Preoperative ultrasonography and magnetic resonance imaging evaluation of the position of the neurovascular bundle for Dupuytren’s disease of the fifth digit: doi: 10.7417/CT.2021.2336

Background. Dupuytren’s contracture (DC) is a fibrosing disorder that produces pathological subcutaneous nodules and cords in the normal fascia. The isolated occurrence of Dupuytren’s disease of the fifth digit is uncommon. This study is aimed to describe the imaging features of an isolated digital cord of the small finger and its relationship with the neurovascular bundle. Methods. A total of 13 hands in 13 patients who were clinically diagnosed with an isolated occurrence of Dupuytren’s disease of the small finger were included between October 2008 and October 2013. Two independent radiologists used ultrasound and magnetic resonance imaging (MRI) to record size, signal or echogenicity, contrast enhancement or hyperemia, calcification, and anatomical features of the cord and its relationship with the neurovascular bundle. Results. We found that ultrasound and MRI were accurate for the detection of the cords and neurovascular bundles in the small finger. The intermodality agreement between MRI and ultrasound was 100% for the detection of 6 spiraling bundles containing 13 isolated cords (46.2%). Among the subjects examined, 100% of the hands had abductor digiti minimi (ADM) area involvement, and the distal insertion of the cord was on the ulnar side of the base of the middle phalanx. On MRI, all of the cords showed predominantly low signal intensity on both T1- and T2-weighted images. On ultrasound, the ulnar cord showed a hyperechoic or isoechoic appearance in 69.3% of hands and a hypoechoic appearance in 30.7% of hands. Conclusions. The spiraling of the bundle in the isolated occurrence of Dupuytren’s disease at the small finger is a frequent occurrence. MRI and ultrasound are good imaging modalities for the evaluation of the relationship between the neurovascular bundle and the isolated cord.