The influence of L4–S1 Dynesys® dynamic stabilization versus fusion on lumbar motion and its relationship with lumbar degeneration: a retrospective study

Chinese Medical Journal

et al. 2018

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.

Section: Discussionmentioning

confidence: 99%

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

Chinese Medical Journal

et al. 2018

“…However, the blinding of participants and personnel was of high risk. For the comparative cohort studies assessed by NOS, six studies 3,7,16,19,24,29 were considered to be su ciently high quality, and the seven remaining studies 4,15,17,18,20,22,28 were evaluated as moderate quality.…”

Section: Risk Of Bias In the Included Studiesmentioning

confidence: 99%

“…Postoperative ROM Five studies 3,15,19,20,22 provided data on ROM at stabilized segments. The pooled data indicated that the ROM at the stabilized segment in the fusion group decreased signi cantly than that in the Dynesys group (MD = 2.79, 95% CI of 1.84 to 3.75, P< 0.01, I 2 = 97%; Figure 5).…”

Section: Radiographic Outcomesmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

“…Some clinical and radiographical measurements showed opposite results in different durations of follow-up. 7,16,20,22,24 Thus, the purpose of this meta-analysis was to compare the radiographic and clinical outcomes of dynamic DS and instrumented fusion for treatment of degenerative lumbar spine diseases with a minimum followup period of 2 years.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Zhou

et al. 2020

Preprint

ObjectiveDynesys stabilization (DS) is utilized to preserve mobility at the instrumental segments and prevent adjacent segment pathology (ASP) in clinical practice. However, the advantages of DS method remain controversial. This meta-analysis was to compare the radiographic and clinical outcomes between DS and instrumented fusion in patients with or without grade I spondylolisthesis at a minimum follow-up period of 2 years. MethodsWe conducted a comprehensive search of PubMed, EMBASE, Cochrane, and Web of Science databases for potentially eligible articles. Clinical outcomes were assessed in terms of surgical time, intraoperative blood loss, length of hospital stay, in-hospital complications, VAS and ODI scores, screw loosening and breakage, and reoperation. Radiographic outcomes were assessed in terms of postoperative range of movement (ROM) and disc heigh. Moreover, adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis) were evaluated. Data are expressed as risk ratio or standardized mean difference with the associated 95% confidence intervals. The meta-analysis was performed using RevMan 5.3 and STATA 15.1 software.ResultsFourteen studies with 1078 patients were included in the meta-analysis. The mean durations of follow-up ranged from 26.64 ± 5.16 months to 93.6 ± 16.5 months. The DS group was associated with significantly shorter surgical time, fewer intraoperative blood loss, shorter length of hospital stay, less in-hospital complications, lower postoperative VAS scores for low-back and leg pain than the fusion group (P < 0.05). Moreover, the ROM at the stabilized segments of the fusion group decreased significantly (P < 0.01) and that at the adjacent segments increased significantly compared with those of the Dynesys group (P < 0.01). Additionally, the Dynesys group showed significantly less ASDeg than the fusion group (P < 0.01) but showed no significant advantage over the fusion group in terms of preventing ASDis (P = 0.33). Furthermore, the Dynesys group was insignificantly different from the fusion group in terms of ODI, screw loosening, screw breakage, surgical reoperation, and disc heigh at stabilized and adjacent segments (P > 0.05).ConclusionDynesys stabilization showed satisfactory clinical outcomes and provided additional benefits in preserving the motion at the stabilized segments and limiting the hypermobility at the adjacent segments compared with fusion method. Dynesys stabilization represented a complementary choice in the treatment of degenerative spinal lumbar disease with or without grade I spondylolisthesis.

Biomechanical analysis of lumbar nonfusion dynamic stabilization using a pedicle screw‐based dynamic stabilizer or an interspinous process spacer

Fan

Numer Methods Biomed Eng

et al. 2022

This study aimed to investigate and compare the effects of two widely used nonfusion posterior dynamic stabilization (NPDS) devices, pedicle screw-based dynamic stabilizer (PSDS) and interspinous process spacer (IPS), on biomechanics of the implanted lumbar spine under static and vibration loadings.The finite element model of healthy human lumbosacral segment was modified to incorporate NPDS device insertion at L4-L5 segment. Bioflex and DIAM were used as PSDS-based and IPS-based NPDS devices, respectively. As a comparison, lumbar interbody fusion with rigid stabilization was also simulated at L4-L5. For static loading, segmental range of motion (ROM) of the models under moments of four physiological motions was computed using hybrid testing protocol. For vibration loading, resonant modes and dynamic stress of the models under vertical excitation were extracted through random response analysis. The results showed that compared with the rigid fusion model, ROM of the nonfusion models was higher at L4-L5 level but lower at adjacent levels (L1-L2, L2-L3, L3-L4, L5-S1). Compared with the Bioflex model, the DIAM model produced higher ROM at L4-L5 level but lower ROM at adjacent levels, especially under lateral bending and axial rotation; resonant frequency of the DIAM model was slightly lower; dynamic response of nucleus stress at L4-L5 level was slightly higher for the DIAM model, and the dynamic stress at adjacent levels was no obvious difference between the nonfusion models. This study reveals biomechanical differences between the Bioflex and DIAM systems, which may provide references for selecting surgical approaches in clinical practice.