Effects of different crosslinking conditions on the chemical-physical properties of a novel bio-inspired composite scaffold stabilised with 1,4-butanediol diglycidyl ether (BDDGE).

Serious cartilage lesions (Outerbridge III, IV) may be successfully treated with a three-layered gradient scaffold made by magnesium-doped hydroxyapatite and type I collagen, manufactured through a bio-inspired process and stabilised by a reactive bis-epoxy (1,4-butanediol diglycidyl ether, BDDGE). Each layer was analysed to elucidate the effects of crosslinking variables (concentration, temperature and pH). The chemical stabilisation led to an homogeneous and aligned collagenous matrix: the fibrous structures switched to a laminar foils-based arrangement and organic phases acquired an highly coordinated 3D-organization. These morphological features were strongly evident when crosslinking occurred in alkaline solution, with BDDGE concentration of at least 1 wt%. The optimised crosslinking conditions did not affect the apatite nano-crystals nucleated into self-assembling collagen fibres. The present work allowed to demonstrate that acting on BDDGE reaction parameters might be an useful tool to control the chemical-physical properties of bio-inspired scaffold suitable to heal wide osteochondral defects, even through arthroscopic procedure.

Aortopulmonary size discrepancy is not a contraindication to the pediatric Ross operation.

BACKGROUND: Modification of the aortic annulus or the ascending aorta, or both, may be required in pediatric patients undergoing the Ross operation. The fate of these autografts remains uncertain. METHODS: Retrospective review of 15 patients undergoing Ross operation without aortic annular modification (group 1), 11 patients requiring annular reduction (group 2, n = 11), and 8 patients requiring annular enlargement (group 3, n = 8). Autograft function and dimensions were evaluated by echocardiography. RESULTS: Autograft insufficiency was less than or equal to mild in 33 patients and moderate in 1 patient. The annulus body surface area ratio increased in group 1 from 19.7 +/- 5 to 20.3 +/- 5 mm/M2 (p = 0.8). The average annular reduction in group 2 was 5 +/- 1.5 mm, and 10 of 11 patients required reduction of the ascending aorta (mean 11 +/- 5 mm). The annulus body surface area ratio increased from 18.6 +/- 7 to 20.5 +/- 9 mm/M2 (p = 0.2). The mean augmentation in annulus diameter in group 3 was 6 +/- 4 mm; the annulus body surface area ratio decreased from 23.7 +/- 14 to 20.3 +/- 8 mm/M2 (p = 0.5). CONCLUSIONS: We continue to offer the Ross operation to pediatric patients even when aortic annular or ascending aortic size discrepancies mandate surgical modifications.