A Nerve Conduction study on Dogs with Intervertebral Disc Extrusion

Purpose

The purpose of this study is to determine if a nerve test, performed on paralyzed dogs before surgery for a slipped disc, can predict whether they will regain the ability to walk.

Background

Thoracolumbar intervertebral disc extrusion (TL-IVDE) is like a "slipped disc" in a dog.  This problem is quite common, especially in certain breeds.   About 3.5% of all dogs seen by veterinarians have IVDE.  It is estimated that 20,000 to 30,000 cases of IVDE are diagnosed by veterinarians in the U.S. every year.  Dachshunds are especially prone to this condition, with as many as 1 in 5 having it in their lifetime. 

The severity of the injury impacts recovery.  The most severe form of the injury is when a dog with a back injury (TL-IVDE) becomes paralyzed and loses all feeling in its back legs.  This happens in about 16% of dogs with IVDE.  Even with surgery, dogs with this severe type of injury often have a poor recovery. 

In dogs with TL-IVDE, a nerve conduction test can measure electrical signals in a dog's nerves to see how well they are working.  The "F-wave" is a particular kind of electrical signal that gives information about the health of the nerves and the spinal cord.

For severely affected dogs, veterinary neurologists still struggle to predict which ones will recover well.  Finding reliable warning signs, or indicators, to better predict a dog's recovery after a severe spinal injury remains an important area for research.

Eligibility

1. Age at time of enrollment between 1 and 11 years old
2. Neurologic examination findings of paraplegia without pain perception in the hind limbs and tail confirmed by a board-certified neurologist
3. Thoraco-Lumbar Intervertebral Disc Extrusion diagnosis between the 3rd Thoracic and 3rd Lumbar spinal cord segment confirmed via surgery

Exclusion Criteria

1. A history of previous spinal surgery
2. Suspected spinal cord disease called progressive myelomalacia
3. Severe illness or cancer

Study Design

All dogs in this study will undergo standardized, gold-standard diagnostics and surgical procedures. F-wave nerve conduction testing will be conducted preoperatively. At six months post-surgery, dogs will be categorized into one of two clinical outcome groups:

• Successful: Dogs that achieve independent ambulation.
• Unsuccessful: Dogs that remain non-ambulatory or experience IVDE-related mortality within the observation period. This includes cases of progressive myelomalacia or euthanasia due to prolonged non-ambulatory status (>3 months)

Compensation

As an incentive for participating in the study, a $1,000 credit will be applied to the hospital bill for enrolled dogs that meet the specified surgical outcome criteria. All recheck appointments for the study will be at no cost to the owner. 

Funded by:

The American Kennel Club Canine Health Foundation