Radiation Therapy

Why does lock-jaw occur 36 weeks after radiation therapy begins?

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2008-10-18 00:55:49

For treatment of patients with cancer, radiation oncology is a

common treatment to help fight and treat the cancerous region. One

of the side effects of radiation therapy is a progressive

stiffening of the tissues under radiation. The more radiation a

tissue receives, the more likely the stiffening will occur; and

patients with long treatment schedules or on a second round of

radiation often see these effects. This stiffening is usually

treated with stretching to the affected areas.

For head and neck cancer patients, if radiation is applied to

areas around the mouth and jaw, the stiffening of the facial

tissues causes trismus. Trismus is the limited opening (or

range-of-motion) of the mouth. Severe cases of trismus are often

called "lockjaw." Unfortunately, the mouth does not easily lend

itself to be stretched open, and the stiffening is significant.

Additionally, patients are rarely warned of this side-effect to

prevent it. Patients often only discover it after the stiffening

has caused limitations in their ability to eat, drink, speak,


Exercises and stretching to prevent trismus is the best course

when head-and-neck cancer patients are receiving radiation therapy.

However, treatment for stiffening of the jaw or trismus includes

heat, medication and stretching. Stretching the jaw is difficult

and a number of aids have been developed to assist patients, like

the OraStretch Press or the TheraBite systems. These devices are

used by patients to press their mouth open and stretch the jaw and

facial muscles, to overcome the stiffening caused by radiation.

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