A supraomohyoidal plexus block designed to avoid complications

Abstract

Interscalene blocks of the brachial plexus are used for surgery of the shoulder and are frequently associated with complications such as temporary phrenic block, Horner syndrome or hematoma. To minimize the risk of these complications, we developed an approach that avoids medially directed needle advancement and favors spread to lateral regions only: the supraomohyoidal block. We tested this procedure in 11 cadavers fixed by Thiel's method. The insertion site is at the lateral margin of the sternocleidomastoid muscle at the level of the cricoid cartilage. The needle is inserted in the axis of the plexus with an angle of approximately 35°t o the skin, and advanced in lateral and caudal direction. Distribution of solution was determined in ten cadavers after bilateral injection of colored solution (20 and 30 ml) and followed by dissection. In an eleventh cadaver, computerized tomography and 3D reconstruction after radio contrast injection was performed. In additional five cadavers we performed Winnie's technique with bilateral injection (20 and 30 ml).Concerning the supraomohyoidal block the injection mass reached the infraclavicular region surrounded all trunks of the brachial plexus in the supraclavicular region and the suprascapular nerve in all cases. The solution did not spread medially beyond the lateral margin of the anterior scalene muscle into the scalenovertebral triangle.Therefore, phrenic nerve, stellate ganglion, laryngeal nerve nor the vertebral artery were exposed to the injected solution. Distribution was comparable with the use of 20 and 30 ml of solution. Injections on five cadavers performing the interscalene block of Winnie resulted in an extended spread medially to the anterior scalene muscle.We conclude that our method may be a preferred approach due to its safety, because no structures out of interest were reached. Solution of 20 ml is suggested to be enough for a successful block.

Walter Thiel's Embalming Method: Review of Solutions and Applications in Different Fields of Biomedical Research

“…Studies have been done on a supraomohyoid plexus block to avoid complications or collateral effects on other nerves (Feigl et al, 2006) and the spread of local anesthetic to block peripheral nerves (Munirama et al, 2012). For their part, Feigl et al (2013b), identified a simple orientation mark to carry out the vertical obturator nerve block.…”

Hypotensive bradycardic events during shoulder arthroscopic surgery under interscalene brachial plexus blocks

“…The symptoms from these complications might be associated with psychological factors to the vasovagal reflex reaction. Feigl et al [53] demonstrated in their cadaveric study that the group of interscalene blocks by the Winnie technique, with the use of 30 ml, showed spread in a lateral direction in all cases and the dye additionally distributed medial to the anterior scalene and disseminated ventrally and dorsally to the anterior scalene muscle. It reached the phrenic nerve, the vagus nerve, the sympathetic trunk, and the great vessels of the superior mediastinum.…”

Feasibility of ultrasound-guided posterior approach for interscalene catheter placement during arthroscopic shoulder surgery

“…Therefore, the phrenic nerve, stellate ganglion, laryngeal nerve and the vertebral artery were not exposed to the injected solution. Whereas in the cadavers group received an interscalene block by the Winnie technique, the dye spreaded medially to the anterior scalene muscle and reached the phrenic nerve, the vagus nerve and the sympathetic trunk [15]. Urmey et al [6] showed that 100% of the patients with an interscalene brachial plexus anesthesia by the Winnie technique developed ipsilateral hemidiaphragmatic paresis detected by ultrasonography.…”