MR imaging of the stellate ganglion: normal appearance

Anatomic evaluation of Pancoast tumors using three-dimensional models for surgical strategy development

OBJECTIVE

Pancoast tumor resection planning requires precise interpretation of 2-dimensional images. We hypothesized that patient-specific 3-dimensional reconstructions, providing intuitive views of anatomy, would enable superior anatomic assessment.

METHODS

Cross-sectional images from 9 patients with representative Pancoast tumors, selected from an institutional database, were randomly assigned to presentation as 2-dimensional images, 3-dimensional virtual reconstruction, or 3-dimensional physical reconstruction. Thoracic surgeons (n = 15) completed questionnaires on the tumor extent and a zone-based algorithmic surgical approach for each patient. Responses were compared with surgical pathology, documented surgical approach, and the optimal "zone-specific" approach. A 5-point Likert scale assessed participants' opinions regarding data presentation and potential benefits of patient-specific 3-dimensional models.

RESULTS

Identification of tumor invasion of segmented neurovascular structures was more accurate with 3-dimensional physical reconstruction (2-dimensional 65.56%, 3-dimensional virtual reconstruction 58.52%, 3-dimensional physical reconstruction 87.50%, P < .001); there was no difference for unsegmented structures. Classification of assessed zonal invasion was better with 3-dimensional physical reconstruction (2-dimensional 67.41%, 3-dimensional virtual reconstruction 77.04%, 3-dimensional physical reconstruction 86.67%; P = .001). However, selected surgical approaches were often discordant from documented (2-dimensional 23.81%, 3-dimensional virtual reconstruction 42.86%, 3-dimensional physical reconstruction 45.24%, P = .084) and "zone-specific" approaches (2-dimensional 33.33%, 3-dimensional virtual reconstruction 42.86%, 3-dimensional physical reconstruction 45.24%, P = .501). All surgeons agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction benefit surgical planning. Most surgeons (14/15) agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction would facilitate patient and interdisciplinary communication. Finally, most surgeons (14/15) agreed that 3-dimensional virtual reconstruction and 3-dimensional physical reconstruction's benefits outweighed potential delays in care for model construction.

CONCLUSIONS

Although a consistent effect on surgical strategy was not identified, patient-specific 3-dimensional Pancoast tumor models provided accurate and user-friendly overviews of critical thoracic structures with perceived benefits for surgeons' clinical practices.

Establishment of ultrasound-guided stellate ganglion block in rats

Background

A novel protocol for accurate stellate ganglion block under ultrasound guidance was designed in rats. This technique raises the success rate of stellate ganglion block and reduces the incidence of brachial plexus and vagus nerve block.

Methods

Fifty-six Sprague-Dawley were randomly divided into an ultrasound-guided group (n = 28) and a blind technique group (n = 28). The rats in the blind technique group were injected with 1.5% lidocaine mixed with methylene blue after signs of brachial plexus stimulation were elicited. The lateral side of the cephalic brachial vein was located under the first rib, where lidocaine was injected into the rats in the ultrasound-guided group. The up-and-down sequential method of Dixon was used to determine the minimum effective volume for stellate ganglion block in rats. Furthermore, we calculated the required operative duration of the two methods and observed the difference in the lidocaine diffusion range between the two groups.

Results

The minimum effective volume for stellate ganglion block in the ultrasound-guided group was 0.040 ml, and the 95% CI was 0.026-0.052 ml. In the blind technique group, the minimum effective volume was 0.639 ml, and the 95% CI was 0.490-0.733 ml. Within the 95% CI of the lowest effective volume, the incidence of brachial plexus block as a complication of stellate ganglion block under ultrasound guidance was 10.00%.

Conclusion

Stellate ganglion block under ultrasound guidance is more accurate than blind detection, which the incidence of complications of stellate ganglion block under ultrasound guidance was significantly lower than under blind detection; the rate of methylene blue staining in the vagus nerve was significantly lower under ultrasound guidance.

Subfascial versus extrafascial ultrasound-guided stellate ganglion block in patients with post-mastectomy sympathetically mediated pain: A randomized clinical trial

Background

Despite being a well-described intervention, the optimal anatomical approach to perform a stellate ganglion block (SGB) has been disputed. We compared the subfascial and extrafascial ultrasound-guided (USG) SGB.

Methods

A randomised clinical trial was conducted, consisting of 50 patients in two groups. Group I received SGB via the subfascial approach while Group II received an SGB via the extrafascial approach. The primary endpoint was successful sympathetic blockade (as indicated by a measured temperature rise of ≥2°C). Secondary endpoints included analgesic efficiency (extent of early onset of pain relief as indicated by >50% improvement in Visual Analogue Scale (VAS) score at 300's post-procedure); occurrence of Horner's syndrome; extent of local anaesthetic distribution; and adverse events.

Results

The mean increase in sympathetic blockade was significantly higher in the subfascial group (2.6 ± 0.6°C; p = .003). Analgesic efficacy was also significantly higher in the subfascial group (p < .001). The difference in the average dermatomal spread of local anaesthetic down to T2 and up to C4 between the groups was also statistically significant (p = .021 and p = .019, respectively).

Conclusions

The degree of temperature rise, pain relief and occurrence of Horner's syndrome were higher in the subfascial than the extrafascial group. The subfascial approach to SGB, with a limited volume of local anaesthetic agent, is a more reliable technique when compared to the extrafascial approach.

