This is literally an IPSIS fact finder discussed by Zack McCormick and others ad nauseam.
Myth: Corticosteroids can be mixed with local anesthetics for injection during interventional spine procedures without concern for adverse consequences due to the interactions between two agents combined for injection.
Fact: There is in vitro evidence that ropivacaine precipitates crystal formation larger than the diameter of an arteriole when combined with either dexamethasone or betamethasone.
Hwang H, Park R, Lee WK, Leigh I-H, Lee JJ, Chung SG, Lim C, Park SJ, Kim K. Crystallization of local anesthetics when mixed with corticosteroid solutions. Ann Rehabil Med 2016;40:21-27. 3. Watkins TW, Dupre S, Coucher JR. Ropivacaine and dexamethasone: a potentially dangerous combination for therapeutic pain injections. J Med Imaging Rad Oncology 2015;59:571-577.