Ultrasound can be routinely used in the diagnosis of the carpal tunnel syndrome?: Electrophysiological and ultrasonographic study of the of carpal tunnel

摘要

Purpose: To determine electrophysiological and ultrasonographic features of the carpal tunnel during flexion and extension of the wrist. Methods: This study included 35 right-handed healthy volunteers, of whom 24 were females and 11 males. The mean age of females and males were 37,5 ± 2.4 and 42 ± 1,9 years respectively. All subjects gave oral informed consent. Anterio-posterior and medio-laterally diameters of the carpal tunnel were measured on ultrasonography during flexion and extension of the wrist. Electrophysiological features of the median nerve sensorimotor conduction in the first digit of the right hand were determined during flexion and extension of the hand. Data from ultrasonographic and electrophysiological measurements were analyzed with SPSS 10.0 package program and the data were compared with ANOVA and Tukey tests. Results: There was a decrease in median n. motor amplitude on flexion and extension of the wrist (p<0.0001), while median n. motor conduction speed decreased only on extension of the wrist (p<0.005). Median n. sensory conduction decreased (p<0.0001) and distal latency lengthened (p<0.0001) on flexion of the wrist. On ultrasonography, the medio-laterally diameter of the carpal tunnel increased on flexion and extension of the wrist (p<0.0001), wile there was a considerable decrease in anterio-posterior diameter of the tunnel on flexion of the wrist (p<0.0001). Conclusions: The diagnosis of carpal tunnel syndrome (CTS) is usually based on clinical and electrophysiological findings and then an appropriate treatment alternative is determined accordingly. Incorporation of ultrasonography (US), computed tomography (CT) and/or magnetic resonance imaging (MRI) into diagnostic efforts will help determine both etiopathogenesis and the most apropriate treatment alternative. Introduction Compression of the median nerve is the most common peripheral nerve pathology [1]. It is the primary factor in constriction of the carpal tunnel; i.e. carpal tunnel syndrome (CTS). The syndrome results from increased tunnel contents or a decreased tunnel size [2]. Among its etiological factors is hereditary predisposition (hereditary pressure sensitive neuropathy), trauma, (dislocation, fracture, forearm-wrist hematoma), occupational factors (recurrent percussion to the wrist or recurrent flexion and extension of the wrist), infection-inflammation (tenosynovitis, sarcoidosis), metabolic disorders (amiloidosis, gout), endocrine conditions (acromegaly, diabetes, hypothroidism, pregnancy), neoplastic conditions (ganglion cyst, lipoma, myeloma), collagen vascular diseases (rheumatoid arthritis, scleroderma) degenerative disorders (osteoarthritis) and iatrogenic factors (stent insertion for dialysis, radial artery puncture) [1,3]. As to the pathophysiology of CTS, compression on the median n. in the tunnel or its ischemia first causes segmental demyelinization and then axonal degeneration [1]. There have been many studies on features of the carpal tunnel in CTS [4,5,6,7,8]. Electrophysiological investigations, the most frequent method for diagnosis of CTS, reveal the real-time severity of median n. involvement some time after the syndrome appears. Ultrasonographic, tomographic or magnetic resonance imaging of the carpal tunnel will offer information on anatomy of the tunnel. There have been a lot of studies on ultrasonographic features of the carpal tunnel; however, there have been few studies on changes in the tunnel depending on physiological positions and on features of median nerve conduction. Therefore, we aimed to investigate ultrasonographic features of the carpal tunnel and electrophysiological changes in median n. conduction during various positions of the wrist. Materials And Methods The study was performed on 35 healthy volunteers. The subjects gave oral informed consent. The exclusion criteria were problems with peripheral nervous system, fracture or the history of fracture in the forearm and the wrists, hereditary or acqu