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Objectives/Hypothesis: To define normative amplitude and latency of vagus, recurrent laryngeal nerve (RLN), and external branch of superior laryngeal nerve (EBSLN) and to apply them to postoperative neural function documentation. To our knowledge, this is the first study to report electrophysiologic characteristics of all three nerves in a consecutive patient series.Study Design: Prospective.Methods: Quantitative analysis of evoked waveform data was performed on both sides in consecutive patients undergoing thyroid surgery by a single surgeon. Mean values, standard error of mean, and standard deviation were calculated for latency (in milliseconds) and amplitude (in microvolts) of the vagus nerves, RLN, and EBSLN. Pre-and postoperative vocal cord function was normal in all patients.Results: Normative latency analysis showed mean right and left vagal latency of 5.47 ms (60.73) and 8.14 ms (60.86), respectively (P <.0001). Pooled RLN latency was 3.96 ms (60.69), and pooled EBSLN latency was 3.56 ms (60.49), both significantly shorter than vagal latencies (P <.0001). There was no association between amplitude and latency parameters and tumor-size (> or <5 cm), body mass index (> or <25), age (> or <50 years), gender, or degree of neural dissection.Conclusions: The unique right vagus, left vagus, and RLN latencies are characteristic of the individual nerves and allow identification (through the characteristic waveform latency) of an intact left or right vagus/RLN system. Timed recording of vagal waveform after thyroid lobectomy consequently documents intact ipsilateral vagal-RLN neural circuit and may be placed into the medical record as electrophysiologic documentation of existence of postresection complete neural integrity.

Background: Head and neck (H&N) squamous cell carcinoma (SCC) is a significant contributor to worldwide mortality and morbidity. Human papillomavirus (HPV) has been linked with H&N cancer and HPV-positive H&N SCC have been shown to have better survival outcomes.Objective: To evaluate the effect of human papillomavirus (HPV) on laryngeal carcinoma (LSCC) survival outcomes and prognosis.Method: A systematic review and meta-analysis were performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. LSCC was confirmed based on histopathology, and HPV status was confirmed by either polymerase chain reaction, immunohistochemistry, and/or in-situ hybridization.Results: There were 1214 studies which were identified, of which 14 studies were eligible for our review. A total of 2,578 cases of LSCC were included in analysis with 413 (16.0%) HPV-positive. Overall survival (OS) was not significant for HPV-positive LSCC in first five years (year one: OR 1.44 p=0.13; year two: OR 1.24 p=0.30; year three: OR 1.01 p=0.97; year four: OR 1.13 p=0.63; year five: OR 1.01 p=0.98). Disease-free survival (DFS) was similarly not significant for HPV-positive LSCC (year one: OR 1.08 p=0.68; year two: OR 1.22, p=0.31; year three: OR 1.13, p=0.69; year four: OR 0.93, p=0.80 and year five: OR 1.42, p=0.30). When studies are sub-divided into global regions, Chinese studies had better HPV-positive survival compared to North American studies in year five (OR 1.84 vs OR 0.46, p=0.04).Conclusion: This is the first study of its kind to evaluate the survival impact of HPV-positive LSCC patients. Unlike oropharyngeal cancer, HPV status does not make a difference to OS or DFS in LSCC. This supports data that HPV is not a prognostic factor in squamous carcinoma of the larynx.