Manual Therapy beneficial in survivors of head and neck cancer with radiation associated trismus: JAMA

Trismus, defined as the inability to fully open the mouth, is a common oral morbidity associated with head and neck cancer (HNC) therapy. After xerostomia, trismus was reported as the second most burdensome morbidity for survivors of HNC. Radiation-related trismus is often attributed to fibrosis, scar tissue formation, nerve damage, muscle atrophy, or a combination thereof, thus restricting the muscles of mastication. Associated deficits have physical, psychosocial, and safety implications, affecting function such as swallowing (difficulty with food insertion, biting, chewing, oral transfer), communication (voice, resonance, and speech), and oral access (dental restoration/examination, oral intubation, hygiene, emesis).

Manual therapy (MT) is an umbrella term for soft tissue mobilization techniques that uses physical and movement related manipulations of the body. Manual therapy encompasses various techniques, including manual lymphatic drainage, myofascial release, massage, and passive and active stretching. These techniques apply variable amounts of pressure and stretch connective tissue and joints to restore fluid transport and range of motion. Manual therapy techniques improve circulation, reduce local ischemia, stimulate proprioception, decrease muscle spasms and adhesions, and improve MIO in patients with temporomandibular joint disorders.

A study by Holly McMillan et al aimed to demonstrate that MT can be considered either as a frontline or adjuvant treatment for radiation induced trismus. The purpose of this study was to estimate effect size of MT to increase MIO in the setting of radiation associated trismus, specifically after a single session and serial sessions, and explore factors associated with response to MT in the treatment of radiation-associated trismus.

This retrospective case series was conducted at the University of Texas MD Anderson Cancer Center between 2016 and March 2020 (before COVID-19 interruption) and included 49 disease-free survivors of HNC who were referred for treatment of radiation-associated trismus.

A total of 49 survivors of HNC (13 women [27%]; 24 [49%] 64 years or younger; 25 [51%] 65 years or older; mean [range] of 6.6 [0-33] years postradiotherapy were included, 9 [18.4%] of whom underwent a single MT session; 40 [81.6%] who underwent multiple sessions [mean, 6; median (range), 3 (2-48)]). The MIO improved after a single session by a mean (SD) of 4.1 (1.9) mm (0.45 effect size) and after serial MT sessions by a mean (SD) of 6.4 (4.8) mm with an effect size of 0.7. No covariates were found to be clinically meaningfully associated with MIO improvement following MT.

Clinical response to MT as a frontline or adjuvant treatment for radiation-associated trismus is unknown. This case series, mostly comprising patients with moderate to severe radiation-associated trismus, found clinically meaningful improvement in MIO with a moderate 0.45 effect size after a single session of MT and a large 0.7 effect size exceeding MCID after serial MT sessions.

In this case series study, following treatment with MT, oral opening increased an average of 4.1mm (95% CI, 4-5) after a single session and 6.4mm (95% CI, 5-8) after serial MT sessions in patients with radiation-associated trismus. The largest increase in oral opening was achieved after the initial treatment; however, oral opening may continue to improve with serial treatment. Risk factor analyses suggest that even patients who have been traditionally considered treatment-refractory and are 5 years or longer posttreatment with coexisting morbidities, advanced disease, and/or received aggressive oncology treatment have the potential to benefit from treatment with MT. Partial and full compliance with an HEP likely improves MIO gains. Increased oral opening has the potential to improve swallow function, speech, pain, and quality of life; however, more research is needed to determine effect of oral opening and these functional outcomes. Based on these findings, MT may potentially be considered as a frontline treatment modality to improve oral opening quickly as a noninvasive method or adjuvant treatment to improve trismus outcomes.

Source: Holly McMillan; Carly E. A. Barbon; Richard Cardoso; JAMA Otolaryngol Head Neck Surg.

doi:10.1001/jamaoto.2022.0082

Trismus, defined as the inability to fully open the mouth, is a common oral morbidity associated with head and neck cancer (HNC) therapy. After xerostomia, trismus was reported as the second most burdensome morbidity for survivors of HNC. Radiation-related trismus is often attributed to fibrosis, scar tissue formation, nerve damage, muscle atrophy, or a combination thereof, thus restricting the muscles of mastication. Associated deficits have physical, psychosocial, and safety implications, affecting function such as swallowing (difficulty with food insertion, biting, chewing, oral transfer), communication (voice, resonance, and speech), and oral access (dental restoration/examination, oral intubation, hygiene, emesis).