MATERIALS AND METHODS: A dedicated, anonymized database was established in 2012 with a minimum eighteen-month follow up set for this report. Internationally validated self- and observer-reported measures were recorded preoperatively and at six, 12 and, 18 months together with demographics, diagnoses, and operative details.
RESULTS: A total of eight patients with a median age of 46 (37-54) underwent excision of vagal paraganglioma (five) and schwannoma (three) with few mild complications. Three underwent selective and five non selective reinnervation. Seven out of eight patients underwent synchronous injection medialization. The voice handicap index (VHI-30) improved from a baseline median 83 (range 52-102) to 7.5 (5-58) at 18 months; maximum phonation time improved from median 8 (range 5-15) to 10.5 (8.5-11); voice grade ("G" in grade, roughness, breathiness, asthenia, and strain [GRBAS] scoring) improved from median three (severe impairment, range 0-3) to one (mild impairment, 0-2); Eating Assessment Tool (EAT-10) score improved from median 12 (range 3.5-27) preoperatively to one (0-16); and reflux symptom index (RSI) improved from median 25 (range 17-36) to 7 (0-36). One patient exhibited no discernible reinnervation, while the remainder exhibited good cord bulk and tone, though without purposive abduction.
CONCLUSION: Delayed laryngeal reinnervation for high vagal paralysis is a safe technique associated with good voice and swallowing outcomes by 12-18 months. Potential confounders in this small series and the absence of a control arm both limit conclusions, but this study suggests that further prospective, controlled studies, and/or case registration are merited.
METHODS: To verify this hypothesis, a computational model was developed to simulate the thermochemical processes involved during TCA with sequential injection. Four major processes that take place during TCA were considered, i.e., the flow of acid and base, their neutralisation, the release of exothermic heat and the formation of thermal damage inside the tissue. Equimolar acid and base at 7.5 M was injected into the tissue intermittently. Six injection intervals, namely 3, 6, 15, 20, 30 and 60 s were investigated.
RESULTS: Shortening of the injection interval led to the enlargement of coagulation volume. If one considers only the coagulation volume as the determining factor, then a 15 s injection interval was found to be optimum. Conversely, if one places priority on safety, then a 3 s injection interval would result in the lowest amount of reagent residue inside the tissue after treatment. With a 3 s injection interval, the coagulation volume was found to be larger than that of simultaneous injection with the same treatment parameters. Not only that, the volume also surpassed that of radiofrequency ablation (RFA); a conventional thermal ablation technique commonly used for liver cancer treatment.
CONCLUSION: The numerical results verified the hypothesis that shortening the injection interval will lead to the formation of larger thermal coagulation zone during TCA with sequential injection. More importantly, a 3 s injection interval was found to be optimum for both efficacy (large coagulation volume) and safety (least amount of reagent residue).