Amit Badhwar

Background: Absorbable scaffolds such as poly-4-hydroxybutyrate (P4HB) are increasingly used in aesthetic breast surgery to support implants. However, the nature and timing of scaffold–implant interactions during early healing remain uncharacterized. Objectives: Evaluate whether contact between P4HB Scaffolds and silicone implants can cause mechanical weaking of either device or wear-related particulate generation. Methods: Two independent studies were performed. An animal study assessed early P4HB Scaffold-tissue integration. Characteristics and histology of scaffold explants were compared to native capsules after 4 weeks in a porcine silicone implant model. A separate benchtop study evaluated scaffold and implant mechanical integrity and particulate generation after interactive cyclic loading for 12 weeks, exceeding the in vivo integration period, to conservatively evaluate interaction. Mechanical testing was performed of implants and scaffolds after interaction and compared to non-tested devices. Particulate analysis was performed on fluid collected from the bench apparatus. Results: Scaffold-tissue capsules show surface characteristics similar to native tissue capsules, indicating complete integration at 4-weeks. After 12-week benchtop loading, mechanical properties of scaffolds and implants were comparable to controls and met standard specifications for new devices. Particulates were below detection limits. Conclusions: This preclinical study evaluated early scaffold–implant interaction during the period of maximal direct polymer contact and assessed mechanical interactions under worst-case simulated conditions. By 4 weeks in animals, tissue integration limits direct polymer–implant contact. After 12 weeks on the bench, no compromise of implant or scaffold mechanical integrity or detectable particulates were observed under the tested conditions. These findings provide preliminary data and do not address long-term effects.

Background/Objectives: The porcine mammary anatomy is poorly characterized, and structures are difficult to differentiate macroscopically, unlike human mammary tissue. The objective of this exploratory study was to describe the Yucatan porcine breast tissue morphology and identify the basic differences and similarities to human breast tissue. Methods: Samples from an adult, non-parous female Yucatan pig were prepared utilizing various methods: freezing at −80 °F (−26.67 °C) with a thickness of 0.5 cm/post-fixation in formalin; freezing at −20 °F (−6.67 °C) with a thickness of 0.5 cm/post-fixation in formalin; or formalin fixed and incised at ~0.8 cm. A descriptive comparison of the gross and microscopic images of the porcine breast morphology to the previously described human breast anatomy was performed. Results: As examined grossly, frozen sections allowed narrower serial cross-sectioning and better visualization of the structures and relationships. The mammary glands were poorly demarcated with extensive interspersed adipose tissue throughout the periphery. The mammary tissue appeared grossly as pigmented tissue and extended within ~0.5 cm from the skin surface, ~2.0 cm deep (within ~0.5 cm of the deep muscle layer), and ~6.5 cm laterally (centered on a teat). There were a number of similarities between Yucatan porcine and human breast tissue, yet there were several inherent structural differences. In contrast to human mammary tissue, porcine mammary glands consist of more diffuse acinar tissue, less well demarcated by defined fascial, lamellar, and ligamentous structures. Conclusions: The Yucatan porcine mammary morphology and similarities to the human mammary region allow for the use of this animal model to guide those developing relevant technologies or performing local surgical interventions in the preclinical setting.

Background: Permanent synthetic meshes such as polypropylene (PP) have been utilized for hernia repair for decades, but concerns remain regarding potential long-term, mesh-related complications. A resorbable polymer such as poly-4-hydroxybutyrate (P4HB) represents an alternative with high initial strength, that gradually resorbs, leaving an abdominal wall that is at least as strong as it would be in its native state. We aimed to compare early wound morbidity and clinical outcomes associated with P4HB to traditional, permanent PP in umbilical and small to medium, routine ventral hernias using data from the Abdominal Core Health Quality Collaborative (ACHQC).Methods: Inclusion criteria for the umbilical cohort included: all Centers for Disease Control and Prevention (CDC) wound classes, all Ventral Hernia Working Group (VHWG) hernia grades, and hernia defects p < 0.05 in all cases).Conclusions: Short-term clinical outcomes associated with resorbable P4HB mesh are comparable to permanent synthetic PP mesh in umbilical and small to medium, routine ventral hernia repairs, despite significant differences in operative time and length of stay. Longer-term follow-up is needed to expand on the clinical relevance of these short-term findings.

