Risk factors for symptomatic hematoma following cervical spine surgery: a systematic review and meta-analysis

This study aimed to investigate the risk factors for symptomatic hematoma (SH) after cervical spine surgery, thereby providing evidence-based guidance for the early prevention, timely intervention, and appropriate management.

Relevant observational studies were retrieved from PubMed, Embase, the Cochrane Library, and Web of Science from inception to September 2025. Meta-analyses were performed to assess potential risk factors across several domains, including patient demographics, comorbidities, antithrombotic therapy, preoperative evaluation, and surgical factors. The odds ratio (OR), weighted mean difference (WMD), and 95% confidence interval (CI) were adopted to evaluate associated factors. Subgroup analyses, meta-regression, and sensitivity analyses were conducted.

Seventeen studies involving 564,700 patients were included. The overall incidence of SH was 0.11% (608/564,700), with individual study estimates ranging from 0.03 to 1.51%. The meta-analysis identified the male sex (OR = 1.68, 95% CI 1.39 to 2.03), advanced age (WMD = 2.53 years, 95% CI 1.57 to 3.48), presence of ossification of the posterior longitudinal ligament (OPLL) (OR = 3.38, 95% CI 1.54,7.41), and undergoing anterior cervical corpectomy and fusion (ACCF) (OR = 1.71, 95% CI 1.26 to 2.31) as being significantly associated with an increased risk of SH after cervical spine surgery Meta-regression revealed that male proportion significantly modified the OPLL-SH association. The subgroup analysis results showed that in study populations with a lower proportion of male participants, OPLL was significantly associated with an increased risk of postoperative SH (when the male proportion < 60%, OR = 7.89, 95% CI 4.02 to 15.49); whereas no significant association was observed in study populations with a higher male proportion (when the male proportion ≥ 60%, OR = 1.42, 95% CI 0.87 to 2.33). Prolonged operative duration was associated with SH (WMD = 13.66 min, 95% CI 3.97 to 23.35), but this relationship was substantially influenced by factors related to surgical complexity, as differences in the number of surgical segments explained a substantial portion (76.96%) of the heterogeneity observed across studies. No significant associations were observed for body mass index (BMI), smoking history, common comorbidities, antithrombotic therapies, and most laboratory parameters. A statistically significant but clinically small difference was noted for preoperative PT (WMD = 0.20 s, 95% CI 0.07 to 0.33).

Male sex, advanced age, OPLL, and ACCF were identified as being significantly associated with an increased risk of SH after cervical spine surgery. Importantly, male sex also acts as an effect modifier, substantially influencing the association between OPLL and hematoma risk. Prolonged operative duration was linked with an increased risk of SH, though this relationship was substantially influenced by factors related to surgical complexity. These findings underscore the importance of comprehensive preoperative risk assessment that considers both individual factors and their potential interactions, alongside meticulous surgical technique, for effective hematoma prevention.