Block the Nerve, Not the Airway! Nerve Block - An Alternative to Sedation for Shoulder Reduction

 

Written by: Jay Lee, DO; Edited By: Timothy Khowong, MD, MSEd

 

Background

Shoulder dislocations are the most common major joint dislocation, representing ~200,000+ ED visits annually. Usual reduction techniques may fail if inadequate analgesia or anxiolysis is not performed, leaving ED providers to resort to procedural sedation which come with their own risks. Nerve blocks represent a safe and attractive option in providing total analgesia to help facilitate easier reductions.

Shoulder dislocation facts

The vast majority of shoulder dislocations are anterior (95%), followed by posterior (2-4%), and inferior (<1%).

In shoulder dislocation, the inferior capsule becomes stretched, allowing the humeral head to become displaced from the glenoid fossa. Possible associated injuries are the Bankart lesion, Hill-sachs lesion, rotator cuff tear (especially common in older adults), or axillary nerve neuropraxia. 

Plan AP radiograph of anterior shoulder dislocation

 

Anterior dislocation pathophysiology

Shoulder Innervation: 

When discussing nerve blocks, it is important to consider the innervation of the shoulder. The major sensory contributors of the shoulder are the:

  • Suprascapular nerve (~60–70%)

  • Axillary nerve

  • Lateral pectoral nerve

  • Subscapular nerve

 

Advantages and disadvantages:

Now that we understand the anatomy of the shoulder, it’s time to talk about pain control for the reduction. Outlined below are the advantages and disadvantages of various techniques for analgesia.

 
 

Introducing the Shoulder Blocks

 

So now that we know that nerve blocks look great, let’s focus on two nerve blocks that work great for shoulders:

Intra-articular shoulder block

  • Mechanism: Local anesthetic injected directly into the glenohumeral joint.

  • Advantages

    • Simple

    • Quick

    • Minimal respiratory risk

    • No difference in reduction success rate compared to sedation

  • Limitations

    • Does not directly block motor nerves

  • Evidence: 

    • Study Design

      • Systematic review and meta-analysis of 12 RCTs

      • 630 patients

      • Intra-articular lidocaine vs IV sedation for reduction

    • Key Findings

      • No difference in reduction success rate

      • No difference in pain scores between groups

    • Advantages of Intra-Articular Lidocaine

      • Fewer adverse events

      • Shorter emergency department length of stay by 1.48 HOURS

      • Shorter procedure time by 8 MINUTES

Intra-articular shoulder block: Technique

Proper positioning for intra-articular injection of lidocaine

 

  • Position:

    • Seated with arm in neutral or slight internal rotation or lateral decubitus with affected shoulder up

  • Probe:

    • Curvilinear or linear (thin patients)

    • Transverse 1–2 cm inferior to posterolateral acromion

  • Target:

    • Posterior glenohumeral joint capsule

  • Technique (Posterior approach)

    • In-plane lateral → medial

    • Identify humeral head and glenoid

    • Advance needle into joint capsule

    • Inject 10–20 mL 1% lidocaine

 

Suprascapular Nerve Block

  • Mechanism

    • Blocks majority of posterior capsule sensory input

  • Advantages

    • No diaphragm paralysis compared to Interscalene block

    • Comparable pain control to Interscalene block

    • No difference in reduction success rate compared to sedation

    • Partial motor inhibition compared to intraarticular injection

  • Limitations

    • May require adjunct (axillary block)

  • Evidence:

    • Study Design

        • Single-center, prospective, randomized, controlled, clinical study

        • 41 patients

        • Compared suprascapular nerve block (SNB) to IV ketamine sedation

      • Key Findings

        • No difference in reduction success rate

        • No difference in pain scores between groups

    • Advantages of SNB

      • Significantly shorter time in the ED

      • No side effects were observed

Suprascapular Nerve Block: Technique

  • Position: Seated or lateral decubitus with affected shoulder up

  • Target: Suprascapular nerve at the suprascapular notch

  • Probe:

    • Linear probe (curvilinear in larger patients)

    • Transverse orientation across the scapular spine ⟶ slide superiorly toward the suprascapular fossa

  • Injection:

    • 5–10 mL of local anesthetic adjacent to the nerve, NOT intraneural!

