Cerebral fat embolism after traumatic bone fractures: a structured literature review and analysis of published case reports

Background The incidence of cerebral fat embolism (CFE) ranges from 0.9-11%, with a mean mortality rate of around 10%. Although no univocal explanation has been identified for the resulting fat embolism syndrome (FES), two hypotheses are widely thought: the 'mechanical theory', and the 'chemical theory'. The present article provides a systematic review of published case reports of FES following a bone fracture. Methods We searched MEDLINE, Web of Science and Scopus to find any article related to FES. Inclusion criteria were: trauma patients; age >= 18 years; and the clinical diagnosis of CFE or FES. Studies were excluded if the bone fracture site was not specified. Results One hundred and seventy studies were included (268 cases). The male gender was most prominent (81.6% vs. 18.4%). The average age was 33 years (+/- 18). The mean age for males (29 +/- 14) was significantly lower than for females (51 +/- 26) (p < 0.001). The femur was the most common fracture site (71% of cases). PFO was found in 12% of all cases. Univariate and multivariate regression analyses showed the male gender to be a risk factor for FES: RR 1.87 and 1.41, respectively (95%CI 1.27-2.48, p < 0.001; 95%CI 0.48-2.34, p < 0.001). Conclusions FES is most frequent in young men in the third decades of life following multiple leg fractures. FES may be more frequent after a burst fracture. The presence of PFO may be responsible for the acute presentation of cerebral embolisms, whereas FES is mostly delayed by 48-72 h.