title: External Compression Versus Intravascular Injection: A Mechanistic Animal Model of Filler-Induced Tissue Ischemia.
abstract: OBJECTIVE
  Soft tissue ischemia is a devastating and unpredictable complication following dermal filler injection. Multiple mechanisms to explain this complication have been proposed, including vascular compression, vessel damage, and intraarterial filler emboli. To elucidate the mechanism of injury, the authors introduce a mouse model, imaged with optical microangiography and laser speckle contrast imaging technologies, to demonstrate in vivo microvascular response to soft tissue and intravascular filler injection.
  
  
  METHODS
  To determine the effect of external vascular compression on distal perfusion, the authors attempted to occlude vessels with subcutaneous hyaluronic acid gel (HAG) bolus injections into the pinna of hairless mice. The authors also performed suture ligation of a major vascular bundle. Following these interventions, laser speckle and optical microangiography were performed serially over 1 week follow up. To determine the effect of intravascular HAG injection, the authors devised and validated a novel method of cannulating the mouse external carotid artery for intraarterial access to the pinna vasculature. Using this model, the authors performed intraarterial HAG injections and completed optical microangiography and laser speckle contrast imaging.
  
  
  RESULTS
  Despite large HAG bolus injections directly adjacent to vascular bundles, the authors were unable to induce compressive occlusion of the mouse pinna vessels. Vascular occlusion was successfully performed with suture ligation, but optical microangiography and laser speckle contrast imaging confirmed undisturbed distal capillary bed perfusion. With intravascular HAG injection, large segments of pinna showed distinct perfusion reduction along a vascular distribution when compared with preinjection images, most noticeably at the capillary level.
  
  
  CONCLUSIONS
  The novel mouse pinna model combining intravascular access and in vivo microvascular perfusion imaging has furthered the understanding of the mechanism of filler-induced tissue ischemia. Distal capillary perfusion was maintained despite external vascular compression. Intraarterial HAG filler injection, however, resulted in large areas of capillary nonperfusion and is the most likely etiology for filler-induced tissue necrosis that is observed clinically.
authors.affiliation: * Division of Ophthalmic Plastic and Reconstructive Surgery, University of Washington Eye Institute, Seattle, Washington; †Department of Bioengineering, University of Washington, Seattle, Washington; and ‡Arkansas Ophthalmology Associates, Little Rock, Arkansas, U.S.A.
authors.forename: Shu-Hong
authors.initials: SH
authors.lastname: Chang
authors.forename: Sivash
authors.initials: S
authors.lastname: Yousefi
authors.forename: Jia
authors.initials: J
authors.lastname: Qin
authors.forename: Kristin
authors.initials: K
authors.lastname: Tarbet
authors.forename: Suzan
authors.initials: S
authors.lastname: Dziennis
authors.forename: Ruikang
authors.initials: R
authors.lastname: Wang
authors.forename: Michael C
authors.initials: MC
authors.lastname: Chappell
mesh_terms: D000818:Animals; D003357:Cosmetic Techniques; D000067548:Dermal Fillers / Q000008:administration & dosage*; D004195:Disease Models, Animal; D006820:Hyaluronic Acid / Q000008:administration & dosage*; D007511:Ischemia / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D051379:Mice; D008812:Mice, Hairless; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply*
chemical_list: D000067548:Dermal Fillers; D006820:Hyaluronic Acid