Prevalence of hematoma after anterior cervical spine surgery: A meta-analysis

Background: Hematoma is a well-known complication following anterior cervical spine surgery. A lot of lit-eratures have reported the incidence of hematoma but no meta-analysis of the epidemiological data on hematoma has been published. Objective: The purpose of this review is to investigate the prevalence of hematoma following anterior cervical spine surgery by meta-analysis. Methods: PUBMED, CNKI and WANFANG database were searched for articles reported the incidence of hematoma following anterior cervical spine surgery. Sample size and number of hematoma were extracted. Incidence rate with 95% confidence intervals (CI) were calculated for each articles. Then we pooled the data to derive a pooled incidence rate and 95% CI. Data analysis was conducted with the software STATA 12.0. Results: A total of 95 studies with 34497 patients were included in the final analysis. The pooled analysis showed that the prevalence of total hematoma was 0.8% (95% CI 0.7%-1.0%), that of wound hematoma 1.0% (95% CI 0.7%-1.2%) and epidural hematoma 0.4% (95% CI 0.3%-0.5%). In anterior cervical corpectomy and fusion (ACCF) and anterior cervical decompression and fusion (ACDF) subgroup, the prevalence of hematoma were 0.4% and 1.0% respectively. In cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) subgroup, the prevalence of hematoma were 0.3% and 4.2% respectively. In China, America, France, Germany and Norway subgroup, the prevalence of hematoma were0.7%, 1.0%, 0.5%, 1.7% and 1.4% respectively. In Chinese and English subgroup, the prevalence of hematoma were 0.7% and 1.1% respectively. In retrospective, prospective and randomized controlled trial (RCT) subgroup, the prevalence of hematoma were 0.8%, 1.4% and 1.0% respectively. Conclusions: Anterior cervical spine surgery is associated with higher risk of hematoma particularly in wound hematoma, OPLL patients, ACDF surgery and Germany subgroup. These figures may be useful in the estimation of the probability of hematoma following anterior cervical spine surgery. Considering the statistical heterogeneity and publication bias, this conclusion should be interpreted cautiously.