title: Predictors of free flap loss in the head and neck region: A four-year retrospective study with 451 microvascular transplants at a single centre.
abstract: BACKGROUND
  Microvascular free flaps have become an essential part of reconstructive surgery following head and neck tumour ablation. The authors' aim was to investigate the influence of cardiovascular risk factors, preoperative irradiation, previous operations and metabolically active medication on free flap loss in order to predict patients at risk and to improve their therapy.
  
  
  METHODS
  All patients who underwent reconstructive surgery with microvascular free flaps in the head and neck region between 2009 and 2013 were retrospectively analysed. Uni- and multivariate logistic regressions were performed to determine the association between possible predictor variables for free flap loss.
  
  
  RESULTS
  We included 451 patients in our analysis. The overall free flap failure rate was 4.0%. Multivariate regression analysis revealed significantly increased risks of free flap failure depending on prior attempts at microvascular transplants (p < 0.001, OR = 14.21) and length of hospitalisation (p = 0.007, OR = 1.05).
  
  
  CONCLUSIONS
  With consistently low rates of flap failure, microvascular reconstruction of defects in the head and neck region has proven to be highly reliable, even in patients with comorbidities. The expertise of the operating team seems to remain the main factor affecting flap success. The only discerned independent predictor was previously failed attempts at microvascular reconstruction.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mücke
authors.affiliation: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Germany. Electronic address: Lucas.Ritschl@tum.de.
authors.forename: Lucas M
authors.initials: LM
authors.lastname: Ritschl
authors.affiliation: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Roth
authors.affiliation: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Germany.
authors.forename: Florian D
authors.initials: FD
authors.lastname: Güll
authors.affiliation: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Rau
authors.affiliation: Life Sciences Mathematics Unit, Technische Universität München, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Grill
authors.affiliation: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Germany.
authors.forename: Marco R
authors.initials: MR
authors.lastname: Kesting
authors.affiliation: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Germany.
authors.forename: Klaus-Dietrich
authors.initials: KD
authors.lastname: Wolff
authors.affiliation: Department of Oral and Maxillofacial Surgery, Klinikum rechts der Isar, Technische Universität München, Germany.
authors.forename: Denys J
authors.initials: DJ
authors.lastname: Loeffelbein
mesh_terms: D015897:Comorbidity; D005260:Female; D058752:Free Tissue Flaps / Q000098:blood supply* / Q000637:transplantation*; D006084:Graft Rejection; D006258:Head and Neck Neoplasms / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019651:Plastic Surgery Procedures / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Head and neck tumour; Medication; Microvascular free flaps; Radiotherapy; Risk factor analysis