2026 FSA Podium and Poster Abstracts

Background: Ultrasound guidance is widely used for peripheral nerve blocks as an alternative to landmark based approaches (including peripheral nerve stimulation and paresthesia/anatomic techniques). However, the practical advantages of ultrasound for block success and complication reduction are best understood by synthesizing evidence across randomized trials and large clinical series.

Methods: We conducted a systematic review following PRISMA 2020 guidelines. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and trial registries were searched from inception through December 2023. We included randomized controlled trials and large observational cohort studies (n > 500) comparing ultrasound guided peripheral nerve blocks (alone or combined with nerve stimulation) to landmark-based techniques (peripheral nerve stimulation, paresthesia, anatomical landmarks, transarterial approaches) for upper and lower extremity blocks. Three independent reviewers screened titles, abstracts, and full texts, where disagreements were resolved by consensus. Primary outcomes were block success (adequacy for surgery, need for supplementation or conversion to general anesthesia) and procedure-related complications. Secondary outcomes included vascular puncture, paresthesia during placement, LAST, nerve injury, hematoma, and other patient-centered outcomes.

Results: Thirty-two randomized controlled trials (2,844 participants) and five large observational cohorts (>40,000 participants) met inclusion criteria. Across randomized trial evidence, ultrasound guidance consistently improved block success, with more blocks adequate for surgery and fewer requiring supplementation or conversion to general anesthesia. Ultrasound also reduced common minor complications, including vascular puncture and paresthesia during placement. Large observational and registry-based evidence supported similar directional findings and suggested ultrasound is associated with a lower risk of LAST. Evidence regarding persistent or long-term neurologic symptoms remained inconclusive, with no consistent difference demonstrated between ultrasound and landmark techniques.

Conclusions: Ultrasound guidance improves peripheral nerve block technical success and reduces several common minor complications compared with landmark-based techniques. Observational evidence suggests reduced risk of LAST, though low event rates and study design limitations preclude definitive conclusions. Ultrasound does not appear to reduce long-term neurological injury. Ultrasound guidance should be favored when expertise and equipment are available, alongside rigorous training, safe dosing practices, and meticulous technique regardless of localization method.