Tag: artificial disc

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Lumbar Total Disc Replacement for Discogenic Low Back Pain

Lumbar Total Disc Replacement for Discogenic Low Back Pain

Spine 2015;40:1873–1881

A prospective, multicenter, randomized, controlled, investigational device exemption (IDE) noninferiority trial.

Objective. The aim of this study was to evaluate the comparative safety and effectiveness of lumbar total disc replacement (TDR) in the treatment of patients with symptomatic degenerative disc disease (DDD) who are unresponsive to nonsurgical therapy.

Summary of Background Data. Lumbar TDR has been used to alleviate discogenic pain and dysfunction while preserving segmental range of motion and restoring stability. There is a paucity of data available regarding the comparative performance of lumbar TDR.

Methods. Patients presenting with symptomatic single-level lumbar DDD who failed at least 6 months of nonsurgical management were randomly allocated (2:1) to treatment with an investigational TDR device (activL1, n=218) or FDA-approved control TDR devices (ProDisc-L or Charité, n=106). The hypothesis of this study was that a composite effectiveness outcome at 2 years in patients treated with activL would be noninferior (15% delta) to that in controls.

Results. The primary composite endpoint of this study was met, which demonstrated that the activL TDR was noninferior to control TDR (P<0.001). A protocol-defined analysis of the primary composite endpoint also confirmed that activL was superior to controls (P=0.02). Radiographic success was higher with activL versus controls (59% vs. 43%; P<0.01). Mean back pain severity improved by 74% with activL and 68% with controls. Oswestry Disability Index scores decreased by 67% and 61% with activL and controls, respectively. Patient satisfaction with treatment was over 90% in both groups at 2 years. Return to work was approximately 1 month shorter (P=0.08) with activL versus controls. The rate of device-related serious adverse events was lower in patients treated with activL versus controls (12% vs. 19%; P=0.13). Surgical reintervention rates at the index level were comparable (activL 2.3%, control 1.9%).

Conclusion. The single-level activL TDR is safe and effective for the treatment of symptomatic lumbar DDD through 2 years.

Level of Evidence: 2

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3D motion analysis comparing ACDF with an artificial disc

3D motion analysis comparing ACDF with an artificial disc

J Neurosurg Spine 20:245–255, 2014

Cervical arthroplasty with an artificial disc (AD) has emerged as an alternative to anterior cervical discectomy and fusion (ACDF) for the management of cervical spondylosis. This study aims to provide 3D motion analysis data comparing patients after ACDF and AD replacement.

Methods. Ten patients who underwent C5–6 ACDF and 7 who underwent C5–6 AD replacement were enrolled. Using biplanar fluoroscopy and a model-based track technique (accurate up to 0.6 mm and 0.6°), motion analysis of axial rotation and flexion-extension of the neck was performed. Three nonoperative segments (C3–4, C4–5, and C6–7) were assessed for both intervertebral rotation (coronal, sagittal, and axial planes) and facet shear (anteroposterior and mediolateral).

Results. There was no difference in total neck motion comparing ACDF and AD replacement for neck extension (43.3° ± 10.2° vs 44.3° ± 12.6°, p = 0.866) and rotation (36.0° ± 6.5° vs 38.2° ± 9.3°, p = 0.576). For extension, when measured as a percentage of total neck motion, there was a greater amount of rotation at the nonoperated segments in the ACDF group than in the AD group (p = 0.003). When comparing specific motion segments, greater normalized rotation was seen in the ACDF group at C3–4 (33.2% ± 4.9% vs 26.8% ± 6.6%, p = 0.036) and C6–7 (28.5% ± 6.7% vs 20.5% ± 5.5%, p = 0.009) but not at C4–5 (33.5% ± 6.4% vs 31.8% ± 4.0%, p = 0.562). For neck rotation, greater rotation was observed at the nonoperative segments in the ACDF group than in the AD group (p = 0.024), but the differences between individual segments did not reach significance (p ≥ 0.146). Increased mediolateral facet shear was seen on neck extension with ACDF versus AD replacement (p = 0.008). Comparing each segment, C3–4 (0.9 ± 0.5 mm vs 0.4 ± 0.1 mm, p = 0.039) and C4–5 (1.0 ± 0.4 mm vs 0.5 ± 0.2 mm, p = 0.022) showed increased shear while C6–7 (1.0 ± 0.4 mm vs 1.0 ± 0.5 mm, p = 0.767) did not.

Conclusions. This study illustrates increased motion at nonoperative segments in patients who have undergone ACDF compared with those who have undergone AD replacement. Further studies will be required to examine whether these changes contribute to adjacent-segment disease.

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