Background: Brachial plexus block by the posterior approach described by Pippa is not widely used in contrast to the lateral approach of Winnie. We compared the clinical efficacy of both approaches in a randomized prospective study.
Methods: Eighty patients, American Society of Anesthesiologists physical status I or II, scheduled for surgery of the shoulder or upper arm were randomized in 2 groups: lateral (Winnie, n = 40) or posterior approach (Pippa, n = 40). A single injection of ropivacaine 7.5 mg/mL, 0.5 mL/kg, was made after obtaining a motor response in the distribution of the axillary nerve at a current below 0.5 mA (2 Hz, 0.1 millisecond). Onset and distribution of analgesia and motor block were assessed at 5, 10, 15, 20, 30, and 60 minutes after the local anesthetic injection. Complete block was defined as anesthesia in all dermatomes C3-C6 at 60 minutes after injection.
Results: The posterior approach provided complete block in 36 patients (90%) and the lateral approach in 33 patients (83%). Corresponding motor block was similar in both approaches, but the block procedure time was faster in the posterior approach (6.2 [5.2-7.2] minutes v 8.4 [7.1-10.2] minutes; P < .001). Surgical success rate (posterior 95% v lateral 93%) and side effects were similar in both approaches. One complication (thoracic epidural block) was seen using the lateral approach, whereas none occurred in the posterior approach. There was no difference in patient satisfaction scores of the 2 approaches, which were equally high in both groups (posterior 98% v lateral 95%).
Conclusion: Both approaches are comparable regarding clinical efficacy for anesthesia of the shoulder and upper arm.