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Neurology

Clinical Trial for Dogs with Acute Disc Herniations
Call for Patients

Funded by the Morris Foundation for Animals

 

Severe acute intervertebral disc herniations (IVDD) are a common problem in dogs currently treated by surgical decompression of the spinal cord. However, there is a lot of controversy as to whether adjunctive medical therapy is also beneficial. The two drugs that are advocated for use are a high dose regimen of methylprednisolone sodium succinate (MPSS) and a relatively new drug called polyethylene glycol (PEG).

• MPSS is believed to act as a free radical scavenger and as such to decrease the extent of secondary damage that occurs after the injury. Clinical trials in humans (the NASCIS trials) suggested a small benefit in patients but this finding has become extremely contentious and side effects from the drug (gastrointestinal hemorrhage, increased incidence of infections) are also concerning. A prospective blinded clinical trial has not been performed in dogs, and currently veterinary neurosurgeons are split in their recommendations on the use of this drug. The possibility of causing side effects by using this drug increases the need to demonstrate that it is effective at treating spinal cord injury prior to advocating its widespread use.
• PEG acts by fusing damaged axonal membranes and has been shown to be safe in a phase I clinical trial in dogs. Although not a blinded study, the trial suggested potential benefit for patients who receive this therapy.

This blinded, prospective clinical trial will compare MPSS, PEG, and saline placebo as adjunctive medical therapies to surgical decompression in dogs with acute intervertebral disc herniations. The data generated will represent the first objective information on the medical management of acute disc herniations in dogs. We hope to resolve the controversies surrounding the medical treatment of this common disease and to improve the outcomes for our patients. We hope that owners will support this study by agreeing to participate or sharing this website with those who may find it useful.

Study Hypothesis

Polyethylene glycol, but not methylprednisolone sodium succinate, will improve the outcome of acute intervertebral disc herniations in dogs when used as an adjunct to surgical decompression.

Inclusion Criteria

There are 12 hospitals currently committed to taking part in this trial. Please see the list of participants at the bottom of the page to verify that the hospital in your area is actively recruiting cases at this time. Provided the hospital is currently recruiting cases, all patients who are either referred to or seen on emergency for paraplegia with no sensation in the hind limbs are potentially eligible for the study. Once the patient is admitted to the hospital, the clinician will ask a series of questions and perform a physical exam to determine if it is appropriate for the dog to be enrolled in the study.

We will only be including dogs with the most severe grade of spinal cord injury, paralysis with loss of sensation. This is the group of dogs most likely to have an incomplete recovery with surgical therapy. The decision to include or exclude a patient from this study is entirely at the discretion of the clinician.

The inclusion criteria are:

1. Dogs aged between two and ten years and weighing less than 20kg.
2. Paraplegic with no deep pain sensation in the pelvic limbs.
3. Known paraplegia of 24 hours duration or less. It is anticipated that there may be instances when the patient was found to be paralyzed after being left alone for a long period of time; such dogs may be included provided the duration of KNOWN paralysis is 24 hours or less. Patients may also be included who have had less severe symptoms of a disc herniation that have progressed to paralysis, provided the paralysis has been recognized for 24 hours or less.
4. No history of systemic illness that would preclude the use of high doses of MPSS. The clinician responsible for the case will discuss the dog’s medical history to determine appropriateness for inclusion.
5. The clinician will discuss any medications the dog has been taking recently. Administration of certain medications may raise the risks of side effects if the dog is given the study medications. Based on this information, the clinician will assess the potential risks and help the owner to make an informed decision about the inclusion of the dog in the study.
6. Patients MUST have decompressive surgery to be eligible for the study.
7. The owner must be willing to return to the hospital for scheduled rechecks at 2, 4, 8, and 12 weeks after discharge.

