Figures S1-S16 and Table S1 and S2, which depict additional results (PDF) The authors declare the following competing financial interest(s): W.Z. is a co-founder of Velox Biosystems Inc., Baylx Inc., and Amberstone Biosciences Inc. J.L. has equity in Codiak BioSciences and holds the rights to multiple extracellular vesicle diagnostics and therapeutics patents.

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Objective/Hypothesis Needle electrode-based electromechanical reshaping (EMR) is a novel, ultra-low cost nascent surgical technology to reshape cartilage with low morbidity. EMR uses direct current (DC) to induce mechanical relaxation in cartilage that is first deformed into a required geometry, which in turn leads to permanent shape change. The objective of this study was to determine the effect of EMR voltage and time on the shape change of costal cartilage grafts. Study Design Electromechanical reshaping of ex vivo porcine costal cartilage. Method Graft specimens obtained from the central core of porcine costal cartilage were bent at a 90° angle with a custom jig and then reshaped via EMR. The effect of voltage (3–7 V) and application time (1–5 min) on the amount of shape change were systematically examined. Bend angles were analyzed using ANOVA (analysis of variance) and paired t-tests to determine significant reshaping times at each voltage setting. Results There is a threshold for voltage and time above which the retention of bend angle is statistically significant in treated specimens compared to the control (P<0.05). Above the threshold of 3V, shape retention initially increased with application time for all voltages tested and was then observed to reach a plateau. Shape retention was noted to be greatest at 6V without a rise in temperature. Conclusions EMR provides a novel method to bend and shape costal cartilage grafts for use in facial plastic surgery. A low voltage can reshape cartilage grafts within several minutes and without the heat generation. This study demonstrates the feasibility of EMR and brings this minimally invasive procedure closer to clinical implementation.

Importance Subglottic stenosis (SGS) is a severe, acquired, potentially life-threatening disease that can be caused by endotracheal tube intubation. Newborns and neonates are particularly susceptible to SGS owing to the small caliber of their airway. Objective To demonstrate optical coherence tomography (OCT) capabilities in detecting injury and scar formation using a rabbit model. Optical coherence tomography may provide a noninvasive, bedside or intensive care unit modality for the identification of early airway trauma with the intention of preventing progression to SGS and can image the upper airway through an existing endotracheal tube coupled with a small fiber-optic probe. Design Rabbits underwent suspension laryngoscopy with induction of of SGS via epithelial injury. This model was used to test and develop our advanced, high-speed, high-resolution OCT imaging system using a 3-dimensional microelectromechanical systems-based scanning device integrated with a fiber-optic probe to acquire high-resolution anatomic images of the subglottic epithelium and lamina propria. Setting All experiments were performed at the Beckman Laser Institute animal operating room. Intervention or Exposure Optical coherence tomography and endoscopy was performed with suspension laryngoscopy at 6 different time intervals and compared with conventional digital endoscopic images and histologic sections. Fifteen rabbits were killed at 3, 7, 14, 21, and 42 days after the induction of SGS. The laryngotracheal complexes were serially sectioned for histologic analysis. Main Outcome and Measure Histologic sections, endoscopic images, and OCT images were compared with one another to determine if OCT could accurately delineate the degree of SGS achieved. Results The rabbit model was able to reliably and reproducibly achieve grade I SGS. The real-time OCT imaging system was able to (1) identify multiple structures in the airway; (2) delineate different tissue planes, such as the epithelium, basement membrane, lamina propria, and cartilage; and (3) detect changes in each tissue plane produced by trauma. Optical coherence tomography was also able demonstrate a clear picture of airway injury that correlated with the endoscopic and histologic images. With subjective review, 3 patients had high correlation between OCT and histologic images, 10 demonstrated some correlation with histologic images, and 2 showed little to no correlation with histologic images. Conclusions and Relevance Optical coherence tomography, coupled with a fiber-optic probe, identifies subglottic scarring and can detect tissue changes in the rabbit airway to a depth of 1 mm. This technology brings us 1 step closer to minimally invasive subglottic airway monitoring in the intubated neonate, with the ultimate goal of preventing SGS and better managing the airway.