  • Technique

    • In-plane from medial to lateral

    • Visualize the supraspinous fossa, supraspinatus muscle, and trapezius muscle

    • Pass through the trapezius and supraspinatus

 
 

Conclusion:

Shoulder dislocations are common and are sometimes difficult to reduce without adequate analgesia and sometimes procedural sedation. Consider adding a nerve block to your toolkit when approaching these patients, they can save you time and help the patient avoid an adverse event.

 

References:

  • American Family Physician. (2018, February 19). Ultrasound-guided Shoulder Injection. YouTube. https://www.youtube.com/watch?v=r7a0LlBHV40

  • Caldwell, G. L., & Selepec, M. A. (2020). Surgeon-Administered Nerve Block During Rotator Cuff Repair Can Promote Recovery with Little or No Post-operative Opioid Use. HSS Journal ®, 16(S2), 349–357. https://doi.org/10.1007/s11420-019-09745-4

  • Clarius Mobile Health. (2024, January 15). Suprascapular Nerve Block. YouTube. https://www.youtube.com/watch?v=J_i7Wex4x5E

  • ‌Cleveland Clinic. (2023, January 30). How Your Shoulder Joint Works. Cleveland Clinic.
    https://my.clevelandclinic.org/health/body/24780-shoulder-joint

  • Figure 2. Schematic diagram of sensory innervation of the shoulder... (2024). ResearchGate. https://www.researchgate.net/figure/Schematic-diagram-of-sensory-innervation-of-the-shoulder-joint-A-anterior-view-B_fig1_343174815

  • Hassen, G. W., Bergmann-Dumont, D., Duvvi, A., Sudol, S., Choy, D., Yeo, T., Viswanath, A., Roffe, E., Kim, C. L., Elnatour, A., Arias, M. G., & Kalantari, H. (2022). The Use of a Suprascapular Nerve Block to Facilitate the Reduction of an Anterior Shoulder Dislocation: An Alternative for Elderly and Patients With Cardiopulmonary Comorbidities? Journal of Emergency Medicine, 63(2), 265–271. https://doi.org/10.1016/j.jemermed.2022.04.010

  • Long, B., & Gottlieb, M. (2023). Intra‐articular lidocaine versus intravenous sedation for anterior shoulder dislocation reduction. Academic Emergency Medicine, 30(2), 151–153. https://doi.org/10.1111/acem.14653

  • MBBS NAIJA. (2024, December 8). Anatomy of the Suprascapular Notch and Spinoglenoid notch of the Scapula Bone. YouTube. https://www.youtube.com/watch?v=wbMFCZuhp5w

  • Nabil ebraheim. (2012, January 27). Shoulder Pain Injection Suprascapular Nerve Block - Everything You Need To Know - Dr. Nabil Ebraheim. YouTube. https://www.youtube.com/watch?v=dgAedXjhxHw

  • NYSORA. (2022, November 10). Ultrasound Pain Block Tip of the Week: Suprascapular Nerve Block - NYSORA. NYSORA. https://www.nysora.com/education-news/ultrasound-pain-block-tip-of-the-week-suprascapular-nerve-block/

  • SMUG MSK ultrasound training. (2022, August 18). Ultrasound guided glenohumeral joint injection - 2 min series MSKUS. YouTube. https://www.youtube.com/watch?v=uQO6DxfHTkw

  • Stanislavsky, A. (2024). Anterior shoulder dislocation | Radiology Reference Article | Radiopaedia.org. Radiopaedia. https://radiopaedia.org/articles/anterior-shoulder-dislocation

  • Tezel, O., Kaldirim, U., Bilgic, S., Deniz, S., Eyi, Y. E., Ozyurek, S., Durusu, M., & Tezel, N. (2014). A comparison of suprascapular nerve block and procedural sedation analgesia in shoulder dislocation reduction. The American Journal of Emergency Medicine, 32(6), 549–552. https://doi.org/10.1016/j.ajem.2014.02.014

  • TikTok - Make Your Day. (2026). Tiktok.com. https://www.tiktok.com/@greenscreens4memes/video/7601210826011266324

  • Using Point-of-Care Ultrasound to Aid Shoulder Reduction. (2015, February 14). Emra.org. https://www.emra.org/emresident/article/using-point-of-care-ultrasound-to-aid-shoulder-reduction

  • Waterbrook, A. L., & Paul, S. (2011). Intra-articular Lidocaine Injection for Shoulder Reductions. Sports Health: A Multidisciplinary Approach, 3(6), 556–559. https://doi.org/10.1177/1941738111416777

 
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