title: Is lateral stabilization enough in thoracolumbar burst fracture reconstruction? A biomechanical investigation.
abstract: BACKGROUND
  Traditional reconstruction for burst fractures involves columnar support with posterior fixation at one or two levels cephalad/caudad; however, some surgeons choose to only stabilize the vertebral column.
  
  
  OBJECTIVE
  The aim was to distinguish biomechanical differences in stability between a burst fracture stabilized through a lateral approach using corpectomy spacers of different end plate sizes with and without integrated screws and with and without posterior fixation.
  
  
  METHODS
  This was an in vitro biomechanical study assessing thoracolumbar burst fracture stabilization.
  
  
  METHODS
  Six human spines (T11-L3) were tested on a six-degrees-of-freedom simulator enabling unconstrained range of motion (ROM) at ±6 N·m in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) after a simulated burst fracture at L1. Expandable corpectomy spacers with/without integrated screws (Fi/F; FORTIFY Integrated/FORTIFY; Globus Medical, Inc., Audubon, PA, USA) were tested with different end plate sizes (21×23 mm, 22×40-50 mm). Posterior instrumentation (PI) via bilateral pedicle screws and rods was used one level above and one level below the burst fracture. Lateral plate (LP) fixation was tested. Devices were tested in the following order: intact; Fi21×23; Fi21×23+PI; F21×23+PI+LP; F21×23+LP; F22×40-50+LP; F22×40-50+PI+LP; Fi22×40-50+PI; Fi22×40-50.
  
  
  RESULTS
  In FE and AR, constructs without PI showed no significant difference (p<.05) in stability compared with intact. In LB, F22×40-50+LP showed a significant increase in stability relative to intact, but no other construct without PI reached significance. In FE and LB, circumferential constructs were significantly more stable than intact. In AR, no construct showed significant differences in motion when compared with the intact condition.
  
  
  CONCLUSIONS
  Constructs without posterior fixation were the least stable of all tested constructs. Circumferential fixation provided greater stability in FE and LB than lateral fixation and intact. Axial rotation showed no significant differences in any construct compared with the intact state.
authors.affiliation: Department of Neurological Surgery, University of California, Davis, 4860 Y St, Ste. 3740, Sacramento, CA 95817, USA.
authors.forename: Ripul R
authors.initials: RR
authors.lastname: Panchal
authors.affiliation: Muskuloskeletal Education and Research Center, A Division of Globus Medical Inc., 2560 General Armistead Ave., Audubon, PA 19403, USA. Electronic address: ematheis@globusmedical.com.
authors.forename: Erika A
authors.initials: EA
authors.lastname: Matheis
authors.affiliation: Muskuloskeletal Education and Research Center, A Division of Globus Medical Inc., 2560 General Armistead Ave., Audubon, PA 19403, USA.
authors.forename: Manasa
authors.initials: M
authors.lastname: Gudipally
authors.affiliation: Muskuloskeletal Education and Research Center, A Division of Globus Medical Inc., 2560 General Armistead Ave., Audubon, PA 19403, USA.
authors.forename: Mir M
authors.initials: MM
authors.lastname: Hussain
authors.affiliation: Department of Neurological Surgery, University of California, Davis, 4860 Y St, Ste. 3740, Sacramento, CA 95817, USA.
authors.forename: Kee D
authors.initials: KD
authors.lastname: Kim
authors.affiliation: Muskuloskeletal Education and Research Center, A Division of Globus Medical Inc., 2560 General Armistead Ave., Audubon, PA 19403, USA.
authors.forename: Brandon S
authors.initials: BS
authors.lastname: Bucklen
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001860:Bone Plates / Q000009:adverse effects; D005260:Female; D005592:Fracture Fixation / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D065289:Pedicle Screws / Q000009:adverse effects; D016059:Range of Motion, Articular; D013131:Spine / Q000503:physiopathology / Q000601:surgery*
keywords: Biomechanics; Burst fracture; Range of motion; Stabilization; Thoracolumbar; Trauma