medically. In 24 of 40 (60%) cases, there was imaging confirmation of recurrent extrusion; in medically managed dogs, recurrence mostly occurred at the same site, whereas after surgery, recurrence most commonly involved an adjacent disc. Of the 40 recurrences, 32 (80%) occurred within 2 years of diagnosis. Rate of recurrence was similar between treatment methods in both univariable and multivariable time-to-event analyses (hazard ratio 1.03; 95% confidence interval: 0.67 to 1.53; P=0.87).

CLINICAL SIGNIFICANCE

Following successful initial medical or surgical treatment, clinical signs consistent with recurrent cervical disc extrusion occurred with similar frequency. Medically treated cases tended to have recurrence at the same site as initial presentation, whereas surgical treatment prevented this. Recurrence usually occurred within 2 years. The retrospective study design, small number of recurrences and lack of imaging confirmation of every recurrence should be considered when interpreting the results.

Ultrasound-guided paravertebral perineural glucocorticoid injection for signs of refractory cervical pain associated with foraminal intervertebral disk protrusion in four dogs

CASE DESCRIPTION

4 dogs, 7.5 to 10 years of age, were presented for evaluation of signs of chronic cervical pain and forelimb lameness secondary to cervical foraminal intervertebral disk protrusion (IVDP). All dogs were refractory to ≥ 2 weeks of conservative management including strict rest and pain management with anti-inflammatory drugs, methocarbamol, and gabapentin.

CLINICAL FINDINGS

The MRI findings included left foraminal IVDP at C2-3 causing mild C3 nerve root compression (dog 1), multifocal degenerative disk disease with mild focal left-sided disk protrusion at C6-7 without associated spinal cord or nerve root compression (dog 2), left foraminal C6-7 IVDP with suspected focal spinal cord atrophy or mild compression (dog 3), and right foraminal C6-7 IVDP and multifocal cervical intervertebral disk degeneration with annulus fibrosus protrusion (dog 4).

TREATMENT AND OUTCOME

Ultrasound-guided paravertebral perineural injections with methylprednisolone acetate (1 mg/kg [0.45 mg/lb]) at the C3 nerve root in dog 1 and at the C7 nerve root in the other 3 dogs were performed. Injections were repeated at intervals of 4 weeks to 3 months on the basis of clinical response. None of the dogs had any complications from the procedures. For dogs 1 and 4, there was complete resolution of lameness and signs of cervical pain following perineural injections, and for dog 3, there was complete resolution of lameness and only minimal residual cervical pain. Dog 2 did not have long-lasting improvement.

CLINICAL RELEVANCE

Findings indicated that ultrasound-guided paravertebral perineural injection can be an effective treatment of cervical foraminal IVDP for some dogs. Additional studies to determine appropriate case selection and better assess the overall success rate and risks associated with this technique are warranted.

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.

Agreement of surgeon's perception of the effectiveness of spinal cord decompression with findings on postoperative magnetic resonance imaging for dogs surgically treated for intervertebral disk extrusion

OBJECTIVE

To determine the accuracy of the surgeon's perception versus postoperative MRI findings in assessing the effectiveness of spinal cord decompression achieved in dogs surgically treated for intervertebral disk extrusion (IVDE) and whether postoperative MRI findings were more likely to be associated with various outcomes.

ANIMALS

68 dogs surgically treated for cervical or thoracolumbar IVDE.

PROCEDURES

Data on clinical, neurologic, pre- and postoperative MRI, and intraoperative findings as well as outcomes and recovery times (6-month follow-up period) were prospectively collected and compared between various groups.