Stellate ganglion intervention for chronic pain: A review

Stellate ganglion (SG) intervention is currently widely being studied in many kinds of chronic pain. As one of the convenient ways to treat the sympathetic nervous system, the indications for stellate ganglion intervention (SGI) include complex regional pain syndrome, postherpetic neuralgia, cancer pain of different origins, orofacial pain, and so forth. SGI refers to the reversible or irreversible blocking of the cervical sympathetic trunk, cervical sympathetic ganglion, and their innervation range through noninvasive or minimally invasive treatment. Current treatment options include stellate ganglion block (SGB), SG pulsed radiofrequency, continuous radiofrequency treatment, and noninvasive SGB. In particular, SGB continues to be one of the most studied methods in chronic pain management. However, a single SGB usually provides only short-term effects; repeated SGB may result in complications such as hoarseness, light-headedness, and vessel or nerve injury. Meanwhile, the mechanism of SGI is still unclear. This review discusses the research progress of SGI methods, effectiveness, complications, and possible mechanisms in the management of chronic pain.

Magnetic resonance imaging validation of medial transthyroid ultrasound-guided stellate ganglion block: A pilot study

OBJECTIVE

Ultrasound-guided stellate ganglion block (usSGB) facilitates improved accuracy of needle position and application of lesser volumes of local anesthetic (LA). Approaches of usSGB, however, have not fully been optimized with respect to efficacy and technical convenience. This pilot study examined the anatomical position and spatial distribution of a small volume of LA injectate dispensed by medial transthyroid usSGB via magnetic resonance imaging (MRI) and assessment of its effect on cervical sympathetic nerves.

METHODS

Twelve healthy males were tested in a double-blinded within-subject design. In a total of 37 usSGB, 3 ml of LA and saline 0.9% solution were injected intramuscularly into the longus colli muscle (LCM) preventing uncontrollable spread of LA within cervical structures. Immediately after injection, distribution of injectate was traced by MRI. Twenty-four out of the 37 usSGB-injections with 3 ml ropivacaine 1% (verum) and saline 0.9% (placebo) were compared. Efficacy of usSGB was assessed by the appearance of oculosympathetic paresis and increases in skin temperature.

RESULTS

All usSGBs were positioned in the proximity of the LCM muscle belly. Most of the axial injectate was distributed within the transversal plane between the middle section of C5 and the upper section of T1 vertebra. Signs of oculosympathetic paresis and skin temperature increase were found exclusively under verum conditions.

CONCLUSION

This pilot study demonstrated the feasibility of medial transthyroid usSGB using an out-of-plane technique and a volume of 3 ml of LA. Further studies are required to establish the relative value and safety of this technique compared to other published approaches.

The efficacy of ultrasound-guided stellate ganglion block in alleviating postoperative pain and ventricular arrhythmias and its application prospects

Stellate ganglion block (SGB) has been applied in clinic for almost a century as a therapeutic procedure to alleviate pain-related syndromes and vascular deficits in the upper extremities. A great number of causative side effects and complications due to technological insufficiency and anatomical variations called for the popularity of ultrasound-guided SGB which has made tremendous contribution for clinical diagnosis and therapy, primarily in postoperative pain and cardiac and vascular disorders. This work was aimed at systematically summarizing the current clinical application of ultrasound-guided SGB and putting forward the potential prospective application in future. By searching ultrasound-guided SGB-related works on PubMed database, we mainly elucidated the analgesic effect of preoperative SGB in patients undergoing surgical procedures and substantial reduction in patients with ventricular arrhythmias. The volume of local anesthetics used in ultrasound-guided SGB has been diminished in the recent few years' investigations and successful operation of ultrasound-guided SGB could be achieved with minimal safe volume of local anesthetics. This invasive and safe procedure shows vast potential for future development in clinical treatment for autonomic nervous system and autoimmune disorders. We also put forward hypothesis that ultrasound-guided SGB could be applied combined with controlled hypotension to reduce the intraoperative complications in orthopedic surgery such as insufficiency of cerebral blood flow and reflexive tachycardia. Thus, it is of vital essence to improve the professional skills of physicians for the high rate of success and explore more effective measures which could enhance therapeutic effects when combined with ultrasound-guided SGB in alleviating misery of patients.

Is the level of diffusion restriction in celiac and cervico-thoracic sympathetic ganglia helpful in their proper recognition on PSMA ligand PET/MR?

AIM

 To check if diffusion weighted imaging (DWI) might be helpful in proper recognition of celiac (CG) and cervicothoracic (CTG) sympathetic ganglia on the whole-body multimodal PSMA-ligand PET/MR imaging, in the view of their common misleading avidity on PET potentially suggestive of malignant lesions, including metastatic lymph nodes.

METHODS

 The thickness and the level of diffusion restriction was assessed qualitatively and quantitatively in 406 sympathetic ganglia (189 CTG in 101 males and 217 CG in 116 males) on DWI maps (b-value 0 and 800 s/mm²) and apparent diffusion coefficient (ADC) maps (mean ADC) of the whole-body PET/MR 68Ga-PSMA-11 PET/MR. To form a reference group of a matching ganglia size, the smallest lymph node was chosen from each patient with metastases and underwent the same procedure.

RESULTS

 Very low and low level of diffusion restriction was noted in the majority of sympathetic ganglia (81.0 % CTG, 67.3 % CG, and 73.6 % of all). In the majority (91.7 %) of metastatic lymph nodes the level of diffusion restriction was moderate to high.The mean ADC values in sympathetic ganglia were statistically significantly higher in CTG, CG and all ganglia than in metastatic lymph nodes (p < 0.001; the effect size was large).

CONCLUSIONS

 Sympathetic celiac and cervicothoracic ganglia present very low and low level of diffusion restriction in visual DWI assessment, and significantly higher than metastatic lymph nodes mean ADC values in the majority of cases, which may serve as additional factors aiding differential diagnosis on multimodal PSMA-ligand PET/MR imaging.Therefore, PSMA-ligand PET/MR appears potentially superior to PSMA-ligand PET/CT in proper identification of sympathetic ganglia.

