Prevalence of trismus in patients with head and neck cancer: A systematic review with meta-analysis.

BACKGROUND: The purpose of this systematic review and meta-analysis was to determine the prevalence of trismus in patients with head and neck cancer. METHODS: Four electronic databases were searched: Cochrane Library, MEDLINE, EMBASE, and Web of Science up to April 2018. Level of evidence was assessed based on Oxford Centre for Evidence-based Medicine. Publications were restricted to prospective cohort studies (n = 15), randomized clinical trials (n = 3), and cross-sectional studies (n = 5) reporting on trismus as mouth maximum opening less than or equal to 35 mm in the English language. RESULTS: A total of 636 abstracts were reviewed for inclusion. Twenty-three studies were included in qualitative analysis and 15 studies in meta-analysis. The results included 2786 patients with head and neck cancer treated with surgery, radiotherapy, and/or chemotherapy either alone or in combination. Based on meta-analyses, the weighted average prevalence of trismus increased from 17.3% at baseline (95% confidence interval [CI], 10.8%-26.5%) to a peak of 44.1% at 6 months (95% CI, 36.7%-51.8%) and decreased to 32.1% at 12 months (95% CI, 27.2%-37.4%) and continued in average 32.6% at 3-10 years (95% CI, 22.0%-45.3%). CONCLUSIONS: Having a primary site of the oral cavity or oropharynx was associated with a higher risk for developing trismus based on individual studies. Prospective cohort studies or randomized controlled trials with multiple objective trismus measurements, evaluation of disease characteristics, and treatment variables are needed to further investigate the prevalence of trismus secondary to head and neck cancer treatment.

Acidic beta-galactosidase in the developing mouse submandibular gland.

Acidic beta-galactosidase (beta-gal) is expressed at high concentrations in the salivary glands, where its function is unknown but probably related to lysosomal catabolism of glycolipids or glycoproteins such as mucin. Here, the developmental pattern of the enzyme activity in the submandibular gland of B10A/SGSNJ mice was investigated in relation to the expression of mucin. Biochemical studies indicated that the activity of acidic beta-gal increases significantly from birth to 3 weeks of age (P<0.05). Histochemical staining of the submandibular glands of embryonic day 15 (E15), E18, 3-week-old and adult mice showed a trend of increasing staining intensity accompanied by a change in the cellular distribution of enzyme activity from E15 to adulthood. Acidic beta-gal activity was first evident at E18, around the time mucin production starts, primarily in terminal-bud epithelial cells. The spatial and temporal coordination between the appearance of beta-gal and embryonic mucin in the terminal buds of acinar cells might be related to a role of this enzyme in lysosomal degradation of embryonic mucin. In contrast, in adult mice, beta-gal activity was primarily found in granular-duct cells. The function of beta-gal in duct cells is unclear, but the change in the cellular distribution of beta-gal in the mouse submandibular gland could reflect a change in the substrate specificity of this enzyme between E18 and adulthood.