title: Double-bar application decreases postoperative pain after the Nuss procedure.
abstract: OBJECTIVE
  This biomechanical study aims to elucidate whether additional bar application increases postoperative pain after the Nuss procedure for pectus excavatum.
  
  
  METHODS
  Clinical evaluation: The intensity of postoperative pain was compared between patients for whom a single-bar was used (single-bar group: n = 14) and those for whom double bars (double-bar group: n = 10) were used to correct the thoracic deformity. The evaluation was performed by referring to the frequency with which local anesthetics were self-injected in a patient-controlled anesthetic system and how many days were needed for the patients to resume ambulation. Theoretical evaluation: An original simulation system for the Nuss procedure was developed by producing 3-dimensional finite element analysis models from computed tomographic data of patients with pectus excavatum. With this system, single-bar and double-bar placement was simulated separately for the thorax models of the double-bar group. The stresses occurring on the thoraces were then compared between the two situations.
  
  
  RESULTS
  Clinical evaluation: Self-injection of local anesthetic was more frequent for the single-bar group than for the double-bar group; single-bar patients restarted ambulation later than the double-bar group. Theoretical evaluation: Stresses on the thoraces were smaller when double bars were applied than when a single bar was applied.
  
  
  CONCLUSIONS
  Performing double-bar placement decreases postoperative pain. Therefore, surgeons should not hesitate to perform double-bar correction in patients in whom the deformity extends to multiple intercostal spaces, requiring correction of the thorax shape at multiple sites.
authors.affiliation: Department of Plastic and Reconstructive Surgery, School of Medicine, Keio University, Tokyo, Japan. nagasao@sc.itc.keio.ac.jp
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Nagaso
authors.forename: Junpei
authors.initials: J
authors.lastname: Miyamoto
authors.forename: Kiyokazu
authors.initials: K
authors.lastname: Kokaji
authors.forename: Ryohei
authors.initials: R
authors.lastname: Yozu
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.forename: HongMei
authors.initials: H
authors.lastname: Jin
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Tamaki
mesh_terms: D000293:Adolescent; D000328:Adult; D016058:Analgesia, Patient-Controlled / Q000379:methods; D000779:Anesthetics, Local / Q000008:administration & dosage; D001696:Biomechanical Phenomena; D002648:Child; D003198:Computer Simulation; D005260:Female; D020342:Finite Element Analysis; D005660:Funnel Chest / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D009983:Orthopedic Equipment; D019637:Orthopedic Procedures / Q000009:adverse effects / Q000295:instrumentation*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000209:etiology / Q000517:prevention & control*; D020127:Recovery of Function; D012646:Self Administration; D013314:Stress, Mechanical; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D016138:Walking; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local