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