ULTRASOUND IMAGING FOR STELLATE GANGLION BLOCK - DIRECT VISUALIZATIONOF PUNCTURE SITE AND LOCAL-ANESTHETIC SPREAD - A PILOT-STUDY

Background and Objectives. Stellate ganglion block (SGB) inhibits symp athetic innervation and is a common treatment for reflex sympathetic d ystrophy. During the positioning of the needle, there is a risk of inj ury to the adjacent structures. The aim of the study was to develop an ultrasonographic imaging technique for the performance of SGB. Method s. Twelve patients (ASA I-II) underwent SGB first by using the blind s tandard technique (group A: 8 mt bupivacaine 0.25%) and a second time by using an ultrasonographic imaging technique (group B: 5 mt bupivaca ine 0.25%). In group B a 10 MHz ultrasound scanning probe was used to identify the anatomic structures and to guide the needle toward the tr ansverse process of C6. Results. Stellate ganglion block was satisfact ory in 11 of 12 attempts by the blind technique. Ultrasonographic guid ance (group B) resulted in a complete block in all patients. Onset of block was observed within 10 minutes in only 10 of 12 group A patients , while all patients in group B exhibited an adequate block after 10 m inutes. During the imaging technique, the needle was inserted to an av erage depth of 22 +/- 3 mm and the injection of 5 mt bupivacaine resul ted in an anesthetic depot with a mean diameter of 14 +/- 3 mm. Distan ce from the depot to the vagal nerve was 5 +/- 3 mm and 5 +/- 4 mm to the root of C6. All patients (n = 4) with a distance of <1 mm between anesthetic depot and the root of C6 developed paresthesia within the c orresponding cutaneous segment. Blind technique resulted in hematoma f ormation in three study patients, with no hematoma occurring during im aging technique. Conclusions. UItrasonographic guided SGB may improve safety and allows the visualization of the local anesthetic depot. Stu dying the local anesthetic spread might allow the avoidance of side ef fects as well as typical complications of SGB.