Cervical Cord Neuropraxia (CCN) and incomplete cord injuries such as Central Cord Syndrome (CCS) are more prevalent in patients with congenitally narrow spinal canals. The aim of this study was to identify if racial groups were over represented in patients with incomplete cord injuries, and if there was an ethnic variation in mid sagittal cervical spine diameter in the general population.

CT scan was used to measure the mid sagittal diameter of the C3 to C7 cervical vertebrae in a group of 166 sequential trauma patients who had CT scans of the cervical spine at Middlemore Hospital. Patient’s race was that declared by the patient. Four different observers used computer digitisation to measure the mid sagittal diameters and mean sagittal diameter for each level. Measurements were compared between races.

Maori cervical spine canals were found to be 1mm smaller than Europeans (P values less than 0.005) whilst Polynesians had on average a 2mm smaller mid sagittal diameter compared to Europeans (all P values less than 0.001).

This study has demonstrated that Polynesians were over represented in the group of patients who experienced CCS or Transient Cervical Neuropraxia. CT scan assessment demonstrated that both Maoris and Polynesians had significantly narrower canals than their European counterparts. The implications of this study are that Maori and Polynesians involve in high impact activities such as rugby may be at increased risk of incomplete or complete spinal cord injuries. There is however no reliable screening tool available for congenital spinal canal stenosis.

Introduction Cervical cord neuropraxia (CCN) and incomplete cord injuries such as central cord syndrome (CCS) are more prevalent in patients with congenitally narrow spinal canals. At Middlemore Hospital, Polynesian and Maori males are frequent in that group of patients who have experienced a single episode of CCN or CCS. The aim of this study was determine if these racial groups were over-represented in patients with incomplete cord injuries, and if there was an ethnic variation in mid-sagittal diameter of the cervical spine in the general population.

Methods A chart review of all patients who experienced either CCS or CCN in the absence of significant fracture dislocation or disc prolapse was performed. The ethnic origin of these patients was noted. CT scan was used to measure the mid-sagittal diameter of the spinal canal from C3 to C7 in a group of 166 sequential trauma patients who had CT scans of the cervical spine at Middlemore Hospital. Patient’s race was that declared by the patient. Four different observers used computer digitisation to measure the mid-sagittal diameters and mean sagittal diameter for each level. Measurements were compared between races.

Results Between 2000 and 2004, eight patients (7 males, 1 female) were noted to have a central cord syndrome or cervical neuropraxia in the absence of fracture dislocation, acute disc prolapse or developmental spinal stenosis. Five patients were Polynesian, two Maori and one European. CT scan assessment of the 166 patients noted Maori cervical spine canals to be 1mm smaller than Europeans (P values less than .005 at all levels of the C-spine) whilst Polynesians had on average 2mm smaller mid-sagittal diameter compared to Europeans (all P values less than 0.001).

Discussion Patients with congenital reduction in spinal canal diameter have an increased risk of transient neuropraxia (Torg J. J Bone Joint Surg. 1996), neurological injury (Matsura P et al. J Bone Joint Surg. 1989) and more significant myelopathy in the presence of trauma (Eismont FJ et. al. Spine 1984). This study demonstrates that Polynesians were over-represented in the group of patients who experienced central cord syndrome or transient cervical neuropraxia. CT scan assessment demonstrated that both Maoris and Polynesians had significantly narrower canals than their European counterparts. Previous studies have demonstrated that South African blacks have significantly narrow mid-sagittal diameter than Caucasians (Taitz C. Clin Anat. 1996). The implications of this study are that Maori and Polynesians involved in high impact activities such as rugby may be at increased risk of incomplete or complete spinal cord injuries. There is however no reliable screening tool available for congenital spinal canal stenosis.