Subsidence and Nonunion after Anterior Cervical Interbody Fusion with Stand-Alone Polyetheretherketone (PEEK) Cage

Comparison of titanium and polyetheretherketone (PEEK) cages in the surgical treatment of multilevel cervical spondylotic myelopathy: a prospective, randomized, control study with over 7-year follow-up

“…Subsidence of titanium cages is observed in 13 to 45 % of cases in larger series [3,25]. The reported rate of PEEK cage subsidence varies from 8 to 15 % [13,35]. Risk factors related to the cage subsidence may include endplate preparation, size of the contact area between implant and endplate, over-distraction of the involved segment, and the bone mineral density of the vertebral body.…”

Dynamic Radiographic Criteria for Detecting Pseudarthrosis Following Anterior Cervical Arthrodesis

“…I n many studies 16,17,[19][20][21][22] , the authors defined anterior cervical fusion status using only motion analysis and/or radiographic findings. However, we are aware of no standardized motion criteria for pseudarthrosis that include both the segmental angle and the interspinous distance; the criteria range from no motion to a 4°segmental angle and range from absent motion to 2 mm of interspinous motion [1][2][3] .…”

“…Unfortunately, the measurement of motion on dynamic radiographs can be inaccurate and affected by the voluntary effort of the patient [10][11][12] , giving rise to questions regarding the amount of motion on dynamic radiographs that is compatible with pseudarthrosis 1,3 . Many reports [11][12][13][14][15][16][17][18] have described radiographic parameters indistinctly, including the degree of magnification used and how it was determined whether the dynamic motion on radiographs was inadequate. Furthermore, only a few authors 6,10,15 have related their criteria to surgical confirmation of anterior cervical fusion status.…”

“…This suggests that authors of studies 1,7,[15][16][17][18]24 using the cutoff value of 2 mm of interspinous motion have overestimated their fusion rate and could have missed the pseudarthrosis cases that had interspinous motions ranging from 1 to 2 mm. Some laboratory studies 10,13,25 have also suggested an inherent inaccuracy of interspinous motion analysis because, even with solid fusion, some motion can occur between spinous processes due to elastic deformation of bone and facet joints.…”

What are the associative factors of adjacent segment degeneration after anterior cervical spine surgery? Comparative study between anterior cervical fusion and arthroplasty with 5-year follow-up MRI and CT

“…For fusion group, we only chose ACDF with only PEEK box cage without a plate. The use of cage and plate for ACDF has several merits in respect to lordotic alignment, cage subsidence and fusion rate [17,[31][32][33], but because plate fixation increases fixation force, a stress generated in the adjacent disc, these effect can increase the possibility to get ASD rather than ACDF with cage alone [17,31]. Currently, cage made of PEEK is primarily used for ACDF due to its biomechanical similarities to those of bone [17].…”