High resolution sonographic examination: a newer technique to study ulnar nerve neuropathy in leprosy

A prospective case control study was conducted to calculate normal dimensions of ulnar nerve and study the size, echotexture and morphologic alterations in ulnar nerve in patients with leprosy.

The study group included 48 patients diagnosed with leprosy on basis of clinical, bacteriologic and/or histopathologic evaluation. Sonographic measurements were taken at 3 levels around elbow. The morphology and vascularity were also studied. Control group consisted of 60 clinically normal ulnar nerves, on which ultrasound was performed to calculate normal parameters. 96 Ulnar nerves were independently evaluated clinically and on ultrasound. The mean cross sectional area and diameters (both antero-posterior and mediolateral) of controls at all three levels were calculated. The normal sonographic dimensions of ulnar nerve were calculated based on Mean ± 2SE and beyond the upper limit of normal was considered enlarged on ultrasound. Statistical analysis was done using SSPS version 17.0.

The dimensions of ulnar nerve were significantly larger in leprosy group for all levels (P value , 0.001). Sonographic abnormalities included hypoechoic areas (61·45%), loss of fascicular pattern (same 61·45%) and focal hyperechoic areas (48·95%). 37·5% of nerves (6 out of 16) with clinical evidence of reaction showed endoneural vascularity.

We conclude that by detecting enlargement and/or morphologic alterations of ulnar nerve, sonography can objectively determine involvement of ulnar neuropathy in leprosy.