Superior vena cava syndrome (SVCS) is caused by the obstruction of the superior vena cava (SVC) and/or the brachiocephalic veins and gives rise to a variety of symptoms such as cough, dyspnea, facial edema, plethora, and swelling of the upper extremity [1]. In some cases, swelling can even lead to pain in the neck or arm [2]. Definitive treatment of SVCS is removing the cause of the SVC obstruction through surgery or intervention [1]. However, in the cases where this is not possible, such as in terminal cancer patients, alleviation of the presenting symptoms could be the only therapeutic option.

The stellate ganglion is a sympathetic ganglion formed by the fusion of the inferior cervical and the first thoracic ganglion, and it mediates pain of autonomic origin in the head, neck, and upper extremity [3]. Stellate ganglion block (SGB) is therefore used for the treatment of several painful conditions including complex regional pain syndrome, post-herpetic neuralgia, and peripheral vascular diseases [4-6]. The ganglion generally resides lateral to the longus colli muscle and anterior to the transverse process of C7, and under ultrasound guidance, the target point of the injection is just below the prevertebral fascia and above the fascia covering the longus colli muscle at C6-C7 level [3]. Use of ultrasound in the block has made it possible to directly observe the injectate spread in the targeted fascial plane and brought about better block outcomes [3]. In several recent studies, sympathetic blocks including SGB were found effective in reducing swelling in cancer-related lymphedema [7-11]. In this case, we report that ultrasound-guided SGB was effective for reducing pain in a patient with SVCS involving brachiocephalic veins due to metastases of uterine sarcoma.

A 58-year-old female with multiple metastases of uterine sarcoma was referred to our pain clinic for severe pain in the right shoulder and arm. She suffered from continuous dull pain with a numerical rating scale (NRS; 0 = no pain, 10 = worst pain imaginable) score of 9. She had received various pain medications including oral oxycodone/naloxone, fentanyl patch, sublingual fentanyl, and intravenous morphine. However, she experienced no significant improvement. Physical examination revealed whole body edema, especially in the right arm, and chest computed tomography (CT) obtained on the previous day showed a pulmonary metastatic mass compressing the right brachiocephalic vein and enlarged lymph nodes around the lower tracheal, subclavian, and axillary regions (Fig. 1).

Figure 1. Transverse and coronal view of chest computed tomography (CT) showing a right pulmonary metastatic mass compressing (yellow arrow) the right brachiocephalic vein.

On arrival to the pain clinic, 3L of oxygen via nasal cannula was applied, and the patient’s peripheral oxygen saturation was 96- 99%. We planned to perform SGB in order to ease her pain. Since the patient was unable to lie down or lean back on the bed due to dyspnea and possibility of desaturation, SGB was performed in a sitting position with slight neck extension to the left side. Electrocardiography, heart rate, blood pressure, and pulse oximetry were monitored, and oxygen was supplied throughout the procedure.

A high-frequency linear probe was used to visualize the anatomy. Under ultrasound guidance, C6 anterior tubercle and the carotid artery were identified. The anatomy under the sonographic view was not easy to clearly identify because of large number of enlarged cervical lymph nodes which made the view very crowded and the patient’s limited position. The needle was inserted with out-of-plane technique. After checking the blood vessels using color Doppler, 5 ml of 2% lidocaine was slowly injected at the prevertebral fascia of longus colli muscle (Fig. 2). Successful SGB was confirmed by the occurrence of Horner’s syndrome. The perfusion index (PI; Masimo, Masimo Corporation, Irvine, CA, U.S.A.) was additionally measured at the right index finger for further confirmation, but the PI decreased from 2.2 at baseline to 1.9 at 10 minutes post-procedure. The patient was observed for 30 minutes after the procedure to monitor for early complications. After SGB, her pain slightly decreased, with an NRS ranging from 3 to 5 out of 10. A week later, she was referred to our pain center again for relapsed pain in the right upper limb. Ultrasound-guided SGB was performed in the same manner as the last time. Horner’s syndrome was again observed this time, and the PI increased from 7.5 to 10, which was indicative of a successful block. Also, the patient expressed that she felt much better than the day before. Ten days after the last SGB, she was transferred to a hospice care facility, and we could not follow up on her thereafter.

