De novo tissue formation using custom microporous annealed particle hydrogel provides long-term vocal fold augmentation.

Biomaterial-enabled de novo formation of non-fibrotic tissue in situ would provide an important tool to physicians. One example application, glottic insufficiency, is a debilitating laryngeal disorder wherein vocal folds do not fully close, resulting in difficulty speaking and swallowing. Preferred management of glottic insufficiency includes bulking of vocal folds via injectable fillers, however, the current options have associated drawbacks including inflammation, accelerated resorption, and foreign body response. We developed a novel iteration of microporous annealed particle (MAP) scaffold designed to provide persistent augmentation. Following a 14-month study of vocal fold augmentation using a rabbit vocal paralysis model, most MAP scaffolds were replaced with tissue de novo that matched the mixture of fibrotic and non-fibrotic collagens of the contralateral vocal tissue. Further, persistent tissue augmentation in MAP-treated rabbits was observed via MRI and via superior vocal function at 14 months relative to the clinical standard.

A Simple and Reproducible In Vivo Rabbit Phonation Model for Glottic Insufficiency.

OBJECTIVE: The objective of this study is to describe an in vivo rabbit phonation model for glottic insufficiency that is simple and reproducible by means of unilateral transcricothyroid laryngeal muscle stimulation and high-speed video recordings of evoked phonation. STUDY DESIGN: Nonrandomized controlled animal trial. SETTING: Academic medical center. METHODS: A single operation including evoked phonation with bilateral and unilateral transcricothyroid laryngeal muscle stimulation conditions was modeled using 6 New Zealand white rabbits. The effect of stimulation method on glottic cycle, pitch, and loudness was compared. Endoscopic recordings using 5000 frames-per-second image capture technology and audiologic recordings were obtained for all phonation conditions. Primary outcome measures included means of maximum glottal area (MGA)/length pixel ratio, right and left amplitude/length pixel ratios, calculated cycle frequency, auditory recorded frequency, and maximum auditory intensity. Measurements were obtained via pixel counts using ImageJ. RESULTS: Mean MGA/length was significantly greater with unilateral, 20.30, vs bilateral, 9.62, stimulation (P = .043). Mean frequency of 479.92 Hz vs 683.46 Hz (P = .027) and mean maximum intensity of 76.3 dB vs 83.5 dB (P = .013) were significantly increased from unilateral to bilateral stimulation. There was no significant difference in mean right amplitude/length between unilateral and bilateral. CONCLUSION: The described model demonstrates a simple and reproducible means of producing glottic insufficiency due to unilateral vocal fold bowing and represents a pathway for better understanding the biomechanics and pathophysiology of glottic insufficiency due to superior laryngeal nerve injury and vocal fold immobility and offers the potential to compare treatment modalities through in vivo study.

Change in parathyroid hormone levels from baseline predicts hypocalcemia following total or completion thyroidectomy.

BACKGROUND: This study aims to identify the strongest predictor of postoperative hypocalcemia following thyroid surgery. METHODS: Study of patients who underwent total/completion thyroidectomy. No patients received postoperative calcium supplementation. Demographic and perioperative data were collected including preoperative baseline parathyroid hormone (PTH) levels, PTH levels at 30 min and 6 h post-excision, and 18 h post-excision calcium levels. RESULTS: Of 124 patients studied, 20.2% developed temporary hypocalcemia (Ca <8.5 mg/dL at 18 h post-excision). In multivariate analyses, absolute PTH levels at 30 min and 6 h post-excision as well as change in PTH from baseline at 30 min and 6 h post-excision were statistically significantly associated with postoperative hypocalcemia. Per 10 units decrease in PTH from baseline at 30 min post-excision, the risk of developing temporary hypocalcemia increases by 17%. CONCLUSION: Absolute PTH levels and change in PTH from baseline at 30 min and 6 h post-excision predict hypocalcemia after total or completion thyroidectomy.

Airway Management in Substernal Goiter Surgery.

OBJECTIVE(S): To review the experience of 3 hospitals with airway management during surgery for substernal goiter and identify preoperative factors that predict the need for advanced airway management techniques. METHODS: A retrospective chart review between 2009 and 2017 of patients with substernal goiter treated surgically at 1 of 3 hospitals was performed. RESULTS: Of the 179 patients included in the study, 114 (63.7%) were female, the mean age was 55.1 years (range 20-87). Direct laryngoscopy or videolaryngoscopy was successful in 162 patients (90.5%), with fiberoptic intubation used for the remaining 17 patients. Thirty-one patients (17.4%) required >1 intubation attempt; these patients had larger thyroids (201.3 g, 95% CI 155.3-247.2 g) than those intubated with 1 attempt (144.7 g, 95% CI 127.4-161.9 g, P = .009). Those who required >1 attempt had higher BMI (38.3, 95% CI 34.0-42.6 vs. 32.9, 95% CI 31.5-34.3, P = .02). Mallampati score was found to be a predictor of >1 attempt, though tracheal compression and tracheal shift were not found to be predictors of >1 attempt, nor was the lowest thyroid extent. BMI was the only independent factor on multivariable logistic regression of needing >1 attempt (odds ratio 1.056, 95% CI 1.011-1.103, P = .015). CONCLUSIONS: The majority of patients undergoing surgery for substernal goiter can be intubated routinely without the need for fiberoptic intubation. Thyroid-specific factors such as lowest thyroid extent and mass effect of the gland on the trachea do not appear to be associated with difficult intubation, whereas classic patient factors associated with difficulty intubation are. LEVEL OF EVIDENCE: VI.