Paravertebral blockade for inguinal herniorrhaphy-novice performance of anatomic versus nerve stimulator-guided techniques

Background: Paravertebral block (PVB) has been previously determined to provide considerable advantages versus general anesthesia for inguinal herniorrhaphy. However, this block is still under-utilized due, in part, to concerns over the potential difficulty of the procedure that may result in low efficacy in less experienced hands, and possible side effects. The aim of this study was to obtain a preliminary comparison of traditional anatomic versus nerve stimulator-guided PVB for inguinal herniorrhaphy in novice hands to explore whether one of the techniques might provide enhanced success. Methods: Fifty patients were randomized to receive either anatomic or nerve stimulator-guided PVB. Time to perform the block, efficacy of block, and side effects were determined for both approaches. Results: The nerve stimulator guided approach took a slightly longer but comparable amount of time to perform (mean of 9.0 versus 6.6 minutes, p = 0.056). The proportion of patients with a successful block who had the nerve stimulator-guided approach was 80% (20/25) compared to 68% (17/25) among patients with the anatomic approach (p = 0.52). Epidural spread was observed more frequently with the nerve stimulator guided approach (5/25 versus 1/25, p = 0.19). Conclusion: In novice hands, nerve stimulator-guided PVB for inguinal herniorrhaphy may be more efficacious than anatomic techniques. These results may be due, in part, to epidural spread of local anesthetic.