Effects of lumbar spinal fusion on the other lumbar intervertebral levels (three-dimensional finite element analysis)

Goto, Keisuke; Tajima, Naoya; Chosa, Etsuo; Totoribe, Koji; Kubo, Shinichiro; Kuroki, Hiroshi; Arai, Takashi

doi:10.1007/s00776-003-0675-1

Cited by 90 publications

(47 citation statements)

References 23 publications

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“…The concept of adjacent-level disc degeneration is best noted in spinal fusion cases in which adjacent-level disc changes manifest or are accelerated proximal to an immobile fused segment and taper off as segments become more distal (40)(41)(42)(43). To a lesser degree, adjacent-level disc degeneration has also been observed in cases in which inter- * Hosmer and Lemeshow goodness-of-fit chi-square P ϭ 0.362 (5df), Nagelkerke's R 2 ϭ 0.083.…”

Section: Discussionmentioning

confidence: 99%

Intervertebral disc degeneration: New insights based on “skipped” level disc pathology

Cheung¹,

Samartzis²,

Karppinen³

et al. 2010

Arthritis & Rheumatism

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Objective. Typically, age and abnormal physical loading ("wear and tear") have been associated with the development of intervertebral disc degeneration. In the past decade, various additional etiologic factors for disc degeneration have been sporadically reported in the literature; however, many investigators continue to place tremendous emphasis on the effects of age and biomechanics associated with disc degeneration. The aim of this study was to provide additional insight into the notion that age and biomechanics are key factors in the development of disc degeneration. To this end, we addressed the prevalence of and risk factors associated with a unique pattern of disc degeneration of the lumbar spine, "skipped" level (nonconsecutive) disc degeneration (SLDD).Methods. As part of a large genetics-based study in southern Chinese individuals (n ‫؍‬ 1,989), a crosssectional analysis was performed in subjects exhibiting disc degeneration in >2 levels (n ‫؍‬ 838) who were then categorized as having SLDD (n ‫؍‬ 174) or non-SLDD (contiguous, multilevel; n ‫؍‬ 664). Various radiographic parameters were assessed based on T2-weighted magnetic resonance imaging (MRI). Subject demographics were assessed, and univariate and multivariate logistic regression analyses were performed.Results. Overall, 8.7% of the whole population (n ‫؍‬ 1,989) had SLDD, while it was present in 20.8% of subjects with multilevel disc degeneration (n ‫؍‬ 838). SLDD was more prevalent in male subjects (adjusted odds ratio [OR] 1.48, 95% confidence interval [95% CI] 1.04-2.10, P ‫؍‬ 0.028). SLDD was significantly associated with the presence of Schmorl's nodes (adjusted OR 2.72, 95% CI 1.78-4.15, P < 0.001), which also presented in levels with no disc degeneration. A history of disc bulge/extrusion (P ‫؍‬ 0.004) and/or a history of back injury (P ‫؍‬ 0.010) was significantly associated with non-SLDD, and a greater degree of overall severity of disc degeneration was also associated with non-SLDD. Other demographic and MRI findings did not significantly differ between groups.Conclusion. To our knowledge, this report is the first to describe the prevalence and risk factors associated with SLDD. Our study challenges the paradigm that age and biomechanics are the key factors associated with the development of disc degeneration. Although age and biomechanical factors may play a role in the manifestation of disc degeneration, our novel findings of SLDD patterns provide further awareness of and support for the notion that additional etiologic factors may play a role in the development of disc degeneration. Such factors warrant further investigation to shed light on the cause of disc degeneration.

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Section: Discussionmentioning

confidence: 99%

Intervertebral disc degeneration: New insights based on “skipped” level disc pathology

Cheung¹,

Samartzis²,

Karppinen³

et al. 2010

Arthritis & Rheumatism

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“…The average follow-up time was 12.6 years (range [10][11][12][13][14][15][16][17]. The mean age at the start of the study was 39 years and at the end of the study was 52 years.…”

Section: Radiographic Analysismentioning

confidence: 99%

“…The rationale for this is that biomechanical studies have shown that a fused part of the spine imposes increased stress on adjacent levels in animal [6,9,18,36,41] as well as in human models [3,8,10,17,25,50].…”

