Laryngeal paralysis results in the inability of your pet to inspire ( "can't get his/her breath").
Diagnosis of the problem is made by examining the voice box under light general anesthesia.
A corrective surgery can help your pet breathe well again.
What is it?
Laryngeal paralysis is a condition in which the muscles which open the voice box become paralyzed, which results in the inability of your pet to inspire - the result is your pet "can't get his/her breath"
Anatomy
The larynx is the voice box.
Components:
vocal cords, which allow vocalization in dogs and cats.
arytenoid cartilages form the structural "doors" of the larynx
muscles - one set of muscles attached on the arytenoid cartilages open the "doors" (called the CAD or cricoarytenoideus dorsalis muscle) and another closes the doors (called the CAL or cricoarytenoideus lateralis muscle).
glottis - is the airway of the larynx through which air passes from the mouth into the windpipe and then into the lungs
epiglottis is a flap or valve that flips over the larynx during swallowing to help prevent aspiration of food or water into the windpipe. In addition the CAL (cricoartynoideus lateralis) muscle will pull the "doors" of the larynx tightly closed to help prevent aspiration during swallowing
Clinical signs
Most dogs that develop laryngeal paralysis are geriatric larger breed dogs
Occasionally we will see this problem in young large breed dogs (congenital laryngeal paralysis)
Cats rarely get this problem
Signs of laryngeal paralysis are more evident in warm weather and include
exercise intolerance
difficulty breathing in (inspiratory dyspnea)
raspy or noisy breathing sounds
blue or gray tongue or gums may indicate that your pet is not getting enough oxygen
collapse
death
Diagnosis
In order to examine the larynx your pet will be lightly anesthetized. As the pet breathes in and out the function of the larynx is evaluated. See animation above which is a larynx that has normal function - take note that as the dog breathes in the glottis enlarges to allow air to pass into the airway.
The animation to the right demonstrates laryngeal paralysis - when the dog tries to breathe in, the negative pressure from the windpipe will also pull the arytenoid cartilages together, which even further compromises the airway. This is called paradoxical movement of the larynx.
Additional testing that may be done
complete blood count
full chemistry profile
urinalysis
chest x-rays
neck x-rays
Treatment
Emergency treatment of a dog with laryngeal paralysis
sedation
oxygen
If body temperature is high - water soaks with fanning
anesthetize patient and place tube in airway if sedation is not effective
Surgery
A major contraindication for surgery is swallowing difficulties or regurgitation as these dogs will develop pneumonia after surgery.
The side of the neck (usually the left) is shaved. An incision is made on the side of the neck over the larynx. Two non dissolving sutures are used to replace the paralyzed left CAD muscle. The arytenoid cartilage is therefore "tied-back" in a permanent open position.
Below is a an illustration of a larynx after tie-back surgery has been completed - take note that the airway (black) is nicely open
After care and convalescence
After surgery has been completed intensive care must be provided for the best chance for a successful outcome. Intravenous fluids may be continued over night. Most patients having a routine tie-back surgery are discharged from the hospital the next day after surgery.
After your pet leaves the hospital pain is controlled with oral medication on an as needed basis.
Antibiotics may be prescribed to your pet if the surgeon feels that this is needed.
The feeding and water bowls should be elevated about 8 to 10 inches off of the floor. Canned food should be cut into chunks for the couple of weeks. Kibble could also be moistened with warm water before it is fed. Which ever food type seems to cause less coughing should be fed.
Dusty environments should be avoided.
Swimming will no longer be permitted. If your pet’s head would go under water, the larynx would not be able to close and drowning could occur.
Exercise should be restricted for one month to prevent break down of the laryngeal tie-back.
A harness should be used instead of a collar, in order to take pressure off of the windpipe and the larynx.
Prognosis
Most pets do well following laryngeal tie-back surgery.
Breathing is greatly improved and your pet should not get into a crisis again.
Your pet likely will not be able to bark again or the bark will be hoarse. During heavy panting your pet could still have increased respiratory noise, as only one side of the larynx has been tied open and the other vocal cord may flutter as air moves in and out.
Potential complications
As with any surgery, complications may arise. Even though rare, anesthetic death can occur. With the use of modern anesthetic protocols and extensive monitoring devices (blood pressure, EKG, pulse oxymetry, inspiratory and expiratory carbon dioxide levels, and respiration rate), the risk of problems with anesthesia is minimal.
Infection is an unusual complication as strict sterile technique is used during the surgery and antibiotics are administered.
Seroma formation can also occur, as there may be an empty space between the tissues. This problem in general will resolve with time. Occasionally the seroma or fluid that has built up may require draining.
Pneumonia can occur after surgery because the airway is permanently kept open on one side.
Recurrence of laryngeal paralysis signs can occur if the cartilages (that are pulled open with sutures) are abnormally soft or brittle and do not hold the sutures well. In the event that this occurs, surgery can be done on the other side of the larynx.
Coughing is a expected following tie-back surgery on the larynx. Usually coughing is associated with drinking or eating. Within 6 weeks this usually improves, but occasional cough can occur. If the cough becomes deep and productive, or your dog becomes depressed, you should alert us as pneumonia may be developing.
MVS Surgery Team
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