Three-dimensional ultrasonography for visualization of muscular anomalies in type VI and VII radial polydactyly.

Abstract

To describe a technique and its clinical applications of three-dimensional ultrasonography to type VI and VII radial polydactyly for identification of potential muscular anomalies. Ultrasonographic examinations were performed at an out-patient department without sedation or an operative room prior to surgery. The palm was scanned in the transverse direction using a 18-MHz linear transducer under speed regulation at 3 mm/s. Sequential images acquired at 0.2 mm intervals were converted into volume data. After validation of the technique, patients with a radial polydactyly in association with triphalangism (type VII) or with polydactylies of metacarpal duplication (type VI) were included for the examination. Five hands of five patients, one with type VI and four with type VII, were included the study. All the patients were male and the ages at examination ranged from 7 months to 2 years. Of the five patients, four examinations were performed at an out-patient department without sedation and one was under anesthesia just prior to surgery. The muscular abnormalities identified were mal-positions of the thenar muscles in a type VI case and a deficiency of the abductor pollicis brevis muscle in a type VII case with a delta phalanx in the ulnar part. Three-dimensional ultrasound technique could be an aid to plan strategies in radial polydactyly if intrinsic muscular anomalies are suspected to be involved.