High-frequency sonography of the volar digital nerves of the hand.

INTRODUCTION: The purpose of this study is to describe our technique for high-frequency sonography of the volar digital nerves and to define the course, caliber, and morphology of normal volar digital nerves. METHODS: The volar digital nerves of 10 volunteers were imaged in the long axis using a linear ultrasound transducer. Height, weight, glove size, and hand dominance were recorded. Each radial and ulnar nerve was divided into four segments. Segment thickness and depth were measured. A mixed model analysis for repeated measures was utilized (α = 0.05). RESULTS: The average nerve thickness (NT) was 1.1 mm (± 0.01 SE), and the average nerve depth (ND) was 2.8 mm (± 0.04 SE). Neither NT nor ND demonstrated any significant correlation with height, age, weight, body mass index, or glove size. Nerves ranged in thickness from 0.7 to 1.5 mm and in depth from 0.7 to 6.8 mm. CONCLUSION: High-frequency sonography permits high-resolution imaging of the volar digital nerves.

Sonographic assessment of suture artifact obscuring visualization of the digital nerve.

INTRODUCTION: The purpose of this study was to grade the severity of sonographic artifact produced by four suture materials and to determine whether these artifacts affect visualization of a digital nerve. METHODS: A needle was placed into a pig foot to mimic a normal volar digital nerve. Incisions superficial to the needle were closed with different suture types, specifically nylon (N), chromic (C), vicryl (V), and prolene (P). Sonographic images were obtained using a high-frequency transducer. Twenty radiology residents and attending physicians graded the severity of artifact and nerve obscuration. Two image types were shown: one suture type per image and a composite image of each suture type, adjacent to one another. RESULTS: Severity of nerve obscuration was as follows: composite image: P = N = V > C; individual images: P > N > V > C. Severity of artifact was: composite image: V = N > P > C; individual image: P > N > V > C. CONCLUSION: Although all sutures produced artifact, only C produced mild artifact, which did not significantly obscure visualization of the nerve model.