Spinal Cord Damage from IVDD
Therapeutic Strategies Based on Disease Stage
Steven Garner, DVM, DABVP
Chief of Staff, Safari Veterinary Care Centers
In canine IVDD the spinal cord is compressed by the intervertebral disc. This may happen suddenly and abruptly where the pet is normal one moment and paralyzed the next or it may happen more gradually progressing through stages of pain and stiffness with muscle spasms secondary to disc pain and compression on the spinal nerve roots. Ultimately the disease is progressive and causes significant compression and death of the spinal cord nerves. Even in the most severe cases however there are nerves that are spared and the number of spared nerves and their fate can be determined by how the case is managed. The following presents new information for the veterinary profession and also refutes some of the existing information that is being used to guide management of these cases.
I will use the classic terms to denote timing or course of a disease to describe the different stages of injury and repair, regeneration or return to function.
Peracute – This is defined as the initial stage in the course of a disease. It is usually measured in hours.
Acute – This is a more common term associated with the first few days of the course of a disease.
Subacute – This term indicates that the disease course is continuing to progress over a period of a few weeks up to a month.
Chronic – Diseases that have been present for a month or more fall into the chronic disease definition.
This guidance enables rational therapy for each of these stages. The peracute spinal cord injury with IVDD is related to compression of the spinal cord and death of neurons with secondary inflammation. Initial rapid surgical decompression before permanent neuron death is the treatment of choice. Without decompressive surgery, the spinal cord degenerates secondary to inflammation, toxic metabolites, over excitation of neurons and loss of blood supply all occurring during the acute stage. During this stage, therapeutic modalities such as anti-inflammatory medications, pain medications, cold therapy, therapeutic laser and electrostimulation are beneficial. The key goal of therapy during the acute stage is to reduce the scar tissue within the damaged spinal cord “glial scar” that may impede future healing. One week after the initial event the spinal cord starts to heal and during this phase stem cell therapy alone or along with decompressive surgery and other therapeutic modalities offers great promise. Therapy in the chronic stage of healing involves promoting the re-tasking of neurons. Regenerated or rescued neurons must learn or relearn their functions. This can only be accomplished by physical and mental stimulation of the nerves through physical therapy and environmental enrichment.