F133. Safe-zone data of the deep branch of the ulnar nerve

Introduction Deep branch of the ulnar nerve (DBUN) study using ultrasound has just begun with the development of high-resolution ultrasound (HRUS) technology. In this study, we would like to present the safe-zone data that can be used to accurately locate the DBUN using HRUS. So it could be used as reference for various procedures such as acupuncture and botox injection. Methods We performed HRUS with high-frequency probes (5–12 MHz). In both hands of 10 healthy volunteers (n = 20), the cross-sectional area (CSA) was measured at medial side of the hook of the hamate bone. Depth from the skin and distance from the tip of the hook of the hamate were also measured. Same data were measured from 1 patient who was diagnosed as DBUN neuropathy which was confirmed by electromyography study. Results DBUN was clearly observed in the medial wall of the hook of the hamate bone in all subjects. The mean CSA value of healthy volunteers was 1.4 ± 0.2 mm 2 , the depth from the skin was 7.4 ± 1.1 mm, and the distance from the tip of the hook of the hamate bone was 6.0 ± 0.8 mm. The depth from the skin of DBUN neuropathy patient was 9.6 mm and the distance from the hook of the hamate was 7.1 mm, which was not significantly different from healthy volunteers, but CSA was significantly increased to 2.9 mm 2 . Conclusion This study provides data that can predict the location of the DBUN, which will help avoid complications when performing various injection procedures on the hand. In addition, HRUS could be helpful for diagnosis of DBUN neuropathy.