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1352 - Unlocking New Possibilities: Botox’s Emerging Role in Managing Trismus in a Tonsillar Cancer Patient

Thursday, February 27, 2025

5:00 PM - 6:30 PM MST

Presenting Author(s)

GA

Gary B. Allen, MD

Resident Physician
Vanderbilt University Medical Center
Nashville, Tennessee, United States

Co-Author(s)

KG

Kevin Gilbert, MD

Resident
Vanderbilt Stallworth Physical Medicine & Rehabilitation
Nashville, Tennessee, United States
CK

Cristina Kline-Quiroz, DO

Assistant Professor
Department of Physical Medicine & Rehabilitation
Nashville, Tennessee, United States

Case Diagnosis: Severe Trismus due to Radiation Fibrosis Syndrome

Case Description: A 58-year-old male with a history of tonsillar squamous cell carcinoma status post tonsillectomy, chemotherapy, and radiation, treated 14 years prior, presented with severe trismus as a late effect of cancer treatment. On initial evaluation, his maximal inter-incisal opening was 10 mm, severely limiting his oral function and quality of life. The patient reported difficulty in eating, speaking, and maintaining oral hygiene. A multidisciplinary treatment plan was initiated, including regular jaw stretching exercises and botulinum toxin injections to the masseter and temporalis muscles. After one month, his maximal inter-incisal opening increased to 32 mm, and the patient reported reduced pain and improved ability to perform daily activities involving oral function. Improvement waned over 3-4 months, but he experienced similar response with repeat injections.

Discussions: Trismus, characterized by a restricted ability to open the mouth, is a common late effect of treatments for head and neck cancer survivors (HNC). It can severely impact a patient’s quality of life by limiting essential functions such as eating, speaking, and maintaining oral hygiene. Trismus in HNC survivors is a potential clinical manifestation of the late effects of radiation fibrosis syndrome involving nerve and muscle injury with ectopic activity, fibrosis and fibroblastic proliferation in the muscles and tissues involved in mastication. Current evidence suggests that botulinum toxin (Botox) can be effective in reducing pain and muscle spasms associated with trismus. However, its effectiveness in improving jaw opening remains under-researched. In this case, the patient’s response to Botox injections, combined with regular jaw stretching exercises, supports the need for further studies to evaluate the efficacy of Botox for severe trismus.

Conclusions: This case highlights the potential of botulinum toxin in managing trismus in HNC patients. Further prospective studies are needed to confirm the effectiveness and broader applicability of Botox for trismus.