title: Effect of cement volume and placement on mechanical-property restoration resulting from vertebroplasty.
abstract: OBJECTIVE
  Concern exists that vertebral bodies augmented with cement placed laterally may be at risk of collapse on the nonaugmented side. The purpose of the current study was to determine if placing the cement laterally rather than centrally resulted in risk of collapse on the nonaugmented side.
  
  
  METHODS
  Vertebral bodies (L2-L5) were harvested from eight osteoporotic female cadaver spines. Simulated vertebral-body compression fractures were created and stabilized by injecting 3.5 or 7.0 mL of cement centrally or laterally. Vertebral bodies were recrushed to measure their augmented strength and stiffness. Anterior, posterior, left, and right lateral heights were measured initially, after augmentation, and after recompression.
  
  
  RESULTS
  Lateral and central 3.5-mL injections of cement restored strength, whereas 7.0-mL injections significantly increased strength compared with initial values. The stiffness of vertebral bodies receiving central 3.5-mL injections was significantly less than it was initially, although the stiffness of bodies receiving 3.5-mL laterally was not significantly different from initial values. Initial and posttreatment stiffness values did not significantly differ in vertebral bodies receiving 7.0-mL, lateral or central injections. Vertebral heights did not significantly differ between the augmented and the final compression states in any location. Height loss between central and lateral injections did not differ significantly.
  
  
  CONCLUSIONS
  Vertebral bodies in which cement is placed laterally do not appear to be at risk for collapse on the unaugmented side.
authors.affiliation: Orthopaedic Instrumentation Laboratory, Department of Orthopaedic Surgery, the Johns Hopkins University/Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue A672, Baltimore, MD 21224-2780, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Molloy
authors.forename: Lee H
authors.initials: LH
authors.lastname: Riley
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Belkoff
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001843:Bone Cements; D002102:Cadaver; D005260:Female; D006801:Humans; D019637:Orthopedic Procedures / Q000379:methods*; D013131:Spine / Q000601:surgery*
chemical_list: D001843:Bone Cements