HPI:
18 yo M with 2 prior shoulder dislocations presented with acute onset shoulder pain 3 hours
prior to arrival. Reminded him of past dislocations. Was bracing himself against a wall at onset.
Has not seen orthopedics post reduction in the past. ED visit delayed as patient went to his
COVID testing appointment prior to coming to ED.
PE:
Left arm held in slight abduction and external rotation resting against bed. Asymmetric when
compared to contralateral shoulder. Patient resists any pROM of the shoulder. Strong radial
pulses. Sensation intact to light touch in all nerve distributions
POCUS for shoulder dislocations
Technique – A posterior shoulder approach is used in the diagnosis of shoulder dislocations. The patient can be positioned in a lateral decubitus position or sitting up with back exposed. The linear or curvilinear probe is placed transversely along the scapula just below the scapular spine. Scan laterally towards the shoulder until the posterior glenohumeral articular surface comes into view. Assess the location of the glenohumeral head in relation to the glenoid fossa.
Appropriate transducer alignment to image the glenohumeral joint via posterior approach
Posterior approach to shoulder ultrasound: dynamic guidance
Posterior approach to shoulder ultrasound: Anterior dislocation (left), normal shoulder (right)
Initial radiograph consistent with anterior shoulder dislocation
The patient was offered and opted for an interscalene nerve block for reduction (below)
Interscalene nerve block (screen left- lateral, screen right- medial)
Following the nerve block, reduction was successful with only mild external rotation of the upper extremity. The patient reported no pain during reduction and voiced it was much more comfortable than his prior reductions.
Post reduction radiograph
The patient was observed for 30 minutes and found to have no evidence of respiratory compromise or hemodynamic complications. He was placed in a sling and given follow up with local orthopedic surgery providers.
EVIDENCE REVIEW
Musculoskeletal Ultrasonography to Diagnose Dislocated Shoulders: A Prospective Cohort https://pubmed.ncbi.nlm.nih.gov/32111508/
Multicenter prospective observational study. Ultrasound fellows and fellowship trained ED attendings at two different academic emergency departments. Involved adult patient with suspected shoulder dislocations. Excluded patients with multiple traumatic injuries, with decreased level of consciousness, and those who were hemodynamically unstable.
Watched short training video prior
Sonographers were blinded in that they did not take or know of the H&P and performed US prior to plain films
Reductions by treating physician performed after Xray read. Sonographer would then perform post reduction US as well
Recorded the presence of a dislocation based on point-of-care ultrasonography, presence of a fracture based on point-of-care ultrasonography, time to perform the point-of-care ultrasonographic examination, sonographer confidence, glenohumeral distance, and the time of the point-of-care ultrasonographic examination
65 patients enrolled. 32 with shoulder dislocations (49%)
Primary outcome was diagnostic accuracy of POCUS
Secondary outcomes included time to diagnosis from triage, length of POCUS exam, determination of glenohumeral distance, presence of fractures, and sonographer confidence
Sensitivity, specificity, PPV, NPV all 100%
25 patients had fractures on radiography. Of those 13 were identified on POCUS (52%).
POCUS was faster from triage than standard radiology (median difference 43 min)
POCUS median time for diagnosis was only 19 seconds
Point-of-care ultrasound for the diagnosis of shoulder dislocation: A systematic review and meta-analysis https://pubmed.ncbi.nlm.nih.gov/30797607/
Seven studies comprising 739 assessments with 306 dislocations.
Overall, POCUS was 99.1% sensitive and 99.9% specific for the diagnosis of shoulder dislocation
LR+ of 796.2 and a LR− of 0.01
POCUS was also 97.9% (95% CI 10.5% to 100%) sensitive and 99.8% (95% CI 28.0% to 100%) specific for the diagnosis of associated fractures.
US- Guided Interscalene Block
Position –
Place patient supine or semi upright with head turned 45 degrees or lateral decubitus with affected extremity facing upwards
Technique –
Recommend dynamic guidance and in-plane approach under sterile precautions
The linear probe is placed transversely laterally the trachea at around the level of the thyroid cartilage. The probe is then moved laterally until the muscle bellies of the anterior and middle scalene are identified. Particular note is made of the carotid artery and internal jugular vein. Identify the ventral rami of C5, C6, and likely C7 within the interscalene groove, which will appear as hypoechoic structures in a "stoplight" pattern.
