Computerized axial tomography to define the distribution of solution after stellate ganglion nerve block

Percutaneous left stellate ganglion block for refractory ventricular tachycardia in structural heart disease: our single-centre experience

INTRODUCTION

When electrical storm (ES) is amenable to neither antiarrhythmic drugs, nor deep sedation or catheter ablation, autonomic modulation may be considered. We report our experience with percutaneous left stellate ganglion block (PSGB) to temporarily suppress refractory ventricular arrhythmia (VA) in patients with structural heart disease.

METHODS

A retrospective analysis was performed at our institution of patients with structural heart disease and an implantable cardioverter defibrillator (ICD) who had undergone PSGB for refractory VA between January 2018 and October 2021. The number of times antitachycardia pacing (ATP) was delivered and the number of ICD shocks/external cardioversions performed in the week before and after PSGB were evaluated. Charts were checked for potential complications.

RESULTS

Twelve patients were identified who underwent a combined total of 15 PSGB and 5 surgical left cardiac sympathetic denervation procedures. Mean age was 73 ± 5.8 years and all patients were male. Nine of 12 (75%) had ischaemic cardiomyopathy, with the remainder having non-ischaemic dilated cardiomyopathy. Mean left ventricular ejection fraction was 35% (± 12.2%). Eight of 12 (66.7%) patients were already being treated with both amiodarone and beta-blockers. The reduction in ATP did not reach statistical significance (p = 0.066); however, ICD shocks (p = 0.028) and ATP/shocks combined were significantly reduced (p = 0.04). At our follow-up electrophysiology meetings PSGB was deemed ineffective in 4 of 12 patients (33%). Temporary anisocoria was seen in 2 of 12 (17%) patients, and temporary hypotension and hoarseness were reported in a single patient.

DISCUSSION

In this limited series, PSGB showed promise as a method for temporarily stabilising refractory VA and ES in a cohort of male patients with structural heart disease. The side effects observed were mild and temporary.

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.

Sympathetic blocks for complex regional pain syndrome: a survey of pain physicians

BACKGROUND

Sympathetic blocks (SB) are commonly used to treat pain from complex regional pain syndrome (CRPS). However, there are currently no guidelines to assist pain physicians in determining the best practices when using and performing these procedures.

METHODS

A 32-question survey was developed on how SBs are used and performed to treat CRPS. The survey was conducted online via SurveyMonkey. The responses were statistically analyzed using descriptive statistics, and comparing academic versus non-academic, and fellowship versus non-fellowship-trained physicians.

RESULTS

A total of 248 pain physicians responded with a response rate of 37%. Forty-four percent of respondents schedule the first SB at the first clinic visit; 73% perform one to three consecutive blocks; over 50% will repeat the block if a patient receives at least 50% pain relief from the previous one lasting 1-7 days.Fifty-four percent of respondents perform stellate ganglion blocks (SGB) at the C6 vertebral level, 41% at C7; 53% perform lumbar sympathetic blocks (LSB) at L3 level, 39% at L2; 50% use fluoroscopy to guide SGB, 47% use ultrasound. More respondents from academic than non-academic centers use ultrasound for SGB. About 75% of respondents use a total volume of 5-10 mL for SGB and 10-20 mL for LSB. The most commonly used local anesthetic is 0.25% bupivacaine. About 50% of respondents add other medications, mostly steroids, for these blocks.

CONCLUSION

Our study showed a wide variation in current practice among pain physicians in treating CRPS with SBs. There is a clear need for evidence-based guidelines on when and how to perform SBs for CRPS.

Ultrasound Features of Middle Cervical Sympathetic Ganglion

OBJECTIVES

To evaluate the feasibility of ultrasound (US) detection of the middle cervical sympathetic ganglion (CSG).

MATERIALS AND METHODS

We examined 52 consecutive patients with 104 bilateral middle CSGs. We identified middle CSG according to our sonographic assessment criteria. After finding oval-shaped hypoechoic structure on transverse scan, we verified a continuous, hypoechoic line connecting the bulbous structure at both sides. The basic US characteristics were evaluated using the size, location, relationship to the common carotid artery, and relationship to the inferior thyroidal artery.

RESULTS

The middle CSG was identified in 41% (43/104). The mean size of the middle CSG was 3.8±1.5 mm in width, 1.9±0.7 mm in height, and 8.7±3.2 mm in length. They were primarily located at the C6 level (41/43, 95%). Regarding the relationship with common carotid artery, 88% (38/43) were lateral type and 12% (5/43) were medial type. Regarding the relationship with the inferior thyroid artery, 34% (15/43) were anterior type, 26% (11/43) were posterior type, and 40% (17/43) were unable to access the relationship.

DISCUSSION

Direct visualization of middle CSG based on the understanding of both its location and US features may reduce complications and improve the accuracy of US-guided neck procedures.

Ultrasound-guided pain interventions - a review of techniques for peripheral nerves

Ultrasound has emerged to become a commonly used modality in the performance of chronic pain interventions. It allows direct visualization of tissue structure while allowing real time guidance of needle placement and medication administration. Ultrasound is a relatively affordable imaging tool and does not subject the practitioner or patient to radiation exposure. This review focuses on the anatomy and sonoanatomy of peripheral non-axial structures commonly involved in chronic pain conditions including the stellate ganglion, suprascapular, ilioinguinal, iliohypogastric, genitofemoral and lateral femoral cutaneous nerves. Additionally, the review discusses ultrasound guided intervention techniques applicable to these structures.

Ultrasound in regional anaesthesia

Ultrasound guidance is rapidly becoming the gold standard for regional anaesthesia. There is an ever growing weight of evidence, matched with improving technology, to show that the use of ultrasound has significant benefits over conventional techniques, such as nerve stimulation and loss of resistance. The improved safety and efficacy that ultrasound brings to regional anaesthesia will help promote its use and realise the benefits that regional anaesthesia has over general anaesthesia, such as decreased morbidity and mortality, superior postoperative analgesia, cost-effectiveness, decreased postoperative complications and an improved postoperative course. In this review we consider the evidence behind the improved safety and efficacy of ultrasound-guided regional anaesthesia, before discussing its use in pain medicine, paediatrics and in the facilitation of neuraxial blockade. The Achilles' heel of ultrasound-guided regional anaesthesia is that anaesthetists are far more familiar with providing general anaesthesia, which in most cases requires skills that are achieved faster and more reliably. To this ends we go on to provide practical advice on ultrasound-guided techniques and the introduction of ultrasound into a department.

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.

Severe hypertension after stellate ganglion block

Haemodynamic effects may occur after stellate ganglion block (SGB) arising from autonomic imbalance and local anaesthetic infiltration to barosensitive areas. We report seven patients who developed severe hypertension (systolic arterial pressure >200 mm Hg) after SGB in our pain clinic service. We postulate that diffusion of the local anaesthetic along the carotid sheath may produce vagal blockade causing unopposed sympathetic activity as a result of attenuation of the baroreceptor reflex. We recommend close monitoring of arterial pressure measurement in patients who received SGB.