A New Approach of Ultrasound-Guided Stellate Ganglion Block

To the Editor: Ultrasound-guided C6 stellate ganglion block (C6-SGB) was first described by Kapral et al. in 1995 (1). According to their report, a 22-guage needle was inserted toward the transverse process of C6 under ultrasound guidance using a high-frequency linear transducer. Regrettably, their ultrasound technique has not prevailed because linear transducers are generally too large for this procedure. Christie et al. (2) used computed tomography to study distribution patterns of injectate during C6-SGB. C6-SGB injections were frequently made beneath the prevertebral fascia in the longus colli muscle (subfascial-SGB injection). The longitudinal spreadof injectate following subfascial-SGB injections was more extensive and caused less hoarseness than that following C6-SGB injections made just anterior to the prevertebral fascia (suprafascial-SGB injection). However, no injectate reached the stellate ganglion by either route. They suggested that the effect of C6-SGB on upper extremity sympathectomy resided in the contact of local anesthetic with postganglionic fibers from the middle cervical ganglion and the stellate ganglion, which join the 4th, 5th, 6th, 7th, and 8th cervical, and 1st thoracic roots. We hypothesized subfascial-C6-SGB injection could be performed easily and safely under ultrasound guidance using techniques that differ from those of Kapral et al. Using a Sonosite 180 PLUS ultrasound system with an 11-mm broadband (4–7 MHz) tightly curved array transducer (Sonosite, Bothell, WA), 33 ultrasound-guided subfascial-C6-SGBs were performed in 11 patients suffering from complex regional pain syndrome of the head and upper extremity. Patients were supine with the neck slightly hyperextended. After aseptic preparation of the skin, the transducer is placed on the neck to enable cross sectional visualization of anatomical structures at the level of C6. The carotid artery, internal jugular vein, thyroid gland, trachea, esophagus (if left SGB was performed), longus colli covered with the prevertebral fascia, root of C6, and transverse process of C6 are all visualized. The transducer was then gently pressed between the carotid artery and trachea to retract the carotid artery laterally and to position the transducer close to the longus colli (Fig. 1). A 1.0-inch, 25-gauge long-bevel needle was paratracheally inserted toward the middle of the longus colli, while staying within the ultrasound beam plane. The endpoint for injection was the ultrasound image demonstrating the tip of needle penetrating the prevertebral fascia in the longus colli. After negative aspiration, 8 mL of 1% lidocaine is injected. The injection and spread (including longitudinal spread) of local anesthetic were visualized in real time (Fig. 2).Figure 1.: Ultrasound image of the left neck at the level of C6 before stellate ganglion block. CA, carotid artery; PF, prevertebral fascia; C6, root of C6; LC, longus colli muscle; TP, transverse process of C6; TH, thyroid gland; ES, esophagus.Figure 2.: Ultrasound image during C6-stellate ganglion block injection beneath the prevertebral fasica in the longus colli muscle; white arrow indicates the prevertebral fascia distended with local anesthetic. CA, carotid artery; PF, prevertebral fascia; C6, root of C6; LC, longus colli muscle; TP, transverse process of C6; TH, thyroid gland; ES, esophagus; LA, local anesthetic.Twenty-six SGB injections were made beneath the prevertebral fascia in the longus colli, and 7 anterior to the fascia because the available needles were too short. Horner’s syndrome was observed in all subfascial SGB injections and in 5 of 7 suprafascial SGB injections. Changes in ipsilateral and contralateral palm temperature after subfascial SGB injections were 2.14°C ± 1.39°C and 0.60°C ± 1.06°C, respectively; those after suprafascial SGB injections were 0.67°C ± 0.25°C and 0.62°C ± 0.73°C, respectively. Following subfascial SGB injections, there were no complications such as hoarseness or associated brachial plexus blockade, but 2 injections resulted in paresthesia within the cutaneous segment of C6: the ultrasound images showed that the injectate had spread laterally over the anterior tubercles of the transverse process of C6 beneath the prevertebral fascia. In patients receiving suprafascial SGB injections, four blocks caused hoarseness: the ultrasound images showed that the injectate had spread into the space between the thyroid gland and trachea where the recurrent laryngeal nerve resides. No hematoma formation was observed following any of the injections. Ultrasound-guided C6-SGB was easily performed beneath the prevertebral fascia in the longus colli muscle, with few complications. We suggest that this technique should be further evaluated in clinical trials. Yasuyuki Shibata, MD Yoshihiro Fujiwara, MD, PhD Toru Komatsu, MD, PhD Department of Anesthesiology Aichi Medical University School of Medicine Aichi [email protected]