Transducer Position for interscalene block (right), Location of C5-C7nerve roots
Axial apparance of nerve roots (yellow) in interscalene groove
*It may be helpful to begin at the supraclavicular notch, identifying the subclavian artery with trunks of the brachial plexus located laterally. Nerve tissue appears more hyperechoic and "honeycomb" like at this level. From there, follow the nerves, scanning cephalad and identify nerve roots within the interscalene groove as above.
Axial appearance or neurovascular structures at level of clavicle/1st rib
Once identified, needle introduced in plane (lateral to medial). Following aspiration,10-15cc of local anesthetic is injected in the area surrounding the C5-C7 nerve roots.
Nerve distribution –
Supplies innervation to the upper extremity excluding the trapezius (spinal accessory nerve), the cape of the shoulder (superficial cervical plexus), and a portion of the axilla (intercostobrachial nerve). Targets the C5 -C7 nerve roots or superior trunk of the brachial plexus with the interscalene groove.
Complications -
The phrenic nerve runs vertically down the anterior surface of the anterior scalene muscle at the level of C6 so there is a very high likelihood of hemidiaphragmatic paralysis. As such, should not be used in patients with limited pulmonary reserve.
Multiple arterial branches may be present in this location. Particular attention should be paid to avoiding branches of thyrocervical trunk. Recommend screening with color doppler prior to injection
Use the shortest acting agent available. 1% lidocaine without epinephrine or 5-chloroprocaine are great options.
EVIDENCE REVIEW
Ultrasound-guided interscalene nerve block vs procedural sedation by propofol and fentanyl for anterior shoulder dislocations
https://pubmed.ncbi.nlm.nih.gov/28460809/
Randomized clinical trial comparing outcomes following reduction of anterior shoulder dislocations using US guided interscalene brachial plexus blocks vs procedural sedation with propofol and fentanyl
Convenience sample of isolated anterior shoulder dislocations in 11 month period. Patient randomly assigned to Interscalene block (ISBPB) vs Sedation (PSA)
60 patients total. 30 in each group.
Primary outcomes were pain scores and emergency room length of stay
Secondary outcomes were defined as, total number of attempts at reduction, number of techniques used for reduction, occurrence of complications, and patient satisfaction with the procedure
No significant difference in reduction attempts or number of techniques used
The emergency room length of stay was significantly lower in the ISBPB group with mean of 80.2 minutes compared to 108.6 minutes for PSA
Pain scores during reduction and patient satisfaction were significantly better in the PSA group -Pain scores of 0.38 in PSA vs 3.43 in ISBPB. (Pain scale measured as a score of 1 to 4: poor, intermediate, good, and excellent, respectively)
Author: Jordan Esposito, MD
Edited and peer reviewed by: Aalap Shah, MD
References
1. Raeyat Doost E, Heiran MM, Movahedi M, Mirafzal A. Ultrasound-guided interscalene nerve block vs procedural sedation by propofol and fentanyl for anterior shoulder dislocations. Am J Emerg Med. 2017 Oct;35(10):1435-1439. doi: 10.1016/j.ajem.2017.04.032. Epub 2017 Apr 14. PMID: 28460809.
2. Secko MA, Reardon L, Gottlieb M, Morley EJ, Lohse MR, Thode HC Jr, Singer AJ. Musculoskeletal Ultrasonography to Diagnose Dislocated Shoulders: A Prospective Cohort. Ann Emerg Med. 2020 Aug;76(2):119-128. doi: 10.1016/j.annemergmed.2020.01.008. Epub 2020 Feb 25. PMID: 32111508.
3. Wilson, E. H., Maniker, R., & Crowler, M. (2020, November 10). Interscalene block procedure guide. UpToDate. Retrieved September 23, 2021, from https://www.uptodate.com/contents/interscalene-block-procedure-guide#H4153544579.
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