Anesthesiology 2002; 96:1315–24 © 2002 American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc. Distribution of Local Anesthetic in Axillary Brachial Plexus Block A Clinical and Magnetic Resonance Imaging Study Øivind Klaastad, M.D.,* Orjan¨ Smedby, Dr.Med.Sci.,† Gale E. Thompson, M.D.,‡ Terje Tillung, R.T.,§ Per Kristian Hol, M.D.,ʈ Jan S. Røtnes, D.M.Sc.,# Per Brodal, D.M.Sc.,** Harald Breivik, D.M.Sc.,†† Karl R. Hetland, M.D.,‡‡ Erik T. Fosse, D.M.Sc.§§ Background: There is an unsettled discussion about whether injected local anesthetic, inadequate concentration of the distribution of local anesthetic is free or inhibited when the anesthetic, or unintentional movement of the needle performing brachial plexus blocks. This is the first study to use or the patient. In 1927, Labat4 proposed that the answer Downloaded from http://pubs.asahq.org/anesthesiology/article-pdf/96/6/1315/335346/0000542-200206000-00009.pdf by guest on 01 October 2021 magnetic resonance imaging (MRI) to help answer this question. could be found in an appreciation of “minute anatomy.” Methods: Thirteen patients received axillary block by a cath- He stated that a solution injected on one side of a fascia eter–nerve stimulator technique. After locating the median normally does not reach the other side of that fascia. nerve, a total dose of 50 ml local anesthetic was injected via the Thompson and Rorie5 made similar observations using catheter in four divided doses of 1, 4, 15, and 30 ml. Results of computed tomography of patients with axillary blocks sensory and motor testing were compared with the spread of local anesthetic as seen by MRI scans taken after each dose. The and histologic examination of the brachial plexus from distribution of local anesthetic was described with reference to cadavers. They concluded that fascial compartments ex- a 20-mm diameter circle around the artery. ist for each nerve of the plexus and that these fascial Results: Thirty minutes after the last dose, only two patients barriers serve to limit circumferential (cross-sectional) demonstrated analgesia or anesthesia in the areas of the radial, spread of injected local anesthetic solutions. Conse- median, and ulnar nerve. At that time, eight of the patients had incomplete spread of local anesthetic around the artery, as seen quently, they recommended injecting into multiple 6 7 by MRI. Their blocks were significantly poorer than those of the sites. Partridge et al. also studied cadavers but ques- five patients with complete filling of the circle, although incom- tioned the functional importance of these fascial com- plete blocks were also present in the latter group. partments based on the spread of injected methylene Conclusion: This study demonstrated that MRI is useful in blue dye. This view is similar to that of Winnie et al.,8 examining local anesthetic distribution in axillary blocks be- cause it can show the correlation between MRI distribution who described a perivascular concept for brachial pattern and clinical effect. The cross-sectional spread of fluid plexus blocks. They claimed that only a single needle around the brachial–axillary artery was often incomplete–in- insertion is necessary because the injected solution lo- hibited, and the clinical effect often inadequate. cates the various nerves to be blocked.8 The controversy regarding whether the spread of local anesthetic is free BRACHIAL plexus blocks may often give patchy and or inhibited has still not been settled.9 Therefore, the delayed anesthesia in one or more nerves.1–3 Among the aim of the current study was to contribute to the solu- many proposed explanations are inadequate volume of tion of this question. We hoped to gain new information about the distribution of local anesthetic by taking re- Additional material related to this article can be found on the peat magnetic resonance images after injections of local ANESTHESIOLOGY Web site. Go to the following address, click on anesthetic and then correlating these images with the the Enhancements Index, and then scroll down to find the sensory and motor status of the upper extremity. appropriate article and link. http://www.anesthesiology.org. Materials and Methods * Staff Anesthesiologist, Department of Anesthesiology, ‡‡ Staff Surgeon, De- partment of Hand Surgery, Oslo Orthopedic University Hospital. † Professor, The Interventional Centre, Rikshospitalet University Hospital, and Department of After obtaining approval of the protocol from the re- Radiology, University Hospital Linköping, Linköping, Sweden. ‡ Staff Anesthe- gional ethical committee (Regional Komite´ for Medisinsk siologist, Department of Anesthesiology, The Mason Clinic, Seattle, Washington. § Radiological Technologist, ʈ Staff Radiologist, # Senior Scientist, §§ Professor Forskningsetikk, Helseregion II, Oslo, Norway), 14 adult and Chairman, The Interventional Centre, †† Professor and Chairman, Depart- patients scheduled for elective hand or forearm surgery ment of Anesthesiology, Rikshospitalet University