title: Technical innovations in the minimally invasive approach for treating pectus excavatum: a paradigm shift through six years' experience with 630 patients.
abstract: OBJECTIVE
  : The multiple-momentum (MM) based multitarget (MT) approach has been developed through a single surgeon's experience to overcome the limits of the conventional Nuss procedure, which is the single target-single momentum approach that corrects only symmetric pectus excavatum (PE). The new techniques that have been devised on a morphologic basis, according to the Terrain Contour Matching (TERCOM) system, have made this approach a comprehensive one that can cover all types of pectus deformity. The aim of this study was to elucidate the difference between the conventional technique and the new approach.
  
  
  METHODS
  : The data of 630 PE patients who received the modified Nuss procedure, based on the MM-MT-TERCOM approach, between 1999 and 2005, were retrospectively studied. The conceptual differences between the new approach and the conventional one were determined. The techniques according to a new paradigm, for treating asymmetry, adults, and complex morphology, as well as the bar fixation technique, were analyzed. The results of the repair were assessed with a new CT index, the Asymmetry Index (AI).
  
  
  RESULTS
  : According to the morphologic classification, 269 patients were asymmetric (42.7%): 138 were eccentric (53 Grand Canyon type), 88 were unbalanced, and 36 were combined. On the basis of the MM-MT-TERCOM concept for repairing complex morphology, multiple targets were selected in 224 patients (35.6%). To correct targets simultaneously, positive momentum (630 patients, 100%) and negative momentum (124 patients, 19.7%) were applied as appropriate. The techniques used were an asymmetric bar (250 patients, 39.7%), a seagull bar (107 patients, 17%), a complex bar via TERCOM (126 patients, 20%), the crest compression technique (59 patients, 9.4%), and a compound bar (84 patients, 13.3%). The postoperative changes of the AI were from 1.03 ± 0.06 to 1.02 ± 0.13 (P = 0.117) in the symmetric group and they were from 1.1 ± 0.05 to 1.02 ± 0.02 (P < 0.001) in the asymmetric group.
  
  
  CONCLUSIONS
  : Refinement of techniques in accordance with the morphology and cause-effect basis of the bar action provided reproducible results for achieving postrepair symmetry for treating complex PE. Therefore, the new approach with techniques that use multiple momentums (MM-MT-TERCOM) supports the new paradigm of the Nuss procedure is effective in repair of all morphologic types of PE.
authors.affiliation: From Korea University Medical Center, Ansan Hospital, Ansan, South Korea.
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Park