Authors: Auerbach JD, Anakwenze OA, Milby AH, Lonner B, Balderston RA.
Source: Spine Volume 36 - Issue 25 -
Auerbach et al. report that compensation for the loss of motion at the operative level in ACDF is seen throughout the unfused cervical spine. Cervical disc arthroplasty, however, increases total cervical ROM compared with ACDF and maintains a physiologic distribution of ROM throughout the cervical spine at 2 years.
The authors state that: "The development of symptomatic adjacent segment disease after ACDF has served as the impetus for the development of motion-preserving alternatives, most notably cervical disc arthroplasty. While previous reports have evaluated device-level and total cervical motion, no study has comprehensively quantified the relative contribution made from each of the adjacent levels to total cervical ROM in TDR-C and ACDF".
Auerbach et al.
performed radiographic review of 187 randomized patients. This is a
multicenter, prospective, randomized trial comparing TDR-C with ACDF
for one-level cervical disc disease. There were 93 TDR-C and 94 ACDF
patients included. To evaluate total cervical ROM and relative
contribution to total ROM from each level from C2 to C7 preoperatively
and at 24 months, ROM measurements were performed independently using
quantitative motion analysis, a custom digitized image stabilization
The authors found that: "The most common operative level was C5/C6 (57%) followed by C6/C7 (34%). At 2 years, the TDR-C group underwent a statistically greater improvement in total cervical ROM (+5.9°) compared with ACDF (–0.8°, P = 0.001). In TDR-C, the relative contributions to total cervical ROM from the operative level and each caudal and cranial adjacent level were statistically equivalent from baseline to 24 months. In contrast, ACDF patients had significantly reduced contribution to total cervical ROM from the operative level (by 15%, P < 0.001), and significantly elevated contribution from the caudal adjacent level (by 5.9%, P < 0.001), first cranial adjacent level (by 3.3%, P < 0.001), second cranial adjacent level (by 5.3%, P < 0.001), and third cranial adjacent level (by 3.0%, P<0.001)".
The authors concluded that compensation for the loss of motion at the operative level in ACDF is seen throughout the unfused cervical spine. Cervical disc arthroplasty, however, increases total cervical ROM compared with ACDF and maintains a physiologic distribution of ROM throughout the cervical spine at 2 years, potentially lowering the risk for adjacent segment breakdown.
Link for the abstract: http://www.ncbi.nlm.nih.gov/pubmed/21508886
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