Background and objectives Image-guided intervention of the suprascapular nerve is a reported treatment to manage chronic shoulder joint pain. The suprascapular nerve is conventionally targeted at the suprascapular notch; however, targeting of its branches, the medial and lateral trunks, which are given off just posterior to the notch has not been considered. Since the lateral trunk supplies the posterior supraspinatus and articular branches to the glenohumeral joint capsule, while the medial trunk provides motor innervation to the anterior region, it may be possible to preserve some supraspinatus activation if the medial trunk is spared. The main objective was to investigate whether midpoint between suprascapular and spinoglenoid notches is the optimal target to capture articular branches of lateral trunk while sparing medial trunk.
Methods In 10 specimens, using ultrasound guidance, one 17 G needle was placed at the suprascapular notch and a second at midpoint between suprascapular and spinoglenoid notches. The trunks and needles were exposed in the supraspinous fossa, digitized and modeled in 3D. Lesion volumes were added to the models to asses medial and lateral trunk capture rates. Mean distance of needle tips to origin of medial trunk was compared.
Results Conventional notch technique captured both lateral and medial trunks, whereas a midpoint technique captured only lateral trunk. Mean distance of needles from the origin of medial trunk was 5.10±1.41 mm (notch technique) and 14.99±5.53 mm (midpoint technique).
Conclusions The findings suggest that the midpoint technique could spare medial trunk of suprascapular nerve, while capturing lateral trunk and articular branches. Further clinical investigation is required.
- joint innervation
- shoulder joint
- radiofrequency ablation
- suprascapular nerve
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Presented at Interim data from this work were presented at the 2019 American Association of Anatomists Annual Meeting at Experimental Biology in Orlando, 6–10 April 2019 and 2019 International Symposium of Ultrasound in Regional Anesthesia and Pain Medicine in Porto, 9–11 May 2019.
Contributors All authors contributed to the experimental design, data acquisition, analysis of data, drafting and revising the manuscript critically for important intellectual content.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests AA is an Anatomy Faculty with Allergan Academy of Excellence. PP received equipment support from Sonosite Fujifilm Canada.
Patient consent for publication Not required.
Ethics approval Approval was received from the University of Toronto Health Sciences Research Ethics Board (#27210).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.