Figure 2. Sonographic view (upper) with structures marked (bottom), obtained after stellate ganglion block. yellow dashed arrow: the injection site, 1: carotid artery, 2: anterior tubercle of C6 vertebra, 3: posterior tubercle, 4: longus colli muscle.

SVCS can present with a large variety of symptoms precipitated by SVC obstruction, ranging from face or neck ~ arm swelling to more morbid ones such as dyspnea and dizziness [1,12,13]. Also, these symptoms are often accompanied by pain or discomfort in the areas with edema [1,12]. Malignant SVCS develops in about 2-4% of lung cancer, and non-Hodgkin-lymphomas, germ cell tumors, adenocarcinomas, sarcomas and esophageal carcinoma are often associated with SVCS [14]. In SVCS from malignant causes, the definitive treatment is to relieve the obstruction caused by the malignant mass through surgery, intervention, chemotherapy, and radiotherapy [1,13]. However, in terminal cancer patients, none of these options might be suitable for their general condition, and supportive care of the discomfort caused by the symptoms could be the only available therapeutic choice.

The stellate ganglion is known to be involved in sympathetically mediated pain in the head to upper extremity [15]. Therefore, SGB has been of use in management of various pain conditions such as complex regional pain syndrome, post-herpetic neuralgia, and peripheral vascular diseases [4-6]. Most of these peripheral vascular diseases which were reported to have benefited from SGB are of arterial origin, but there have been reports that SGB also had some effects in pain and swelling of venous and lymphatic origins, such as venous malformation and cancer-related lymphedema [7-11,15]. However, the effectiveness of SGB on pain caused by edema in SVCS has never been reported, and our case is the first to report its effect.

Although the exact mechanism by which the SGB alleviated the pain elicited by SVCS is unclear, one possible suggestion could be that SGB improved the obstructed venous flow [16]. Also, because the patient of this present case had experienced some pain relief, it can be deduced that some portion of the pain from SVCS is mediated through autonomic nervous system.

As observed in the present case, in patients with SVCS, the anatomy around the stellate ganglion can often be distorted due to the obstructed SVC and/or the brachiocephalic veins. In addition, when there are enlarged malignant lymph nodes, the sonographic view can be even more confusing. Furthermore, because patients with SVCS usually present with dyspnea, they often have difficulties with complete supine position or even semi-Fowler’s position. Therefore, we performed SGB with the patient in a sitting position, and this made the process of identifying the relevant anatomy even more difficult. One should meticulously evaluate the ultrasound image and be extra-careful when performing the procedure in this patient group.

Because the anatomy is not typical around the region of the interest in patients with SVCS, confirming a successful SGB with the sonographic view alone might not be sufficient. In general, the occurrence of Horner’s syndrome after SGB is indicative of an appropriate block, but absence of such syndrome does not always mean that block would be unsuccessful [17]. Therefore, clinicians have searched for additional methods to predict the effect of SGB and proposed to observe change in PI because it reflects the peripheral perfusion state of the measured site [17,18]. A high PI means that the region is well-perfused, and several studies have reported increased PI after SGB and its correlation with success of the block [17,18]. In the present case, although Horner’s syndrome and relief of pain expressed by the patient was observed in both times after SGB, the PI increased after the second attempt of the procedure but not in the first time. One possible explanation for this could be that because the patient could not hold still during the measurement due to discomfort caused by dyspnea, PI measurement could have been inaccurate owing to motion artifacts. In addition, because the laser-Doppler blood flowmetry, which is the science behind the measurement of PI, is known to be able to detect flow at up to 3mm of depth, the edematous state of the patient’s right arm and fingers might have impaired an accurate detection [17]. Also, PI would have been more useful if measured on the affected and unaffected sides and compared.

In conclusion, in patients with pain caused by SVCS, who are not candidates for aggressive treatments such as surgery or intervention, ultrasound-guided SGB can be helpful for pain relief. However, in these patients who often exhibit anatomical distortion and difficulties with positioning, the procedure should be carried out with extra-attention, and a clinician should keep in mind that evaluating the success of the block might be more complicated than in patients with normal anatomy.

No potential conflict of interest relevant to this article was reported.

Poster presentation at the 71st annual meeting of the Korean Pain Society, Pain Medicine amid the New World 2022. May 22-23, 2022. Live Web Seminar.