title: Computer-assisted hemivertebral resection for congenital spinal deformity.
abstract: BACKGROUND
  No studies have reported on osteotomies utilizing a navigation system in congenital scoliosis surgery. This study aimed to evaluate the surgical outcomes of eight patients with congenital scoliosis or kyphoscoliosis due to hemivertebrae treated by computer-assisted hemivertebral resection using only a posterior approach.
  
  
  METHODS
  Eight consecutive patients (two scoliotics and six kyphoscoliotics) managed by computer-assisted hemivertebral resection using only a posterior approach with transpedicular instrumentation were investigated retrospectively. A CT-based navigation system was used to confirm the positions of the vertebra, spinal cord and aorta in real-time when we inserted a pedicle screw and conducted the osteotomy. The mean patient age at surgery was 18 years (range 11-41 years). The mean follow-up was 46 months (range 18-84 months).
  
  
  RESULTS
  Before surgery, the mean kyphotic curve was 55.8° (range 26-83°), and the mean scoliotic curve was 50.0° (range 36-62°). At the final follow-up period, the curves averaged 23.2° (range 15-40°) and 31.6° (range 21-44°), respectively, yielding kyphotic angle corrections of 32.7° (range 11-58°) and Cobb angle correction rates of 36.8% (range 24.1-48.3%). A total of 72 pedicle screws were inserted with the navigation system, and two screws revealed a perforating pedicle. No neurovascular complications occurred. The perforation rate was 2.8%.
  
  
  CONCLUSIONS
  Hemivertebral resection via a single posterior approach is less invasive than combined anterior and posterior approaches; however, this procedure increases the risk of spinal cord and vascular injuries. Computer-assisted hemivertebral resection enables safe and accurate performance of a hemivertebral resection via a single posterior approach.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan. jtaka@shinshu-u.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Takahashi
authors.forename: Sohei
authors.initials: S
authors.lastname: Ebara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hashidate
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hirabayashi
authors.forename: Nobuhide
authors.initials: N
authors.lastname: Ogihara
authors.forename: Keijiro
authors.initials: K
authors.lastname: Mukaiyama
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kato
mesh_terms: D000293:Adolescent; D000328:Adult; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data; D001863:Bone Screws; D016025:Bone Transplantation; D002648:Child; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000151:congenital / Q000601:surgery*; D008297:Male; D010027:Osteotomy / Q000379:methods*; D012189:Retrospective Studies; D012600:Scoliosis / Q000151:congenital / Q000601:surgery*; D013131:Spine / Q000601:surgery*; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome; D055815:Young Adult