Utility of MRI for cervical spine clearance after blunt traumatic injury: a meta-analysis

To quantify the rate of unstable injuries detected by MRI missed on CT in blunt cervical spine (CS) trauma patients and assess the utility of MRI in CS clearance. We undertook a systematic review of worldwide evidence across five major medical databases and performed a meta-analysis. Studies were included if they reported the number of unstable injuries or gave enough details for inference. Variables assessed included severity, CT/MRI specifications, imaging timing, and outcome/follow-up. Pooled incidences of unstable injury on follow-up weighted by inverse-of-variance among all included and obtunded or alert patients were reported. Of 428 unique citations, 23 proved eligible, with 5,286 patients found, and 16 unstable injuries reported in five studies. The overall pooled incidence is 0.0029 %. Among studies reporting only obtunded patients, the pooled incidence is 0.017 %. In alert patients, the incidence is 0.011 %. All reported positive findings were critically reviewed, and only 11 could be considered truly unstable. There is significant heterogeneity in the literature regarding the use of imaging after a negative CT. The finding rate on MRI for unstable injury is extremely low in obtunded and alert patients. Although MRI is frequently performed, its utility and cost-effectiveness needs further study. There were 16 unstable injuries on follow-up MRI among 5286 patients. The positive finding rate among obtunded patients was 0.12 %. The positive finding rate among alert, awake patients was 0.72 %. MRI has a high false-positive rate; its utility mandates further studies. The use and role of "confirmatory" tests shows wide variations.