Continuous axillary brachial plexus block--a clinical and anatomical study.

In order to decrease both the failure rate and inadvertent arterial puncture rate that may be associated with continuous axillary brachial plexus block, a new technique of insertion of the catheter in the axilla was studied in 52 patients and in 12 fresh cadavers. With the arm abducted, externally rotated, and flexed at the elbow, an 80-mm long catheter was inserted under the skin at a site located 40-mm below the axilla and medial to the biceps muscle. Injection of lidocaine and bupivacaine produced sensory and motor blockades of the median, radial, ulnar, and musculocutaneous nerves in 98% of the patients. Arterial puncture occurred in one. The catheter was left in situ up to 9 days without complications. In the anatomical study, injection of dye and molding solutions showed that the tip of the catheter lay not in the perivascular sheath, but in a virtual cavity that was very superficial, under the skin, and surrounding the perivascular space. The technique used was safe and had a high success rate. It is particularly useful in patients undergoing long operations and in patients in whom pain would otherwise prevent postoperative physiotherapy of the upper arm.