Trismus
Trismus, or lockjaw, is when you have a hard time opening your mouth. This can change how you look and make it hard to:
- Eat.
- Swallow.
- Speak.
- Perform mouth care.
What causes trismus?
Trismus can happen because of head and neck cancer or as a side effect of treatment. Trismus can also be caused by trauma, swelling, surgery, or infection. Trismus may develop due to cancer because there is:
- A tumor in your jaw.
- Nerve damage from surgery that was done to remove your tumor.
- Scar tissue from your radiation treatment.
Radiation is the most common cause of trismus related to cancer. Trismus cause by radiation, is often associated with other side effects as well. These side effects may include dry mouth (xerostomia), mouth sores (mucositis), and pain. Your chance of having trismus is related to the amount of radiation your jaw got during treatment. The more radiation your jaw gets the higher the chances of having trismus.
Other side effects of trismus include pain in the ear and jaw, headaches, and trouble hearing.
How is trismus diagnosed?
Trismus develops slowly and can get worse over time. Your provider can take a series of measurements to see how wide your mouth will open and if it is getting better or worse.
You can also check for trismus yourself with the 3-finger test. You can do this by holding your index, middle and ring fingers together, putting them into your mouth between your top and bottom teeth. If you can’t do this easily, you may have trismus. Talk to your provider if you notice this.
How is trismus prevented and managed?
Exercises to prevent trismus should start before treatment and continue forever. Treatment is most effective when started early. You will be taught how to do exercises that maintain maximum opening of the jaw. These exercises should be done 3 to 4 times a day. How wide you can open your jaw will be measured before, during, and after treatment.
Physical therapy may use multiple tongue depressors bound together or devices such as TheraBite® and Dynasplint to exercise and stretch the muscles and help mobility and flexibility.
Medications like pain relievers, muscle relaxants, and anti-inflammatories can be used to help manage trismus. A soft diet can also be helpful.
Trismus can really affect your daily life, so it's important to start exercises before it becomes a problem. Your care team will talk to you about your risk for trismus, give you exercises to prevent it, and help manage any problems. They can also check if your insurance will cover any special devices for treatment.