Risk factors related to accidental intravascular injection during caudal anesthesia

Recently, ultrasound-guided caudal anesthesia has been performed for postoperative pain management after lumbar spine surgery. Although it is well known that intravascular injection often occurs in the caudal part of the spine, and that this cannot be detected at the time of injection under ultrasound screening, the risk factors for intravascular injection have not been evaluated. To assess the risk index for prediction of accidental intravascular injection during caudal anesthesia, we retrospectively examined the hospital records of patients suffering from chronic low back pain who underwent sacral epidurography. Multivariate logistic regression analysis demonstrated that radicular symptoms of the lumbar spine (OR, 2.511, 95 % CI, 1.097–5.748) and duration of symptoms (OR, 1.006, 95 % CI, 1.002–1.010) were significant and independent risk factors for accidental intravascular injection during sacral epidurography. This study suggests that the incidence of accidental intravascular drug injection during caudal anesthesia would be higher in patients with chronic radicular symptoms of the lumbar spine.