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 preoperatively to postoperatively ( ). 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. 1. Introduction Instrumented spinal fusion is the treatment of choice for degenerative spondylosis with instability refractory to conservative treatment [1, 2]. Spine surgeons have also used modern biologics such as recombinant human bone morphogenetic protein-2 to increase the rate of spinal fusion in selected patients [3–7]. However, using biologics to enhance spinal fusion has been sometimes reported with complications postoperatively and during followup. Moreover, even autograft has been repeatedly reported with adverse events, such as donor site morbidity. Not to mention that loss of segmental motion and subsequent adjacent segmental degeneration have also been concerned for the spinal fusion surgery [8–10]. In the recent years, there is the emerging option of dynamic stabilization to spare spinal fusion and still yield satisfactory outcomes in the surgical management of lumbar spondylosis and back pain. Fischgrund and colleagues reported application of the Dynesys (Zimmer Spine, Minneapolis, USA), a pedicle-based lumbar dynamic stabilization system, as an effective alternative to treat lumbar spondylosis in 1994 [11–16]. Theoretically Dynesys can unload the intervertebral disc while providing a restricted
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