Magnetic resonance imaging features of the superior cervical ganglion and expected changes after radiation therapy to the head and neck in a long-term follow-up

PURPOSE

This study aimed to assess the magnetic resonance (MRI) features of the superior cervical ganglion (SCG) and to track changes to it induced using radiotherapy across a long-term follow-up.

METHODS

In total, 75 patients who underwent radiotherapy for head and neck malignancies and who were studied with MRI were recruited from two centers. MRI was performed before and after radiotherapy, with a median long-term follow-up of 4.5 years. Baseline SCG features were assessed. Changes in axial cross-sectional area, T2-normalized signal, and apparent diffusion coefficient (ADC) (the latter available in about half of the patients) were analyzed. Repeated measures analysis of variance with Bonferroni's correction was used to analyze changes in the aforementioned parameters (significance level 0.05).

RESULTS

Out of a potential 149 SCGs, 136 were visible at baseline MRI. A variable spatial relationship with the internal carotid artery was found. SCGs showed the "black dot" sign in almost all of the patients. ADC was higher in SCGs than in regional lymph nodes. Cross-sectional area, normalized T2, and ADC increased in the period up to 1 year after radiotherapy and then remained stable in subsequent longer-term follow-up.

CONCLUSION

The SCG has unusual features that allow differentiation from the regional lymph nodes. Changes in morphology and signal after radiotherapy must be taken into account by radiologists to avoid misdiagnosis as recurrent nodal disease. Changes induced using radiotherapy are stable in long-term follow-up and are thus likely attributed to other factors (such as Schwann cell hypertrophy/proliferation) rather than edema.

Do not follow the bone, follow the nerve ultrasound-guided stellate ganglion block: a reconfirmation

Indirect and direct methods have been used to localize the stellate ganglion. Identifying the C6 and C7 transverse process can be a technical challenge for practitioners when performing an ultrasound-guided stellate ganglion block. Following the nerve roots from the interscalene plexus into the corresponding foramen can serve as a reconfirmation for identifying the C6 and C7 transverse process.

The "question-mark" MR anatomy of the cervico-thoracic ganglia complex: can it help to avoid mistaking it for a malignant lesion on 68Ga-PSMA-11 PET/MR?

Background

Detectable uptake of ⁶⁸Ga-PSMA-ligands in sympathetic ganglia may potentially lead to mistaking them for malignant lesions. Our aim was to investigate the anatomy of cervico-thoracic-ganglia-complex (CTG-C) in the MR part of multimodal ⁶⁸Ga-PSMA-11 PET/MR imaging, in view of PET factors hindering its proper identification.

Patients and methods

In 106 patients, 212 sites of the CTG-C were retrospectively reviewed to assess the radiotracer uptake (SUV_max), size, shape, position, symmetry of location and visual uptake intensity. Asymmetry of PSMA-ligand uptake and increased uptake were regarded as risk factors of malignancy.

Results

In 66.0% left (L) and 53.8% right (R) CTG-C we noticed configurations, resembling the shape of an exclamation-mark, a question-mark, or its part (called “typical”). Tumor-like CTG-C shapes (oval, binodular or longitudinal) were detected in 28.3% L-CTG-C and in 40.6% R-CTG-C. When visual assessment of PET suggested malignancy, the recognition of “typical” shape of underlying CTG-C on MR generated a rise in the accuracy of their proper identification (from 34.4% to 75%, χ2(1) = 70.4; p < 0.001). Recognizing the shape of the CTG-C as “typical” in MR allowed us to classify as “not-suspicious” 61.9% of all CTG-C which were treated as “suspicious” after sole PET assessment.

Conclusions

The characteristic shape of cervico-thoracic-ganglia-complex (resembling a question-mark, or its part) helps in proper recognition of CTG-C on multimodal whole-body ⁶⁸Ga-PSMA-ligand PET/MR imaging, when detectable uptake might lead to considering pathology.

Comparison of ultrasound-guided stellate ganglion block at 6th and 7th cervical vertebrae using the lateral paracarotid out-of-plane approach for sympathetic blockade in the upper extremity

Background

The authors have performed ultrasound-guided stellate ganglion block (SGB) in our clinic using a lateral paracarotid approach at the level of the 6th cervical vertebra (C6). Although SGB at C6 is a convenient and safe method, there are ongoing concerns about the weak effect of sympathetic blockade in the ipsilateral upper extremity. Therefore, ultrasound-guided SGB was attempted using a lateral paracarotid approach at the level of the 7th cervical vertebra (C7). This prospective study aimed to compare changes in skin temperature after SGB was performed at C6 and C7, and to introduce a lateral paracarotid approach for SGB.

Methods

Thirty patients underwent SGB twice: once at C6 and once at C7. For every SGB, the skin temperature of the patient’s hypothenar area was measured for 15 min at 1-min intervals. Skin temperatures before and after SGB and side effects were compared between C6 and C7 groups.

Results

The temperature of the upper extremity increased after SGB was performed at C6 and C7. There were significant differences between mean pre-SGB and the largest increases in post-SGB temperatures (0.50±0.38℃ and 1.41±0.68℃ at C6 and C7, respectively; p<0.05). Significantly increased post-SGB temperatures (difference >1℃) were found in 5/30 (16.7%) and 24/30 (80%) cases for C6 and C7, respectively (p<0.05). There were no significant differences in side effects between SGB performed at C6 or C7 (p>0.05).

Conclusion

The lateral paracarotid approach using out-of-plane needle insertion for ultrasound-guided SGB performed at C7 was feasible and more effective at elevating skin temperature in the upper extremity than SGB at C6.

