Aspirin therapy discontinuation and intraoperative blood loss in spinal surgery: a systematic review

The purpose of this study was to determine the effect of aspirin therapy discontinuation on intraoperative blood loss in spinal surgery. We searched Medline and Google Scholar 1946 to January 2017 inclusive for case-control studies, cohort studies, and controlled trials reporting intraoperative blood loss during spinal surgery in patients on pre-operative aspirin. Other outcome measures reported in the eligible studies were collected as secondary outcomes. Two reviewers independently screened and extracted data from each study. Five retrospective cohort and two case-control studies were eligible for inclusion. Of the 1173 patients identified, 587 patients were never on aspirin (Ax), 416 patients had aspirin discontinued before surgery (Ad), ranging from 3 to 10 days, and 170 patients had aspirin continued until surgery (Ac). Six out of seven studies reported no statistically significant difference in intraoperative blood loss irrespective of aspirin discontinuation. Meta-analysis was not possible due to high risk of bias. Of the secondary outcome measures, operative time and postoperative complications were most commonly reported. One of six studies evaluating operative time reported a significantly longer operative time in the Ad group compared with the Ac group. The overall risk of postoperative haematoma in Ax, Ad, and Ac groups is 0.2% (n/N = 1/587), 0.2% (n/N = 1/416), and 1.2% (n/N = 2/170), respectively. No study reported a statistically significant difference in postoperative complications. There is no strong evidence demonstrating a difference in intraoperative blood loss, operation time, and postoperative complications, irrespective of aspirin discontinuation. This is, however, based on a limited number of studies and higher-quality research is required to answer this question with a higher degree of confidence.