title: A Biomechanical Stability Study of Extraforaminal Lumbar Interbody Fusion on the Cadaveric Lumbar Spine Specimens.
abstract: BACKGROUND
  Transforaminal lumbar interbody fusion (TLIF) is an effective surgery for lumbar degenerative disease. However, this fusion technique requires resection of inferior facet joint to provide access for superior facet joint resection, which results in reduced lumbar spinal stability and unnecessary trauma. We have previously developed extraforaminal lumbar interbody fusion (ELIF) that can avoid back muscle injury with direct nerve root decompression. This study aims to show that ELIF enhances lumbar spinal stability in comparison to TLIF by comparing lumbar spinal stability of L4-L5 range of motion (ROM) on 12 cadaveric spine specimens after performing TLIF or ELIF.
  
  
  METHODS
  12 cadaveric spine specimens were randomly divided and treated in accordance with the different internal fixations, including ELIF with a unilateral pedicle screw (ELIF+UPS), TLIF with a unilateral pedicle screw (TLIF+UPS), TLIF with a bilateral pedicle screw (TLIF+BPS), ELIF with a unilateral pedicle screw and translaminar facet screw (ELIF+UPS+TLFS) and ELIF with a bilateral pedicle screw (ELIF+BPS). The treatment groups were exposed to a 400-N load and 6 N·m movement force to calculate the angular displacement of L4-L5 during anterior flexion, posterior extension, lateral flexion and rotation operation conditions.
  
  
  RESULTS
  The ROM in ELIF+UPS group was smaller than that of TLIF+UPS group under all operating conditions, with the significant differences in left lateral flexion and right rotation by 36.15% and 25.97% respectively. The ROM in ELIF+UPS group was higher than that in TLIF+BPS group. The ROM in the ELIF+UPS+TLFS group was much smaller than that in the ELIF+UPS group, but was not significantly different than that in the TLIF+BPS group.
  
  
  CONCLUSIONS
  Despite that TLIF+BPS has great stability, which can be comparable by that of ELIF+UPS. Additionally, ELIF stability can be further improved by using translaminar facet screws without causing more tissue damage to patient.
authors.affiliation: Department of Spine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Song
authors.initials: S
authors.lastname: Guo
authors.affiliation: Department of Spine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zeng
authors.affiliation: Department of Spine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Meijun
authors.initials: M
authors.lastname: Yan
authors.affiliation: Department of Spine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Spine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Dongdong
authors.initials: D
authors.lastname: Xia
authors.affiliation: Department of Traumatology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Guixin
authors.initials: G
authors.lastname: Sun
authors.affiliation: Department of Spine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Spine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Mingjie
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Spine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Tan
mesh_terms: D001696:Biomechanical Phenomena; D001863:Bone Screws; D002102:Cadaver; D006801:Humans; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000601:surgery*; D016059:Range of Motion, Articular / Q000502:physiology*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods; D013131:Spine / Q000601:surgery*