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Updated: Dec 11, 2025
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Anterior Cervical Discectomy and Fusion in the Ovine Model
Published on: October 5, 2009
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Adjacent Level Ossification Development Following Anterior Cervical Fusion: How Does it Affect the Next Level Disc?
Dong-Ho Lee1, Sehan Park1, Jae-Woo Park1
1Department of Orthopaedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Spine
|August 25, 2020
Summary
Adjacent level ossification development (ALOD) after anterior cervical fusion impacts spinal motion and degeneration. Severe ALOD reduces motion at the fused level but increases it at adjacent levels, potentially accelerating disc degeneration.
Area of Science:
- Spine surgery
- Orthopedics
- Degenerative disc disease
Background:
- Adjacent level ossification development (ALOD) is a known complication after anterior cervical fusion.
- Clinical implications of ALOD, particularly its effect on adjacent and next-level discs, are not well understood.
Purpose of the Study:
- To investigate the impact of ALOD on range of motion (ROM) and degenerative changes.
- To assess ROM and degeneration at the adjacent and next-level discs following anterior cervical fusion.
Main Methods:
- Retrospective matched cohort analysis of 48 patients undergoing anterior cervical instrumented fusion with minimum 2-year follow-up.
- Patients were grouped based on ALOD severity (grade 0-1 vs. 2-3).
- Assessed disc height, osteophytes, ROM, and listhesis at adjacent and next-level discs preoperatively and at follow-up.
Main Results:
- Severe ALOD (grade 2-3) significantly reduced ROM at the adjacent segment (P=0.002).
- Increased ROM was observed at the next segment in the severe ALOD group (P=0.016).
- Greater osteophyte growth, listhesis progression, and disc height reduction occurred at the next segment in the severe ALOD group (P<0.05).
Conclusions:
- Severe ALOD following anterior cervical fusion negatively impacts spinal biomechanics.
- Increased motion at the next-level disc due to severe ALOD may accelerate disc degeneration.
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