Trismus
Trismus is a disorder in which it becomes difficult, painful, or impossible to fully open your mouth due to a decrease in the range of motion of the muscles or joints of the jaw. It is one of many possible long-term side effects of treatment for head and neck cancer. Trismus is diagnosed by measuring how wide the mouth opens or by the degree of pain with attempted mouth opening.
What Causes Trismus?
Trismus occurs when radiation and/or surgery for head and neck cancer causes scarring or damage to the jaw muscles or jaw joint, or nerve damage. Trismus is not always an immediate side effect; it may develop immediately upon surgical removal of the jaw or jaw muscles, or it can develop slowly, often unnoticed in its earliest stages, over a period of approximately 12-18 months. Once it begins, it is often irreversible, though there are options for treatment.
It is important to prevent trismus by stretching the jaw during the course of radiation. When trismus occurs, it is important to start treatment as soon as possible as it becomes more difficult to treat the longer it has been present. Research shows that muscles and joints that are unable to move through their full range of motion will begin to show changes after as little as 3 days.
Risk Factors
Trismus will affect between 10% and 40% percent of head and neck cancer patients, with severity varying from person to person.
Risk factors for developing trismus include:
- Radiation treatment for oral, oropharyngeal, nasopharyngeal, base of tongue, salivary gland, skin of the face, and jaw cancers. The structures responsible for trismus (upper and lower jaw and muscles of the jaw) are directly in the radiation field when treating these specific cancers.
- Radiation dosages higher than 60 Gr.
- Previous radiation treatment, including patients who are being treated for a recurrence of their cancer.
How Might Trismus Affect Me?
Trismus has the potential to seriously impact one’s health and quality of life.
- Trismus makes it difficult and painful to eat, often resulting in inadequate nutrition and significant weight loss. When mouth opening is limited, it is difficult to eat foods like sandwiches and raw fruits.
- Speaking becomes difficult due to the inability to fully open the mouth and the associated reduction in vocal quality. You may speak quietly or seem to be mumbling. Your tongue may not be able to make normal speech sounds if your mouth cannot open fully.
- It may be difficult or impossible to wear dentures.
- Physical exams of the mouth, including medical and dental exams, may be very uncomfortable and even impossible in severe cases.
- It may be difficult or impossible to maintain proper oral hygiene (toothbrushing and flossing), which is tremendously important to head and neck cancer patients and survivors.
- Poor oral hygiene can result in cavities and radiation-related osteoradionecrosis of the jaws.
Symptoms
Symptoms of trismus include:
- Jaw stiffness
- Reduced ability to open your mouth wide
- Pain when opening or closing the mouth
Trismus develops very slowly and often goes unnoticed by patients in its earliest stages. So, vigilance is needed to catch it early, when it can still be managed effectively. You may wish to regularly do the “ three finger test” to make sure you can open your mouth fully. Insert three stacked fingers vertically into your mouth. If your fingers fit between your top and bottom front teeth, your mouth opening is considered functional. If you can only fit two or fewer fingers, you may be suffering from trismus.
Treatment & Management
If trismus is treated early, patients can minimize their symptoms and prevent it from getting worse. Treatment generally includes stretching or passive motion exercises, with the latter shown to be more effective than static stretching. Recent research at the University of Pittsburgh has also shown that passive motion offers a significant reduction in inflammation and pain as well. It is recommended that you seek the advice of a professional before starting treatments for trismus, as some interventions can make things worse for some patients. Trismus is most commonly managed by speech-language pathologists and physical therapists.
- Stretching: Basic stretching of the jaws is the most important first step to preventing and managing trismus. Frequent stretching (e.g. several times per day) may be more effective than stretching done less frequently.
- Passive Motion Devices: Passive range of motion devices are used to open and close the mouth, working the associated joints and muscles, without the patient exerting any effort. There are a variety of passive motion devices available to patients suffering from trismus, including custom-made options.
- Manual therapies: Massage-type techniques may be helpful for reducing tightness in the jaw and may facilitate better and more comfortable jaw function. These treatments are usually provided by a rehabilitation specialist like a speech-language pathologist or a physical therapist.
Preventing Trismus
Because trismus can be irreversible and often goes unnoticed until it is advanced, patients may wish to focus on preventing it early, even during treatment for their cancer. Some exercises that may help prevent trismus include:
- Open your mouth wide, as if you’re yawning. Keep it open for 30 seconds at a time. Rest and repeat several times. Ideally, do this at least 2-3 times per day.
- Use a passive motion device if recommended by your medical team.
- You may also wish to regularly do the “3 finger test” (see above) to make sure you haven’t lost any range of motion.
Ask your doctor before you begin these, or any other, exercises. If you’ve had surgery, you may have to wait to do any stretching or passive motion exercises until your surgery site has healed.
