Development of a novel anisotropic self-inflating tissue expander: in vivo submucoperiosteal performance in the porcine hard palate

Plast Reconstr Surg. 2012 Jan;129(1):79-88. doi: 10.1097/PRS.0b013e3182362100.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anisotropy
  • Dental Impression Technique
  • Female
  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Palate, Hard*
  • Polymethyl Methacrylate
  • Prosthesis Design
  • Pyrrolidinones
  • Silicones
  • Swine
  • Tissue Expansion / instrumentation
  • Tissue Expansion / methods*
  • Tissue Expansion Devices*

Substances

  • Pyrrolidinones
  • Silicones
  • Hydrogel, Polyethylene Glycol Dimethacrylate
  • Polymethyl Methacrylate