Difficulty opening mouth

Trismus is debilitating. Treatment is aimed at the cause.

As it can be caused (or made more likely to develop) by several different conditions including infections, trauma, surgical treatment, dental treatment, temporomandibular (jaw) joint disorders, radiotherapy, some drugs, congenital conditions and some other rare disorders, the treatment may range from advice on coping mechanisms to radical surgery.

Transient trismus, where the limited mouth opening is entirely or mainly due to the acute phase of the cause will usually resolve with the treatment of the cause plus (if needed) physiotherapy. This active movement can range from jaw mobilisation exercises to the slightly medieval ‘trismus screw’ (Figure 1).

Figure 1: The mouth gag known as the trismus screw.

Chronic trismus, where the limited mouth opening persists months after the precipitating cause (if that cause had an acute phase and it has been completely treated) has been dealt with, or where the trismus is the only sign and symptom of the cause (for example a jaw joint disorder), will be best managed on a ‘shared care’ basis. This means that the benefits of any intervention must be very carefully balanced against potential risks or the impact of treatment. While this is true in all medical problems, it is particularly important in this condition where only a few millimetres of additional movement may be considered a success by the individual suffering from it and a relative failure by the surgeon, or the other way round.  

On the following pages we will consider types of treatment available and their most relevant indications.

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