title: The effect of spinal shortening after total en bloc spondylectomy: a biomechanical study in the thoracic spine.
abstract: METHODS
  A biomechanical study using human cadaveric thoracic spine specimens.
  
  
  OBJECTIVE
  To evaluate and compare the biomechanical effects of spinal shortening and cross-links in reconstruction after total en bloc spondylectomy (TES).
  
  
  BACKGROUND
  There have been no studies that have examined the biomechanical effects of spinal reconstruction after multilevel TES or the biomechanical effects of spinal shortening in reconstruction after TES.
  
  
  METHODS
  Eight human cadaveric spines (T2-T9) were used. After the intact specimen had been biomechanically tested to determine the stiffness in compression, flexion, extension, left and right lateral bending, and left and right axial rotation, a TES at T5-6 was carried out. Three reconstruction methods were tested biomechanically (same as for the intact specimen) for their ability to restore stiffness to the specimen: (1) anterior short cage and multilevel posterior instrumentation at T3-8 with 2 cross-links (S2C), (2) anterior short cage and multilevel posterior instrumentation at T3-8 with 1 cross-link (S1C), and (3) anterior long cage and multilevel posterior instrumentation at T3-8 with 2 cross-links (L2C). A cage that was 6-10 mm shorter in height than the space created by the TES at T5-6 was selected as the "short cage" and a cage 10 mm taller in height than the short cage was selected as the "long cage" in each specimen.
  
  
  RESULTS
  All 3 reconstruction methods using an anterior cage and multilevel posterior instrumentation provides a stiffer construct than that shown by the intact specimen. The reconstruction method using the 10-mm shorter cage (S2C vs. L2C) provided more stiffness than the one using the longer cage. The reconstruction using 2 cross-links (S2C vs. S1C) did not provide a stiffer construct than the one using 1 cross-link.
  
  
  CONCLUSIONS
  The reconstructions using an anterior cage and multilevel posterior instrumentation provided a stiffer construct than that shown by the intact specimen. The reconstruction using a 10-mm shorter cage provided a stiffer construct than the reconstruction using the longer cage.
authors: Department of Orthopaedic Surgery, Emory Spine Center, Atlanta, GA 30329, USA.
authors: Satoshi
authors: S
authors: Kato
authors: Hideki
authors: H
authors: Murakami
authors: Kosaku
authors: K
authors: Higashino
authors: Motohiro
authors: M
authors: Okada
authors: Zenya
authors: Z
authors: Ito
authors: Satoru
authors: S
authors: Demura
authors: Norio
authors: N
authors: Kawahara
authors: Katsuro
authors: K
authors: Tomita
authors: Hiroyuki
authors: H
authors: Tsuchiya
authors: William C
authors: WC
authors: Hutton
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001863:Bone Screws; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000379:methods*; D013123:Spinal Fusion / Q000379:methods*; D013904:Thoracic Vertebrae / Q000601:surgery*