PubMed · 13065211
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W CEELEN. 1953-04-02. [Meniscus pathology].. https://pubmed.ncbi.nlm.nih.gov/13065211/
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This work describes the development of a non-invasive means of simultaneously delivering insulin-like growth factor-1 (IGF-1) and transforming growth factor-beta1 (TGF-beta1) to injured cartilage tissue in a controlled manner. This novel delivery technology employs the water-soluble polymer, oligo(poly(ethylene glycol) fumarate) (OPF), in the fabrication of biodegradable hydrogels which encapsulate gelatin microparticles. Release studies first examined the effect of gelatin isoelectric point (IEP) and crosslinking extent on IGF-1 release from these microparticles. In the presence of collagenase, highly crosslinked, acidic gelatin (IEP=5.0) provided sustained release of IGF-1, 95.2+/-2.9% cumulative release at day 28, while less crosslinked microparticles and microparticles of alternate IEP exhibited similar release values after only 6 days. Encapsulation of these highly crosslinked microparticles in a network of OPF provided a means to further control release, reducing final cumulative release to 70.2+/-4.7% in collagenase-containing PBS. Final release values from OPF-gelatin microparticle composites could be altered by incorporating less crosslinked, non-loaded microparticles within these constructs. Finally, this technology was extended to the dual delivery of IGF-1 and TGF-beta1 by loading these growth factors into either the OPF hydrogel phase or gelatin microparticle phase of composites. Release profiles were successfully manipulated by altering the phase of growth factor loading and microparticle crosslinking extent. For instance, by loading TGF-beta1 into the gelatin microparticle phase, a burst release of 10.8+/-0.7% was achieved, while loading this growth factor into the OPF hydrogel phase resulted in a burst release of 25.2+/-1.5%. With either system, simultaneous, slow release of IGF-1 over a 4-week period was accomplished by selectively loading this protein into highly crosslinked, encapsulated microparticles. These results demonstrate the utility of these systems in future studies to assess the interplay and time course of multiple growth factors in cartilage repair.
The nasal ala and helical rim of the ear are common sites for the development of skin neoplasms. Removal of skin cancers from these aesthetically delicate areas may leave defects that free skin grafts alone may not adequately repair. The contractural forces of scarring within and around the skin graft during healing may produce elevation or notching of the rim and may lead to functional compromise. The use of a composite graft or the inclusion of a free cartilage graft in conjunction with a skin graft or flap repair can provide structural support, which may help to prevent undesirable outcomes. This article focuses on the use of composite or free cartilage grafts harvested from the ear to repair nasal alar or helical rim defects within a single surgical session. Preoperative considerations, surgical technique, and postsurgical complications are discussed.
Over the past decade, rhinoplasty techniques have moved away from excisional methods and focused more on repositioning and restructuring existing tissues. These changes in surgical technique were made in part because of some of the untoward long-term complications noted in noses that were treated with excisional techniques. The incidence of many of these complications is greater in patients with certain nasal anatomy. It is the responsibility of the surgeon to identify these anatomic variants and make necessary adjustments in surgical technique to avoid complications.