Dorsales Impingement nach lumbaler Bandscheibenprothetik - eine statische und dynamische Röntgenanalyse
LicenseStandard (Fassung vom 03.05.2003)
Introduction: In lumbar total disc replacement (TDR), polyethylene (PE) wear may worsen outcome. One factor might be increased segmental lordosis following TDR with posterior component impingement. Methods: 56 patients with degenerative disc disease or postdiscectomy syndrome with a total of 66 ProDisc (Synthes Spine) TDRs (monosegmentally: L3/4: n = 2, L4/5: n = 13, L5/S1: n = 31; bisegmentally: L4-S1: n = 10) were assessed radiographically regarding posterior component impingement. All TDRs had a configuration of 6° angulation/10 mm PE-inlay. Segmental angulation was measured twice (6 week interval) on lateral standing X-rays (neutral/maximum extension) using the Spike method. Component impingement was assumed at segmental angulation of the fins of > 16°. Intra-observer variability was checked with t-test, Pearson correlation coefficient (PCC) and 95 %-confidence interval (95 %-CI). Results: The average segmental angulation of the TDR in neutral position was 9.9° (± 4.8°) and 9.9° (± 4.9°) at first and second measurement, and for maximum extension it was 11.3° (± 4.9°) and 11° (± 4.9°), respectively. Regarding angulation and extension, data showed no significant difference (t-test: p = 0.51 and p = 0.19) and PCC suggested near perfect agreement (0.99 and 0.85). 95 %-CI was ± 1.2° and ± 1.4°. Data interpretation was conducted using absolute measurements (AM) and 95 %-CI, suggesting an impingement > 16° (AM) and > 17,2° (95 %-CI) of segmental angulation. In neutral position, 11 % (AM) and 5 % (95 %-CI) of TDRs showed an impingement and in neutral position and/or maximum extension, this rate was 15 % (AM) and 9 % (95 %-CI). Impingement rate was higher at L4/5 and in bisegmental TDRs. 79 % (AM) and 32 % (95 %-CI) of the implants were mobile. Discussion: Posterior component impingement following TDR exists in a considerable amount of cases in this cohort. Regarding clinical consequences like PE-wear, further studies are needed to investigate the correlation between radiological and clinical findings.
Subject HeadingsImpingement-Syndrom [GND]
Intervertebral disk. Radiography [MeSH]