Pooja Swami

Background: Slide tracheoplasty and end‐to‐end anastomosis are two common reconstructive techniques for airway stenosis. While slide tracheoplasty is often preferred for its larger luminal diameter and reduced anastomotic tension, its mechanical integrity relative to end‐to‐end repair remains incompletely characterized. This study aimed to compare tensile strength and elastic properties between the two repair techniques in an ex vivo porcine model. Methods: Porcine tracheas were harvested, bisected, and reattached using either end‐to‐end anastomosis or slide tracheoplasty. Tensile testing was performed to a maximum load of 45 N using a uniaxial testing system. Load at failure, stress–strain behavior, and Young's modulus were calculated. Survival analysis was performed using the log‐rank test to compare construct integrity between groups. Negative and positive pressure testing was performed. Results: Seventy‐five percent of slide tracheoplasty samples failed under tension, with a median failure load of 32.96 N, whereas none (0%) of the end‐to‐end repairs failed within the 45 N test limit ( p = 0.0401). At equivalent strain, slide tracheoplasty constructs demonstrated lower stress compared with end‐to‐end anastomoses. Young's modulus was similarly reduced in the slide group. Conclusion: Slide tracheoplasty constructs demonstrated lower tensile strength and stiffness than end‐to‐end repairs, suggesting that the redistribution of mechanical forces across a larger surface area reduces localized stress but limits overall load‐bearing capacity. This broader force dispersion may protect the anastomotic site from focal tension and dehiscence but results in susceptibility to elongation or deformation under chronic strain. These mechanical considerations are important for surgeons when selecting a repair technique and ensuring long‐term postoperative airway stability. Level of Evidence: N/A.

Introduction Despite efforts to use scaffolds to treat meniscus tears, minimal progress has been made in facilitating meniscus regeneration and return of function. Our research objective was to develop a meniscus repair and regeneration implant by applying a resorbable scaffold in combination with cells and growth factors. We report here the results of using platelet-rich plasma (PRP) as a source of growth factors to induce fibrochondrogenic differentiation of human adipose-derived mesenchymal stem cells (hADSC) in a three-dimensional (3D) Type I collagen-based scaffold in vitro. Methods Scaffold Preparation. Type I collagen scaffolds were prepared following a protocol previously published. Two different densities of scaffolds, high density (HD) and low density (LD), were produced for in vitro study. hADSC and PRP Preparation. hADSCs were cultured to the fifth passage to reach the desired number for experimentation. PRP was collected from human blood and activated. Cell Culture Procedure. Effects of PRP on hADSC proliferation and differentiation into fibrochondrogenic cells were examined in four scaffold groups: LD, HD, LD+PRP and HD+PRP. hADSCs were seeded onto scaffolds (n=5) at a concentration of 2 × 106 cells/scaffold. 1% of PRP was added to the experimental media. Cellular proliferation was assessed at 1, 7, 14, and 21 days. Differentiation was measured using qRT-PCR on Days 14 and 21. qRT-PCR analysis of gene expression was completed with primers for COLLAGEN 1 and AGGRECAN. Data Analysis. ANOVAs were conducted (two-tailed tests) at the .05 significance level. Results Cellular proliferation of hADSCs seeded on each scaffold increased over time. Similar trend was observed for cells seeded on HD scaffolds with and without PRP. hADSC showed significant increase in cellular proliferation on the LD scaffolds at Days 1 and 7. At Day 21, PRP treatment and LD scaffold had a synergistic positive effect on Type I collagen gene expression. PRP did not elevate type I collagen gene in the HD group, the HD scaffold alone had the same level of type I collagen gene expression as LD+PRP. Aggrecan expression was elevated in the presence of PRP in both the HD and LD scaffold groups, indicating enhanced fibrochondrogenic differentiation of hADSCs. Effective cell infiltration was observed across both HD and LD scaffolds with and without PRP treatment. HD scaffolds displayed larger cell clusters and more extensive cell migration over time compared to LD scaffolds. However, LD scaffolds resulted a more uniform cellular distribution than HD scaffolds. Conclusion Our study demonstrates that PRP can play an important role in directing hADSCs towards fibrochondrogenic differentiation in Type I collagen-based scaffolds in vitro. Additionally, our study shows that collagen scaffold density can influence the spatial distribution and cellular behavior of infiltrated cells.