Hospital. ** Professor, De- partment of Anatomy, University of Oslo, Oslo, Norway. gave written, informed consent to participate in the Received from Oslo Orthopedic University Hospital and The Interventional study. The same investigator performed all blocks. An Centre, Rikshospitalet University Hospital, Oslo, Norway. Submitted for publica- 18-gauge cannula (Contiplex®A/D; B. Braun, Melsungen, tion September 7, 2001. Accepted for publication February 6, 2002. Support was provided solely from institutional and/or departmental sources. Presented in part Germany) with an outside short catheter (length, 45–55 at the 19th Annual Congress of the European Society of Regional Anesthesia and mm) was inserted approximately 4 cm distal to the Pain Therapy, Rome, Italy, September 22, 2000. Address reprint requests to Dr. Klaastad: Rikshospitalet University Hospital, lateral border of the pectoralis major muscle and imme- Department of Anesthesiology, Sognsvannsveien 20, 0027 Oslo, Norway. diately superior to the brachial artery, while the patients Address electronic mail to: [email protected]. Individual arti- cle reprints may be purchased through the Journal Web site, abducted the arm approximately 90° (fig. 1A). The can- www.anesthesiology.org. nula–catheter was directed toward the axilla and parallel Anesthesiology, V 96, No 6, Jun 2002 1315 1316 KLAASTAD ET AL. Downloaded from http://pubs.asahq.org/anesthesiology/article-pdf/96/6/1315/335346/0000542-200206000-00009.pdf by guest on 01 October 2021 Fig. 1. (A) Illustration of the point of needle insertion. The patient is in a supine position with the right arm abducted 90° and maximally rotated externally, exposing the medial surface of the arm. The cannula with an outside catheter was inserted immedi- ately superior to the brachial artery, approximately 4 cm distal to the lateral border of the pectoralis major muscle. It was directed toward the axilla, parallel to the artery. The initial cannula angle to the skin was 30–40°. After fascial click, the cannula–catheter was advanced (aided by a nerve stimulator) with a flat angle to the skin. The catheter was taped in median nerve–stimulating position. Subsequently, the cannula was withdrawn and a flexible extension tube was connected to the catheter for later injections of local anesthetic. (B) Schematic cross-sectional drawing from the right arm illustrating the quadrant system around the brachial artery and the common position of the four terminal nerves. The musculocutaneous nerve is usually found in the deep superior quadrant (Q1), the median nerve in the superficial superior quadrant (Q2), the ulnar nerve in the superficial inferior quadrant (Q3), and the radial nerve in the deep inferior quadrant (Q4). The terms deep and superficial refer to the medial surface of the arm. to the artery with an initial needle angle to the skin of local anesthetic injection. Scanning and clinical testing 30–40°. After “fascial click,”10 the cannula–catheter was were also repeated 10, 20, and 30 min after the last dose advanced with a flat angle to the skin, aided by a periph- and at a variable time after the end of surgery. eral nerve stimulator (Stimuplex®DIG/HNS11; B. Braun). Giving the total dose of local anesthetic in divided Continuous suction (using a syringe) was applied to the doses, with MRI performed between each dose, was cannula to detect inadvertent intravascular position of its expected to yield a better dynamic impression of the tip. Muscle twitches distinctive for median nerve stimu- local anesthetic distribution than after a single large lation were sought with a maximum current of 0.5 mA bolus dose. In particular, the position of the 1-ml dose in and an impulse width of 0.1 ms. The catheter was fixed the cross-sectional MRI plane would indicate if the cath- in this nerve-stimulating position, the cannula was with- eter tip had an appropriate position in this plane, close drawn, and the catheter was connected to a flexible to the brachial–axillary artery. extension tube for later injection of local anesthetic. The Imaging was performed with an open 0.5 T GE Signa extension tube had a dead space of 0.5 ml and was SP scanner (GE Medical, Milwaukee, WI). Twenty-two prefilled with local anesthetic solution. sagittal images, covering the lateral part of the clavicle as Subsequently, the patients entered the magnetic reso- well as the proximal part of the abducted arm, were nance imaging (MRI) scanner. Its open design allowed acquired with a T2-weighted fast-spin echo sequence the patients to be supine with the arm abducted 90°. The (repetition time, 7,700 ms; effective echo time, 95 ms; local anesthetic was injected in divided doses (1, 4, 15, slice thickness, 4 mm; slice interval, 4 mm; matrix, and 30 ml) at a speed of approximately 0.5 ml/s and with 128 ϫ 256; field of view, 32 ϫ 24 cm). The images were 10 min between each dose. The total volume was always evaluated by the radiology team, who were blinded to 50 ml, usually as 1% lidocaine with 5 ␮g/ml epinephrine.