Segmental Height Decrease Adversely Affects Foraminal Height and Cervical Lordosis, But Not Clinical Outcome After...

Area of Science:

• Spine surgery
• Orthopedic research
• Biomaterials in fusion

Background:

• Anterior cervical discectomy and fusion (ACDF) is a common procedure.
• Allografts are frequently used as interbody spacers in ACDF.
• Postoperative changes in segmental height can occur, but their clinical significance is not fully understood.

Purpose of the Study:

• To investigate the clinical significance of postoperative segmental height decrease (SHD) following ACDF using allografts.
• To identify factors associated with SHD and its impact on fusion and clinical outcomes.

Main Methods:

• Retrospective review of 88 patients undergoing ACDF with allografts.
• Assessment of cervical lordosis, segmental lordosis, segmental height, foraminal height, fusion, and allograft integrity.
• Definition of significant SHD as a decrease of ≥2 mm.
• Comparison of outcomes between segments with significant SHD and those without.

Main Results:

• Significant SHD was observed in 36.4% of patients and 23.1% of segments.
• SHD segments showed significantly reduced segmental lordosis, global lordosis, and foraminal height.
• Fusion rates were lower in SHD segments (58.9% vs. 77.9%).
• No significant difference in neck or arm pain, or disability scores between patients with and without significant SHD.

Conclusions:

• Significant SHD is associated with diminished cervical lordosis and foraminal height but does not worsen clinical symptoms.
• Larger allograft size increases the risk of significant SHD.
• Allograft resorption or fracture may negatively influence fusion and contribute to SHD.