Ultrasound assessment of blood flow in the median nerve in normal conditions and in carpal tunnel syndrome

Abstract

Carpal tunnel syndrome is the most common compressive neuropathy of the upper extremity, which manifests with painful paresthesia in the fingers and impaired hand function. The ultrasound method is successfully used to diagnose this disease. The ultrasound criterion for carpal tunnel syndrome is swelling of the median ner ve, which is a manifestation of poor circulation in the nerve. The study involved 29 people (56 limbs), divided into 2 groups: group 1 — healthy volunteers (14 people, image processing. In group 1, the intraneural type of blood flow was found in 75 % of cases, paraneural — in 3.6 %, and the blood flow was not determined in 21.4 %. In group 2, in 78.6 % of cases there was an intraneural type of blood flow, in 7.1 % — paraneural, and in 14.3 % the blood flow was not determined. There was no statistically significant difference between the groups. In the group of the patients, the area averaged at 15,350 px2, which is statistically significantly higher than the area of the median ner ve in the group of the volunteers, where this figure averaged at 6,665 px2. The average cross-sectional area of the visualized vessels of the median nerve in the group of the patients was 226 px 2, and in the group of healthy volunteers — 101.025 px2. The blood flow area in the patients was statistically significantly higher than in the volunteers, and the blood flow velocity was 5 cm/sec on average, which is statistically significantly higher than in the control group, where this figure averaged at 3 cm/sec. The type of blood supply to the median nerve does not affect the development of carpal tunnel syndrome and does not determine its origin. Analysis of blood flow velocity may be an important predictor of treatment success in patients with carpal tunnel syndrome.