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Anterior Suprascapular Nerve Block Versus Interscalene Brachial Plexus Block for Shoulder Surgery in the Outpatient Setting: A Randomized Controlled Patient- and Assessor-Blinded Trial

Wiegel, Martin MD*; Moriggl, Bernhard MD, PhD; Schwarzkopf, Peter MD; Petroff, David PhD§; Reske, Andreas W. MD, PhD∥**

Regional Anesthesia & Pain Medicine: May/June 2017 - Volume 42 - Issue 3 - p 310–318
doi: 10.1097/AAP.0000000000000573
Regional Anesthesia and Acute Pain: Original Articles

Background and Objectives: The interscalene brachial plexus block (ISB), a potent option to control pain after shoulder surgery, has notable adverse effects. The anterior suprascapular nerve block (SSNB) might provide comparable analgesia and cause less grip-strength impairment. These characteristics were studied in this randomized controlled patient- and assessor-blinded trial.

Methods: Outpatients were randomized to single-shot ultrasound-guided SSNB (10 mL ropivacaine 1%) or ISB (20 mL ropivacaine 0.75%) before general anesthesia for arthroscopic shoulder surgery. Pain (Numerical Rating Scale, 0–10), grip strength, degree of satisfaction, and strength of recommendation were assessed.

Results: We randomized 168 patients to each group and analyzed 164 in the SSNB group and 165 in the ISB group. Nerve blocks were successful in 98% of the patients from each group. Both procedures provided good postoperative analgesia, and the mean pain level for SSNB was slightly but significantly lower by 0.32 units (95% confidence interval, 0.18–0.46; P < 0.001) and noninferior given a margin of 1.1 units; P < 0.001. Within the first 24 hours, 162 (99%) of SSNB patients had unimpaired grip strength compared to 81 (49%) of ISB patients (P < 0.001). The multiple primary outcome, superior unimpaired grip strength, and noninferior pain control was significant; P < 0.001. Compared to ISB patients (n = 130 [79%]), significantly more SSNB patients (n = 150 [91%]) were satisfied/highly satisfied. Patients in the SSNB group were more likely to recommend the procedure highly.

Conclusions: For outpatients undergoing arthroscopic shoulder surgery under general anesthesia, the SSNB seems preferable to ISB. It provides excellent postoperative analgesia without exposing patients to impaired mobility and to risks of the more potent but also more invasive ISB.

Trial Registry Number: This trial was registered retrospectively with the German Clinical Trials Register (DRKS00009565).

From the *Department of Anesthesiology, ACQUA Clinic, Leipzig, Germany; †Department of Anatomy, Histology and Embryology, Division of Clinical and Functional Anatomy, Innsbruck Medical University, Innsbruck, Austria; ‡Department of Anesthesiology, Intensive Care Medicine, Pain Therapy and Palliative Medicine, Sana Hospital, Borna, Germany; §Clinical Trial Centre, University of Leipzig, Leipzig, Germany; ∥Department of Anesthesiology and Intensive Care Medicine, University Hospital Leipzig, Leipzig, Germany; and **Department of Anesthesiology and Intensive Care Medicine, Heinrich-Braun-Hospital Zwickau, Zwickau, Germany.

Accepted for publication December 19, 2016.

Address correspondence to: Andreas W. Reske, MD, PhD, Heinrich-Braun-Klinikum Zwickau, Zentrum für Anästhesiologie, Intensivmedizin, Notfallmedizin und Schmerztherapie, Karl-Keil-Straße 35, D-08060 Zwickau, Germany (e-mail: awreske@gmail.com).

The authors declare no conflict of interest.

This work was supported solely by institutional sources.

Martin Wiegel and Bernhard Moriggl contributed equally to this work.

Trial Registry Number: This trial was registered retrospectively with the German Clinical Trials Register (DRKS00009565).

Copyright © 2017 by American Society of Regional Anesthesia and Pain Medicine.