Introduction: Excessive bleeding in trauma and surgical settings leads to increased operative time, reoperation rates, and overall healthcare costs. A wide range of hemostatic agents have been developed to control bleeding that can vary considerably in type of hemostatic action, ease of application, cost, risk of infection, and dependence on patient coagulation. Microfibrillar collagen-based hemostatic materials (MCH) have yielded beneficial results in a variety of applications. Methods: A new flowable collagen product, containing a modified MCH flour, but in a more convenient flowable delivery system, was evaluated for hemostatic efficacy in preclinical models of solid organ injury and spinal cord exposure. The primary objective of this study was to compare the hemostatic potential and local tissue responses to this novel, flowable collagen-based hemostatic agent to the original flour formulation to confirm that the new method of delivery did not interfere with the hemostatic properties of the MCH flour. Results: When observed visually, the flowable MCH flour mixed with saline (FL) provided more precise application and uniform coverage to injured tissues compared to the dry MCH flour alone (F₀). All of the treatments (FL, F₀, and gauze) exhibited comparable Lewis bleed grade at all three time points evaluated in the capsular resection liver injury model (bleed grade: 1.0– 1.3; p> 0.05 in all cases). FL and F₀ exhibited comparable 100% acute hemostatic efficacy and similar long-term histomorphological properties (up to 120 days) in a capsular resection liver injury in pigs, while gauze resulted in significantly lower rates of acute hemostatic efficacy (8– 42%, p< 0.05 in all cases). In an ovine model of dorsal laminectomy and durotomy, FL and F₀ again exhibited comparable results without any neurological effects. Conclusion: Flowable microfibrillar collagen was shown to yield favorable short- and long-term outcomes in two representative applications where hemostatic efficacy is critical to surgical success.

Background: Poly-4-hydroxybutyrate (P4HB) is a fully resorbable, biologically-produced polymer with a strength and flexibility comparable to permanent synthetic polymers. The objective was to identify/summarize all peer-reviewed publications involving P4HB mesh.Methods: A scoping review was conducted within PubMed and included articles published through October 2022.Results: A total of n = 79 studies were identified (n = 12 in vitro/bench; n = 14 preclinical; n = 6 commentaries; n = 50 clinical). Of the clinical studies, n = 40 reported results applicable to hernia and n = 10 to plastic/reconstructive surgery and involved patients of all Centers for Disease Control (CDC) wound classes and Ventral Hernia Working Group (VHWG) grades.Conclusion: P4HB mesh provides long-term hernia repair strength and exhibits promising clinical outcomes beyond its resorption period. Future studies should include randomized controlled trials comparing P4HB to other biomaterials, as well as optimal patient selection, operative technique, long-term outcomes, minimization of potential mesh-related complications, and potential contraindications/complications for P4HB in hernia/abdominal wall reconstruction.

The objective of this study was to determine mechanical and histological properties of Phasix™ ST Mesh in various defect sizes and characterize the tissue replacing Phasix™ ST Mesh in a porcine mod...

Hybrid hernia meshes combine biological tissue-derived extracellular matrix with permanent or resorbable synthetic. The objective of this study was to evaluate hybrid meshes (Gore® Synecor, Zenapro™, Ovitex™ 1S Reinforced Bioscaffold Permanent, and Ovitex™ 1S Reinforced Bioscaffold Resorbable) compared to non-hybrid, bioresorbable synthetic mesh (Phasix™ Mesh) in a rabbit bacterial inoculation model. Subcutaneous pockets were bilaterally created in male, New Zealand White rabbits (n = 25). Circular meshes (3.8 cm diameter) were implanted and inoculated with 1 × 106 colony forming units (CFU) of clinically-isolated methicillin-resistant Staphylococcus aureus (MRSA). A given animal received a single mesh type. Seven days post-inoculation, animals were euthanized and white material and microbial colonization were assessed by abscess scoring and CFU quantification, respectively. Non-parametric Kruskal-Wallis with Dunn's post-hoc tests compared results for different meshes. Phasix™ Mesh and Synecor exhibited significantly lower abscess scores than Zenapro™, Ovitex™ 1S Permanent, and Ovitex™ 1S Resorbable (p < 0.05). All pocket swabs for Zenapro™ and Ovitex™ meshes were positive for MRSA (100%), with 20% of Synecor and 0% Phasix™ Mesh. Microbial colonization was significantly lower for Phasix™ Mesh (0 CFU) relative to Zenapro™ (6.73 × 107 CFU (median)), Ovitex™ 1S Permanent (7.87 × 107 CFU) and Ovitex™ 1S Resorbable (1.45 × 108 CFU), and for Synecor (0 CFU) relative to both Ovitex™ meshes. Phasix™ Mesh was the only device with no detectable abscess or microbial colonization. Phasix™ Mesh demonstrated no detectable abscess or microbial colonization at 7-days post-implantation and inoculation, in contrast with four hybrid meshes, which all demonstrated colonization in a rabbit bacterial inoculation model.