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Post-Cancer Treatment Care

Trismus After Cancer Treatment

Trismus, or difficulty opening the mouth fully, is a common complication after head and neck cancer treatment. It can interfere with eating, speaking, and oral hygiene—significantly reducing quality of life. The good news: with early recognition and consistent therapy, improvements are often achievable.

What Is Trismus?:

Trismus refers to mouth opening restricted to 35 millimeters (about two fingers’ width) or less between the upper and lower teeth (Dijkstra et al., 2006). It often arises gradually after surgery or radiotherapy for head and neck cancers.

Common Causes:

  • Radiation therapy: Leads to fibrosis (scarring and stiffness) of the chewing muscles and connective tissues (Stubblefield & Manfield, 2010).

  • Surgery: Can cause scarring near the jaw joint or removal of supporting tissues (Bensadoun et al., 2010).

  • Muscle spasm or fibrosis: May involve the jaw, neck, or throat muscles.

  • Other factors: Dental infections, temporomandibular joint (TMJ) disorders, or prolonged immobilization.

How Common Is It?:

​Trismus affects 30–40% of patients treated with radiation for head and neck cancer (Bensadoun et al., 2010; Kent et al., 2008). Risk is higher with large treatment fields, high-dose radiation, or when surgery and radiation are combined (van der Geer et al., 2018).

Why It Matters:

  • Difficulty chewing and swallowing

  • Challenges with speech

  • Poor dental hygiene and increased cavities

  • Jaw pain and fatigue

  • Reduced social interaction and emotional well-being

Treatment Options:

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Physical Therapy:

Physical therapists play a central role in managing trismus by combining manual therapy, exercise prescription, and patient education.

1. Manual Therapy

  • Mobilization of the jaw joint (TMJ) and surrounding soft tissue.

  • Myofascial release targeting tight chewing muscles (masseter, pterygoids, temporalis).

  • Scar tissue mobilization to reduce adhesions.

 

2. Stretching & Mobility Training

  • Guided jaw-opening and side-to-side stretches.

  • Integration of neck stretching to reduce radiation-induced fibrosis.

 

3. Strengthening & Motor Control

  • Exercises to maintain chewing muscle strength and coordination.

 

4. Posture & Breathing Training

  • Correcting forward head posture to reduce jaw strain.

  • Relaxation with diaphragmatic breathing.

 

5. Education & Self-Management

  • Teaching home routines with evidence-based hold times.

  • Safe device use (TheraBite®, OraStretch®).

  • Tips for incorporating exercises into daily life.

 

6. Multidisciplinary Collaboration

  • Working with speech-language pathologists, dentists, and oncologists for holistic care.

 

Research shows that structured PT-guided programs can improve mouth opening by 7–11 mm within 10 weeks to 6 months, especially when started early (Kamstra et al., 2013; Pauli et al., 2016; Karlsson et al., 2020).

Step-by-Step Self-Stretching Routine (Jaw Mobility):

Frequency: ~5–6 sessions per day
Equipment: Clean hands, tongue depressors, or a jaw stretching device

  1. Warm-up: Sit upright, relax shoulders and neck.

  2. Active mouth opening: Open gently, hold 10 seconds, relax. Repeat 5 times (Karlsson et al., 2020).

  3. Passive finger stretch: Use thumb and index finger, hold 5–10 seconds, repeat 5 times (Kamstra et al., 2013).

  4. Tongue depressor stack: Insert stacked depressors, hold 30 seconds, repeat 3–5 times (Buchbinder et al., 1993).

  5. Device-assisted stretch: Use TheraBite® or OraStretch®, hold 30 seconds, repeat 5 times (Kamstra et al., 2013).

  6. Cool-down: Gentle side-to-side and circular jaw movements.

Prognosis and Recovery:

Radiation fibrosis often stiffens neck muscles, worsening trismus (Stubblefield & Manfield, 2010). Daily stretches help maintain mobility:

  1. Neck Flexion: Chin to chest. Hold 20 seconds ×3.

  2. Neck Extension: Look up comfortably. Hold 20 seconds ×3.

  3. Side Bending: Ear to shoulder. Hold 20 seconds each side ×3.

  4. Rotation: Turn head side to side. Hold 20 seconds each side ×3.

  5. Shoulder Rolls: Roll shoulders backward 10×, forward 10×.

Neck Stretching Routine:

  • Early therapy = better outcomes: Patients starting PT during or soon after treatment achieve better results (Kraaijenga et al., 2014).

