Postoperative Hematomas in the Era of Outpatient Mastectomy: Is Ketorolac Really to Blame?

Background: Enhanced recovery after surgery (ERAS) protocols following mastectomy with or without implant-based breast reconstruction (IBBR) include ketorolac for multimodal perioperative analgesia. There are concerns that ketorolac could be associated with increased risk of postoperative hematoma formation. Methods: Retrospective review of patients undergoing mastectomy with or without IBBR between January 2013 and December 2019 at a single institution. Patients received 15 mg, 30 mg, or no ketorolac depending on ERAS protocol adherence, patient characteristics, and surgeon preference. Clinically significant hematoma was defined as requiring surgical intervention on day of surgery or postoperative day 1. Patients were compared by demographics, surgical characteristics, ketorolac dose, and hematoma prevalence. Univariable and multivariable logistic regression evaluated hematoma formation odds. Results: Eight hundred patients met inclusion criteria: 477 received ketorolac. Those who received ketorolac were younger, had lower ASA scores, were more likely to have bilateral procedures and undergo concomitant IBBR, had longer operative times, were less likely to take antiplatelet or anticoagulation medications, had higher PACU pain scores, and had higher incidence of hematomas requiring surgical intervention. Of the cohort, 4.4% had clinically significant hematomas. The 15 mg and 30 mg ketorolac groups had similar prevalence (6.0% vs 5.8%, p = 0.95). On univariable regression, there were increased odds of hematoma formation in patients who were younger, had bilateral procedures, had longer OR times, and who received ketorolac. On multivariable regression, none of the prior variables remained significant. Conclusion: After accounting for associations with longer operative times, concomitant IBBR, and bilateral procedures, ketorolac administration did not remain an independent risk factor for hematoma formation.