Soft tissue distribution pattern of facial soft tissue fillers with different viscoelastic properties

Soft tissue filler product distribution and tissue integration have been shown to depend on myriad factors including the injector type, injector size, and injection angle.

This study aims to investigate the magnitude of product spread across fascial soft tissue layers in relation to product viscoelastic properties.

A total of 168 injection procedures were conducted in two female Caucasian body donors with a mean age of 80 years (range: 79-81) and a mean body mass index of 23.6 kg/m² (range: 21.0-26.6). The injection procedures were performed in the forehead, scalp, zygomatic arch, mandible, clavicle, and sternum. The injected materials included Belotero^® Soft, Belotero^® Balance, Belotero^® Intense, Belotero^® Volume, Radiesse^® , and Radiesse^® Plus. Layer-by-layer dissections were performed to investigate the vertical distribution of the injected product.

The mean product spread was for Belotero^® Soft 4.54 ± 0.91; Belotero^® Balance 3.85 ± 1.19; Belotero^® Intense 3.04 ± 1.34; Belotero^® Volume 2.58 ± 1.27; Radiesse^® 1.31 ± 0.47; and Radiesse^® Plus 1.27 ± 0.45 with P < .001. Bivariate correlations between product spread and storage modulus (G') revealed an inverse relationship of moderate strength with r_p  = -0.651 and P < .001.

The results of the present study revealed that products that were more fluid and less viscous distributed into more superficial fascial layers than products that were less fluid and more viscous (P < .001). This relationship held true irrespective of injected location.