Background The frequency of peripheral nerve involvement has been debated in systemic sclerosis (SS). Despite the patients have clinical symptoms such as numbness and paresthesia the electrodiagnostically proven neuropathy incidence is low.
Objectives The aims of this study are to document peripheral neuropathies in a cohort of SS and compare the sonoelastrographic measurements of median nerves in systemic sclerosis, idiopathic carpal tunnel syndrome and healthy controls.
Methods The clinical, electrophsiological and ultrasonographic assessments were done by three masked researchers. Patients with SS and CTS were assessed with nerve conduction studies. The sonoelastography and sonographic assessments of the median nerve were perfomed with 6–18 Mhz lineer transducer. The measurements of cross sectional areas (CSA)were performed at psiform and forearm level from axial US images. The sonoelastrography was performed with same transducer and same sonographer. The median nerve was visualized in axial view and kept in center of the screen. Seven-10 slight compressions were made periodically by the sonographer until the device determined that the proper elastographic view was obtained. The elastic ratio is the ratio of strain distribution in two selected region of interests (ROI). A round ROI was positioned in the center median nerve, while a same size of ROI was positioned in a homogeneously soft anatomical structure, which was considered as internal control. Second ROI was positioned on the flexor carpi radialis for the wrist level and flexor digitorum superficialis for the forearm level. The ROIs were fixed to 2 mm. By using this method, a higher elastic ratio reflects a lower elasticity of median nerve.
Results The study was completed with 47 hands of 24 patients with SS, 53 hands of patients with CTS and 38 hands of health controls. According to electrodiagnostic testing 17 patients were normal, 4 patients were diagnosed as CTS and 3 patients were diagnosed as polyneuropathy in patients with SS. The CSA of CTS group was significantly higher than systemic sclerosis and control groups. The elastic ratio at psiform level and forearm levels of systemic sclerosis group were significantly higher than the CTS and control groups. There was no statistical difference between CTS and control groups.
Conclusions The frequency of peripheral neuropathy is increased in SS. The median nerves loose the elasticity in both wrist and forearm level where the CSA's are in the normal range. These results suggested that the increased peripheral nerve involvement in SS is about the increased stiffness of the nerves.
Disclosure of Interest None declared