title: Intervertebral disc rehydration after lumbar dynamic stabilization: magnetic resonance image evaluation with a mean followup of four years.
abstract: Objective. To compare the clinical and radiographic outcomes in patients of different ages who underwent the Dynesys stabilization. Methods. This retrospective study included 72 patients (mean age 61.4 years) with one- or two-level lumbar spinal stenosis who underwent laminectomy and the Dynesys (Zimmer Spine, Minneapolis) dynamic stabilization system. Thirty-seven patients were younger than 65-year old while the other 35 were older. Mean followup was 46.7 months. Pre- and postoperative radiographic and clinical evaluations were analyzed. Results. The mean calibrated disc signal (CDS) at the index level was significantly improved from 60.2 ± 25.2 preoperatively to 66.9 ± 26.0 postoperatively (P > 0.001). Screw loosening occurred in 22.2% of patients and 5.1% of screws. The improvement in CDS at index level was seen to be significant in younger patients but not in older patients. Overall, the mean visual analogue scale (VAS) of back pain, VAS of leg pain, and the Oswestry disability index (ODI) scores improved significantly after operation. There were no significant differences in pre- and postoperative VAS and ODI and screw loosening rates between the younger and older patients. Conclusions. There is significant clinical improvement after laminectomy and dynamic stabilization for symptomatic lumbar spinal stenosis. Intervertebral disc rehydration was seen in younger patients.
authors.affiliation: Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei 11217, Taiwan ; School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan ; Institute of Pharmacology, National Yang-Ming University, Taipei 11221, Taiwan.
authors.forename: Li-Yu
authors.initials: LY
authors.lastname: Fay
authors.forename: Jau-Ching
authors.initials: JC
authors.lastname: Wu
authors.forename: Tzu-Yun
authors.initials: TY
authors.lastname: Tsai
authors.forename: Tsung-Hsi
authors.initials: TH
authors.lastname: Tu
authors.forename: Ching-Lan
authors.initials: CL
authors.lastname: Wu
authors.forename: Wen-Cheng
authors.initials: WC
authors.lastname: Huang
authors.forename: Henrich
authors.initials: H
authors.lastname: Cheng