Dimensions of the spinous process and interspinous space: a morphometric study

Area of Science:

• Spinal anatomy and biomechanics
• Orthopedic device development
• Surgical implant design

Background:

• Interspinous devices are used for spinal stabilization.
• Accurate anatomical data is crucial for device design and patient selection.
• Previous studies may lack specific data for East Asian populations.

Purpose of the Study:

• To quantify spinous process (SP) and interspinous space dimensions in an East Asian cohort.
• To establish a morphological basis for developing effective interspinous devices.
• To identify anatomical variations relevant to implant design and placement.

Main Methods:

• Retrospective analysis of anatomical parameters from 120 patients.
• Measurements included SP height, length, width, cortical thickness, spino-laminar (S-L) angle, and interspinous distance (supine, standing, dynamic).
• Correlations with age and gender were investigated.

Main Results:

• L3 exhibited the greatest SP height, length, cortical thickness, and S-L angle; S1 had the greatest width.
• Interspinous distance decreased significantly from L2-3 to L5-S1 and was larger in supine vs. standing posture at L5-S1.
• SP cortical thickness tapered anteriorly; S-L angle decreased from L3 to S1. Males had larger dimensions than females. Aging correlated with increased width and decreased distance.

Conclusions:

• The interspinous space is wider anteriorly with thicker anterior cortex, suggesting optimal anterior implant positioning.
• Interspinous space variability with posture and age necessitates careful device sizing.
• Gender-specific anatomical differences must be considered in implantable device design.