Do universal critical spine dimensions exist

The effective spinal canal diameter is the fundamental index which will determine whether a patient of any compressive cervical spine pathology will get neurological deficit or not. So we analysed this index in our subset of population. 180 subjects with normal or near normal cervical spine magnetic resonance imaging were included. Antero-posterior diameter and transverse diameter of spinal canal from C3 to C7 was measured. Similarly spinal cord antero-posterior and transverse diameters were measured. Space available for cord was calculated at each of these levels in both sexes as the difference between the antero-posterior diameter of the spinal canal and that of the spinal cord. The mean value with standard deviation of cervical spinal canal diameter antero-posterior diameter at C3, C4, C5, C6 and C7 was 13.69±1.248, 13.34±1.186, 13.15±1.233, 13.12±1.275 and 13.73±1.226 mm respectively. The spinal cord antero-posterior diameter at the same level was 7.61±0.728, 7.58±0.677, 7.40±0.653, 7.12±0.657 and 6.69±0.622 mm respectively. The mean cervical spinal canal diameter of the local population in our region is different from the rest of the country. This has two implications; first the ancestral lineage is matching with some remote races of the world for which a detailed study may be needed. Secondly the dimension at which we call critical stenosis may be different in the region as compared with the rest of the country.