Amplification, Resistance, and Kinetics of the Jaw Stretching Device (ARK-JSD): analysis of the force variation and implications for trismus therapy

Emma Charters; Kai Cheng; Masako Dunn; Aaron Luo; Y M Aung; Will Lewin; Jonathan R Clark

doi:10.1007/s10006-024-01218-1

Amplification, Resistance, and Kinetics of the Jaw Stretching Device (ARK-JSD): analysis of the force variation and implications for trismus therapy

Oral Maxillofac Surg. 2024 Feb 6. doi: 10.1007/s10006-024-01218-1. Online ahead of print.

Authors

Emma Charters^{1

2}, Kai Cheng^{3

4}, Masako Dunn³, Aaron Luo⁴, Y M Aung³, Will Lewin^{5

6}, Jonathan R Clark^{3

4

7}

Affiliations

¹ Department of Head and Neck Surgery, Chris O'Brien Lifehouse, 119-143 Missenden Road, Camperdown, Sydney, NSW, 2050, Australia. Emma.Charters@lh.org.au.
² Faculty of Medicine and Health, Sydney School of Health Sciences, The University of Sydney, Camperdown, Sydney, NSW, 2006, Australia. Emma.Charters@lh.org.au.
³ Department of Head and Neck Surgery, Chris O'Brien Lifehouse, 119-143 Missenden Road, Camperdown, Sydney, NSW, 2050, Australia.
⁴ Sydney Local Health District, Royal Prince Alfred Institute of Academic Surgery, Camperdown, Sydney, NSW, 2050, Australia.
⁵ Sarcoma and Surgical Research Centre, Chris O'Brien Lifehouse, Camperdown, Sydney, NSW, 2050, Australia.
⁶ Biomedical Innovation, Chris O'Brien Lifehouse, Camperdown, Sydney, NSW, 2050, Australia.
⁷ Faculty of Medicine and Health, Sydney Medical School, The University of Sydney, Anderson Stuart Building, Camperdown, NSW, 2006, Australia.

PMID: 38319397
DOI: 10.1007/s10006-024-01218-1

Abstract

Purpose: Jaw-stretching devices, including the Amplification, Resistance, and Kinetics of the Jaw (ARK-JSD), are an effective option for treating trismus after head and neck cancer (HNC) treatment. The force, however, that is applied to the patient's jaw is unknown.

Methods: Ten ARK-JSD devices were constructed for each of the levels of resistance (total of 30 samples). Each sample was tested using a Universal Testing Machine (UTM).

Results: The easy, medium, and hard ARK-JSD had a mean maximum force of 12.3, 21.0, and 32.7 Newtons (N) at a mean interincisal distance (IID) of 8.0 mm, 13.0 mm, and 16.0 mm, respectively. The force varied by 6.9 N for the easy and 24.1 N for the hard ARK-JSD. Fatigue analysis demonstrated up to 5.5 N loss of force over 10 weeks.

Conclusion: The ARK-JSD is a low-cost trismus device that can force between 12.3 and 32.7 N. The variation in resistance may impact efficacy. Understanding this variation will assist clinicians and patients using the ARK-JSD for trismus therapy.

Keywords: Head and neck cancer; Medical devices; Oral cancer; Trismus.