title: Preoperative radiation and free flap outcomes for head and neck reconstruction: a systematic review and meta-analysis.
abstract: BACKGROUND
  There is a general consensus among reconstructive surgeons that preoperative radiotherapy is associated with a higher risk of flap failure and complications in head and neck surgery. Opinion is also divided regarding the effects of radiation dose on free flap outcomes and timing of preoperative radiation to minimize adverse outcomes. Our meta-analysis will attempt to address these issues.
  
  
  METHODS
  A systematic review of the literature was conducted in concordance to PRISMA protocol. Data were combined using STATA 12 and Open Meta-Analyst software programmes.
  
  
  RESULTS
  Twenty-four studies were included comparing 2842 flaps performed in irradiated fields and 3491 flaps performed in non-irradiated fields. Meta-analysis yielded statistically significant risk ratios for flap failure (RR 1.48, P = 0.004), complications (RR 1.84, P < 0.001), reoperation (RR 2.06, P < 0.001) and fistula (RR 2.05, P < 0.001). Mean radiation dose demonstrated a trend towards increased risk of flap failure, but this was not statistically significant. On subgroup analysis, flaps with >60 Gy radiation had a non-statistically significant higher risk of flap failure (RR 1.61, P = 0.145).
  
  
  CONCLUSIONS
  Preoperative radiation is associated with a statistically significant increased risk of flap complications, failure and fistula. Preoperative radiation in excess of 60 Gy after radiotherapy represents a potential risk factor for increased flap loss and should be avoided where possible.
authors.affiliation: Regenerative Surgery Group, Australian Catholic University and O'Brien Institute Regenerative Tissue Engineering Centre (AORTEC), Melbourne, Victoria, Australia.
authors.forename: Pradyumna
authors.initials: P
authors.lastname: Herle
authors.forename: Lipi
authors.initials: L
authors.lastname: Shukla
authors.forename: Wayne A
authors.initials: WA
authors.lastname: Morrison
authors.forename: Ramin
authors.initials: R
authors.lastname: Shayan
mesh_terms: D058752:Free Tissue Flaps; D006085:Graft Survival; D006258:Head and Neck Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D015233:Models, Statistical; D020360:Neoadjuvant Therapy / Q000009:adverse effects; D011183:Postoperative Complications / Q000209:etiology; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D019651:Plastic Surgery Procedures / Q000379:methods; D012086:Reoperation; D012307:Risk Factors; D016896:Treatment Outcome
keywords: free flap surgery; head and neck neoplasm; microsurgery; neoadjuvant therapy; radiotherapy; tissue transfer