Plastic and Reconstructive Surgery

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Plastic & Reconstructive Surgery:
doi: 10.1097/PRS.0b013e3182362100
Experimental: Original Articles

Development of a Novel Anisotropic Self-Inflating Tissue Expander: In Vivo Submucoperiosteal Performance in the Porcine Hard Palate

Swan, Marc C. D.Phil., M.R.C.S.; Bucknall, David G. Ph.D.; Czernuszka, Jan T. Ph.D.; Pigott, David W. F.R.C.A.; Goodacre, Timothy E. E. F.R.C.S.

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Background: The advent of self-inflating hydrogel tissue expanders heralded a significant advance in the reconstructive potential of this technique. Their use, however, is limited by their uncontrolled isotropic (i.e., uniform in all directions) expansion.

Methods: Anisotropy (i.e., directional dependence) was achieved by annealing a hydrogel copolymer of poly(methyl methacrylate-co-vinyl pyrrolidone) under a compressive load for a specified time period. The expansion ratio is dictated by the percentage of vinyl pyrrolidone content and the degree of compression. The expansion rate is modified by incorporating the polymer within a silicone membrane. The in vivo efficacy of differing prototype devices was investigated in juvenile pigs under United Kingdom Home Office Licence. The devices were implanted within a submucoperiosteal pocket in a total of six porcine palates; all were euthanized by 6 weeks after implantation. A longitudinal volumetric assessment of the expanded tissue was conducted, in addition to postmortem analysis of the bony and mucoperiosteal palatal elements.

Results: Uncoated devices caused excessive soft-tissue expansion that resulted in mucoperiosteal ulceration, thus necessitating animal euthanasia. The silicone-coated devices produced controlled soft-tissue expansion over the 6-week study period. There was a statistically significant increase in the volume of expanded soft tissue with no evidence of a significant acute inflammatory response to the implant, although peri-implant capsule formation was observed. Attenuation of the bony palatal shelf was noted.

Conclusion: A unique anisotropic hydrogel device capable of controlled expansion has been developed that addresses a number of the shortcomings of the technology hitherto available.

©2012American Society of Plastic Surgeons


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