STUDY OBJECTIVE:

To report the results of single and continuous interscalene blocks (ISB) performed using ultrasound (US) guidance only.

DESIGN:

Prospective, observational study.

SETTING:

Operating room of a university-affiliated orthopaedic hospital.

PATIENTS:

200 ASA physical status I, II, and III patients undergoing shoulder or elbow surgery.

INTERVENTIONS:

Single or continuous ISB were placed using US guidance only. All blocks were performed by anesthesiology residents and supervised by faculty anesthesiologists.

MEASUREMENTS:

Success rate and frequency of untoward events such as needle paresthesia, vessel puncture, infection, and persistent neurologic deficits were prospectively recorded.

MAIN RESULTS:

99% of patients reported sensory and motor changes in the distribution of the brachial plexus and postoperative pain scores <or= 2. The rates of needle paresthesia and vessel puncture were 6% and 1%, respectively. Two patients (1%) reported transient neurologic deficits. No signs or symptoms of infection or intravascular injection were noted. There were also no permanent neurologic deficits.

CONCLUSIONS:

In this group of 200 consecutive patients, the success rate for postoperative analgesia using US guidance only was 99%. Untoward events such as needle paresthesia and persistent neurologic deficits were lower than existing data on nerve stimulation and paresthesia techniques. Ultrasound can be successfully used as a "stand alone" method to perform ISB.