A Randomized Comparison between 4, 6 and 8 mL of Local Anesthetic for Ultrasound-Guided Stellate Ganglion Block

Background: Because it affords greater accuracy than landmark-based techniques, ultrasound guidance may reduce the volume of local anesthetic required for sympathetic blockade of the upper extremity. We hypothesized that 4 mL would provide a similar clinical effect when compared to larger volumes. Methods: One hundred and two patients with chronic neuropathic pain of the upper extremity or face were randomly assigned to receive an ultrasound-guided (USG) stellate ganglion block (SGB) with either 4 mL (group A), 6 mL (group B) or 8 mL (group C) mL of 1.0% lidocaine. Skin temperatures of the face, hand, and axillary fold were measured bilaterally at baseline, 10, 20, and 30 min after the block. Our primary outcome was the relative increase in hand temperature on the blocked side at 30 min and our non-inferiority margin was −0.6 °C. Secondary outcomes included success rate (as defined by a relative temperature increase of ≥1.5 °C), pain relief, degree of ptosis and side-effects. Results: The 95% confidence intervals for the difference of the means exceeded our non-inferiority margin (A versus B: −0.76 to 0.24; A versus C: −0.89 to 0.11) for temperature changes in the hand; however, success rates were similar (44, 45 and 55% for A, B and C respectively, p = 0.651). No intergroup differences were found in temperature-related outcomes for the other measurement sites (face, axilla). The incidence of minor side-effects was significantly higher in group C and no block-related complications were noted. Conclusions: We were unable to establish the non-inferiority of a 4 mL volume for sympathetic blockade of the hand. The clinical significance of these findings is unclear as success rates were similar between the different groups. In contrast, the 6- and 8 mL volumes were not associated with greater temperature changes in the face and axilla.

Clinical effects of pulsed radiofrequency to the thoracic sympathetic ganglion versus the cervical sympathetic chain in patients with upper-extremity complex regional pain syndrome: A retrospective analysis

Pulsed radiofrequency (PRF) to the thoracic sympathetic ganglion (TSG PRF) or to the cervical sympathetic chain (CSC PRF) can be performed to overcome transient effects of single sympathetic blocks in patients with upper-extremity complex regional pain syndrome (CRPS).We retrospectively compared the clinical effects of TSG PRF and CSC PRF. Seven TSG PRF cases and 10 CSC PRF cases were enrolled in the present analysis. We assessed effectiveness with multiple clinical measurements: a numerical rating scale (NRS) of pain before and 1 week after the procedure, postprocedure temperature, effect duration, and a self-described patient satisfaction score.The temperature was significantly higher in TSG PRF cases than in CSC PRF cases. Pain values (according to the NRS) 1 week after the procedure were significantly lower, and the effect duration was significantly longer, after TSG PRF than after CSC PRF.TSG PRF is a more effective procedure than CSC PRF for managing chronic upper-extremity CRPS.

Cardiac Denervation for Arrhythmia Treatment with Transesophageal Ultrasonic Strategy in Canine Models

Stellate ganglion (SG) modification has been investigated for arrhythmia treatment. In this study, transesophageal SG imaging and intervention were explored using a homemade 30F integrated focused ultrasonic catheter in healthy mongrel canines in vivo. Anatomic details of SGs were ultrasonically imaged and evaluated. SG had a heterogeneous echoic structure and characteristic profiles sketched by hyper-echoic outlines in an ultrasonogram. Left SGs in the experimental group were successfully ablated through the esophagus under ultrasonic guidance provided by the catheter itself. Two weeks after the ablation, the QT and QTc of the experimental group decreased compared with those of the sham group and at baseline (both p values < 0.001). Histologic examination revealed that left SGs were destroyed. No major complications were observed. This approach may be further explored as a method for ganglia remodeling evaluation and as a strategy of ganglia modification for arrhythmia and for other diseases.

Effects of ultrasound-guided stellate ganglion block on cervical vascular blood flow: study protocol for a randomized controlled trial

BACKGROUND

The stellate ganglion block (SGB) can lead to vasodilation of the head and neck. However, controversy remains concerning the changes in extracerebral blood flow. The objective of this study is to assess the effects of SGB on the blood flow to the neck.

METHODS

A randomized controlled crossover trial with 38 participants will be conducted. Participants who have primary headaches will be assigned to either group A or B. Patients in group A will receive SGB with 6 ml 1% lidocaine, and after a one-week washout period, they will undergo the second SGB with 6 ml normal saline. In contrast, patients in group B will receive the opposite protocol. Data will be collected at baseline (T0) and at 15 min after the first intervention (T1), 15 min before the second intervention (T2), 15 min after the second intervention (T3) and at a 3-week follow up (T4). T1 is the primary time point for the primary outcome analysis. The primary outcomes include the peak systolic velocity (PSV), the end diastolic velocity (EDV), resistance index (RI) and vessel diameter of the common carotid artery (CCA) and vertebral artery (VA). The secondary outcomes include the rate of ptosis, the rate of conjunctival flushing, and the numerical rating scale (NRS) pain score. Additionally, adverse events (AEs) or serious adverse events (SAEs) will be collected at each assessment point.

DISCUSSION

This study will comprehensively investigate the efficacy of SGB in extracerebral blood flow. Our research may also suggest that SGB will be effective in reducing pain in patients with primary headaches.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, identifier ChiCTR-IOR-17011536 . Registered on 1 June 2017.

Several aspects of stellate ganglion block

Background and Study Goal. Stellate ganglion block (SGB) has been used in the treatment of cerebral derangements associated with headache, for the purpose of reliving spasm and presumably increasing the cerebral blood flow, normalizing endovascular resistance. Materials and Methods. 30 volunteers underwent unilateral SGB, 30–40 years (21 females, 9 males), with cluster headache. 5 ml 0,25 % ropivacaine were administered + 4 mg dexamethasone under C6 level paratracheal ultrasound guid. The confirmation was the presence of Horner´s syndrome. The resistive index (RI) was measured by ultrosound transcranial CV doppler of middle cerebral artery at the baseline and 1 min, and 10 min after SGB on both sides (the other side was taken for control). Normal values of RI corresponded to the age. Results and discussion. Our observations showed that after SGB in all patients there was a significant change in RI with normalization of cerebral blood flow, reduction or disappearance of headache. Conclusions. The difference between the block and the nonblock sides was significant before procedure (p < 0,0001) and after 10 min become the same with an insignificant difference (p = 0,001). A higher RI in patients with a cluster headache may be as an indicator for choosing the block side. Ultrasound technique will be helpfull for providing safe block and effect control.