Study Protocol

Patients who are admitted to the study will initially have a neurologic exam and videotaping prior to having diagnostics performed to confirm a disc herniation. Administration of the study medication (a bolus followed by a 24 hour continuous rate infusion with a second bolus at 4 hours) will be started once the diagnosis has been confirmed and will continue during surgery. Each of the 3 therapies (MPSS, PEG and placebo) will be prepared to appear identical and will be assigned to patients in a random order. The identity of the medication will be unknown to the veterinarians and the dog owners. Following surgery, the patient will be recovered from anesthesia and the 24-hour drug infusion will be completed. In addition, all dogs will receive gastrointestinal protectants both because of the high incidence of gastrointestinal irritation in dogs with disc herniations, and because they may have been treated with MPSS. Post operative care will follow normal protocols including administration of pain medications as needed. Twenty-four hours after admission, the neurologic exam and videotaping will be repeated.

Patients will be discharged when the attending clinician feels it is appropriate in consultation with the owner. Dogs will return for repeat videotaped neurological examinations at 2, 4, 8, and 12 weeks after surgery. In between appointments, the owners will be asked to fill out a short questionnaire. If at any time the patient suffers any adverse event, whether or not it is likely to be associated with one of the test drugs, it will be reported. In the case of severe complications, the study safety monitor may request the identity of the drug administered from the pharmacists.

Frequently Asked Questions by Owners

What are the benefits of enrolling my dog?

The biggest anticipated benefit for our clients will be the knowledge that you and your dog have made an important contribution to a very large and important study that we hope will help set the standard of care for IVDD in the future. There is also some financial benefit, as the study medications and recheck appointments will be without cost to you.

Are there any risks to my dog?

There are inherent and potentially life-threatening risks to any patient who undergoes surgery for IVDD that are unrelated to the study. We encourage you to discuss this with your clinician prior to surgery. As for the study medications, both PEG and the placebo (saline) have not been associated with any side effects in dogs. MPSS can in some cases cause or exacerbate gastrointestinal problems. As a corticosteroid, it will suppress the immune system and may be associated with higher rates of infection. In rare incidents it has been associated with pancreatitis. All patients enrolled in the study will be placed on GI protectant medications, as dogs presented to the hospital with IVDD often develop GI upset whether they are given steroid medications or not. All owners should be aware that, though rare, life-threatening complications can develop after surgery. These complications may or may not be directly related to the study medications. All complications will be reviewed by the study safety monitor, and if it is deemed necessary, the identity of the drugs will be revealed to the monitor to assess the likelihood of a medication-induced complication.

What are my responsibilities if I elect to enroll my dog in this study?

The most important responsibility, should you choose to take part in this study, will be to return for your required re-check appointments. We will also ask you to fill out a short questionnaire in between your recheck visits. The data that will allow us to evaluate the efficacy of the study medications will be generated via these appointments. If you feel you will have significant problems in bringing your dog back to the hospital for these appointments, please let us know immediately.

We will contact you at several points during the course of your participation in the study. If your contact information should change, we ask that you update us so we can stay in touch.

As we think this will be an important study for dogs that have IVDD, we also hope that you will become an advocate for our study. Please feel free to share the study website with your veterinarian, breeder, and friends should you wish to.

If I have some questions, who should I call?

All of the veterinary hospitals participating in the study are listed at the bottom of the page with clinician names, contact information, and websites links. The principal investigator for this study is Natasha Olby, VetMB, PhD, DACVIM (Neurology) and the research fellow is Audrey Chanoit, DVM, MS. They are based at North Carolina State University.  If you have questions about the study, please contact the Neurology Laboratory at 919-513-7235 to leave a message or email ivddstudy@lists.ncsu.edu.  You will receive a reply as soon as possible, but delays may be experienced dependent on personnel availability. Please keep in mind they will be unable to answer specific questions about the ongoing care of your pet. These questions should instead be referred to your neurosurgeon.

More Information

For more information about intervertebral disc disease, go to http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/ IntervertebralDiscDisease/

Centers Currently Recruiting Cases for This Study

 

The following centers will begin recruiting cases at a later date: