Blasco, Laurent

Background: Suprascapular nerve (SSN) block using bone reference points (BARO) is a technique that in principle is accessible to practitioners without experience in locoregional anesthesia or ultrasound guidance. The primary objective was to validate the feasibility of SSN BARO by an orthopedic surgeon. The secondary objective was to provide a description of the path of the sensory branches from the SSN to the shoulder. Methods: A BARO was performed on 15 cadaveric shoulders by an intern in orthopedic surgery. Ten ml of methylene blue and 0.75% ropivocaine were injected around the SSN. 2.5ml of a red latex solution were also injected to identify the injection site. The distribution of the sensory branches of the NSS was also described. Results: The average distance between the SSN and the injection site was 1.5cm (0-4.5cm). The most frequent injection site was the proximal third of the scapular neck. Fifteen SSNs were marked upstream of the origin of the sensory branches. The 15 SSN produced 3 sensory branches that innervate the posterior glenohumeral capsule, the subacromial bursa, and the coracoclavicular and acromioclavicular ligaments. Conclusion: SSN BARO by an orthopedic surgeon is a simple, reliable, and accurate technique. Injection near the suprascapular notch is recommended to mark the SSN upstream of its three sensory branches.

Purpose To compare the accuracy of distal suprascapular nerve (dSSN) blockade performed with the use of ultrasound‐guided regional anesthesia (USRA) versus with a landmark‐based approach (LBA). A secondary aim was to describe the anatomic features of the sensory branches of the dSSN. Methods USRA and LBA were performed in 15 shoulders each from 15 cadavers (total of 30 shoulders). Then, 10 mL of methylene blue‒infused ropivacaine 0.75% was injected into the dSSN. Simultaneously, 2.5 mL of red latex solution was injected to identify the position of the needle tip. The division and distribution of the sensory branches originating from the SSN were described. Results The tip of the needle was identified at 1.3 cm (range, 0‐5.2 cm) and 1.5 cm (range, 0‐4.5 cm) with USRA and the LBA, respectively ( P = .90). Staining diffused past the origin of the most proximal sensory branch in 27 cases. The most proximal sensory branch arose 2.5 cm from the suprascapular notch. Among the 3 failures that occurred in the USRA group, the sensory branches also failed to be marked. All 30 dSSNs gave off 3 sensory branches, which innervated the posterior glenohumeral capsule, the subacromial bursa, and the coracoclavicular and acromioclavicular ligaments. Conclusions An LBA is as reliable and accurate as US guidance for anesthetic blockade of the dSSN. Marking of the suprascapular nerve must be proximal to the suprascapular notch to involve the 3 sensory branches in the anesthetic blockade. Clinical Relevance The present study demonstrates that a landmark‐based approach to anesthetic blockade of the distal suprascapular nerve is accurate and can be performed by orthopaedic surgeons lacking experience in ultrasound‐guided anesthetic techniques.

Abstract Objectives The primary aim of our study was to evaluate and compare the accuracy of ultrasound (US)-guided distal suprascapular nerve (dSSN) and proximal SSN (pSSN) blocks. Secondary aims were to compare the phrenic nerve involvement between groups and to describe the anatomical features of the sensory branches of the dSSN. Methods pSSN and dSSN blocks were performed in 14 cadavers (28 shoulders). Ten mL of 0.2% ropivacaine colored with methylene blue was injected under US guidance. Accuracy was determined using SSN staining and the distance between predefined anatomical landmarks and the targeted SSN. The phrenic nerve (PN) was judged to be colored or not. The distribution of the sensory branches that originate from the 14 dSSNs is described. Quantitative data are expressed as median (range). Results The pSSN was dyed more frequently than the dSSN (13 vs 11, P = 0.59). The targeted SSN was close to the suprascapular notch (1.3 [0–5.2] cm) and the origin of the SSN (1.4 [0.2–4.5] cm) for dSSN and pSSN blocks, respectively (P = 0.62). For dSSN blocks, the most frequent injection site was the supraspinous fossa. Three PNs were marked in pSSN blocks, compared with none in dSSN blocks (P = 0.22). Three sensory branches were identified for all 14 dSSNs: the medial subacromial branch, the lateral subacromial branch, and the posterior glenohumeral branch. Conclusions US-guided pSSN and dSSN blocks can be realized with accuracy. A distal approach to the SSN could be an alternative to interscalene brachial plexus block for the management of postoperative pain after shoulder surgery in high–respiratory risk patients.