Detection of the Stellate and Thoracic Sympathetic Chain Ganglia with High-Resolution 3D-CISS MR Imaging

BACKGROUND AND PURPOSE

Despite the importance of the sympathetic nervous system in homeostasis and its putative role in various disease states, little is known regarding our ability to image the sympathetic chain and sympathetic chain ganglia, perhaps owing to their small size. In this retrospective study, we sought to evaluate the normal anatomy of the sympathetic chain ganglia and assess the detectability of the sympathetic chain and sympathetic chain ganglia on high-resolution 3D-CISS images.

MATERIALS AND METHODS

This study included 29 patients who underwent 3D-CISS MR imaging of the thoracic spine for reasons unrelated to abnormalities of the sympathetic nervous system. Patients with a prior spinal operation or visible spinal pathology were excluded. The sympathetic chain ganglia were evaluated using noncontrast 3D-CISS MR imaging. Statistical analyses included t tests and measures of central tendency. The Cohen κ statistic was calculated to evaluate interrater reliability.

RESULTS

The stellate ganglion and thoracic chain ganglia were identified in all subjects except at the T10-T11 and T11-T12 levels. The stellate ganglion was found inferomedial to the subclavian artery and anterior and inferior to the transverse process of C7 in all subjects. Thoracic sympathetic chain ganglia were identified ventral to the costovertebral junction in all subjects from T2 to T10. There was strong interobserver agreement for the detection of the sympathetic chain ganglia with κ > 0.80. The size, shape, and location of these structures corresponded with gross anatomic and surgical observations.

CONCLUSIONS

The thoracic sympathetic chain ganglia can be identified on precontrast 3D-CISS MR imaging. This technique may aid in the initial evaluation of stellate ganglion and/or sympathetic chain ganglia size and signal change for comparison in future studies.

MR Imaging of the Superior Cervical Ganglion and Inferior Ganglion of the Vagus Nerve: Structures That Can Mimic Pathologic Retropharyngeal Lymph Nodes

BACKGROUND AND PURPOSE

The superior cervical ganglion and inferior ganglion of the vagus nerve can mimic pathologic retropharyngeal lymph nodes. We studied the cross-sectional anatomy of the superior cervical ganglion and inferior ganglion of the vagus nerve to evaluate how they can be differentiated from the retropharyngeal lymph nodes.

MATERIALS AND METHODS

This retrospective study consists of 2 parts. Cohort 1 concerned the signal intensity of routine neck MR imaging with 2D sequences, apparent diffusion coefficient, and contrast enhancement of the superior cervical ganglion compared with lymph nodes with or without metastasis in 30 patients. Cohort 2 used 3D neurography to assess the morphology and spatial relationships of the superior cervical ganglion, inferior ganglion of the vagus nerve, and the retropharyngeal lymph nodes in 50 other patients.

RESULTS

All superior cervical ganglions had homogeneously greater enhancement and lower signal on diffusion-weighted imaging than lymph nodes. Apparent diffusion coefficient values of the superior cervical ganglion (1.80 ± 0.28 × 10^-3mm²/s) were significantly higher than normal and metastatic lymph nodes (0.86 ± 0.10 × 10^-3mm²/s, P < .001, and 0.73 ± 0.10 × 10^-3mm²/s, P < .001). Ten and 13 of 60 superior cervical ganglions were hypointense on T2-weighted images and had hyperintense spots on both T1- and T2-weighted images, respectively. The latter was considered fat tissue. The largest was the superior cervical ganglion, followed in order by the retropharyngeal lymph node and the inferior ganglion of the vagus nerve (P < .001 to P = .004). The highest at vertebral level was the retropharyngeal lymph nodes, followed, in order, by the inferior ganglion of the vagus nerve and the superior cervical ganglion (P < .001 to P = .001). The retropharyngeal lymph node, superior cervical ganglion, and inferior ganglion of the vagus nerve formed a line from anteromedial to posterolateral.

CONCLUSIONS

The superior cervical ganglion and the inferior ganglion of the vagus nerve can be almost always differentiated from retropharyngeal lymph nodes on MR imaging by evaluating the signal, size, and position.

Patterns of uptake of prostate-specific membrane antigen (PSMA)-targeted 18F-DCFPyL in peripheral ganglia

Objective

Radiotracers targeting prostate-specific membrane antigen (PSMA) have increasingly been recognized as showing uptake in a number of normal structures, anatomic variants, and non-prostate-cancer pathologies. We aimed to explore the frequency and degree of uptake in peripheral ganglia in patients undergoing PET with the PSMA-targeted agent ¹⁸F-DCFPyL.

Methods

A total of 98 patients who underwent ¹⁸F-DCFPyL PET/CT imaging were retrospectively analyzed. This included 76 men with prostate cancer (PCa) and 22 patients with renal cell carcinoma (RCC; 13 men, 9 women). Scans were evaluated for uptake in the cervical, stellate, celiac, lumbar and sacral ganglia. Maximum standardized uptake value corrected to body weight (SUV_max), and maximum standardized uptake value corrected to lean body mass (SUL_max) were recorded for all ganglia with visible uptake above background. Ganglia-to-background ratios were calculated by dividing the SUV_max and SUL_max values by the mean uptake in the ascending aorta (Aorta_mean) and the right gluteus muscle (Gluteus_mean).

