The fate of porous hydroxyapatite granules used in facial skeletal augmentation

Abstract

Facial appearance is largely determined by the morphology of the underlying skeleton. Hydroxyapatite is one of several materials available to enhance projection of the facial skeleton. This study evaluated the long-term maintenance of augmented bony projection when porous hydroxyapatite granules are used on the facial skeleton. Ten female patients aged 28-58 years were studied following aesthetic augmentation of the facial skeleton at 24 sites using porous hydroxyapatite granules. Postoperative CT scans at 3 months served as the baseline measurement and compared with scans taken at 1 and 2 years, with the thickness of the hydroxyapatite measured in axial and coronal planes. Thickness of original bone plus overlay of hydroxyapatite, thickness of the overlying soft tissue, and the overall projection (bone plus soft tissue) were recorded. It was found that 99.7% of the hydroxyapatite was maintained at 2 years, with no statistical difference (t test) from the baseline measurement. The overall projection (bony and soft tissue) was maintained as there was no evidence of native bone resorption or soft tissue atrophy. Radiographic results confirmed that the use of porous hydroxyapatite granules for enhancement of the facial skeleton is not only a predictable procedure, but maintains full bony projection at 2 years.

Fig. 1

Scanning electron micrographs of Pro Osteon 200 hydroxyapatite as used in augmentation of the facial skeleton (left) and the similar physical structure of human cancellous bone (right) (images courtesy of Interpore Cross International: reproduced with permission)

Fig. 2

Axial (left) and coronal (right) CT images showing hydroxyapatite overlying the body of the zygoma (shaded yellow on patient’s right)

Fig. 3

3-D reconstructed CT images of the facial skeleton demonstrating the contour and thickness of hydroxyapatite placed over the zygomatic body (left) and prejowl region of mandibular body (right)

Fig. 4

Axial (top) and corresponding coronal (bottom) CT images of the mandibular body showing the thickness of the hydroxyapatite maintained over a 2-year period (shaded yellow on patient’s right)

Fig. 5

Intraoperative view immediately following placement of hydroxyapatite on the right maxilla and zygoma (2.8 ml granule mixture) with subperiosteal midcheek lift. Left side dissected but not yet augmented or lifted

Fig. 6

Preoperative (left) and 2-year postoperative (right) images and corresponding CT scans (below) following augmentation of the zygoma in a 25-year-old female demonstrating the improvement of soft tissue projection in the midface