title: Ultrasound and Histologic Examination after Subcutaneous Injection of Two Volumizing Hyaluronic Acid Fillers: A Preliminary Study.
abstract: BACKGROUND
  This study examined the influence of hyaluronic acid (HA) crosslinking technology on the ultrasound and histologic behavior of HA fillers designed for subcutaneous injection.
  
  
  METHODS
  One subject received subcutaneous injections of 0.25 ml Cohesive Polydensified Matrix (CPM) and Vycross volumizing HA in tissue scheduled for abdominoplasty by bolus and retrograde fanning techniques. Ultrasound analyses were performed on days 0 and 8 and histologic analyses on days 0 and 21 after injection. A series of simple rheologic tests was also performed.
  
  
  RESULTS
  Day 0 ultrasound images after bolus injection showed CPM and Vycross as hypoechogenic papules in the hypodermis. CPM appeared little changed after gentle massage, whereas Vycross appeared more hyperechogenic and diminished in size. Ultrasound images at day 8 were similar. On day 0, both gels appeared less hypoechogenic after retrograde fanning than after bolus injection. Vycross was interspersed with hyperechogenic areas (fibrous septa from the fat network structure) and unlike CPM became almost completely invisible after gentle massage. On day 8, CPM appeared as a hypoechogenic pool and Vycross as a long, thin rod. Day 0 histologic findings confirmed ultrasound results. Day 21 CPM histologic findings showed a discrete inflammatory reaction along the injection row after retrograde fanning. Vycross had a more pronounced inflammatory reaction, particularly after retrograde fanning, with macrophages and giant cells surrounding the implant. Rheologic tests showed CPM to have greater cohesivity and resistance to traction forces than Vycross.
  
  
  CONCLUSIONS
  CPM HA volumizer appears to maintain greater tissue integrity than Vycross after subcutaneous injection with less inflammatory activity.
authors.affiliation: Private Practice, Geneva, Switzerland; MedImage RX Institute, Geneva, Switzerland; Laboratoire Viollier, Geneva, Switzerland; Private Practice, Neuchâtel, Switzerland; and Private Practice, Oudenaarde, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Micheels
authors.affiliation: Private Practice, Geneva, Switzerland; MedImage RX Institute, Geneva, Switzerland; Laboratoire Viollier, Geneva, Switzerland; Private Practice, Neuchâtel, Switzerland; and Private Practice, Oudenaarde, Belgium.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Besse
authors.affiliation: Private Practice, Geneva, Switzerland; MedImage RX Institute, Geneva, Switzerland; Laboratoire Viollier, Geneva, Switzerland; Private Practice, Neuchâtel, Switzerland; and Private Practice, Oudenaarde, Belgium.
authors.forename: Didier
authors.initials: D
authors.lastname: Sarazin
authors.affiliation: Private Practice, Geneva, Switzerland; MedImage RX Institute, Geneva, Switzerland; Laboratoire Viollier, Geneva, Switzerland; Private Practice, Neuchâtel, Switzerland; and Private Practice, Oudenaarde, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Quinodoz
authors.affiliation: Private Practice, Geneva, Switzerland; MedImage RX Institute, Geneva, Switzerland; Laboratoire Viollier, Geneva, Switzerland; Private Practice, Neuchâtel, Switzerland; and Private Practice, Oudenaarde, Belgium.
authors.forename: Badwi
authors.initials: B
authors.lastname: Elias
authors.affiliation: Private Practice, Geneva, Switzerland; MedImage RX Institute, Geneva, Switzerland; Laboratoire Viollier, Geneva, Switzerland; Private Practice, Neuchâtel, Switzerland; and Private Practice, Oudenaarde, Belgium.
authors.forename: Marva
authors.initials: M
authors.lastname: Safa
authors.affiliation: Private Practice, Geneva, Switzerland; MedImage RX Institute, Geneva, Switzerland; Laboratoire Viollier, Geneva, Switzerland; Private Practice, Neuchâtel, Switzerland; and Private Practice, Oudenaarde, Belgium.
authors.forename: Joan
authors.initials: J
authors.lastname: Vandeputte