Results

Overall, 95 of 98 (96.9%) patients demonstrated uptake in at least one of the evaluated peripheral ganglia. With regard to the PCa cohort, the most frequent sites of radiotracer accumulation were lumbar ganglia (55/76, 72.4%), followed by the cervical ganglia (51/76, 67.1%). Bilateral uptake was found in the majority of cases [lumbar 44/55 (80%) and cervical 30/51 (58.8%)]. Additionally, discernible radiotracer uptake was recorded in 50/76 (65.8%) of the analyzed stellate ganglia and in 45/76 (59.2%) of the celiac ganglia, whereas only 5/76 (6.6%) of the sacral ganglia demonstrated ¹⁸F-DCFPyL accumulation. Similar findings were observed for patients with RCC, with the most frequent locations of radiotracer uptake in both the lumbar (20/22, 90.9%) and cervical ganglia (19/22, 86.4%). No laterality preference was found in mean PSMA-ligand uptake for either the PCa or RCC cohorts.

Conclusion

As PSMA-targeted agents become more widely disseminated, the patterns of uptake in structures that are not directly relevant to patients’ cancers must be understood. This is the first systematic evaluation of the uptake of ¹⁸F-DCFPyL in ganglia demonstrating a general trend with a descending frequency of radiotracer accumulation in lumbar, cervical, stellate, celiac, and sacral ganglia. The underlying biology that leads to variability of PSMA-targeted radiotracers in peripheral ganglia is not currently understood, but may provide opportunities for future research.

A lateral paracarotid approach for ultrasound-guided stellate ganglion block with a linear probe

Recent reports suggest that ultrasound-guided stellate ganglion block (SGB) is safer and more accurate than classic SGB by the using the surface anatomical landmark. However, previous reports concern the classic paratracheal approach using a small specialized curved probe, which may not be appropriate in some patients. The authors have attempted several approaches, including paratracheal, trans-thyroidal, lateral paracarotid, and lateral approaches, to find a safe and suitable method for real-time ultrasound-guided SGB using a standard high-frequency linear probe. A total of 27 injections were performed on 27 patients with sensorineural hearing loss. The lateral paracarotid out-of-plane and lateral in-plane approaches were identified as the easiest and safest methods among the four tested. In this report, we describe a new lateral paracarotid approach for ultrasound-guided SGB. An ipsilateral paratracheal short-axis transverse scan was acquired at the C6 level with a linear probe (6-13 MHz). The probe was moved laterally, scanning the thyroid, carotid artery, internal jugular vein, longus colli muscle, and the transverse process of the C6, placing the carotid artery in the middle of the view. Light pressure was applied to the probe postero-medially to displace the carotid artery medially and completely compress the internal jugular vein. The needle was inserted out-of-plane between the lateral margin of the carotid artery and Chassaignac's tubercle, traversing the collapsed internal jugular vein, and targeted between the longus colli muscle and the prevertebral fascia. A total of 4 ml of 0.2% ropivacaine was injected for each procedure after a negative aspiration test. Successful blockade was confirmed with the onset of Horner's sign. All 27 injections resulted in successful blockade with Horner's sign presenting within 5 min after injection. Side effects were minor and caused minimal discomfort; they included hoarseness and a foreign body sensation. No hematomas formed after any injections. We suggest that this new lateral paracarotid approach, with out-of plane needle insertion at the C6 tubercle under transverse scan, is a convenient and safe method for performing real-time ultrasound-guided SGB, as it provides a wide, safe space for needle passage without risking thyroid or esophageal injury.

Evaluation of Lung Function and Clinical Features of the Ultrasound-Guided Stellate Ganglion Block With 2 Different Concentrations of a Local Anesthetic: A Randomized Controlled Trial

BACKGROUND

One possible complication of stellate ganglion block (SGB) is respiratory compromise. No study has yet addressed the comparison of its effect on lung function and clinical features, including Horner's syndrome, changes in temperature, sensory and motor functions, and adverse events of lower versus higher concentrations (LC and HC, respectively) of local anesthetics in an ultrasound-guided SGB.

METHODS

Fifty patients were randomized into 1 of 2 groups: the LC group (5 mL of 0.5% mepivacaine) and the HC group (5 mL of 1% mepivacaine). One anesthesiologist performed a C6- SGB under ultrasound guidance. Our primary objective was to compare LC and HC of a local anesthetic in terms of its effect on lung function, and the secondary objective was to compare the clinical features between LC and HC of a local anesthetic. Lung function was compared between the 2 groups using the Mann-Whitney U test.

RESULTS

The forced vital capacity at 20 minutes post-SGB was not significantly different between the HC and the LC groups (P = .360); the median difference (95% confidence intervals [CI]) was 1 (-1 to 8). Other parameters of lung function were comparable with the forced vital capacity. Patients in the HC group had significantly greater sensory changes than those in the LC group (% decrease compared with the unblocked side); 95.4 ± 2.1 (CI: 91.11-99.73) vs 87.3 ± 3.5 (CI: 80.12-94.49).

CONCLUSIONS

Lung function between the LC and HC groups after SGB did not differ significantly. Clinical features between the 2 groups also did not differ clinically, except that patients in the HC group had significantly greater sensory loss in the C6 dermatomes.

High-resolution Imaging of Neural Anatomy and Pathology of the Neck

The neck has intricately connected neural structures, including cervical and brachial plexi, the sympathetic system, lower cranial nerves, and their branches. Except for brachial plexus, there has been little research regarding the normal imaging appearance or corresponding pathologies of neural structures in the neck. The development in imaging techniques with better spatial resolution and signal-to-noise ratio has made it possible to see many tiny nerves to predict complications related to image-guided procedures and to better assess treatment response, especially in the management of oncology patients. The purposes of this review is to present imaging-based anatomy of major nerves in the neck and explain their relevant clinical significance according to representative pathologies of regarded nerves in the neck.

