Trismus – Restrictive Mouth opening

Introduction: Trismus is a painful condition in which there is restricted mouth opening.

Pathology: The masticator muscles (Chewing Muscles) of the jaw become contracted, inflamed preventing the mouth from opening fully. Or the elastic mucosa gets fibrosed loosing elasticity to allow mouth opening.

Degree of trismus: Mouth opening between 3.5 cm to 5.5 cm is considered normal. In order words around 3 fingers should go into the mouth in vertical position. For fully normal average Indian, mouth opening is found to be 4 fingers.

Consequences of inadequate mouth opening (trismus)

1. Feeding – the person will have difficulty in taking large bites like rasagolla or panipuri.
2. Difficulty in Swallowing
3. Poor oral hygiene – oral cleaning is inadequate causing foul smell and inflammation in the mouth. Poor dental hygiene with increase risk of caries
4. Difficulty in speaking – many individual experience loss of words and are not able to communicate well because of restrictive mouth opening
5. Tingling sensation and hypersensitivity to certain foods and spices.

Common Causes – Trismus occurs due to damage or injury to mucosa or the masticator muscles due to:

1. Submucosal fibrosis due to paan masala and tobacco chewing – the main ingredient is the beetle nut also known as areca nut.
2. Trauma – due to jaw bone fracture
3. Oral Surgery – injury of the muscles due to hyperextension or stretch on the muscle for mouth opening for the procedure
4. Wisdom tooth extraction – mostly the lower last molars.
5. Mandibular joint with skull bone (temporomandibular joint) dysfunction – This joint is very special as it allows many different movement of the jaw like sliding, rotation, side to side etc. The joint may get affected by trauma, arthritis, habitual clenching and grinding of teeth due to stress, and genetics.
6. Radiation to head and neck – most who receive radiation to head and neck would have trismus. This is due to radiation can affect the temporomandibular joint, the masticator muscles – pterygoids and masseter causing inflammation and fibrosis. The risk of trismus increases with the dose of radiation.
7. Painful ulcers of oral cavity – buccal mucosa may also cause trismus
8. Cancer – ulcers or nodules of the buccal mucosa can lead to trismus by itself
9. Mucosa surgery – for cancer or PML or otherwise heals with scar formation restricting the mouth opening.
10. Partial skin grafting of the mucosa following surgery – especially when whole of the buccal mucosa from upper to lower BG sulcus is involved, or when buccinator muscle is removed.
11. Inadequate flap – the dimensions where inadequate at the beginning or if the flaps get partial necrosis which heals with fibrosis.

Diagnosis and Grading: The diagnosis is based on the mouth opening of the person. The measurement is made between the front teeth of the upper and lower jaws. The measurement can be done with TrisCaRe which is an instrument with measurement scale.

Grading of Trismus: Trismus was graded as mild/grade I (35–26 mm), moderate/grade II (25–16 mm), and severe/grade III (15-0 mm)

For a complete diagnosis assessment is made by the doctor. The doctor would take the history of onset and cause assessment. Following which a clinical examination is done. Radiological examination may be advised as per the requirement.

Treatment:

1. Cause – if it is due to tobacco and beetle nuts, the patient is referred to the Tobacco Cessation Intervention specialist to treat the patient for the tobacco disease. Visit www.icancare.in/quittobacco or call 011-430-77695 for seeking professional help for quitting tobacco and smoking.
2. Mechanical Device (TRISCARE) – TrisCaRe is the optimum device for jaw stretching. TrisCaRe is to be fitted between the upper and lower jaw and the blades are opened with the screw. Jaw stretching with mechanical device is the one and the only way one can ensure mouth opening of a patient with trismus. Studies have shown that mechanical jaw stretching can increase mouth opening by 5-10 mm or more even in severest of form of trismus.
3. Medicines – painkillers, anti-inflammatories and muscle relaxants may be given as per the need. If there is suspicion of infection appropriate antibiotics may be advised.
4. Massages and exercises – two or three times a day. Advised to do massaging and exercise as follows:
   1. Massage – the painful area in circular motion with your fingers for 30 seconds.
   2. Right and left Jaw movement – move your jaw to right and left. Hold at each position for 30 seconds
   3. Circular movement of the jaw – make circular movements of the jaw in left direction and then in right direction repeat each circular motion for 5 times.
   4. Stretch open your mouth little more than what you are comfortable. Hold for 30-60 seconds
   5. Head movement – flex your neck with chin onto your chest, then bring your head back. Now move your head left and then to right. Hold in each position for 30 seconds. Finally, move the head in a circular motion clockwise and anticlockwise 5 times each.

Conclusion –  Trismus may be acute(temporary) or Chronic depending on the cause. Acute responds well to medications and exercises. The chronic long standing needs long term intervention with lifelong use of TrisCaRe. For all patients undergoing surgery or radiation for cancers early intervention with TrisCaRe is advised to avoid or reduce the permanent trismus. Early intervention helps for a better outcome.

(The Author – Dr. Pawan Gupta M.Ch. is Director of Surgical Oncology at Max Super Speciality Hospital, Vaishali. Patparganj and Noida. He is author the book – Win Over Tobacco Made Easy, Be Smart Do Not Start and is highly recognized for his work on Oral Cancer and Tobacco Cessation. He is the convenor for Certified Course in Tobacco Cessation under the Gujarat University)