Brachial Plexus Avulsion in Dogs

You may notice that your dog begins to limp or have a limb that drops. This may follow an injury and may impact any of his limbs. The drop may be a noticeable inability in flexing and controlling the limb and therefore it just hangs there.

This injury can look similar to a less severe injury, or your dog may not want to put pressure on a broken bone or cut. Your dog may not appear to be in any pain making it difficult to identify what is going on.

The brachial plexus are the last 3 cervical and first 2 thoracic nerves in your dog’s spine which impacts his shoulders. When these nerves are torn, ripped or injured it is referred to as an avulsion. This tends to happen if your dog is hit by a car, or if he falls and there is displacement of the thoracic (backbone) limbs.

Symptoms will include the loss of use of your dog’s limbs, changes in his behavior, and other possible medical symptoms.

• Horner’s Syndrome (drooping eye, small pupil, sunken in eye, prominent third eyelid)
• Paralysis of a limb
• Difficulty controlling a limb
• Limbs dragging
• Not putting weight on a limb
• Lack of pain or significant pain when examined 

Types

There are three types of brachial plexus avulsion and they are dependent on what part of the spine is impacted.

Cranial avulsions (C6-C7)

• Rare
• Few clinical signs and symptoms
• Your dog will most likely be able to bear weight on the limb
• Loss of shoulder movement

Caudal avulsions (C8-T2)

• More common
• Cause severe clinical signs
• Your dog may not be able to extend his elbow or bear weight 
• Dragging of the limb 
• May carry the limb flexed off the ground

Complete avulsions (C6-T2)

• Sensory signs are common
• Partial Horner’s Syndrome

The cause of brachial plexus avulsion is typically an injury, however there are other causes of the condition as well:

• If your dog was hit by a car
• If your dog fell from a significant height
• If your dog was grabbed incorrectly or roughly
• Neuromuscular disease
• Endocrine system disorders
• Immunization side effect

If you begin to notice that your dog is not putting weight on a limb, dragging a limb, or if there was recent injury, you will want to contact your veterinarian. It will be important to go to your veterinarian or emergency veterinarian prepared to share any recent injuries, falls or events such as if your dog was hit by a car. 

Your veterinarian will want to perform a full body exam to determine any obvious injuries or signs of brachial plexus avulsion. Your veterinarian will want to test your dog’s nerve reactions and see if there is any damage. This may include testing if your dog feels pain when pinched or poked. 

Your veterinarian may want to perform an MRI as it is the imaging tool of choice to determine a brachial plexus injury. Electrodiagnosis testing can also be performed, this test will involve inserting a needle into your dog’s muscle to see how it responds to stimuli. This will help your veterinarian to determine the cause of your dog’s limb concerns 7 to 10 days’ post injury.

Treatment options are unfortunately limited and long term prognosis is not promising. Your veterinarian may suggest surgery to try and correct some of the damage done to your dog’s nerve endings. It should be noted that if it is a full avulsion (full tearing of your dog’s nerve endings from the spinal cord) the prognosis is poor.

Surgery

Surgery can be done to repair some of the damage done to your dog’s nerve endings. Some of the surgery options are: coaptation splintage, tendon transposition, nerve transposition, ankyloses and amputation. The splintage is done to prevent your dog from harming his limb and is done along with physical therapy and anti-inflammatory medications.

Tendon transposition is done by cutting the tendons and either reconnecting them or loosening them to provide your dog with more use of the limb. Nerve transposition is done by reattaching the nerves to other places to try and provide your dog with some of use of his limbs. Amputation may be suggested if your dog will be dragging the limb causing it ongoing injury or if he is self-mutilating the limb. Long term prognosis is poor for full avulsion, however for partial there is a possibility for recovery with treatment.

Your dog will most likely need ongoing care depending on the severity of his brachial plexus injury. These appointments will be done to determine his condition is getting any worse or if there is any improvement. 

Should he have surgery there will be follow up need per the direction of your veterinarian. A full recovery can be expected within 2 months of surgery. Your veterinarian may also suggest physical therapy once surgery is done and also to try and recover some function.