Evaluation of new approach to ultrasound guided stellate ganglion block

BACKGROUND

Ultrasound imaging is an ideal tool for stellate ganglion block (SGB) due to clarity, portability, lack of radiation, and low cost. Ultrasound guided anterior approach requires the application of pressure to the anterior neck and is associated with more risk of injury to inferior thyroid artery, vertebral artery, and esophagus. The lateral approach does not interfere with nerve or vascular structures. Blockade at the C6 vertebral level results in more successful sympathetic blockade of the head and neck with less sympathetic blockade of the upper extremity compared to sympathetic blockade at C7 vertebral level, which produces successful sympathetic blockade of upper extremity. This is helpful in patients of complex regional pain syndrome of the upper limb. Hence, we conducted a study using the lateral approach at C7 level.

MATERIALS AND METHODS

Ultrasound guided SGBs using lateral in-plane technique at C7 level were given in 20 patients suffering from chronic pain patients of upper extremity, head, and neck using 4 ml of 0.25% bupivacaine and 1 ml of 40 mg triamcinolone. The patients were assessed for a numeric pain intensity score (NPIS), the rise in axillary temperature, the range of motion of joints of upper extremity, and resolution of edema at various time intervals up to 3 months.

RESULTS

NPIS showed a statistically significant decrease from baseline at 30 min, which was sustained till 3(rd) month. The rise in axillary temperature after the block was statistically significant, which was sustained till 2(nd) week. The edema score decreased significantly at all-time intervals (P ≤ 0.001). The restriction of motion in all joints of upper limb decreased from 13 to 3 patients.

CONCLUSION

There is a significant variation in the anatomy of stellate ganglion at the level of C6 and C7. Ultrasound guided lateral approach increases the efficacy of SGB by deposition of drug subfascially with real-time imaging.

CT-guided stellate ganglion blockade vs. radiofrequency neurolysis in the management of refractory type I complex regional pain syndrome of the upper limb

OBJECTIVE

To describe and evaluate the feasibility and efficacy of CT-guided radiofrequency neurolysis (RFN) vs. local blockade of the stellate ganglion in the management of chronic refractory type I complex regional pain syndrome (CRPS) of the upper limb.

METHODS

Sixty-seven patients were included in this retrospective study between 2000 and 2011. All suffered from chronic upper limb type I CRPS refractory to conventional pain therapies. Thirty-three patients underwent stellate ganglion blockade and 34 benefited from radiofrequency neurolysis of the stellate ganglion. CT guidance was used in both groups. The procedure was considered effective when pain relief was ≥50 %, lasting for at least 2 years.

RESULTS

Thirty-nine women (58.2 %) and 28 men (41.8 %) with a mean age of 49.5 years were included in the study. Univariate analysis performed on the blockade and RFN groups showed a significantly (P < 0.0001) higher success rate in the RFN group (67.6 %, 23/34) compared with the blockade group (21.2 %, 7/33) with an odds ratio of 7.76.

CONCLUSION

CT-guided radiofrequency neurolysis of the stellate ganglion is a safe and successful treatment of chronic refractory type I CRPS of the upper limb. It appears to be more effective than stellate ganglion blockade.

KEY POINTS

• Complex regional pain syndrome is painful, disabling and often refractory to treatment. • Sixty-seven percent of patients had lasting pain relief (2 years) after radiofrequency neurolysis. • Retrospective study showed a significantly higher success rate for radiofrequency neurolysis. • CT guidance is mandatory for a successful and safe procedure.

Efficacy of ultrasonography guided stellate ganglion blockade in the stroke patients with complex regional pain syndrome

Objective

To compare the efficacy of ultrasonography guided stellate ganglion block (US-SGB) with that of blind SGB in management of the stroke patients with complex regional pain syndrome (CRPS) type 1.

Method

Forty-two patients with post-stroke CRPS were randomly assigned to either US-guided SGB (22 patients) or blind SGB group (20 patients). The mean age of US-guided SGB and blind SGB groups was 61.3±5.6 years and 59.1±4.5 years. We performed two blockades at 7-day intervals on the affected side of patients with CRPS. Pain intensity, using a visual analog score (VAS), score of CRPS clinical severity, and the amounts of affected hand swelling with a hand volumeter were assessed before, 2 weeks and 4 weeks after treatment.

Results

In both groups, VAS and the amount of hand swelling were significantly decreased after 2 weeks and after 4 weeks. Between two groups, VAS difference of US-guided SGB group and that of blind SGB group were 2.61±1.09, 1.88±0.62 at 2 weeks and 3.67±1.03, 3.13±0.62 at 4 weeks, respectively. US-guided SGB group showed more significant improvement in mean change of VAS compared to the blind SGB group (p-value<0.05).

Conclusion

Both US-guided SGB and blind SGB techniques were effective in relieving pain in subacute stroke patients with CRPS. US-guided SGB was better in pain relief but has no advantages in reduction of hand swelling in this study.

Depth by ultrasound from skin surface to the C6 transverse process while applying pressure

BACKGROUND

A stellate ganglion block is commonly performed on the anterior tubercle of sixth cervical spine's transverse process. When the procedure is performed, identifying the anatomical landmarks and confirming the depth of the needle insertion to the transverse process are essential for ensuring safety. The purpose of this study was to determine the depth of the needle insertion from the skin to the transverse process for a safe stellate ganglion block.

METHODS

One hundred patients were enrolled for this study. The patients' heights, weights, and neck circumferences were measured. In the supine position, the anterior tubercle of the transverse process were palpated and pressed with the examiner's fingers. While spreading the fingers, an ultrasound probe was placed with the same strength as the fingers and the depth from the skin to the transverse process was measured.