RESULTS

54 (79%) dogs had thoracolumbar IVDE, and 14 (21%) had cervical IVDE. Median degree of spinal cord compression as assessed on transverse T2-weighted MRI images was 45.6% before surgery and 8.8% after surgery. The correlation between surgeons' perception (n = 3) and postoperative MRI findings for the degree of spinal cord decompression achieved was only fair (κ = 0.40). Unsatisfactory spinal cord decompression as assessed via postoperative MRI was associated with severity of preoperative neurologic grade and preoperative compression, thoracolumbar (vs cervical) IVDE, and ventral (vs ventrolateral or dorsolateral) circumferential distribution of extruded material. Satisfactory (vs unsatisfactory) decompression as assessed via MRI was associated with a lower postoperative neurologic grade, greater likelihood of a successful outcome, and lower mean recovery time.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that for dogs surgically treated for IVDE, the surgeon's perception of adequate spinal cord decompression may be less reliable than postoperative MRI findings. Postoperative MRI appeared particularly useful for dogs with a severe preoperative neurologic status, severe preoperative spinal cord compression, and thoracolumbar IVDE.

Non-ambulatory dogs with cervical intervertebral disc herniation: single versus multiple ventral slot decompression

OBJECTIVE

To evaluate the proportion of non-ambulatory dogs with cervical intervertebral disc herniation (IVDH) in a private clinic and to compare signalment and outcome between those that underwent single or multiple ventral slot decompression (VSD).

DESIGN

Retrospective cohort study.

METHODS

After screening 43,378 medical records (January 2010-September 2016), those of 185 dogs with non-ambulatory tetraparesis or tetraplegia along with cervical IVDH that had undergone single (123) or multiple (62) VSD were included in this study. Data on signalment, preoperative neurological status, location of affected intervertebral disc(s), time to ambulation and short-term outcome were compared between single and multiple VSD groups.

RESULTS

The proportion of non-ambulatory dogs with IVDH was 35.3%. The prevalence of non-ambulation was higher in male dogs (0.56%) than in female dogs (0.26%; P < 0.001) and in neutered dogs than in unneutered dogs (0.51% and 0.27%, respectively, P < 0.001). After surgery, 96.2% of the dogs reached ambulatory status. Dogs with multiple IVDH were older than those with single IVDH. Sex, neutering status or size did not affect the outcome or ambulation status postsurgery. The Pekingese was the most commonly affected breed in both groups. There was no difference in the time to reach ambulation and the presence of neurological deficits after surgery between dogs that underwent single and multiple VSD.

CONCLUSIONS

In this cohort, dogs undergoing multiple VSD had a good postoperative outcome, and their short-term functional recovery was equal to that of dogs undergoing single ventral slot compression.

Comparison of surgical and conservative treatment of hydrated nucleus pulposus extrusion in dogs

Background

Whether compressive cervical myelopathy caused by hydrated nucleus pulposus extrusion (HNPE) in dogs should be treated surgically or conservatively has been debated. Only 1 recent study has contradicted the former predominant reports of surgical treatment for HNPE.

Hypothesis and method

Single center retrospective study to compare the outcome of client‐owned dogs with HNPE after decompressive surgery or conservative treatment.

Animals

Thirty‐six dogs diagnosed with HNPE confirmed by magnetic resonance imaging (MRI).

Results

Eighteen of 36 dogs underwent surgery whereas 18 dogs were managed conservatively including cage rest and physiotherapy. The most common affected intervertebral disc space was C4‐5. In 3 dogs, HNPE was diagnosed at the level of T13‐L1. Median time to regain ambulation was 6.6 days (range, 0‐28 days) after surgery and 5.9 days (range, 0‐15 days) with conservative management (P = .37).

Only the length of a potential intramedullary lesion in cervical HNPE detected by MRI had an influence on the prognosis to gain ambulatory status in a time period of ≤9 days (P = .0035) and on short‐term survival (P = .0011).

Conclusions and clinical importance

Conservative management of HNPE in the cervical as well as in the thoracolumbar region represents a reasonable alternative to surgery, showing similar favorable outcome.

Differences in Epidural Pathology between Cervical and Thoracolumbar Intervertebral Disk Extrusions in Dogs

Background

Although the basic pathophysiology is the same in both cervical and thoracolumbar intervertebral disk (IVD) extrusions, there are considerable clinical differences that have only been partially explained.

