A Placebo‐Controlled, Prospective, Randomized Clinical Trial of Polyethylene Glycol and Methylprednisolone Sodium Succinate in Dogs with Intervertebral Disk Herniation

Abstract

BackgroundAcute intervertebral disk herniation (IVDH) is a common cause of spinal cord injury in dogs and currently there is no proven medical treatment to counter secondary injury effects. Use of methylprednisolone sodium succinate (MPSS) or polyethylene glycol (PEG) as neuroprotectants is advocated but controversial because neither treatment has been tested in placebo‐controlled, randomized, blinded trials in dogs.HypothesisPolyethylene glycol will improve the outcome of severe spinal cord injury caused by IVDH compared to MPSS or placebo.AnimalsClient‐owned dogs with acute onset of thoracolumbar IVDH causing paralysis and loss of nociception for <24 hours.MethodsDogs were randomized to receive MPSS, PEG, or placebo; drugs appeared identical and group allocation was masked. Drug administration was initiated once the diagnosis of IVDH was confirmed and all dogs underwent hemilaminectomy. Neurologic function was assessed 2, 4, 8, and 12 weeks postoperatively using an open field gait score (OFS) as the primary outcome measure. Outcomes were compared by the Wilcoxon rank sum test.ResultsSixty‐three dogs were recruited and 47.6% recovered ambulation. 17.5% developed progressive myelomalacia but there was no association with group. There was no difference in OFS among groups. Although full study power was not reached, conditional power analyses indicated the futility of continued case recruitment.ConclusionsThis clinical trial did not show a benefit of either MPSS or PEG in the treatment of acute, severe thoracolumbar IVDH when used as adjunctive medical treatment administered to dogs presenting within 24 hours of onset of paralysis.

Associations Between Anesthetic Variables and Functional Outcome in Dogs With Thoracolumbar Intervertebral Disk Extrusion Undergoing Decompressive Hemilaminectomy

“…Another limitation of the current study is the lack of longer term follow‐up data beyond 6 weeks postoperatively, as some dogs that were nonambulatory at 6 weeks could have gone on to recover ambulatory function in the longer term. However, previous studies have shown that the majority of postoperative functional recovery after SCI in dogs occurs within 4–8 weeks of surgery, supporting this observation time frame 11, 13, 32, 42. To maximize the outcome data available, we used 2 functional scoring systems postsurgery; an ordinal 12‐point score (OFS) and a treadmill‐based gait score (RI), both described and validated previously 31, 35.…”

“…All dogs underwent imaging and decompressive surgery, followed by a prescribed standardized home physical therapy plan and strict rest, as is standard protocol at the study institution. As neither trial demonstrated an effect of treatment over placebo, all dogs followed at NCSU were included in this study (from the first trial—MPSS: n = 6, PEG: n = 6, saline: n = 5, and from the second trial—cranberry: n = 32, placebo: n = 35) 32, 33. For each dog, age, breed, sex and body weight were recorded, as well as duration of clinical signs, any preoperative medication administered by the referring veterinarian, IVDE site and ordinal functional grade (modified Tarlov grade: grade 1 = neurologically normal, grade 2 = ambulatory paraparesis, grade 3 = nonambulatory paraparesis, grade 4 = paraplegia with intact conscious pain perception, grade 5 = paraplegia with absent conscious pain perception) at presentation 34.…”

“…Pearson's correlation coefficient was used to test for linear association between continuous variables. Clinical trial drugs were not included in statistical analysis due to the lack of effect demonstrated in prior analysis 32, 33. Data were evaluated for normality using Shapiro‐Wilk tests.…”

First‐opinion approach to the dachshund with intervertebral disc herniation

“…Steroids are no longer considered to be beneficial and may be contraindicated in the management of acute and chronic IVDH (Hurlbert 2000, Levine and others 2007, Olby and others 2016). …”

Clinical Trials in Veterinary Medicine: A New Era Brings New Challenges

“…A glance through recent issues of the Journal of Veterinary Internal Medicine identifies prospective randomized clinical trials (RCTs) involving dogs,1, 2, 3, 4, 5, 6, 7, 8, 9 cats,10, 11, 12, 13 cows,14, 15 and horses16, 17 that cover the fields of neurology,1, 8 oncology,3, 5 cardiology,4, 6, 12 and internal medicine 2, 9, 10, 11, 13, 14, 15, 16, 17. Collectively, these findings suggest that we have entered into an era of prospective veterinary RCTs.…”