title: [Augmentation of VDS(ventral derotation spondylodesis) by double rod instrumentation. A critical analysis of 2-to-4-year outcomes].
abstract: OBJECTIVE
  In order to evaluate the benefits of the doublerod-VDS in the operative treatment of scoliosis the midterm results were critically analysed with specific respect to primary stability.
  
  
  METHODS
  24 patients with either idiopathic or neuromuscular curves were treated with the Doublerod-VDS. In some cases a singlerod instrumentation had to be carried out in the cranial fusion area due to too small vertebrae (Hybrid-VDS). Patients with thoracic curves were ambulated without any external support, the thoracolumbar curves were ambulated in a light, semirigid vest for a few months. All data including early and late complications were collected prospectively and a thorough radiometric analysis was carried out.
  
  
  RESULTS
  Fusion was mostly carried out from end- to end-vertebra. The correction of the idiopathic curves averaged 60.2% (preoperative Cobb angle 67.3 degrees) with a loss of correction of 5.2 degrees. In the neuromuscular curves the average correction was 61.1% (preoperative Cobb angle 99.8% degrees) and the average loss of correction 4.2 degrees. There was no kyphogenic effect noted. In 6 cases a rod fracture was observed, in 4 cases the fracture occurred within the singlerod instrumentation in hybrid-VDS. Two of these patients developed a pseudarthrosis with loss of correction but without any symptoms.
  
  
  CONCLUSIONS
  The hybrid-VDS does not offer any advantages compared to the Zielke-VDS. However, the doublerod-VDS in thoracic curves is primary stable and does not require any external support postoperatively. In thoracolumbar curves a light vest is suggested for the first postoperative months during day time.
authors.affiliation: Klinik und Poliklinik für Allgemeine Orthopädie, Westfälische Wilhelms-Universität Münster.
authors.forename: U
authors.initials: U
authors.lastname: Liljenqvist
authors.forename: H
authors.initials: H
authors.lastname: Halm
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004867:Equipment Design; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008297:Male; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation*