Safety of spinal anaesthesia in the East African population: assessment of spinal cord termination level at and above L2 vertebra in adults.

BACKGROUND

While spinal anaesthesia is a widely used technique, failure to accurately identify the L3-L4 intervertebral space (IVS) during the procedure may expose a patient to a needlestick injury to the spinal cord.

OBJECTIVES

This study aimed to determine the proportion of Conus Medullaris Terminations (CMT) at or above the L2 vertebra in a black East African population and identify any age or gender-based variations.

METHODOLOGY: A prospective observational study of lumbar spine MRI was conducted on 331 patients who had no vertebral deformities or prior spine surgeries. Two radiologists assessed the CMT level by consensus, referencing the nearest vertebral segment divided into thirds and the intervertebral disc.

RESULTS

The median CMT was at Lower third of first lumbar vertebra (LL1)[UT12-LL3], with non-significant variation due to gender (p = 0.057), and age (p = 0.272). The proportion of CMT at or above the L2 vertebra was 97.9% with no significant variation due to age (p = 0.983) or gender (p = 0.977) and, CMT at the L1 vertebra and above was 66.5%, with significant variation with age (p = 0.084), but not with gender (p = 0.265). With the risk of a spinal needle being inaccurately placed 1 or 2 intervetertebral spaces (IVS) above the target, 2.1% (L2-L3 IVS) and 33.5% (L1-L2 IVS) of spinal cords may be exposed to potential neuraxial injury respectively. Risk of exposure to neuraxial injury at L2-L3 IVS was double that seen in other studies of subjects without vertebral deformities.

CONCLUSION

The increased risk of iatrogenic neuraxial injury during spinal anaesthesia highlights the need for thorough training and supervision of healthcare providers, especially non-anaesthetists, performing diagnostic lumbar punctures.