Related Experiment Videos
Occipital morphology. An anatomic guide to internal fixation
R I Zipnick1, A A Merola, J Gorup
1Department of Orthopaedic Surgery, State University of New York, Health Science Center at Brooklyn, USA.
Spine
|August 1, 1996
Summary
This study analyzed occipital bone thickness in cadavers to guide surgical fixation. The thickest bone for safe screw placement is consistently located above the superior nuchal line.
Area of Science:
- Anatomy
- Orthopedic Surgery
- Neurosurgery
Background:
- Occipital bone variability necessitates new internal fixation techniques.
- Anatomic study of 30 cadaveric occiputs to assess bone thickness and variability.
- Evaluation of radial thickness, occipital locations, and gender differences.
Purpose of the Study:
- Determine occipital bone morphologic characteristics.
- Identify significant bone variability.
- Locate the position of greatest bone thickness for safe internal fixation.
Main Methods:
- Sectioning of 26 skulls to analyze inner, middle, and outer table contributions to thickness.
- Determination of the optimal angle for maximal cortical purchase.
- Statistical analysis of mean values and variance for thickness and variability.
Main Results:
- The thickest bone (17.55 mm) is located superiorly on the nuchal line, 43 degrees from the baseline.
- Bone thickness decreases radially; superior thickness exceeds inferior thickness (P < 0.05).
- Minimal gender differences and variability; inner table contributes 10% to thickness.
Conclusions:
- Unicortical purchase above the superior nuchal line is safe, with low risk of venous penetration.
- Internal fixation devices should consider occipital bone thickness distribution.
- Attention to cervical morphology enhances occipitocervical arthrodesis success rates.