Introduction Intravascular injection of a local anesthetic can lead to life-threatening complications, such as deficits in neurological function after caudal epidural block. This study aimed to determine whether the intravascular injection rate of the Tuohy needle is lower than that of the Quincke needle during an ultrasound-guided caudal block. Methods Two-hundred and thirty patients were randomized into the Quincke (n=115) and the Tuohy (n=115) needle groups. The randomly selected needle was introduced at a 45 degrees angle until it penetrated the sacrococcygeal ligament under ultrasound guidance, and intravenous injections were analyzed using contrast-dyed digital subtraction angiography. The relationship between the incidence of intravascular injection and independent variables, including needle type, patient demographics, history of lumbosacral surgery, use of anticoagulants, anatomic variables of the sacrum, presence of bony contact during the procedure, and the number of needle repositioning under ultrasound guidance, were examined. Results Intravascular uptake of contrast medium was surveyed in 25/230 (10.9%) caudal blocks using digital subtraction angiography (DSA). The incidence of intravascular uptake was 13.9% (16/115) using the Quincke needle and 7.8% (9/115) using the Tuohy needle (p=0.14). Although the needle tip type was not associated with the rate of intravascular injection, the occurrence of bony contact during the procedure demonstrated a relationship with the intravenous injection (p<0.01). Conclusions The overall incidence of inadvertent intravascular injections during ultrasound-guided caudal block confirmed using DSA was 10.9%. Tuohy needles did not reduce intravascular injection rates during the ultrasound-guided caudal block.
