title: Kinematic evaluation of the adjacent segments after lumbar instrumented surgery: a comparison between rigid fusion and dynamic non-fusion stabilization.
abstract: The aim of the current study was to evaluate changes in lumbar kinematics after lumbar monosegmental instrumented surgery with rigid fusion and dynamic non-fusion stabilization. A total of 77 lumbar spinal stenosis patients with L4 degenerative spondylolisthesis underwent L4-5 monosegmental posterior instrumented surgery. Of these, 36 patients were treated with rigid fusion (transforaminal lumbar interbody fusion) and 41 with dynamic stabilization [segmental spinal correction system (SSCS)]. Lumbar kinematics was evaluated with functional radiographs preoperatively and at final follow-up postoperatively. We defined the contribution of each segmental mobility to the total lumbar mobility as the percent segmental mobility [(sagittal angular motion of each segment in degrees)/(total sagittal angular motion in degrees) × 100]. Magnetic resonance imaging was performed on all patients preoperatively and at final follow-up postoperatively. The discs were classified into five grades based on the previously reported system. We defined the progress of disc degeneration as (grade at final follow-up) - (grade at preoperatively). No significant kinematical differences were shown at any of the lumbar segments preoperatively; however, significant differences were observed at the L2-3, L4-5, and L5-S1 segments postoperatively between the groups. At final follow-up, all of the lumbar segments with rigid fusion demonstrated significantly greater disc degeneration than those with dynamic stabilization. Our results suggest that the SSCS preserved 14% of the kinematical operations at the instrumented segment. The SSCS may prevent excessive effects on adjacent segmental kinematics and may prevent the incidence of adjacent segment disorder.
authors.affiliation: Oita Orthopedic Hospital, 1-1-41 Iwata-machi, Oita 870-0936, Japan. uchiro1968@mac.com
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Morishita
authors.forename: Hideki
authors.initials: H
authors.lastname: Ohta
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Naito
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: George
authors.initials: G
authors.lastname: Huang
authors.forename: Masato
authors.initials: M
authors.lastname: Tatsumi
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Takemitsu
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Kida
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena / Q000502:physiology*; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D016059:Range of Motion, Articular; D013123:Spinal Fusion / Q000379:methods*; D013130:Spinal Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome