title: Postoperative monitoring of local and free flaps with contrast-enhanced ultrasound (CEUS)--analysis of 112 patients.
abstract: OBJECTIVE
  Tissue defects are a common problem in trauma surgery and oncology. Flap transplantation is often the only therapy to cover such defects. Several monitoring systems are currently available but none has made it to the clinical routine. The aim of this study was to assess perfusion disturbances of local and free flaps using contrast-enhanced ultrasound (CEUS).
  
  
  METHODS
  112 patients were examined during the first 72 hours after operation. CEUS was performed by one experienced examiner with a linear transducer (6 - 9 MHz, LOGIQE9/GE) after a bolus injection of 2.4 ml sulfohexa-fluoride microbubbles (SonoVue®, Bracco, Italy). Retrospective vascular perfusion was quantified by evaluating the stored DICOM cine loops using the perfusion software QONTRAST® (Bracco, Italy). Over a total penetration depth of 3 cm, every centimeter was analyzed separately. 27 complications were observed. Complete flap loss was only seen in 4 cases, while 23 flaps had to undergo minor revision and survived.
  
  
  RESULTS
  Regarding the complete flap size, quantitative analysis showed significantly higher perfusion values in patients without complications compared to patients with complications: PEAK 16.5 vs. 10.0 (p = 0.001), TTP 32.6 vs. 22.2 (p = 0.001), RBV: 738.8 vs. 246.2 (p < 0.001), RBF 17.5 vs. 10.1 (p < 0.001) and MTT 43.1 vs. 29.5 (p = 0.001). Analysis of the correlation of the different flap types, age, sex and etiology of the tissue defect to the complication rate showed no statistical correlation.
  
  
  CONCLUSIONS
  CEUS was capable of detecting vascular disturbances after flap transplantation. TTP, RBV and MTT seem to be the most accurately parameters and are not susceptible to malfunction during measurement.
authors.affiliation: Center of Plastic-, Hand- and Reconstructive Surgery, University Hospital Regensburg.
authors.forename: S
authors.initials: S
authors.lastname: Geis
authors.affiliation: Center of Plastic-, Hand- and Reconstructive Surgery, University Hospital Regensburg.
authors.forename: L
authors.initials: L
authors.lastname: Prantl
authors.affiliation: Center of Plastic-, Hand- and Reconstructive Surgery, University Hospital Regensburg.
authors.forename: J
authors.initials: J
authors.lastname: Dolderer
authors.affiliation: Center of Plastic-, Hand- and Reconstructive Surgery, University Hospital Regensburg.
authors.forename: P
authors.initials: P
authors.lastname: Lamby
authors.affiliation: Department of Cranio-Maxillofacial Surgery, University Hospital Regensburg.
authors.forename: S
authors.initials: S
authors.lastname: Mueller
authors.affiliation: Interdisciplinary ultrasound department, University Hospital Regensburg.
authors.forename: E M
authors.initials: EM
authors.lastname: Jung
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D003287:Contrast Media; D005260:Female; D058752:Free Tissue Flaps / Q000098:blood supply* / Q000601:surgery*; D006085:Graft Survival / Q000502:physiology; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D007511:Ischemia / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010743:Phospholipids; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000601:surgery; D012039:Regional Blood Flow / Q000502:physiology; D012086:Reoperation; D012680:Sensitivity and Specificity; D012984:Software; D013459:Sulfur Hexafluoride; D013524:Surgical Flaps / Q000098:blood supply* / Q000601:surgery*; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride