Osseous alterations at the interface of hydrogel expanders and underlying bone

Area of Science:

• Plastic and Reconstructive Surgery
• Biomaterials Science
• Skeletal Biology

Background:

• Self-activating hydrogel expanders are utilized in plastic and reconstructive surgery for soft-tissue augmentation.
• Constant pressure from these expanders may impact underlying bone morphology.

Purpose of the Study:

• To investigate the morphological bone response to constant pressure from hydrogel expanders.
• To evaluate the effect of a polydioxanone (PDS) foil barrier on bone response.

Main Methods:

• Lewis rats were divided into three groups: direct subperiosteal placement, PDS foil barrier, and control.
• Micro-computed tomography (CT) and histomorphometric analysis were used to assess bone density and thickness.
• Hydroxyapatite density and bone morphology, including resorption lacunae, were analyzed before and after expander insertion.

Main Results:

• A significant decrease in hydroxyapatite density and bone thickness was observed beneath expanders placed directly on calvaria.
• Resorption lacunae were present in animals with direct expander placement.
• No significant bone density changes were noted at the periphery of expanders, and bone thickness was unaffected at the periphery in all groups.

Conclusions:

• Hydrogel expanders directly influence underlying bone, causing resorption and connective tissue formation.
• Using a PDS foil barrier between the hydrogel expander and bone effectively prevents adverse bone effects.
• Appropriate expander placement is crucial to avoid bone resorption during soft-tissue augmentation procedures.