Hypothesis/Objectives

The epidural inflammatory response differs between cervical and thoracolumbar IVD extrusions.

Animals

Fifty‐five dogs with cervical and 80 dogs with thoracolumbar IVD extrusions.

Methods

Clinical data and histopathologic variables were investigated. Associations between severity of epidural inflammation and clinical and pathologic variables, impact of chondrodystrophic phenotype, and localization (cervical versus thoracolumbar) were evaluated statistically.

Results

Dogs with cervical IVD extrusion were significantly older (P < 0.001), had less severe and longer duration of neurologic signs (both P < 0.001), were more painful (P = 0.038), and had a better outcome (P = 0.005) than dogs with a thoracolumbar IVD extrusion. On histopathology, cervical epidural material had less severe calcification (P = 0.002) and inflammation (P < 0.001). No significant differences regarding chondrodystrophic phenotype were found.

Conclusion and Clinical Importance

There was significantly less intensive inflammatory response in the cervical epidural space. This observation correlated positively with less nucleus pulposus calcification in cervical extrusions indicating biochemical, metabolic, and biomechanical differences between the 2 locations, which remain to be characterized in future studies.

A review of associated controversies surrounding glucocorticoid use in veterinary emergency and critical care

OBJECTIVE

To review the literature in human and veterinary medicine regarding the indications for, efficacy of, and controversies surrounding glucocorticoid (GC) administration in the emergency and critical care (ECC) setting, and to provide an overview of the most commonly used synthetic GC formulations.

MEDICATIONS

Synthetic GCs vary in GC and mineralocorticoid potency, hypothalamic pituitary axis suppression, duration of action, route of administration, and clinical indication for use. Some of the GC compounds commonly used in human and veterinary ECC include hydrocortisone, prednisone, methylprednisolone, and dexamethasone.

INDICATIONS FOR USE

GCs are used in human and veterinary ECC for a variety of disorders including anaphylaxis, acute lung injury/acute respiratory distress syndrome, septic shock, and spinal cord injury. Evidence for morbidity or mortality benefit with administration of GC within these populations exists; however, data are sparse and often conflicting.

ADVERSE EFFECTS AND CONTRAINDICATIONS

Routine use of GC in some conditions such as trauma, hemorrhagic shock, and traumatic brain injury is likely contraindicated. GC use has been associated with hyperglycemia, pneumonia, urinary tract infection, gastrointestinal ulceration, or increased mortality in some populations.

Clinical presentation and outcome of dogs treated medically or surgically for thoracolumbar intervertebral disc protrusion

To date, few studies have investigated the clinical characteristics of thoracolumbar intervertebral disc protrusion (IVDP). The aim of this retrospective study was to evaluate the presentation and outcome of dogs receiving medical or surgical treatment for thoracolumbar IVDP. Eighty-four dogs were included, with a median age of 9.4 years. German shepherd dogs and Staffordshire bull terriers were the most common breeds. Significantly more surgically treated dogs (n=53) had neurological deficits and were non-ambulatory, compared with medically treated (n=31). Outcome data were available for 27 of 31 medically managed dogs; 11 initially improved, 7 remained stable and 9 deteriorated. Of 18 dogs that initially improved or stabilised, 10 (55.6 per cent) demonstrated recurrence of clinical signs within 12 months of diagnosis. Outcome data were available for 45 of 50 surgically treated dogs that survived to hospital discharge; 34 improved, 9 remained stable and 2 deteriorated following surgery. Of 43 dogs that improved or stabilised with surgical treatment, 11 (25.6 per cent) demonstrated recurrence of clinical signs within 12 months of surgery. Overall, significantly more surgically treated dogs (71.1 per cent) had a successful outcome, consisting of sustained clinical improvement of more than 12 months duration, compared with medically treated dogs (29.6 per cent).