RESULTS

The mean depth from the skin to the transverse process in men was 9.5 ± 2.7 mm on the left side and 9.7 ± 2.5 mm on the right side, whereas in women, it was 8.0 ± 2.2 mm on the left side and 8.2 ± 2.0 mm on the right side. There was no significant difference between the right and left sides among or between the genders but men showed greater depths than women. Although both genders showed a correlation between body mass index and depth, only men showed a correlation between the neck circumference and depth.

CONCLUSIONS

In this study, the mean depth from the skin to the transverse process did not exceed 10 mm in both genders and the maximum depth was 16.6 mm.

Evidence-based interventional pain medicine according to clinical diagnoses. 16. Complex regional pain syndrome

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy is a pain syndrome with an unclear pathophysiology and unpredictable clinical course. The disease is often therapy resistant, the natural course not always favorable. The diagnosis of CRPS is based on signs and symptoms derived from medical history and physical examination. Pharmacological pain management and physical rehabilitation of limb function are the main pillars of therapy and should be started as early as possible. If, however, there is no improvement of limb function and persistent severe pain, interventional pain management techniques may be considered. Intravenous regional blocks with guanethidine did not prove superior to placebo but frequent side effects occurred.Therefore this technique receives a negative recommendation (2 A-). Sympathetic block is the interventional treatment of first choice and has a 2 B+ rating. Ganglion stellatum (stellate ganglion) block with repeated local anesthetic injections or by radiofrequency denervation after positive diagnostic block is documented in prospective and retrospective trials in patients suffering from upper limb CRPS. Lumbar sympathetic blocks can be performed with repeated local anesthetic injections. For a more prolonged lumbar sympathetic block radiofrequency treatment is preferred over phenol neurolysis because effects are comparable whereas the risk for side effects is lower (2 B+). For patients suffering from CRPS refractory to conventional treatment and sympathetic blocks, plexus brachialis block or continuous epidural infusion analgesia coupled with exercise therapy may be tried (2 C+). Spinal cord stimulation is recommended if other treatments fail to improve pain and dysfunction (2 B+). Alternatively peripheral nerve stimulation can be considered, preferentially in study conditions (2 C+).

MRI of the brachial plexus: a pictorial review

Magnetic resonance imaging (MRI) of the brachial plexus is the imaging modality of first choice for depicting anatomy and pathology of the brachial plexus. The anatomy of the roots, trunks, divisions and cords is very well depicted due to the inherent contrast differences between the nerves and the surrounding fat. In this pictorial review the technique and the anatomy will be discussed. The following pathology will be addressed: neurogenic tumors of the brachial plexus and sympathetic chain, superior sulcus tumors, other tumors in the vicinity of the brachial plexus, the differentiation between radiation and metastatic plexopathy, trauma, neurogenic thoracic outlet syndrome and immune-mediated neuropathies.

Development and validation of a new technique for ultrasound-guided stellate ganglion block

BACKGROUND AND OBJECTIVES

Although the stellate ganglion is located anteriorly to the first rib, anesthetic block is routinely performed at the C6 level. Ultrasonography allegedly improves accuracy of needle placement and spread of injectate. The technique is relatively new, and the optimal approach has not been determined. Moreover, the location of the cervical sympathetic trunk relative to the prevertebral fascia is debatable.

METHODS

Three-dimensional sonography was performed on 10 healthy volunteers, and image reconstruction was completed. On the basis of analysis of pertinent anatomy, a lateral trajectory for needle placement was simulated. Accuracy was tested by injection of methylene blue in cadavers. A clinical validation study was then conducted. A block needle was inserted according to the predetermined lateral path, and 5 mL of a mixture of bupivacaine and iohexol was injected. Spread of the contrast agent was verified fluoroscopically.

RESULTS

Image reconstruction revealed that the cervical sympathetic trunk is located posterolaterally to the prevertebral fascia on the surface of the longus colli muscle. The mean anteroposterior width of the muscle at the C6 level was 11 mm. The lateral approach does not interfere with any visceral or nerve structures. Anatomic dissection in cadavers confirmed entirely subfascial spread of the dye and staining of the sympathetic trunk. The contrast agent spread was seen in all patients between the C4 and T1 levels in a typical prevertebral pattern.

CONCLUSIONS

This study revealed that, at the C6 level, the cervical sympathetic trunk lies entirely subfascially. Subfascial injection via the lateral approach ensures reliable spread of a solution to the stellate ganglion.

Upper extremity regional anesthesia: essentials of our current understanding, 2008

Brachial plexus blockade is the cornerstone of the peripheral nerve regional anesthesia practice of most anesthesiologists. As part of the American Society of Regional Anesthesia and Pain Medicine's commitment to providing intensive evidence-based education related to regional anesthesia and analgesia, this article is a complete update of our 2002 comprehensive review of upper extremity anesthesia. The text of the review focuses on (1) pertinent anatomy, (2) approaches to the brachial plexus and techniques that optimize block quality, (4) local anesthetic and adjuvant pharmacology, (5) complications, (6) perioperative issues, and (6) challenges for future research.

Reversible chest tube horner syndrome

A 54-year-old woman who underwent chest tube placement after a lung biopsy was found on the first postoperative day to have ipsilateral ptosis and miosis, suggesting a Horner syndrome. A chest CT scan showed that the tip of the chest tube was apposed to the stellate ganglion. Repositioning of the chest tube later on the first postoperative day led to complete reversal of the Horner syndrome within 24 hours. We propose that the Horner syndrome arose as a result of pressure on the stellate ganglion, which interrupted neural conduction but did not sever the sympathetic pathway ("neurapraxia"). Whether prompt repositioning of the chest tube was critical in reversing the Horner syndrome is uncertain.