Benefit of the minimal invasive ultrasound-guided single shot femoro-popliteal block for ankle surgery in comparison with spinal anesthesia.

Background: Ultrasound-guided regional anesthesia has gained popularity for ankle and foot surgery. The aim of our study was to investigate the sufficiency of anesthesia for ankle surgery as well as duration of analgesia in postoperative period, using minimal invasive ultrasound-guided regional anesthesia, and to compare it with anesthesia and postoperative analgesia following spinal anesthesia.

Methods: This prospective study included 40 adult trauma patients with bimalleolar fracture who were scheduled for surgery. They were randomly assigned and divided in two groups. Patients from the first group underwent an Ultrasound-guided femoro-popliteal block (US-FPB), while a spinal anesthesia (SA) was performed for the second group. The local anesthetic 0.5% bupivacaine was used in both groups.

Results: Eighteen patients from the first and nineteen patients from the second group completed the study. Levels of anesthesia were sufficient in both groups without significant differences. Duration of postoperative analgesia was significantly higher in US-FPB group in comparison to SA group (12 ± 3 vs. 3 ± 1 h) (p < 0.001). At the same time, onset of complete sensory motor block was significantly faster in SA group in comparison to US-FPB group (5 ± 1 vs. 8 ± 3 min) (p < 0.001).

Conclusion: Minimal invasive US-FPB provides sufficient anesthesia for ankle fracture. In comparison to the SA group, patients from the US-FPB group achieved significantly longer postoperative analgesia, while faster onset of anesthesia was noted in SA group.