Severity of spinal cord dysfunction and pain associated with hydrated nucleus pulposus extrusion in dogs

OBJECTIVE

To identify the severity of neurological deficits, presence of signs of cervical pain, and the site of intervertebral disc space extrusion in 21 dogs diagnosed via magnetic resonance imaging (MRI) with a hydrated nucleus pulposus extrusion (HNPE) and compare those findings to dogs with other compressive cervical myelopathies.

METHODS

Medical records and MRI findings were reviewed in dogs that were presented to two veterinary hospitals between 2006 and 2012 and subsequently diagnosed by MRI to have a HNPE (n = 21) or other compressive cervical myelopathies originating from the intervertebral disc (n = 174). Information obtained included signalment, severity of neurological deficits, presence of signs of neck pain, and site of HNPE. The severity of clinical neurological spinal cord dysfunction was determined for each dog in both groups using the Frankel scoring system (0-4). The MRI were reviewed for confirmation of diagnosis and site of HNPE. An ANOVA was used to compare age between groups and a Mann-Whitney test for pairwise comparisons of the Frankel score between groups. Values of p <0.05 were considered statistically significant.

RESULTS

Significantly more severe Frankel scores and less severe signs of cervical pain detected on palpation were observed in dogs with a HNPE as compared to dogs with other compressive myelopathies. The sites of HNPE were C3-C4 (8/21), C4-C5 (12/21), and C5-C6 (1/21).

CLINICAL SIGNIFICANCE

Dogs affected with HNPE have more severe clinical neurological deficits and less severe signs of cervical pain as compared to dogs with other compressive cervical myelopathies.

Clinical and magnetic resonance imaging features of canine compressive cervical myelopathy with suspected hydrated nucleus pulposus extrusion

OBJECTIVE

To describe clinical and magnetic resonance imaging features in dogs with compressive cervical myelopathy due to acute suspected hydrated nucleus pulposus extrusion.

DESIGN

Retrospective case series.

ANIMALS

Ten dogs with compressive cervical myelopathy caused by acute suspected hydrated nucleus pulposus extrusion.

MATERIALS AND METHODS

Medical records and magnetic resonance images of dogs evaluated from 2005 through 2010 were reviewed. The inclusion criteria were clinical signs compatible with cervical myelopathy, magnetic resonance imaging of the spine performed within 48 hours after onset, magnetic resonance imaging findings consistent with compressive suspected hydrated nucleus pulposus extrusion, complete medical records and follow-up information.

RESULTS

Six dogs were presented with acute onset tetraplegia and four dogs with acute onset of nonambulatory tetraparesis. Compromised respiratory function was present in three dogs. Compressive suspected hydrated nucleus pulposus extrusion was found on magnetic resonance imaging at the C4-C5 (n=6), C3-C4 (n=3) and C5-C6 (n=1) intervertebral disc spaces. Seven dogs underwent surgical treatment and three dogs were treated conservatively. All dogs except one regained ambulatory status within two weeks after the onset, and had a favourable outcome.

CLINICAL SIGNIFICANCE

Compressive myelopathy caused by acute suspected hydrated nucleus pulposus extrusion has not been reported previously and, even though neurological deficits can be severe on presentation, outcome is favourable.

Surgical decompression of a caudal vertebral disc extrusion by dorsal laminectomy

A 3.5-year-old female spayed Beagle cross was presented to our emergency and referral facility for the complaint of acute onset paralysis of the tail. A full physical and neurological examination was performed which confirmed the absence of motor function in the tail. Signs of superficial and deep pain sensation to the tail remained intact. Orthogonal view survey radiographs identified mineralization superimposed over the intervertebral foramen of the first and second caudal vertebrae. A dorsal laminectomy was performed for surgical decompression of the caudal nerve roots. On the fourth postoperative day, the patient exhibited good motor function of the tail. Neurological improvement continued and 11 days postoperatively the patient demonstrated normal neurological function, free range-of-motion of the tail, and it did not exhibit any signs of pain. Follow-up examination was performed 76 days after surgery, at which time the patient exhibited normal neurological function and signs of a pain-free range-of-motion on manipulation of its tail.