title: Accurate preoperative rod length measurement for thoracoscopic anterior instrumentation and fusion for idiopathic scoliosis.
abstract: OBJECTIVE
  Anterior thoracoscopic instrumentation/fusion for adolescent idiopathic scoliosis has long operative times and does not allow surgeons to adjust rod length within the chest. Intraoperative rod length measurement requires placing measurement devices into the chest, adding operative time, and results in overestimation of rod length. The study purpose was to develop a method to preoperatively determine accurate rod length.
  
  
  METHODS
  Two groups of patients were analyzed depending on when the rod length was determined: group 1: intraoperatively using intraoperative rod-measuring device (n = 12); group 2: preoperatively using the new technique (n = 12). For group 2, the preoperative convex length was measured between planned instrumented levels on the preoperative posteroanterior (PA) film, and ideal rod length was measured on the postoperative PA radiograph. The conversion ratio was determined by dividing the preoperative convex length by the ideal rod length and was 1.29 +/- 0.08.
  
  
  RESULTS
  For group 1, the actual rod length was 3.8 cm longer than the ideal length compared with 0.8 cm for group 2 (P < 0.05). Operative times improved (51.4 vs 46.2 min/disc level) after adopting this technique.
  
  
  CONCLUSIONS
  A simple and accurate preoperative method to determine appropriate rod length for thoracoscopically assisted anterior instrumentation/fusion was developed, which saves operative time and is more accurate when compared with the intraoperative method. This technique can be applied when using an open anterior approach.
authors.affiliation: Department of Orthopaedic Surgery, University of Texas at Southwestern Medical Center, Texas Scottish Rite Hospital, Dallas, Texas 75219, USA. dan.sucato@tsrh.org
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Sucato
authors.forename: Reagan
authors.initials: R
authors.lastname: Flohr
mesh_terms: D000886:Anthropometry / Q000295:instrumentation / Q000379:methods; D002648:Child; D005260:Female; D006801:Humans; D016268:Internal Fixators / Q000592:standards*; D007431:Intraoperative Complications / Q000517:prevention & control; D011300:Preoperative Care / Q000295:instrumentation* / Q000379:methods; D011859:Radiography / Q000379:methods; D012107:Research Design / Q000592:standards; D012189:Retrospective Studies; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013906:Thoracoscopy / Q000379:methods*; D016896:Treatment Outcome