Ultrasound-guided interscalene block anesthesia for shoulder arthroscopy: a prospective study of 1319 patients.

BACKGROUND Ultrasound guidance improves the localization of anesthetic placement during regional anesthesia, but a decreased rate of adverse events has not been demonstrated in the current literature. In this large prospective study, we evaluated the safety, efficacy, and patient satisfaction associated with ultrasound-guided interscalene block. METHODS A cohort of 1319 patients undergoing arthroscopic shoulder surgery at an outpatient surgery center was prospectively evaluated. Interscalene blocks were performed by experienced anesthesiologists and trainees with use of ultrasound guidance. Patients were queried by a physician twenty-four hours postoperatively regarding their satisfaction with the interscalene block and were screened for a comprehensive register of minor and major adverse events. Individuals with adverse events were followed until symptoms resolved. RESULTS Interscalene block was ultimately successful in 99.6% of the cases. A total of thirty-eight adverse events (prevalence, 2.88%) were noted. At the time of the latest follow-up, permanent sequelae were present in three patients (0.23%), all of whom had relevant comorbidities. With regard to patient satisfaction, 99.06% of the respondents were "satisfied" or "very satisfied" with the interscalene block, whereas 0.94% of respondents were unsatisfied. In addition, 97.8% of the patients stated that they would elect to have an interscalene block again in the future. CONCLUSIONS The present study supports the use of ultrasound-guided interscalene block by trained anesthesiologists for well-screened patients undergoing shoulder arthroscopy, given the high rate of patient satisfaction and the low rate of adverse events.