title: Concept design and simulation study on a "phantom" anvil for circular stapler.
abstract: BACKGROUND
  Complications and challenges arising from the intraoperative double-stapling technique are seldom reported in colorectal surgery literature. Partial or full-thickness rectal injuries can occur during the introduction and the advancement of the circular stapler along the upper rectum. The aim of this study is to address some of these issues by designing and optimizing a "phantom" anvil manufactured to overcome difficulties throughout the rectal introduction and advancement of the circular stapler for the treatment of benign and malignant colon disease.
  
  
  METHODS
  The design of the "phantom" anvil has been performed using computer-aided modeling techniques, finite element investigations, and 2 essential keynotes in mind. The first one is the internal shape of the anvil, which is used for the connection to the gun. The second is the shape of the cap, which makes possible the insertion of the gun through the rectum. The "phantom" anvil has 2 functional requirements, which have been taken into account. The design has been optimized to avoid colorectal injuries, neoplastic dissemination (ie, mechanical seeding) and to reduce the fecal contamination.
  
  
  RESULTS
  Numerical simulations show that a right combination of both top and bottom fillet radii of the shape of the anvil can reduce the stress for the considered anatomic configuration of >90%. Both the fillet radii at the top and the bottom of the device influence the local stress of the colon rectum.
  
  
  CONCLUSIONS
  A dismountable device, which is used only for the insertion and advancement of the stapler, allows a dedicated design of its shape, keeping the remainder of the stapler unmodified. Computer-aided simulations are useful to perform numerical investigations to optimize the design of this auxiliary part for both the safety of the patient and the ease of the stapler advancement through the rectum.
authors.affiliation: *Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata" §Department of Enterprise Engineering, University of Rome "Tor Vergata," Rome, Italy †Colorectal Surgery Unit, Department of Abdominal Surgery and Transplantation Cliniques Universitaires Saint-Luc, Université Catholique de Louvain (UCL), Brussels, Belgium ‡Catholic University "Nostra Signora del Buon Consiglio," Tirana, Albania.
authors.forename: Francesco
authors.initials: F
authors.lastname: Rulli
authors.forename: Alex
authors.initials: A
authors.lastname: Kartheuser
authors.forename: Sasan
authors.initials: S
authors.lastname: Amirhassankhani
authors.forename: Michel
authors.initials: M
authors.lastname: Mourad
authors.forename: Mario
authors.initials: M
authors.lastname: Stefani
authors.forename: Andrés
authors.initials: A
authors.lastname: de Ferrá Aureli
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Sileri
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Valentini
mesh_terms: D000714:Anastomosis, Surgical / Q000379:methods; D003106:Colon / Q000601:surgery*; D003108:Colonic Diseases / Q000601:surgery*; D003107:Colorectal Surgery / Q000379:methods*; D003198:Computer Simulation; D004867:Equipment Design; D006801:Humans; D013528:Surgical Staplers / Q000592:standards*; D013536:Suture Techniques / Q000295:instrumentation*