Correlating muscle resection with functional swallow outcomes: An anatomic framework informed systematic review of the literature

Objective To perform a systematic review of studies reporting swallow-associated outcomes in patients who received surgery for head and neck cancer (HNC), informed by an anatomic and physiologic framework of pharyngeal phase of swallowing (Pearson's dual-sling model). Methods PUBMED and Google Scholar databases were searched for peer-reviewed papers published between 1990 and 2019 using relevant MeSH terms. Exclusion criteria were 1) discussions comparing reconstruction techniques, 2) case-report/series (n < 10), 3) perspective articles, 4) papers comparing objective instrumental methods of swallowing evaluation, 5) animal/cadaver studies, 6) no instrumental or validated swallow assessment tools used, 7) papers that discuss/include radiotherapy treatment, 8) systematic reviews, 9) papers that discuss swallow training or rehabilitation methods. Two investigators reviewed papers meeting inclusion/exclusions criteria. Muscles resected, anatomic resection site, swallow outcomes, and patient treatment variables were collected. Results A total of 115,020 peer-reviewed papers were identified. 74 papers were relevant to this review, 18 met inclusion and exclusion criteria, and none discussed surgical impact on the pharyngeal phase of swallowing using Pearson's dual-sling model. Most papers discussed the effect of tongue-base, supraglottic, or regional anatomic resection. Post-surgical resection Follow-up times ranged from 1 to 13 months. 67% of studies used objective instrumental swallow studies; 22% used patient reported outcome measures. Follow up time since surgical resection, time to feeding tube removal, feeding tube present/absent, aspiration severity were used to define dysphagia endpoints. Conclusions To date, no surgical HNC studies have used the dual-sling mechanism to guide study design, and dysphagia assessment has been inconsistent. To counsel patients on the effects of surgery on pharyngeal phase of swallow function, specialists need physiologically grounded research that correlates muscles resected with consistent measures of swallow function.