Long-Term Outcome of Dynesys Dynamic Stabilization for Lumbar Spinal Stenosis

Abstract

Background:Many clinical studies over the past decade have indicated positive outcomes for patients treated with Dynesys dynamic stabilization for lumbar degenerative disease. However, long-term outcomes of Dynesys for lumbar spinal stenosis are rarely reported. The aim of this study was to analyze the long-term clinical and radiologic outcomes for patients with lumbar spinal stenosis treated with Dynesys stabilization.Methods:Thirty-eight patients with lumbar spinal stenosis were treated with Dynesys stabilization from July 2008 to March 2010. The minimal duration of follow-up was 72 months. The patients were divided into stenosis and spondylolisthesis groups according to degenerative spondylolisthesis. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and visual analog scale (VAS). Radiographic evaluations included range of motion (ROM) and the disc heights of stabilized segments and the upper adjacent segments. We also evaluated the occurrence of radiographic and symptomatic adjacent segment degeneration (ASD).Results:There were 23 patients in stenosis group and 15 patients in spondylolisthesis group. The ODI scores were significantly improved at the final follow-up evaluation, as compared to the baseline values (16.1 ± 5.7 vs. 57. 2 ± 14.2, t = 61.41, P < 0.01). The VAS scores for back and leg pain were significantly improved from 4.82 ± 0.89 and 4.04 ± 0.82 preoperatively to 0.93 ± 0.61 and 0.54 ± 0.51 postoperatively (t = 6.59, P < 0.01, and t = 5.91, P < 0.01, respectively). There were no differences between the two groups with respect to VAS and ODI scores. The ROM of stabilized segments decreased significantly from 7.8° ± 2.4° to 4.5° ± 1.5° (t = 7.18, P < 0.05), while the upper adjacent segments increased significantly from 8.3° ± 2.4° to 10.4° ± 2.4° (t = 2.87, P = 0.01). The change in disc height of stabilized segments was not significant (11.9 ± 2.1 preoperatively vs. 12.5 ± 1.5 postoperatively, t = 1.43, P = 0.15), whereas the decrease in disc height of the upper adjacent segments was significant (12.5 ± 2.0 preoperatively vs. 11.0 ± 1.7 postoperatively, t = 2.94, P = 0.01). The occurrence of radiographic and symptomatic ASD was 16% (6/38) and 3% (1/38), respectively.Conclusions:Decompression and Dynesys stabilization for lumbar stenosis with or without spondylolisthesis showed good long-term clinical and radiographic results. Lumbar stenosis with or without Grade I spondylolisthesis, particularly in patients <60 years of age with mild-to-moderate lumbar disc degeneration, would be one of the main indications for the Dynesys system.

Which is the better posterior lumbar dynamic device: Dynesys or BioFlex?

“…Under flexion-extension, lateral bending, and axial torsion conditions, the total ROM and the ROM of surgical segment in the surgery-simulation models decreased to some extent in the present study, but the BioFlex system showed a more decrease compared to Dynesys system. This result is similar with the results from some study [15][16][17]. Our study showed an encouraging result in that the Dynesys system model had the closest ROM to the intact group.…”

Radiographic and Clinical Outcomes of Dynesys Dynamic Stabilization Versus Instrumented Fusion for Degenerative Lumbar Spine Diseases With a Minimum Follow-Up Period of 2 Years: A Meta-Analysis

“…1,2 However, instrumented fusion causes complications, including instrumentation failure, pseudoarthrosis, and pain in donor areas. [3][4][5] Moreover, the preservation of lumbar motion is less considered in fusion instrument, leading to the limited motility of stabilized segments and the increased load on adjacent segments, which may increase the risk of adjacent segment degeneration (ASDeg), adjacent segment disease (ASDis), and severe postoperative functional disabilities. [6][7][8] In recent years, non-fusion systems have been applied clinically to prevent the incidence of adjacent segment pathology (ASP, including ASDeg and ASDis) after lumbar surgeries.…”

“…11 This system consists of pedicle screws (Ti alloy), polyethylene-terephtalate (PET) cords, and polycarbonate-urethane (PCU) spacers for stabilization of stabilized segments, restoration of normal segmental kinematics, and preservation of adjacent motion to prevent the instability and decrease the incidence of ASP. 5,[12][13][14] Many studies reported that the Dynesys system (DS) showed signi cant improvement in terms of visual analog scale (VAS) pain scores, Oswestry disability index (ODI) scores, trauma severity, and recovery time than fusion method. 4,[15][16][17][18][19] Moreover, the range of movement (ROM) at adjacent segments and along with the load across the intervertebral and adjacent discs was reduced.…”

“…4,[15][16][17][18][19] Moreover, the range of movement (ROM) at adjacent segments and along with the load across the intervertebral and adjacent discs was reduced. 4,5,7,12,16 However, many studies showed contradicting results. In previous works, DS showed no remarkable advantages over fusion method in terms of surgical time, length of hospital stay, intraoperative blood loss, relief in postoperative pain status (VAS scores), and functional status restoration (ODI scores).…”

“…3,7,[20][21][22] Meanwhile, DS was reported to be associated with high rates of ASDeg and ASDis. 5,6,23 Although DS is a safe and effective treatment in terms of short-term outcomes, the functional status, preservation of mobility, and prevention of ASP in medium-and long-term periods remain controversial. Some clinical and radiographical measurements showed opposite results in different durations of follow-up.…”