title: Osteotomies through a fusion mass in the lumbar spine.
abstract: BACKGROUND
  Flat-back syndrome is one of the main causes of surgical failure after lumbar fusion and can lead to a revision surgery to correct it. Three-column pedicle subtraction osteotomy is an efficient technique to restore lumbar lordosis (LL) for fixed sagittal malalignment. The fusion mass stemming from the past surgeries makes the procedure demanding as most anatomical landmarks are missing.
  
  
  METHODS
  This review article will focus on the correction of this lack of LL through the fusion mass. We will successively review the preoperative management, the surgical specificities, and various types of clinical cases that can be encountered in flat-back syndromes.
  
  
  CONCLUSIONS
  PSO in the fixed fusion mass is technically demanding. Preoperative CT-scan and preoperative navigation allow us to push the limits when anatomical landmarks disappear. Bleeding and neurologic are the two major complications feared by the surgeon. The best way to avoid these revision surgeries is to restore a proper lumbar lordosis at the time of initial surgery by considering lumbo-pelvic indexes.
authors.affiliation: Orthopedic Department, Spine Unit 1, Bordeaux University Hospital, Bordeaux, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Vital
authors.forename: Louis
authors.initials: L
authors.lastname: Boissière
authors.forename: Anouar
authors.initials: A
authors.lastname: Bourghli
authors.forename: Jean-Etienne
authors.initials: JE
authors.lastname: Castelain
authors.forename: Vincent
authors.initials: V
authors.lastname: Challier
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Obeid
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008141:Lordosis / Q000601:surgery; D017116:Low Back Pain / Q000601:surgery; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D011300:Preoperative Care; D011859:Radiography; D012086:Reoperation; D013123:Spinal Fusion / Q000009:adverse effects*