The role of ultrasonography in diagnosing hourglass-like fascicular constriction(s) of the anterior interosseous nerve

Background In the past, the diagnosis of hourglass-like fascicular constriction(s) of the anterior interosseous nerve mostly depended on electrophysiological examination, by which the location could not be diagnosed. There are few studies on the evaluation of hourglass-like fascicular constriction(s) by ultrasonography. Purpose To evaluate the role of ultrasonography in the diagnosis of hourglass-like fascicular constriction(s) of the anterior interosseous nerve. Material and Methods A retrospective analysis of 12 patients with hourglass-like fascicular constriction(s) of the anterior interosseous nerve was carried out, and the characteristics of the high-frequency ultrasonographic images were summarized and compared with surgical exploration. Results The 12 cases of hourglass-like fascicular constriction(s) of the anterior interosseous nerve were all located in the median nerve of the distal upper arm, including nine cases of single hourglass-like fascicular constriction and three cases of multiple hourglass-like fascicular constrictions. High-frequency ultrasonography can accurately locate the hourglass-like fascicular constriction(s) of the anterior interosseous nerve and the extent of neuropathy. The ultrasonographic images of hourglass-like fascicular constriction(s) of the anterior interosseous nerve showed single or multiple hourglass-like change(s) in the median nerve of the distal upper arm. The nerve fascicles on both sides of the affected nerve with hourglass-like change thickened. Conclusions High-frequency ultrasonography could be a reliable, convenient, and non-invasive diagnostic imaging method for hourglass-like fascicular constriction(s) of the anterior interosseous nerve.