Influence of an ultrasound-guided catheter-over-needle technique on the incidence of intravascular injection during caudal epidural injections: a prospective, randomized clinical trial.

Aim: Caudal epidural injection is used for lumbosacral radicular pain but there is a risk of vascular injection. An ultrasound-guided catheter-over-needle technique was proposed to reduce this risk. This study compared the incidence of vascular injections between the catheter-over-needle and Tuohy needle methods for caudal epidural injections.

Material and methods:  This prospective, randomized clinical trial included patients aged ≥19 years with degenerative lumbar disease accompanied by radicular pain who were unresponsive to non-invasive treatments and scheduled for caudal epidural injection. The participants were randomized into two groups: catheter-over-needle and Tuohy needle groups. Under ultrasound guidance, the contrast medium was injected and observed in real time using fluoroscopy. An independent physician assessed the vascular injection rates.

Results: The incidence of vascular injection was significantly lower in the catheter-over-needle group (15.7%) than in the Tuohy needle group (37.5%; p=0.014). Chronic pain lasting >12 months was a significant risk factor for vascular injection (p=0.035). However, no statistically significant association was found between sacral opening depth and vascular injection, although the sacral opening depth was shorter in patients who received intravascular injections.

Conclusions: The catheter-over-needle technique significantly reduces the risk of vascular injection. The depth of the sacral opening may also influence vascular injection.