J Korean Soc Spine Surg.  2008 Sep;15(3):133-139. 10.4184/jkss.2008.15.3.133.

Radiologic Changes of Adjacent-level after Anterior Cervical Spinal Fusion: Midterm Follow-up Results

• Kang MS
• Lee KY
• Hwang JS

• KMID: 1747196
• DOI: http://doi.org/10.4184/jkss.2008.15.3.133

Abstract

STUDY DESIGN: We studied the changes of the adjacent-level after performing anterior cervical interbody fusion.
OBJECTIVES
We retrospectively analyzed the radiologic changes such as the degenerative changes and osteophyte formation in the adjacent-level and the affecting factors that affect the changes of the adjacent level after anterior cervical interbody fusion. SUMMARY OF LITERATURE REVIEW: We studied the patients who were more than sixty years old and who had more degeneration at the time of operation and who developed symptomatic new disease within the first four years after their procedure. When the interbody spacer was shortened by 10% to simulate subsidence, the plate lost nearly 70% of its load-sharing capabilities.
MATERIALS AND METHODS
All the patients were treated with a plate and an autoiliac bone graft. We reviewed the correlation between the changes in the adjacent level and the factors that included gender, age, the fused segments, the plate-to-disc distance, the preoperative degenerative changes in the adjacent level, subsidence of the graft bone, the height of the graft bone, fracture and dislocation, and loosening of the implant.
RESULTS
Radiologic changes in the adjacent-level were seen in 35 cases and these cases included 27 cases in the upper level and 17 cases in lower level. Adjacent level changes were seen in 27 of the 37 (73%) patient who were above 50 years old. Adjacent level changes were seen in 19 (90.5%) of the 21 cases that had preoperative cephalad level degeneration, and adjacent level changes were seen in 9 (81.8%) of the 11 cases that had preoperative caudal degeneration. Adjacent level degeneration developed or increased in the cases of subsidence of a graft over 2 mm.
CONCLUSIONS
The patients who undergo anterior cervical interbody fusion need to be continuously followed up because radiologic changes can increase in the case with degenerative change in the adjacent segment and subsidence of the bone graft of more than 2 mm.

MeSH Terms

Dislocations
Follow-Up Studies
Humans
Osteophyte
Retrospective Studies
Transplants

Figure

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  Fig. 1. (A) 60 years old male has a HNP in C 5-6 level. Preoperative plain lateral radiogragh shows no degenerative changes in upper and lower adjacent-levels. (B) Postoperative plain lateral radiogragh shows anterior interbody fusion with anterior plate and upper and lower plate-disc distance are closer than 5 mm. (C) Last follow-up (postoperative 28 months) plain lateral radiogragh shows no graft subsidence and no degenerative changes in adjacent-levels.

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  Fig. 2. (A) 54 years old male has a HNP in C 5-6 level. Preoperative plain lateral radiogragh shows degenerative changes in upper and lower adjacent-levels. (B) Postoperative plain lateral radiogragh shows anterior interbody fusion with anterior plate and upper and lower plate-disc distance are closer than 5 mm. (C) Last follow-up (postoperative 25 months) plain lateral radiogragh shows graft subsidence more than 2 mm and grade 1 change in upper adjacent level and grade 2 change in lower adjacent level.

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