The SPOT GRADE: A New Method for Reproducibly Quantifying Surgical Wound Bleeding.

STUDY DESIGN: Benchtop model with prospective surgeon video testing. OBJECTIVE: To create a surface bleeding severity scale, the SPOT GRADE (SG), for quantitative assessment of target bleeding site (TBS) blood loss. This is of particular interest for spinal surgery due to epidural bleeding and an inability to use diathermy and radiofrequency cautery close to nerve roots. SUMMARY OF BACKGROUND DATA: A novel apparatus perfusable at known flow rates and simulating different sized wounds was used to create movies to educate surgeons on specific degrees of bleeding. METHODS: Training (36) and testing (108) videos were created using a benchtop apparatus employing different bleeding severities based on the six-level SG (none, minimal, mild, moderate, severe, and extreme) and TBS sizes (1, 10, and 50 cm). Fourteen surgeons in four specialties (cardiothoracic, abdominal, spine, and orthopedic lower extremity) were trained and tested to evaluate SG characteristics including inter-rater and intrarater reliability. RESULTS: The interclass correlation coefficient was estimated to be 0.89840 (95% confidence interval [CI]: 0.85771, 1), whereas the intraclass correlation coefficient was estimated to be 0.93673 (95% CI: 0.89603, 1). In 98% of cases (95% CI: 0.9736, 0.9927), surgeons correctly identified eligible bleeds for a future clinical trial (scores = 1, 2, or 3) and in 91% of cases (95% CI: 0.8895, 0.9344), surgeons correctly identified noneligible bleeds (scores = 4 or 5). In 98.6% of cases (95% CI: 0.9777, 0.9945), physicians correctly identified true hemostasis (score = 0). Based upon these data the probability of a physician rating a bleed incorrectly as hemostasis (score = 0) is estimated to be 1.51% (95% CI: 0.0061, 0.0363). CONCLUSION: This SG is reproducible and reliable providing a basis for educating surgeons on TBS blood loss. It appears to be a new standard for evaluating wound blood loss. LEVEL OF EVIDENCE: 2.

In vivo biodegradability and biocompatibility of porcine type I atelocollagen newly crosslinked by oxidized glycogen.

Oxidized glycogen is used as a collagen crosslinker to prepare materials with defined crosslinking rates. Thus, films are prepared from native or denatured porcine type I atelocollagen crosslinked with three crosslinking levels defined by the ratios between the aldehyde groups of the glycogen and the amino groups of the collagen. The remaining free aldehyde groups and the imine bonds formed in the reaction are subsequently reduced or not. All the materials are subjected to in vivo biocompatibility and biodegradability evaluations by subcutaneous implantation in mice, while immunogenicity is evaluated by rabbit immunizations. As a result, cellular reactions on the implantation site are more important with nonreduced materials, and biodegradability is correlated to the structural integrity of the collagen molecule, the crosslinking rate and the reduction state of the material. No immunological reaction or calcification is detected in our in vivo experimental model. This new method for collagen crosslinking using oxidized glycogen as a crosslinking agent enables the obtention of reproducible and biocompatible materials with a large scale of biodegradability, starting from 28 days to more than 7 months.

Nanofibrous clinical-grade collagen scaffolds seeded with human cardiomyocytes induces cardiac remodeling in dilated cardiomyopathy.

Limited data are available on the effects of stem cells in non-ischemic dilated cardiomyopathy (DCM). Since the diffuse nature of the disease calls for a broad distribution of cells, this study investigated the scaffold-based delivery of human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CM) in a mouse model of DCM. Nanofibrous scaffolds were produced using a clinical grade atelocollagen which was electrospun and cross-linked under different conditions. As assessed by scanning electron microscopy and shearwave elastography, the optimum crosslinking conditions for hiPS-CM colonization proved to be a 10% concentration of citric acid crosslinking agent and 150 min of post-electrospinning baking. Acellular collagen scaffolds were first implanted in both healthy mice and those with induced DCM by a cardiac-specific invalidation of serum response factor (SRF). Seven and fourteen days after implantation, the safety of the scaffold was demonstrated by echocardiography and histological assessments. The subsequent step of implantation of the scaffolds seeded with hiPS-CM in DCM induced mice, using cell-free scaffolds as controls, revealed that after fourteen days heart function decreased in controls while it remained stable in the treated mice. This pattern was associated with an increased number of endothelial cells, in line with the greater vascularity of the scaffold. Moreover, a lesser degree of fibrosis consistent with the upregulation of several genes involved in extracellular matrix remodeling was observed. These results support the interest of the proposed hiPS-CM seeded electrospun scaffold for the stabilization of the DCM outcome with potential for its clinical use in the future.