BACKGROUND: Whereas traditional image guidance for placement of transforaminal epidural steroid injections (TFESI) has been fluoroscopy, it has disadvantages including inability to identify soft tissue, radiation exposure, and contrast administration need. Several studies found that ultrasonography is reliable in localizing lumbar nerve root. Few have investigated the feasibility of performing ultrasound guided TFESI in the lumbar spine. This study seeks to aid in filling this gap. METHODS: Patients meeting inclusion criteria (BMI <
25) and exclusion criteria (no spinal deformity or previous lumbar surgery) were enrolled. Ultrasound visualization of nerve root and proximate placement of needle tip guided needle placement. Vascular signals were monitored. The contrast injection was done under real-time ultrasound visualization. Final needle placement with transforaminal epidural spread was assessed for accuracy by contrast fluoroscopy. Complications were assessed. RESULTS: Thirty ultrasound guided lumbar TFESI were performed. Visualization at the L2, L3, and L4 levels was successful. At the L5 level, needle tip was placed in proximity to the nerve root, but the final needle tip position for transforaminal placement and injection was not visualized
fluoroscopic guidance was used instead. There was no evidence of intravascular injection. No complications were noted. CONCLUSION: Ultrasonography shows feasibility as an imaging modality in localizing lumbar intervertebral foramina at higher lumbar levels in patients with normal BMI and no spinal deformities. However, ultrasonography was consistently unable to assist transforaminal needle placement at the L5 level due to poor final needle tip visualization and the requirement of fluoroscopy to advance needle tip transforaminally. While no complications were seen, further controlled trials with larger sample size are needed to investigate safety.