Stellate ganglion block, cervical sympathetic block and cervicothoracic sympathetic block

Abstract

Sir: More than 30 methods have been reported for stellate ganglion block; however, we suggest that some methods may in fact not block the stellate ganglion. The stellate ganglion is formed by a fusion of inferior cervical and the first thoracic ganglia. The cranial part of the ganglion usually lies on or lateral to the longus colli muscle, at the level between the base of the seventh cervical transverse process and the neck of the first rib. The caudal part of the ganglion is located posterior to the cervical pleura [1]. The gray rami of the ganglion run to the seventh and eight cervical and first thoracic spinal nerves, and sometimes to the fifth and sixth cervical spinal nerves, constituting the major part of the sympathetic nerve supply to the arm [1]. Traditionally, a needle was inserted towards the stellate ganglion using a direct anterior or a lateral approach and a local anaesthetic was infused [2-4]. However, insertion of a needle using these direct approaches might often injure the pleura or the blood vessel, causing a pneumothorax or haemorrhage [5]. To minimize these complications, insertion of a needle at the level of the seventh or even sixth cervical vertebra has been increasingly used [5-7]. It had been believed that a local anaesthetic injected at this level would diffuse to the stellate ganglion, because Horner's syndrome and a rise in skin temperature of the hand were observed after the injection [8]. However, recent studies have indicated that a local anaesthetic which was injected at the level of the six or seventh cervical vertebra may not reach the stellate ganglion [9-11]. One group of researchers found that, when 10 mL of bupivacaine were injected at the level of the sixth cervical vertebra, skin temperature increased in the area innervated by the seventh and eight cervical spinal nerves in only five of 10 patients, indicating that the local anaesthetic often did not reach the stellate ganglion. When 20 mL of bupivacaine were injected, lower cervical sympathetic block occurred in all 10 patients; however, in eight patients hoarseness due to recurrent laryngeal nerve block also occurred, indicating that a local anaesthetic blocked not only the stellate ganglion but also the extensive cervicothoracic sympathetic ganglion. In addition, the upper cervical sympathetic nerve (from the first to the sixth cervical spinal nerve) was always blocked after either volume of bupivacaine [9]. The same group confirmed that in cadavers, 20 mL of a dye, which were injected at the level of the sixth vertebra, did not spread to the second thoracic sympathetic chain [10]. Another group of researchers also found using magnetic resonance imaging that, saline 15 mL, which was injected at the level of the sixth or seventh cervical vertebra, rarely reached the stellate ganglion [11]. Therefore, we suggest that when a needle is inserted at the level of the sixth cervical vertebra (and probably also at the level of the seventh vertebra), it is more appropriate to denote the block as a 'cervical sympathetic block'. If a large volume of a local anaesthetic is injected, the block should be called a 'cervicothoracic sympathetic block', since not only the stellate ganglion but also a wide area the cervicothoracic sympathetic nerves are blocked. The term 'stellate ganglion block' should be used only with a direct approach utilizing methods such as computerized tomography [12] Y. OKUDA* T. KITAJIMA* T. ASAI† *First Department of Anesthesiology, Dokkyo University School of Medicine, Mibu, Tochigi and †Department of Anesthesiology, Kansai Medical University, Moriguchi, Osaka, Japan