Cervical adjacent segment degenerative disease
; Is it a natural history or fusion disease?
-comparison between adjacent level of fusion
and non-fusion segmentByung-Wan Choi, M.D., Byung-Ryeul Choi M.D.,*
Kyung-Jin Song, M.D. * and Kwang-Bok Lee, M.D.*
Departments of Orthopedic Surgery
Gwangju Veterans Hospital,
Chonbuk National University Hospital *
-We have no financial relationships to disclose-
PURPOSE
The purpose of this study was to evaluate the
fusion itself can affect the adjacent segment
degeneration or disease formation by
comparing the radiological and clinical findings
between adjacent to fusion segment and nonfusion segment in single level anterior fusion
cases.
Demographic Data
Adjacent to fusion level
(Group A)
Adjacent above level
Fusion level
Adjacent below level
Adjacent to non fusion level
(Group B)
Natural Segment
Fusion level
Radiological criteria of
degeneration (Criteria I)
1. Modified Hilibrand`s adjacent segmental disc degeneration.
-JBJS 1999Grade
Disease
Plain Radiography
----------------------------------------------------------------------I
None
Normal
II
Mild
Narrowing of disc space (<50%),
no posterior osteophytes
III
Moderate
50< X<75% of normal disc height,
posterior osteophyte
IV
Severe
> 75% of disc height
posterior osteophyte
---------------------------------------
Radiological criteria of
degeneration (Criteria II)
2. Development of adjacent-level ossification
- Park et al, JBJS 2005-
Grade I : none
Grade III : across > 50 %
of the disc space
Grade II : extended across
< 50% of the disc space
Grade IV :
complete bridging
Radiological criteria of
degeneration (Criteria III)
3. Segmental instability
- More than 3mm displacement in flexion/extension
- Abnormal motion
-Dvorak et al, 1988 Spine-
Flex
Ext
Flex
Ext
62 Ms
Adjacent segment disease
- interbody fusion may lead to increases in mechanical stress at
adjacent disc levels, thereby accelerating degenerative changes
and producing clinical symptoms with time: the so-called
‘adjacent segment disease’.
- Clinical evaluation of new radicular or myelopathic symptom
occurrence for evaluation of ‘adjacent segment disease’.
→ Follow up MRI was performed.
RESULTS
Incidence of radiological
degenerative change
1. The percentage of the cases showed degenerative change
(according to fusion or not)
Group A Group B
38/457(8%)
Incidence of radiological
degenerative change
2. The number of the cases showed degenerative change
(in the cases of adjacent to fusion)
Group A
Analysis according to
radiographic criteria
(Criteria I) (Criteria II) (Criteria III)
Incidence of
degenerative disease
Total: 4 cases/ 87 patient (4%)
In group A: 2/174 segment(1%) → 1 re-operation (58ms)
58 Ms
Incidence of
degenerative disease
Total: 4 cases/ 87 patient (4%)
In group B: 2/283 segment(0.7%) → 1 re-operation(64ms) p=0.59
64 Ms
CONCLUSION
Fusion itself can accelerate the severity of adjacent level
degeneration as compared with non-fusion.
But there was no correlation in the incidence of
symptomatic adjacent segment diseases according to the
fusion in single level anterior cervical arthrodesis for the
degenerative cervical diseases.
Adjacent segment disease is more a result of the natural
history.