title: Evolving Concepts of Keystone Perforator Island Flaps (KPIF): Principles of Perforator Anatomy, Design Modifications, and Extended Clinical Applications.
abstract: BACKGROUND
  Keystone flaps have demonstrated growing clinical applications in reconstructive surgery in the past decade. This article highlights flap modifications and their versatility for clinical applications and management of complex defects.
  
  
  METHODS
  A retrospective chart review was conducted of consecutive patients undergoing keystone flap reconstruction at the authors' institution from January of 2012 to December of 2014. Patient demographics, indications, and operative and postoperative details were abstracted.
  
  
  RESULTS
  Forty-two keystone flaps were performed in 36 patients. Indications included malignant melanoma (n = 14), soft-tissue sarcoma (n = 12), benign pathologic conditions (e.g., exposed hardware, enterocutaneous fistula, tissue necrosis) (n = 6), and nonmelanoma skin cancer (n = 4). Twenty-eight percent received neoadjuvant irradiation, and 70 percent of these were for sarcoma. Locoregional adjunct flaps were performed in eight patients. The deep fascia was nearly completely in a circumferential manner in 18 of 36 patients (50 percent), in 92 percent of the sarcoma reconstructions, and located mainly in the lower extremity. Average defect size was 215 cm (range, 4 to 1000 cm). Average defect size was 474 cm and 35.8 cm after sarcoma and malignant melanoma resection, respectively. Average flap size was 344 cm (range, 5 to 1350 cm). Ninety percent of cases had flap sizes exceeding the traditional 1:1 ratio. There was no flap loss or partial necrosis. Mean time to mobilization was 1.8 days, and mean hospital length of stay was 6.8 days.
  
  
  CONCLUSIONS
  Keystone flaps offer an excellent versatile tool for reconstructive surgeons. Fundamental principles behind the vascular basis of the keystone flap and its modifications permit their greater utility in complex wounds in the settings of large oncologic resections, irradiation, and trauma.
  
  
  METHODS
  Therapeutic, IV.
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Anita T
authors.initials: AT
authors.lastname: Mohan
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Charalambos K
authors.initials: CK
authors.lastname: Rammos
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Arya A
authors.initials: AA
authors.lastname: Akhavan
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Jorys
authors.initials: J
authors.lastname: Martinez
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Wu
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Moran
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Franklin H
authors.initials: FH
authors.lastname: Sim
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Felix
authors.initials: F
authors.lastname: Behan
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Samir
authors.initials: S
authors.lastname: Mardini
authors.affiliation: Rochester, Minn.; London, United Kingdom; and Melbourne, Victoria, Australia.|From the Division of Plastic Surgery and the Department of Orthopaedic Surgery, Mayo Clinic; the Restoration of Appearance and Function Charitable Trust; the Department of Surgery, University of Cambridge; Mayo Medical School; and the University of Melbourne and the Peter MacCallum Cancer Institute and Western Hospital.
authors.forename: Michel
authors.initials: M
authors.lastname: Saint-Cyr
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015331:Cohort Studies; D005260:Female; D005548:Foreign-Body Migration / Q000601:surgery*; D006801:Humans; D016268:Internal Fixators / Q000009:adverse effects*; D007412:Intestinal Fistula / Q000601:surgery*; D008297:Male; D008545:Melanoma / Q000601:surgery*; D008875:Middle Aged; D061525:Perforator Flap / Q000473:pathology* / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods*; D012189:Retrospective Studies; D012509:Sarcoma / Q000601:surgery*; D012867:Skin / Q000293:injuries*; D012878:Skin Neoplasms / Q000473:pathology / Q000601:surgery*; D055815:Young Adult