Basic Science
Distal suprascapular nerve block—do it yourself: cadaveric feasibility study

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Background

A bone landmark–based approach (LBA) to the distal suprascapular nerve (dSSN) block is an attractive “low-tech” method available to physicians with no advanced training in regional anesthesia or ultrasound guidance. The primary aim of this study was to validate the feasibility of an LBA to blockade of the dSSN by orthopedic surgeons using anatomic analysis. The secondary aim was to describe the anatomic features of the sensory branches of the dSSN.

Materials and methods

An LBA was performed in 15 cadaver shoulders by an orthopedic resident. Then, 10 mL of methylene blue–infused 0.75% ropivacaine was injected around the dSSN; 2.5mL of red latex solution was also injected to identify the position of the needle tip. The division and distribution of the sensory branches that originate from the suprascapular nerve were described.

Results

The median distance between the dSSN and the site of injection was 1.5 cm (0-4.5 cm). The most common injection site was at the proximal third of the scapular neck (n = 8). Fifteen dSSNs were stained proximal to the origin of the most proximal sensory branch. All 15 dSSNs gave off 3 sensory branches that innervated the posterior glenohumeral capsule, the subacromial bursa, and the coracoclavicular and acromioclavicular ligaments.

Conclusions

An LBA for anesthetic blockade of the dSSN by an orthopedic surgeon is a simple, reliable, and accurate method. Injection close to the suprascapular notch is recommended to involve the dSSN proximally and its 3 sensory branches.

Section snippets

Materials and methods

Fifteen shoulders from 8 fresh frozen cadavers were included. The median age of the specimens (2 men, 6 women) was 82 years (74-98 years) with a median body mass index (BMI) of 24 kg/m2 (range, 18.8-30.1 kg/m2). A history of irradiation to the brachial plexus or shoulder surgery and trauma in the cervical, scapular, supraclavicular, or shoulder girdle area were exclusion criteria. None of the specimens were excluded.

Accuracy of the dSSN block

The median distance between the dSSN at the suprascapular notch and the site of injection was 1.5 cm (range, 0-4.5 cm). The needle tip was distal to the suprascapular notch in all 15 cadaver shoulders (100%); the most common injection site was at the proximal third of the neck of the scapula (n = 8 [53%]) (Fig. 2). Cadaver BMI (coefficient (ß), 0.625; 95% confidence interval, −1.42 to 2.67; P = .516) had no impact on accuracy (ie, distance of the needle’s tip to the dSSN at the suprascapular

Discussion

This study confirmed the primary and secondary hypotheses. LBAs performed by an orthopedic surgeon allowed reliable and accurate marking of 100% of the dSSNs and their sensory branches.

Implementation of this technique as one branch in a multimodal approach to the treatment of perioperative, chronic, and recalcitrant shoulder pain has the potential to significantly reduce the use of narcotic pain medication.4, 6, 12, 22, 26, 27, 33 Anesthetic block of the dSSN is widely used by clinical

Conclusion

Data herein suggest that the LBA for anesthetic blockade of the dSSN by an orthopedic surgeon is a simple, reliable, and accurate method. We recommend injecting close to the suprascapular notch to involve the dSSN proximally as well as the 3 sensory branches, ensuring analgesia about the coracoclavicular ligaments, the subacromial bursa, and the PGH joint capsule. Further studies are needed to determine the safety and analgesic effectiveness of this method when it is performed by an orthopedic

Acknowledgments

The authors would like to thank the persons who donated their bodies to the department of Applied Anatomy (Faculty of Medicine, Toulouse, France; and Faculty of Medicine, Reims, France), without which this study would not have been possible.

Disclaimer

The authors, their immediate families, and any research foundations with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.

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    Institutional Review Board approval was not required for this study.

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