  • Short-term gains: 7–8 mm improvement in 10 weeks, often fastest in first 4–6 weeks (Kamstra et al., 2013; Pauli et al., 2016).

  • Long-term gains: 10–11 mm by 6 months, with sustained results at 3 years (Pauli et al., 2016; Karlsson et al., 2020).

  • Devices: TheraBite® users gained ~7.2 mm at 10 weeks, Dynasplint® ~7.1 mm, though regression occurs if exercises stop (Kamstra et al., 2013; Kamstra et al., 2016).

  • Chronic cases: Untreated >1 year → slower, partial progress, but still possible.

  • Maintenance: Regular stretching required to counter ongoing fibrosis (Stubblefield & Manfield, 2010).

Popular Jaw-Stretching Devices:

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Self-Management Tips:

  • Be consistent: Multiple short sessions daily are best.

  • Hydration & skin care: Helps keep tissues flexible.

  • Good posture: Reduces strain on jaw and neck.

  • Track progress: Measure opening with a ruler or finger-widths.

Scientific References:

  • Bensadoun, R. J., Riesenbeck, D., Lockhart, P. B., Elting, L. S., Spijkervet, F. K., & Brennan, M. T. (2010). A systematic review of trismus induced by cancer therapies in head and neck cancer patients. Supportive Care in Cancer, 18(8), 1033–1038.

  • Buchbinder, D., Currivan, R. B., Kaplan, A. J., & Urken, M. L. (1993). Mobilization regimens for the prevention of trismus in head and neck cancer patients. Head & Neck, 15(6), 579–582.

  • Dijkstra, P. U., Huisman, P. M., & Roodenburg, J. L. (2006). Criteria for trismus in head and neck oncology. International Journal of Oral and Maxillofacial Surgery, 35(4), 337–342.

  • Karlsson, O., Farnebo, L., & Finizia, C. (2020). Jaw exercise therapy for the treatment of trismus in head and neck cancer: A prospective three-year follow-up study. Supportive Care in Cancer, 28(2), 619–627.

  • Kamstra, J. I., Dijkstra, P. U., van Leeuwen, M., Roodenburg, J. L., & Langendijk, J. A. (2013). TheraBite exercises to treat trismus secondary to head and neck cancer. Supportive Care in Cancer, 21(4), 951–957.

  • Kamstra, J. I., et al. (2016). Dynasplint Trismus System exercise therapy for trismus secondary to head and neck cancer: A prospective study. Oral Oncology, 52, 90–95.

  • Kent, M. L., Brennan, M. T., Noll, J. L., Fox, P. C., Burri, S. H., Hunter, J. C., & Lockhart, P. B. (2008). Radiation-induced trismus in head and neck cancer patients. Supportive Care in Cancer, 16(3), 305–309.

  • Kraaijenga, S. A. C., Oskam, I. M., van der Molen, L., Hilgers, F. J., & van den Brekel, M. W. (2014). Efficacy of structured exercise therapy to prevent trismus in head and neck cancer patients: A randomized controlled trial. Oral Oncology, 50(9), 947–952.

  • Pauli, N., Johnson, J., Finizia, C., & Andrell, P. (2016). The effect of jaw exercise intervention in head and neck cancer patients with trismus: A prospective study. Supportive Care in Cancer, 24(2), 563–571.

  • Stubblefield, M. D., & Manfield, L. (2010). Clinical evaluation and management of radiation fibrosis syndrome. Physical Medicine and Rehabilitation Clinics of North America, 21(2), 289–301.

  • van der Geer, S. J., Kamstra, J. I., & Roodenburg, J. L. (2018). Predictors for trismus in head and neck cancer patients: A systematic review. Oral Oncology, 83, 76–82.

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