title: Contrast-enhanced ultrasonography as a new method for assessing autonomization of pedicled and microvascular free flaps in head and neck reconstructive surgery.
abstract: OBJECTIVE
  Evaluating vascular autonomization of pedicled and microvascular free flaps for soft tissue reconstruction in the head and neck area by means of postoperative quantitative measurement of dynamic contrast values obtained with contrast-enhanced ultrasound.
  
  
  METHODS
  8/18 patients underwent lip reconstruction with a pedicle flap, 10 patients reconstruction of other parts of the head with a microvascular free transplant. Ultrasound examinations were conducted within the 1st postoperative week and 4 weeks after surgery. After the intravenous bolus of the ultrasound contrast agent, examinations were carried out for 30 sec without compression followed by 30 sec with compression of the vascular pedicle in bolus and flash kinetics. Digital cine loops were analyzed off-line with a quantification software (VueBox™) to determine the Rise Time (RT) between flap tissue with and without compression.
  
  
  RESULTS
  Measurements showed increasing autonomous perfusion, independent of the vascular pedicle. No transplant was lost, but 4/10 patients with a microvascular flap and 1/8 patients with a pedicle flap developed postoperative complications. RT values for the pedicled and microvascular flaps obtained under compression differed significantly between the 1st and the 4th week (p = 0.025).
  
  
  CONCLUSIONS
  Reliable neovascularization was achieved 4 weeks postoperatively. CEUS showed to be a useful method for assessing the degree of autonomization of pedicle and microvascular free flaps.
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University Medical Center Regensburg, Regensburg, Germany.
authors.forename: Steffen
authors.initials: S
authors.lastname: Mueller
authors.affiliation: Institute of Radiology, University Medical Center Regensburg, Regensburg, Germany.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Wendl
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University Medical Center Regensburg, Regensburg, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Ettl
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University Medical Center Regensburg, Regensburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Klingelhöffer
authors.affiliation: Department of Plastic-, Hand-, and Reconstructive Surgery, University Medical Center Regensburg, Regensburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Geis
authors.affiliation: Department of Plastic-, Hand-, and Reconstructive Surgery, University Medical Center Regensburg, Regensburg, Germany.
authors.forename: Lukas
authors.initials: L
authors.lastname: Prantl
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University Medical Center Regensburg, Regensburg, Germany.
authors.forename: Torsten E
authors.initials: TE
authors.lastname: Reichert
authors.affiliation: Institute of Radiology, University Medical Center Regensburg, Regensburg, Germany.
authors.forename: Ernst Michael
authors.initials: EM
authors.lastname: Jung
mesh_terms: D003287:Contrast Media / Q000627:therapeutic use*; D005260:Female; D058752:Free Tissue Flaps / Q000098:blood supply*; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic; D019651:Plastic Surgery Procedures / Q000379:methods*; D013524:Surgical Flaps / Q000098:blood supply*; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Flap autonomization; contrast-enhanced ultrasound; neovascularisation; perfusion quantification