TECHNICAL COMMUNICATION A Novel Infraclavicular Brachial Plexus Block: The Lateral and Sagittal Technique, Developed by Magnetic Resonance Imaging Studies Øivind Klaastad, MD*, Hans-Jørgen Smith, DMSc†,O ¨ rjan Smedby, DrMedSci‡, Eldrid H. Winther-Larssen, MSc†, Per Brodal, DMSc§, Harald Breivik, DMSc*, and Erik T. Fosse, DMSc#, *Department of Anesthesiology, †Department of Radiology and #The Interventional Centre, Rikshospitalet University Hospital, Oslo, Norway; ‡Department of Radiology, University Hospital Linko ¨ ping, Linko ¨ ping, Sweden; and §Department of Anatomy, University of Oslo, Oslo, Norway A new infraclavicular brachial plexus block method has the patient supine with an adducted arm. The target is any of the three cords behind the pectoralis minor mus- cle. The point of needle insertion is the intersection be- tween the clavicle and the coracoid process. The needle is advanced 0°–30° posterior, always strictly in the sag- ittal plane next to the coracoid process while abutting the antero-inferior edge of the clavicle. We tested the new method using magnetic resonance imaging (MRI) in 20 adult volunteers, without inserting a needle. Com- bining 2 simulated needle directions by 15° posterior and 0° in the images of the volunteers, at least one cord in 19 of 20 volunteers was contacted. This occurred within a needle depth of 6.5 cm. In the sagittal plane of the method the shortest depth to the pleura among all volunteers was 7.5 cm. The MRI study indicates that the new infraclavicular technique may be efficient in reach- ing a cord of the brachial plexus, often not demanding more than two needle directions. The risk of pneumo- thorax should be minimal because the needle is inserted no deeper than 6.5 cm. However, this needs to be con- firmed by a clinical study. (Anesth Analg 2004;98:252–6) I nfraclavicular brachial block methods may often give complete anesthesia distal to the shoulder by a single injection technique. However, there is no infraclavicular technique satisfying all of the following demands: simple landmarks for defining the needle entry site, clear suggestion for the needle direction, a small angle between the needle and the skin (facilitat- ing the insertion of a perineural catheter), minimal risk of pneumothorax, while the patient maintains the arm comfortably in adducted position (1–10). We have tried to develop such a method. In the present study it has been tested using magnetic resonance imaging (MRI), which allows precise simulation of needle passes in three-dimensional images of volunteers, making needle insertion in the volunteers unnecessary (6,11,12). Our aims were to define appropriate needle angles to the cords and to assess the risk of the needle contacting the pleura, the cephalic vein, the axillary artery, and the axillary vein. Methods Using the new approach the patient is supine with relaxed shoulders. The ipsilateral arm is adducted and the hand is on the abdomen. The head rests on a thin pillow and is slightly rotated to the opposite side. The anesthesiologist works from behind the shoulder of the patient. Any of the three brachial plexus cords, posterior to the pectoralis minor muscle, is the target of the method. Sliding a finger laterally below the clavicle, the medial surface of the coracoid process is easily recognized, even in obese or muscular patients, as the first bony prominence. Its most medial palpable point is close to the anterior aspect of the clavicle. All needle directions of the method adhere to the sagittal plane through this coracoid point (Figs. 1, 2A, 2B). The needle is inserted tangentially to the antero-inferior border of the clavicle and directed 0°–30° posterior, to the horizontal (coronal) plane. A nerve stimulator aids in exact positioning of the needle. Accepted for publication August 19, 2003. Address correspondence and reprint requests to Dr. Ø. Klaastad, Rikshospitalet University Hospital, Department of Anesthesiology, Sognsvannsveien 20, NO-0027 Oslo, Norway. Address email to oivindkl@klinmed.uio.no. DOI: 10.1213/01.ANE.0000094337.75996.AE ©2003 by the International Anesthesia Research Society 252 Anesth Analg 2004;98:252–6 0003-2999/03