A Novel Cervical Sagittal Classification for Asymptomatic Population Based on Cluster Analysis.

Area of Science:

• Orthopedics
• Radiology
• Spine Surgery

Background:

• Cervical spine sagittal morphology exhibits significant individual variation.
• A standardized classification for cervical sagittal alignment is currently lacking.

Purpose of the Study:

• To introduce a novel classification system for cervical sagittal alignment in asymptomatic individuals.
• To enhance the understanding of normal cervical sagittal alignment variations.

Main Methods:

• A cross-sectional study involving 183 asymptomatic subjects.
• Measurement of global and segmental cervical sagittal parameters.
• Development of a novel classification based on cluster analysis and defined parameter ranges, validated for reliability and compared to existing methods.

Main Results:

• Four subtypes proposed: Large Lordosis (LL), Small Lordosis (SL), Straight (S), and Kyphosis (K).
• The novel classification demonstrated high inter-observer (ICC=0.856) and intra-observer (ICC=0.851-0.913) reliability, with significantly reduced measurement time compared to the Toyama method.
• SL was the most prevalent subtype (37.7%), with variations in subtype distribution observed across sex and age.

Conclusions:

• A novel, simple, and reliable cervical sagittal classification for asymptomatic populations has been successfully proposed.
• This classification system aids in understanding the spectrum of normal cervical sagittal alignment.