Cervical spine taper ratios: Normal tolerance limits

Area of Science:

• Neurosurgery
• Radiology
• Biomedical Engineering

Background:

• Spinal canal tapering, quantified by taper ratios, influences cerebrospinal fluid (CSF) dynamics.
• Abnormal spinal canal tapering can indicate underlying neurological conditions.
• Establishing normal ranges for cervical spine taper ratios is essential for clinical assessment.

Purpose of the Study:

• To determine the normal tolerance interval for cervical spine taper ratios.
• To provide a quantitative reference for identifying abnormal cervical spine tapering.
• To aid in the detection of conditions associated with altered CSF flow.

Main Methods:

• Retrospective analysis of cervical spine magnetic resonance imaging (MRI) studies from 78 normal patients (aged 2-55 years).
• Measurement of anteroposterior diameters to calculate C1-C4, C4-C7, and C1-C7 taper ratios.
• Calculation of 99% tolerance limits for normal taper ratios and comparison with prior studies.

Main Results:

• The 99% tolerance limits for C1-C4, C4-C7, and C1-C7 taper ratios were determined.
• Age and sex were found to be non-significant factors influencing taper ratios.
• Results aligned with previously reported taper ratios in control populations.
• Patients with syringomyelia showed taper ratios outside established normal limits.

Conclusions:

• Normal tolerance limits for cervical spine taper ratios have been defined.
• These established limits can assist in identifying spinal canal abnormalities.
• The findings support the use of taper ratios in diagnosing neurological conditions affecting CSF flow.