SYMPOSIUM: CURRENT CONCEPTS IN CERVICAL SPINE SURGERY
Operated and Adjacent Segment Motions for Fusion versus
A Pilot Study
Tomoya Terai MD, PhD, Ahmad Faizan PhD,
Koichi Sairyo MD, PhD, Vijay K. Goel PhD
Published online: 30 October 2010
? The Association of Bone and Joint Surgeons1 2010
(ACDF) represent the standard treatment for cervical
spondylolytic radiculopathy and myelopathy. To achieve
solid fusion, appropriate compressive loading of the graft
and stability are essential. Fusion may lead to adjacent
segment degeneration. Artificial discs have been intro-
duced as motion-preserving devices to reduce the risk of
We therefore asked: (1) Does the use
of a plate reduce motion at the operated level and bone
graft compression compared to fusion with bone graft
alone; and (2) is adjacent-segment motion higher after
fusion with a plate?
Motions and compressive loads in the graft were
quantified for intact, C4–C5 ACDF without and with a
plate, and total disc arthroplasty in human cadaver spines.
At the surgery level all motions decreased for
ACDF with a plate. The motions were similar to intact
Anterior cervical discectomy and fusion
motions after total disc arthroplasty. The motions across
the adjacent segment increased after fusion in all loading
modes except lateral bending and were closer to the intact
for the total disc arthroplasty case. The plate maintained a
compressive load on the graft with a maximum increase in
Unlike fusion, the arthroplasty can restore
motion to normal at the surgery and adjacent segments,
compared to fusion cases. A cervical plate with a pre-
compression of the graft provides enhanced stability and
fusion due to improved compression.
Our findings support the clinical
observations that fusion may lead to the degeneration of the
adjacent segments. Disc arthroplasty may be able to cir-
cumvent the adjacent segment degeneration.
Anterior cervical discectomy and fusion (ACDF) repre-
sents a widely accepted surgical procedure to manage
cervical spondylolytic radiculopathy and myelopathy
symptoms. Cloward  and Robinson and Smith 
originally described noninstrumented cervical arthrodesis,
but these approaches reportedly had nonunion rates ranging
from 8.3% to 12% [22, 35, 36]. Bohler  in 1967 reported
what was likely the first use of anterior cervical plate and
screw fixation in a patient with cervical spinal trauma. In
the early 1980s, Caspar et al.  popularized anterior
cervical plating. The constructs of the procedure had lim-
ited fixation at the screw-plate interface, leading to early
screw backouts. However, the concept facilitated graft
compression, allowing for a better chance of bony fusion.
ACDF is a reliable procedure with a fusion rate of
between 85% and 95% [2, 26]. Cervical plates are used to
One or more of the authors (VKG) has received funding from
DePuy Spine, Inc, Raynham, MA.
Each author certifies that his or her institution approved the human
protocol for this investigation and that all investigations were
conducted in conformity with ethical principles of research, and that
informed consent for participation in the study was obtained.
This work was performed at The University of Toledo.
T. Terai, A. Faizan, V. K. Goel
Engineering Center for Orthopaedic Research Excellence
(E-CORE), Departments of Bioengineering and Orthopaedic
Surgery, Colleges of Engineering and Medicine, University
of Toledo, Toledo, OH, USA
T. Terai, K. Sairyo (&)
Department of Orthopedics, University of Tokushima, School
of Medicine, 3-18-15, Kuramoto, Tokushima 770-8503, Japan
Clin Orthop Relat Res (2011) 469:682–687
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