Radiation Fibrosis and Trismus

Incidence: 35-55% of patients develop trismus, highest for patients of oral and nasal cancer. Incidence increases significantly with higher radiation or after second courses of radiation therapy.

Progression: Dramatic losses begin in the first 3 to 12 months AFTER radiation, with continuing loss for 24-48+ months.

Prevention: Trismus can be very difficult to treat, especially when caused by radiation. Preventing its development is imperative for the long-term functionality and quality of the patients recovery.
Therapy and stretching are less effective in treating radiation induced trismus after it has occurred.
Trismus (<35mm MIO) at discharge of radiation therapy is strong predictor of trismus at 6 months.
Preventative early rehabilitation can reduce incidence (by 40%) and severity (by 60%) of trismus.

Trismus Therapy Expectations:

Prevention and treatment of radiation induced trismus depends on patient’s commitment to rehabilitation. Radiation fibrosis is progressive and very difficult to rehab, so prevention is preferable.  Therapy is provided by jaw motion rehab systems like the OraStretch press.

Pain: Patients may experience dull pain in first days of beginning therapy. Like soreness after a new workout. No sharp pain.

Patients will often see post-stretching increases of 1-4 mm immediately after therapy.  Over time, they can achieve long-term increases of 1-2 mm overall ROM, per week.  These are approximate estimates. Not possible for all patients. Results will vary. 

Complications of Radiation Induced Fibrosis and Trismus:

• Reduced Oral Hygiene and Saliva promote dental decay and integrity of mandible.
• Disruption of Cancer Treatments
• Compromised Airway, Aspiration
• Reduced Quality of Life:
• Voice, Speech problems (68%)
• Difficulty Sneezing, Laughing
• Reduced social interaction
• Dysphagia, Eating, drinking (65-73%)
• Malnutrition and Dehydration
• Reduced Oral Access, for:
• Dentures/Prosthetics
• Dental Procedures
• Medical Procedures, Intubation
• Joint Immobilization (oral cancer 73%):
• Muscle contracture and atrophy
• Muscle and joint degradation
• Inflammation, pain, fatigability.