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.

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.

Background Experimental evidence shows benefit of rehabilitation after spinal cord injury (SCI) but there are limited objective data on the effect of rehabilitation on recovery of dogs after surgery for acute thoracolumbar intervertebral disc herniations (TL‐IVDH). Objective Compare the effect of basic and intensive post‐operative rehabilitation programs on recovery of locomotion in dogs with acute TL‐IVDH in a randomized, blinded, prospective clinical trial. Animals Thirty non‐ambulatory paraparetic or paraplegic (with pain perception) dogs after decompressive surgery for TL‐IVDH. Methods Blinded, prospective clinical trial. Dogs were randomized (1:1) to a basic or intensive 14‐day in‐house rehabilitation protocol. Fourteen‐day open field gait score (OFS) and coordination (regulatory index, RI) were primary outcomes. Secondary measures of gait, post‐operative pain, and weight were compared at 14 and 42 days. Results Of 50 dogs assessed, 32 met inclusion criteria and 30 completed the protocol. There were no adverse events associated with rehabilitation. Median time to walking was 7.5 (2 – 37) days. Mean change in OFS by day 14 was 6.13 (confidence intervals: 4.88, 7.39, basic) versus 5.73 (4.94, 6.53, intensive) representing a treatment effect of −0.4 (−1.82, 1.02) which was not significant, P=.57. RI on day 14 was 55.13 (36.88, 73.38, basic) versus 51.65 (30.98, 72.33, intensive), a non‐significant treatment effect of −3.47 (−29.81, 22.87), P = .79. There were no differences in secondary outcomes between groups. Conclusions Early postoperative rehabilitation after surgery for TL‐IVDH is safe but doesn't improve rate or level of recovery in dogs with incomplete SCI.

Spinal cord injury (SCI) due to acute intervertebral disc extrusions (IVDE) is common in dogs and is treated by surgical decompression. Dogs with sensorimotor complete injuries have an incomplete recovery. Pulsed electromagnetic fields (PEMF) reduce postoperative pain through anti-inflammatory effects and there is growing evidence for neuroprotective effects. This randomized, controlled clinical trial evaluated the effect of PEMF on post-operative pain and neurologic recovery in dogs with surgically treated sensorimotor complete SCI due to acute IVDE. Sixteen dogs with surgically treated complete thoracolumbar SCI were randomized to receive PEMF (15 minutes every 2 hours for 2 weeks then twice daily for 4 weeks) or placebo starting immediately after diagnosis. The primary outcome was gait score at 2 weeks. Secondary measures of gait, pain perception and proprioceptive function were evaluated at 2 and 6 weeks. Plasma GFAP concentration was measured as a SCI biomarker. Post-operative pain was quantified by measuring mechanical sensory thresholds (MST) at control and surgical sites. There was no significant difference in demographics or GFAP concentration between the 2 groups at trial entry. There was no difference in primary outcome or in secondary measures of gait, but proprioceptive placing was significantly better at 6 weeks and GFAP concentrations were significantly lower at 2 weeks in the PEMF group. MSTs were significantly higher in the PEMF treated group. We conclude that PEMF reduced incision-associated pain in dogs following surgery for IVDE and may reduce extent of spinal cord injury and enhance proprioceptive placing. Larger clinical trials are warranted.

Background Hypersomatotropism (HST) is an increasingly recognized endocrinopathy in cats and is mostly described associated with diabetes mellitus (DM). Objectives To evaluate the efficacy and safety of transsphenoidal hypophysectomy in treating HST and DM in cats. Animals Sixty‐eight client‐owned cats with HST and DM treated by transsphenoidal hypophysectomy. Methods Retrospective cohort study. Medical records were reviewed for glycemic control and serum insulin‐like growth factor‐1 (IGF‐1) concentrations. Postoperative complications, death within 4 weeks, and proportion achieving diabetic remission were recorded. Survival times and DM‐free intervals were calculated. Results Fifty‐eight cats (85.3%) were alive 4 weeks postoperatively with 10 (15%) postoperative deaths. Complications included hypoglycemia (n = 9), electrolyte imbalance (n = 9), and transient congestive heart failure (n = 5). Fifty‐five cats (95% of 58 surviving cats [81% of all cats undergoing surgery]) had improved control of diabetes. Diabetic remission occurred in 41 cats (71% of 58 surviving cats [60% of all cats]) with insulin administration discontinued after a median of 9 days (range, 2‐120). Postoperative 4‐week serum IGF‐1 concentration nadir was significantly lower in cats achieving diabetic remission (median 20 ng/mL [15‐708] than those that did not (324 ng/mL [15‐1955]; P = .03). All cats received long‐term levothyroxine and hydrocortisone PO, alongside desmopressin (conjunctival) in 38 of 53 cats (72%). Recurrence of DM occurred in 5 of 41 cats (12%) after a median of 248 days (range, 84‐1232). Median survival time of all cats was 853 days (range, 1‐1740). Conclusions and Clinical Importance Transsphenoidal hypophysectomy is an effective treatment for cats with HST and DM, with a long‐term outcome that compares favorably to existing options.

OBJECTIVE To compare clinical signs and outcomes between dogs with presumptive ischemic myelopathy and dogs with presumptive acute noncompressive nucleus pulposus extrusion (ANNPE). DESIGN Retrospective study. ANIMALS 51 dogs with ischemic myelopathy and 42 dogs with ANNPE examined at 1 referral hospital. PROCEDURES Medical records and MRI sequences were reviewed for dogs with a presumptive antemortem diagnosis of ischemic myelopathy or ANNPE. Information regarding signalment, clinical signs at initial examination, and short-term outcome was retrospectively retrieved from patient records. Long-term outcome information was obtained by telephone communication with referring or primary-care veterinarians and owners. RESULTS Compared with the hospital population, English Staffordshire Bull Terriers and Border Collies were overrepresented in the ischemic myelopathy and ANNPE groups, respectively. Dogs with ANNPE were significantly older at disease onset and were more likely to have a history of vocalization at onset of clinical signs, have spinal hyperesthesia during initial examination, have a lesion at C1-C5 spinal cord segments, and be ambulatory at hospital discharge, compared with dogs with ischemic myelopathy. Dogs with ischemic myelopathy were more likely to have a lesion at L4-S3 spinal cord segments and have long-term fecal incontinence, compared with dogs with ANNPE. However, long-term quality of life and outcome did not differ between dogs with ischemic myelopathy and dogs with ANNPE. CONCLUSIONS AND CLINICAL RELEVANCE Results revealed differences in clinical signs at initial examination between dogs with ischemic myelopathy and dogs with ANNPE that may aid clinicians in differentiating the 2 conditions.