INTERSCALENE BRACHIAL-PLEXUS BLOCK FOR SH OULDER SURGERY - A PROSPECTIVE-STUDY OF A CONSECUTIVE SERIES OF 167 PATIENTS

Objectives: To determine the relationship between minimal stimulating current and success rate of interscalene brachial plexus block (IBPB), to assess the quality of anaesthesia and postoperative analgesia, and to evaluate the benefits and drawbacks of this technique in shoulder surgery. Study design: Prospective study of a continuous series of cli nical cases. Patients: Series of 167 patients undergoing shoulder surg ery under IBPB, obtained with Winnie's technique, in 1995. Methods: Th e plexus was located with a nerve stimulator and an insulated needle, 25 mm long and with a short 30 degrees bevel (Stimuplex(TM), Braun). D ata were collected with questionnaires, filled in by the anaesthetists , the surgeon and patients. Results: Shoulder surgery was performed ei ther under IBPB alone in 51.5% of cases (group A), or under IBPB assoc iated with sedation (midazolam: 1-3 mg) in 31.7% (group B), or under I BPB associated with general anaesthesia either on the patient's reques t (11.4% = group C) or due to IBPB failure (5.4% = group D). The succe ss rate was 94.6% and the efficiency of postoperative analgesia obtain ed in 100% of cases (no pain at admission in the recovery room). For t he nerve location a minimal stimulating current of 0.08 to 1 mA (mean minimal stimulating current 0.42 +/- 0.17 mA) had been required, with a significant difference (P = 0.0001) between group A (0.38 +/- 0.14 m A) and the others (0.43 +/- 15 mA in group B, 0.50 +/- 0.21 mA in grou p C, 0.59 +/- 0.23 mA in group D). Conclusions: The correlation betwee n minimal stimulating current and success rate has clearly shown the b enefit of the nerve stimulation. IBPB, which provides a successful and efficient anaesthesia with minimal risk and satisfactory postoperativ e analgesia, has become the standard technique for shoulder surgery.