title: Unilateral extrapedicular vertebroplasty and kyphoplasty in lumbar compression fractures : technique, anatomy and preliminary results.
abstract: OBJECTIVE
  A single balloon extrapedicular kyphoplasty has been introduced as one of the unilateral approaches for thoracic compression fractures; however, the unilateral extrapedicular technique in the lumbar area needs a further understanding of structures in the lumbar area. The purpose of the present study is to describe methods and pitfalls of this procedure based on the anatomy of the lumbar area and to analyze clinical outcome and complications.
  
  
  METHODS
  Anatomical evaluation was performed with 2 human cadavers. A retrospective review of unilateral extrapedicular approaches yielded 74 vertebral levels in 55 patients that were treated with unilateral extrapedicular vertebroplasty and kyphoplasty. Radiographic assessment included the restoration rate of vertebral height and correction of kyphosis.
  
  
  RESULTS
  Anatomical evaluation indicates that the safe needle entry zone of bone for the extrapedicular approach was located in the supero-lateral aspect of the junction between the pedicle and vertebral body. The unilateral extrapedicular procedure achieved adequate pain relief with a mean decreases in pain severity of 7.25±1.5 and 2.0±1.4, respectively. Complications were 1 retroperitoneal hematoma, 6 unilateral fillings and 3 epidural leak of the polymethylmethacrylate.
  
  
  CONCLUSIONS
  The method of a unilateral extrapedicular approach in kyphoplasty and vertebroplasty in the lumbar area might be similar to that in thoracic approach using a route via the extrapedicular space. However, different anatomical characteristics of the lumbar area should be considered.
authors.affiliation: Department of Neurosurgery, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, Korea.
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Cho
authors.forename: Yong-Suk
authors.initials: YS
authors.lastname: Nam
authors.forename: Byung-Moon
authors.initials: BM
authors.lastname: Cho
authors.forename: Sang-Youl
authors.initials: SY
authors.lastname: Lee
authors.forename: Sae-Moo
authors.initials: SM
authors.lastname: Oh
authors.forename: Moon-Kyu
authors.initials: MK
authors.lastname: Kim