J Man Manip Ther. 2026 Jul 15:1-12. doi: 10.1080/10669817.2026.2700322. Online ahead of print.

ABSTRACT

INTRODUCTION: Despite the growing clinical use of dry needling, the anatomical accuracy and safety of ultrasound-unguided approaches to the soleus remain insufficiently standardized and validated. This study aimed to evaluate (i) the anatomical accuracy and safety of a standardized ultrasound-unguided dry needling protocol targeting the mid-third of the soleus, (ii) intra- and inter-rater reliability of key procedural outcomes, and (iii) agreement between ultrasound imaging and cadaveric dissection as validation methods for needle placement.

METHODS: An experimental cross-sectional cadaveric study was conducted on five fresh-frozen human cadavers (10 lower limbs), yielding 24 dry needling events. Two physiotherapists with different levels of dry needling experience (intermediate: 5 years; advanced: >10 years) performed the protocol independently. A blinded sonographer assessed needle tip location and quantitative safety margins using high-resolution ultrasound. Anatomical dissection was subsequently performed to confirm final needle placement in a subset of approaches. Outcomes included soleus placement accuracy, septum puncture (lateral and posterior/deep), and neurovascular/vascular compromise. Reliability was assessed using percentage agreement and Cohen’s kappa.

RESULTS: Accurate needle placement within the soleus was achieved in 22/24 procedures (91.7%), with 2 failures (8.3%), both performed by the intermediate-experience physiotherapist. Lateral septum puncture occurred in 5/24 cases (20.8%), and posterior/deep septum puncture in 3/24 cases (12.5%). No puncture of the tibial neurovascular bundle or vascular structures was observed (0%). Intra-rater agreement for the advanced physiotherapist was 100% across dichotomous outcomes. Inter-rater agreement was 80% for soleus accuracy and overall procedural success. Ultrasound imaging and cadaveric dissection demonstrated 100% agreement across accuracy and safety outcomes in the advanced physiotherapist approaches.

CONCLUSIONS: In this cadaveric model, a standardized ultrasound-unguided dry needling protocol targeting the soleus achieved high anatomical accuracy with no neurovascular injury, and showed excellent agreement between ultrasound and dissection for the advanced operator.

PMID:42454438 | DOI:10.1080/10669817.2026.2700322