A new technique of continuous interscalene nerve block

To describes a technique of indwelling interscalene catheter placement and to evaluate its complications.

One hundred and twenty patients undergoing major shoulder surgery received interscalene nerve block (ISNB) and were studied in three groups. Group 1 ISNB using Winnie's technique; group 2 by Winnie's technique with nerve stimulator and group 3 by epidural needle and catheter technique with nerve stimulator. All patients received 20 mL bupivacaine 0.5% and group 3 patients received an additional bupivacaine 0.25% infusion. Diaphragmatic movements were measured sonographically on emergence from anesthesia. Complications were noted. A visual analogue scale (0-10) was used to assess pain four hours postoperatively.

Mean ipsilateral diaphragmatic movements were 4+/-8, 14+/-11 and 18+/-8 mm (mean +/- SD) in groups 1, 2 and 3 respectively. This was less than contralateral movements in all three groups (P < 0.05). None of the patients in groups 2 and 3 reported postoperative pain. The block failed in 10% of group 1 patients. Complete ipsilateral phrenic nerve block occurred in 85% of the patients in group 1, 35% of group 2 and 20% of group 3 (P < 0.05). Ipsilateral recurrent laryngeal nerve paralysis occurred in 20% of the patients in group 1, 5% of group 2 and in none of the patients in group 3 (P < 0.05). Horner's syndrome was noted in group 1 (30%), group 2 (12%) but not in group 3. None of the catheters in group 3 patients dislodged after an average use of 2.8+/-2.1 days.

Indwelling catheter placement into the brachial plexus sheath as described in this communication was effective and associated with few complications.