Trismus describes restricted range of motion of the jaw. Trismus is commonly caused by tightening or scar formation of the muscles that open and close the jaw, which prevent the mouth from opening fully. For most patients that experience trismus either temporarily or permanently, this condition causes an inability to open their mouth greater than roughly the width of three fingers. However, some patients may develop severe trismus that can limit their opening to a finger breath or less between their upper and lower teeth.
Trismus can have substantial negative impacts on a patient’s quality of life. Because trismus affects the jaw and mouth region, it can cause serious problems with eating, speaking, swallowing, and maintaining oral hygiene. In addition, trismus can cause difficulties for patients that require treatment or have already undergone treatment for head and neck cancer, as the condition impedes comprehensive examination of the oral cavity and thus may limit surveillance of the affected area.
Trismus can present as a side effect for patients who undergo surgery and/or radiation therapy in the head and neck region. The risk of developing trismus is particularly relevant for patients whose treatment area includes structures involved in or near the muscles that open and close the jaw.
Symptoms of Trimus
Most Common Symptoms
The most common symptom of trismus is the inability to fully open the mouth. This can have serious consequences for patients, as it may limit their ability to eat solid food and drink enough liquids to maintain adequate nutrition and hydration. During this time, patients may be advised by their speech and swallowing therapist or dietician to switch to a soft food diet or full liquid diet until they are able to improve their oral opening.
Other Symptoms
Other common symptoms experienced by patients include pain in the jaw, difficulty chewing or swallowing, cramping of the jaw muscles and surrounding area, and discomfort or difficulty with activities that require a full jaw range of motion, such as teeth brushing or yawning.
Although trismus much more commonly presents as a temporary complication, it can become a permanent condition if a patient does not undergo rehabilitative treatment in a timely manner. Depending upon the treatment that may be causing a patient’s trismus, some trismus may be longstanding and necessitate some form of long-term rehabilitative exercise to maintain and maximize the range of motion of the jaw. For example, the late effects of radiation in the head and neck region can cause decline in a patient’s jaw range of motion long after treatment has concluded. The potential for long-term complications necessitates the prolonged routine monitoring of jaw function and associated abilities.
Long-term or permanent trismus can dramatically impact a patient’s quality of life and require the routine practice of jaw range of motion exercises for life. However, therapeutic options are available to minimize or eliminate the difficulties associated with long-term trismus.
Treatments
Patients should work closely with a speech and swallowing therapist to understand the treatment options that are best suited for them. The sooner a patient’s trismus is identified and rehabilitation is initiated, the more success patients have with reversing or reducing the severity of their complication. These rehabilitative options often include therapeutic stretching and exercises, and the use of rehabilitative jaw-stretching devices. Although less common, in some situations, patients can be prescribed medication to help with their trismus or its symptoms. Some severe cases of trismus can also be treated with surgery.
Stretching & Therapeutic Exercises
Stretching and therapeutic exercises can be extremely beneficial for reducing the effects of trismus. This therapy typically involves massaging of the jaw and surrounding region, as well as routine stretching of the jaw and the affected muscles. Patients should practice these exercises at the direction of their speech and swallowing therapist. When done in a timely manner, these exercises can prevent the onset of trismus altogether, or may reverse the development of trismus in patients who already present with the complication. Early intervention prior to the start of treatment is usually advisable.
In cases in which these stretching exercises do not improve trismus, patients can use a rehabilitative jaw range of motion tool to assist with improving and/or maximizing jaw mobility after head and neck cancer treatment. Rehabilitative jaw range of motion tools are typically placed between the teeth. Active pressure opens the jaw to an established width set by the speech and swallowing therapist.
Devices That Can Help
Devices commonly used for patients experiencing trismus include the TheraBite®, OraStretch®, and Jaw Dynasplint® systems, which are aimed at restoring maximal opening to the affected jaw area. Working closely with a speech and swallowing therapist will help patients determine how often and to what extent they can use these devices.
Although less commonly used than both therapeutic stretching exercises and jaw-stretching devices, some patients may be prescribed medication to assist with their trismus. Medications such as muscle relaxants, painkillers, and anti-inflammatory medicines can help to lessen the painful symptoms of trismus. These medications can be obtained by discussing treatment options with a physician, who can assist a patient by choosing and prescribing the best medication option. The medication types listed above have been shown to decrease the extent of trismus in patients following oral surgery, and are also prescribed to help patients comply with therapeutic exercises that may cause patients additional pain when practiced routinely.
Surgical Options That Relieve Trismus
Some patients who are experiencing severe trismus may even undergo surgery to improve their jaw mobility. In these cases, a surgeon may perform a coronoidectomy procedure, which surgically removes the coronoid process of the mandible and thereby increases the jaw range of motion of the patient.
Conclusion
Trismus, marked by limited jaw movement, severely impacts daily activities such as eating and speaking. It often follows head and neck cancer treatments, arising from muscle tightening or scarring. Early detection and intervention are key, with treatments ranging from stretching exercises and rehabilitative devices like TheraBite® and OraStretch®, to medications and surgery for severe cases. Effective management, under professional guidance, can alleviate symptoms and enhance quality of life.
