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cage_subsidence

Progression of settling with endplate collapse is defined as subsidence.

Subsidence irrespective of the measurement technique or definition does not appear to have an impact on successful fusion and/or clinical outcomes. A validated definition and standard measurement technique for subsidence is needed to determine the actual incidence of subsidence and its impact on radiographic and clinical outcomes 1).

PEEK cages showed a high rate of secondary subsidence (32%) 2).

Titanium Wing cage-augmented ACDF was associated with comparatively good long-term results. Subsidence was present but did not cause clinical complications. Furthermore, radiological studies demonstrated that the physiological alignment of the cervical spine was preserved and a solid bone arthrodesis was present at 2 years after surgery 3).

Case series

2017

Mende et al. performed a retrospective analysis of ACDF patients from 2004 to 2010. Numeric analog scale (NAS) score pre-op and post-op, Oswestry Disability Index (ODI) on x-rays, endplate (EP) and cage dimensions, implant position, lordotic/kyphotic subsidence patterns (>5°), and cervical alignment were recorded. Subsidence was defined as height loss >40%. Patients were grouped into single segment (SS), double segment (DS), and plated procedures. We included 214 patients. Prevalence of subsidence was 44.9% overall, 40.9% for SS, and 54.8% for DS. Subsidence presented mostly for dorsal (40.7%) and mid-endplate position (46.3%, p < 0.01); dorsal placement resulted in kyphotic (73.7%) and central placement in balanced implant migration (53.3%, p < 0.01). Larger cages (>65% EP) showed less subsidence (64.6 vs. 35.4%, p < 0.01). There was no impact of subsidence on ODI or alignment. NAS was better for subsided implants in SS (p = 0.06). Cages should be placed at the anterior endplate rim in order to reduce the risk of subsidence. Spacers should be adequately sized for the respective segment measuring at least 65% of the segment dimensions. The cage frame should not rest on the vulnerable central endplate. For multilevel surgery, ventral plating may be beneficial regarding construct stability. The reduction of micro-instability or over-distraction may explain lower NAS for subsided implants 4).

1)
Karikari IO, Jain D, Owens TR, Gottfried O, Hodges TR, Nimjee SM, Bagley CA. Impact of Subsidence on Clinical Outcomes and Radiographic Fusion Rates in Anterior Cervical Discectomy and Fusion: A Systematic Review. J Spinal Disord Tech. 2014 Feb;27(1):1-10. PubMed PMID: 24441059.
2)
König SA, Spetzger U. Distractable titanium cages versus PEEK cages versus iliac crest bone grafts for the replacement of cervical vertebrae. Minim Invasive Ther Allied Technol. 2013 Nov 29. [Epub ahead of print] PubMed PMID: 24289173.
3)
Schmieder K, Wolzik-Grossmann M, Pechlivanis I, Engelhardt M, Scholz M, Harders A. Subsidence of the wing titanium cage after anterior cervical interbody fusion: 2-year follow-up study. J Neurosurg Spine. 2006 Jun;4(6):447-53. PubMed PMID: 16776355.
4)
Mende KC, Eicker SO, Weber F. Cage deviation in the subaxial cervical spine in relation to implant position in the sagittal plane. Neurosurg Rev. 2017 Apr 4. doi: 10.1007/s10143-017-0850-z. [Epub ahead of print] PubMed PMID: 28374128.
cage_subsidence.txt · Last modified: 2017/06/18 11:23 by administrador