Development of a Bioinspired, Self-Adhering, and Drug-Eluting Laryngotracheal Patch.

OBJECTIVES/HYPOTHESIS: Novel laryngotracheal wound coverage devices are limited by complex anatomy, smooth surfaces, and dynamic pressure changes and airflow during breathing. We hypothesize that a bioinspired mucoadhesive patch mimicking how geckos climb smooth surfaces will permit sutureless wound coverage and also allow drug delivery. STUDY DESIGN: ex-vivo. METHODS: Polycaprolactone (PCL) fibers were electrospun onto a substrate and polyethylene glycol (PEG) - acrylate flocks in varying densities were deposited to create a composite patch. Sample topography was assessed with laser profilometry, material stiffness with biaxial mechanical testing, and mucoadhesive testing determined cohesive material failure on porcine tracheal tissue. Degradation rate was measured over 21 days in vitro along with dexamethasone drug release profiles. Material handleability was evaluated via suture retention and in cadaveric larynges. RESULTS: Increased flocking density was inversely related to cohesive failure in mucoadhesive testing, with a flocking density of PCL-PEG-2XFLK increasing failure strength to 6880 ± 1810 Pa compared to 3028 ± 791 in PCL-PEG-4XFLK density and 1182 ± 262 in PCL-PEG-6XFLK density. The PCL-PEG-2XFLK specimens had a higher failure strength than PCL alone (1404 ± 545 Pa) or PCL-PEG (2732 ± 840). Flocking progressively reduced composite stiffness from 1347 ± 15 to 763 ± 21 N/m. Degradation increased from 12% at 7 days to 16% after 10 days and 20% after 21 days. Cumulative dexamethasone release at 0.4 mg/cm2 concentration was maintained over 21 days. Optimized PCL-PEG-2XFLK density flocked patches were easy to maneuver endoscopically in laryngeal evaluation. CONCLUSIONS: This novel, sutureless, patch is a mucoadhesive platform suitable to laryngeal and tracheal anatomy with drug delivery capability. LEVEL OF EVIDENCE: NA Laryngoscope, 131:1958-1966, 2021.

Impact of a Surgical Sealing Patch on Lymphatic Drainage After Axillary Dissection for Breast Cancer: The SAKK 23/13 Multicenter Randomized Phase III Trial.

BACKGROUND: Several studies and a meta-analysis showed that fibrin sealant patches reduced lymphatic drainage after various lymphadenectomy procedures. Our goal was to investigate the impact of these patches on drainage after axillary dissection for breast cancer. METHODS: In a phase III superiority trial, we randomized patients undergoing breast-conserving surgery at 14 Swiss sites to receive versus not receive three large TachoSil® patches in the dissected axilla. Axillary drains were inserted in all patients. Patients and investigators assessing outcomes were blinded to group assignment. The primary endpoint was total volume of drainage. RESULTS: Between March 2015 and December 2016, 142 patients were randomized (72 with TachoSil® and 70 without). Mean total volume of drainage in the control group was 703 ml [95% confidence interval (CI) 512-895 ml]. Application of TachoSil® did not significantly reduce the total volume of axillary drainage [mean difference (MD) -110 ml, 95% CI -316 to 94, p = 0.30]. A total of eight secondary endpoints related to drainage, morbidity, and quality of life were not improved by use of TachoSil®. The mean total cost per patient did not differ significantly between the groups [34,253 Swiss Francs (95% CI 32,625-35,880) with TachoSil® and 33,365 Swiss Francs (95% CI 31,771-34,961) without, p = 0.584]. In the TachoSil® group, length of stay was longer (MD 1 day, 95% CI 0.3-1.7, p = 0.009), and improvement of pain was faster, although the latter difference was not significant [2 days (95% CI 1-4) vs. 5.5 days (95% CI 2-11); p = 0.2]. CONCLUSIONS: TachoSil® reduced drainage after axillary dissection for breast cancer neither significantly nor relevantly.

Management of heat in laser tissue welding using NIR cover window material.

BACKGROUND: Laser tissue welding (LTW) is a novel method of surgical wound closure by the use of laser radiation to induce fusion of the biological tissues. Molecular dynamics associated with LTW is a result of thermal and non-thermal mechanisms. OBJECTIVES: This research focuses exclusively on better heat management to reduce thermal damage of tissues in LTW using a near infrared laser radiation. METHODS: An infrared continuous-wave (CW) laser radiation at 1,450 nm wavelength corresponding to the absorption band from combination vibrational modes of water is used to weld together ex vivo porcine aorta. RESULTS: In these studies we measured the optimal laser power and scan speed, for better tensile strength of the weld and lesser tissue dehydration. Significant amount of water loss from the welded tissue results in cellular death and tissue buckling. Various thermally conductive optical cover windows were used as heat sinks to reduce thermal effects during LTW for the dissipation of the heat. The optimal use of the method prevents tissue buckling and minimizes the water loss. Diamond, sapphire, BK7, fused silica, and IR quartz transparent optical cover windows were tested. CONCLUSIONS: The data from this study suggests that IR-quartz as the material with optimal thermal conductivity is ideal for laser welding of the porcine aorta.