Research Information System
JOURNAL OF MEDICAL ULTRASONICS, 2026 (SCI-Expanded, Scopus)
PurposePosterior interosseous nerve (PIN) syndrome is an uncommon neuropathy that may mimic lateral epicondylitis. High-resolution ultrasound aids its diagnosis by revealing nerve swelling, while ultrasound-guided injection is increasingly employed for decompression. Nevertheless, the influence of injection axis on injectate distribution remains unclear. This study aimed to compare the spread characteristics and accuracy of short-axis vs. long-axis ultrasound-guided injections at the proximal and distal PIN using cadaveric validation.Kindly check and confirm the city name is correctly identified in affiliation [6].It is correctly identified. MethodsTen cadaveric limbs were randomized to short-axis (n = 5) or long-axis (n = 5) injections. Ultrasound parameters, including fascicle count, cross-sectional area, and surrounding muscle or tendon thickness, were recorded. Proximal and distal injections were performed separately with 5 mL of injectate. Subsequent dissection assessed target infiltration and spread dimensions (length, width).ResultsUltrasound findings were comparable between the groups with no significant differences in cross-sectional area or muscle/tendon thickness. On dissection, all injections achieved successful proximal and distal PIN infiltration. At the proximal level, short-axis injections produced significantly greater infiltration width (43.6 +/- 6.2 mm vs. 24.3 +/- 13.2 mm, p = 0.032), while infiltration length was not significantly different (88.8 +/- 17.4 mm vs 77.1 +/- 37.1 mm, p = 0.690). At the distal level, both infiltration length (81.0 +/- 24.4 mm vs. 67.7 +/- 37.4 mm, p = 0.548) and width (28.2 +/- 10.9 mm vs. 22.5 +/- 8.8 mm, p = 0.548) were numerically greater with short-axis injections, although the differences did not reach statistical significance.ConclusionBoth short- and long-axis ultrasound-guided injections consistently achieved target infiltration of the PIN. The short-axis approach provided broader proximal spread, which may enhance circumferential perineural coverage, whereas the distal injections showed no significant differences between techniques. These findings support the reliability of both approaches, while highlighting a potential advantage of short-axis guidance at the proximal forearm.