Section: Introductionmentioning

confidence: 99%

A prospective randomised study on the long-term effect of lumbar fusion on adjacent disc degeneration

et al. 2009

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The existence and importance of an accelerated adjacent segment disc degeneration (ASD) after lumbar fusion have previously not been demonstrated by RCTs. The objectives of this study were, to determine whether lumbar fusion in the long term accelerates degenerative changes in the adjacent disc and whether this affects the outcome, by using a prospective randomised design. A total of 111 patients, aged 18-55, with isthmic spondylolisthesis were randomised to exercise (EX, n = 34) or posterolateral fusion (PLF, n = 77), with (n = 37) or without pedicle screw instrumentation (n = 40). The minimum 10 years FU rate was 72%, with a mean FU time of 12.6 years (range 10-17 years). Three radiographic methods of ASD quantification were used, i.e. two digital radiographic measurement methods and the semi quantitative UCLA grading scale. One digital measurement method showed a mean disc height reduction by 2% in the EX group and by 15% in the PLF group (p = 0.0016), and the other showed 0.5 mm more disc height reduction in the PLF compared to the Ex group (ns). The UCLA grading scale showed normal discs in 100% of patients in the EX group, compared to 62% in the PLF group (p = 0.026). There were no significant differences between instrumented and non-instrumented patients. In patients with laminectomy we found a significantly higher incidence of ASD compared to non laminectomised patients (22/47 vs. 2/16 respectively, p = 0.015). In the longitudinal analysis, the posterior and anterior disc heights were significantly reduced in the PLF group, whereas in the EX group only the posterior disc height was significantly reduced. Except for global outcome, which was significantly better for patients without ASD, the clinical outcome was not statistically different in patients with and without ASD. In conclusion, the long-term RCT shows that fusion accelerates degenerative changes at the adjacent level compared with natural history. The study suggests that not only fusion, but also laminectomy may be of pathogenetic importance. The clinical importance of ASD seems limited, with only the more severe forms affecting the outcome.

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“…While some have proposed a genetic predisposition as a possible reason [13,24], the problem described may be attributable to a compensatory increase in the range of motion in the adjacent segments. This increase can be even higher if an inter-vertebral cage is used for fusion [8,11,12,17]. The disc superior to spondylodesis seems to be more heavily affected than the inferior [1].…”

Section: Introductionmentioning

confidence: 99%

Dynamic stabilization adjacent to single-level fusion: Part I. Biomechanical effects on lumbar spinal motion

et al. 2010

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Progression of superior adjacent segment degeneration (PASD) could possibly be avoided by dynamic stabilization of an initially degenerated adjacent segment (AS). The current study evaluates ex vivo the biomechanics of a circumferential fixation connected to posterior dynamic stabilization at the AS. 6 human cadaver spines (L2-S1) were stabilized stepwise through the following conditions for comparison: intact spine (ISP), single-level fixation L5-S1 (SLF), SLF ? dynamic AS fixation L4-L5 (DFT), and two-level fixation L4-S1 (TLF). For each condition, the moments required to reach the range of motion (ROM) of the intact whole spine segment under ±10 Nm (WSP10) were compared for all major planes of motion within L2-S1. The ROM at segments L2/3, L3/4, and L4/5 when WSP10 was applied were also compared for each condition. The moments needed to maintain WSP10 increased with each stage of stabilization, from ISP to SLF to DFT to TLF (p \ 0.001), in all planes of motion within L2-S1. The ROM increased in the same order at L3/4 (extension, flexion, and lateral bending) and L2/3 (all except right axial rotation, left lateral bending) during WSP10 application with 300 N axial preload (p \ 0.005 in ANOVA). At L4/5, while applying WSP10, all planes of motion were affected by stepwise stabilization (p \ 0.001): ROM increased from ISP to SLF and decreased from SLF to DFT to TLF (partially p \ 0.05). The moments required to reach WSP10 increase dependent on the number of fixated levels and the fixation stiffness of the implants used. Additional fixation shifts motion to the superior segment, according to fixation stiffness. Therefore, dynamic instrumentation cannot be recommended if prevention of hyper-mobility in the adjacent levels is the main target.

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Effects of lumbar spinal fusion on the other lumbar intervertebral levels (three-dimensional finite element analysis)

Cited by 90 publications

References 23 publications

Intervertebral disc degeneration: New insights based on “skipped” level disc pathology

Intervertebral disc degeneration: New insights based on “skipped” level disc pathology

A prospective randomised study on the long-term effect of lumbar fusion on adjacent disc degeneration

Dynamic stabilization adjacent to single-level fusion: Part I. Biomechanical effects on lumbar spinal motion

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