Stellate Ganglion Block for Loss of Smell After Coronavirus

No longer recruiting at 1 trial location

Overseen By Nyssa F Farrell, MD

Age: 18+

Sex: Any

Trial Phase: Phase 1 & 2

Sponsor: Washington University School of Medicine

Must not be taking: Blood thinners, Antiplatelet agents

Disqualifiers: Chronic rhinosinusitis, Neurodegenerative disorders, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 1 Jurisdiction This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 4

Duration: 5-10 days

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether stellate ganglion block (SGB) can help individuals who lost their sense of smell due to COVID-19. A pain specialist uses ultrasound to guide a small injection into the neck to balance the nervous system. The treatment targets those who have experienced COVID-19 for over a year and continue to struggle with smell. Participants should not have had smell issues before COVID-19 or certain other medical conditions. Meeting these criteria may allow the study to help improve your sense of smell and possibly other long COVID symptoms. As a Phase 1 and Phase 2 trial, the research aims to understand how the treatment works and measure its effectiveness in an initial, smaller group of people.

Do I need to stop my current medications for the trial?

The trial requires that you stop taking blood thinners or antiplatelet agents. Other medications are not specifically mentioned, so it's best to discuss with the trial team.

Is there any evidence suggesting that the stellate ganglion block is likely to be safe for humans?

Research has shown that stellate ganglion block (SGB) is generally safe and well-tolerated. In studies on conditions like PTSD and long COVID, SGB has resulted in very few complications. For instance, among many treatments, only one person experienced hoarseness due to a nerve block. Overall, SGB is a minimally invasive procedure, involving only small injections. This makes it a low-risk option for managing symptoms, including those from long COVID. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Unlike other treatments for COVID-19-induced olfactory dysfunction, which often focus on smell training or steroid therapy, the Stellate Ganglion Block targets the autonomic nervous system directly. This method involves an ultrasound-guided procedure that temporarily blocks nerve signals in the stellate ganglion, potentially reducing inflammation and restoring olfactory function. Researchers are excited about this approach because it offers a new mechanism of action by modulating nerve pathways rather than just addressing symptoms, potentially leading to faster and more effective recovery of the sense of smell.

What evidence suggests that stellate ganglion blocks might be an effective treatment for COVID-19-induced olfactory dysfunction?

Research has shown that stellate ganglion block (SGB), the treatment under study in this trial, can aid in managing conditions like post-traumatic stress disorder (PTSD) and pain. One study found that PTSD symptoms improved significantly after two SGB treatments, with noticeable reductions in symptom severity. SGB has also been reported to help maintain stable blood flow and pressure. Some recent reports and a case series suggest that SGB might assist with smell problems and other symptoms related to long COVID. The treatment blocks certain nerve signals, potentially helping to reset the body's stress response. While initial findings are promising, more research is needed to confirm its effectiveness for COVID-19-related smell issues specifically. ^{6 7 8 9 10}

Are You a Good Fit for This Trial?

Inclusion Criteria

Adults age 18 to 70

Ability to read, write, and understand English

You have been diagnosed with COVID at least 12 months prior to study enrollment with self-reported olfactory dysfunction.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive sequential stellate ganglion blocks to treat COVID-19-induced olfactory dysfunction and other long COVID symptoms

5-10 days

2 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

1 month

2 visits (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Stellate Ganglion Block

How Is the Trial Designed?

Group I: Stellate Ganglion Block Experimental Treatment 1 Intervention

The ultrasound guided stellate ganglion blocks will be performed by a pain management specialist with extensive experience performing these blocks. The first SGB at the initial visit will be performed on the right side, and the second SGB will be on the left side 5-10 days after the first SGB, given that the patient tolerated the first SGB.

Stellate Ganglion Block is already approved in United States for the following indications:

Approved in United States as Stellate Ganglion Block for:

• Chronic pain management
• Posttraumatic stress disorder (PTSD) symptoms reduction

Who Is Running the Clinical Trial?

Washington University School of Medicine

Lead Sponsor

Trials

2,027

Recruited

2,353,000+

Published Research Related to This Trial

A 59-year-old male with refractory ventricular tachycardia (VT) experienced immediate cessation of VT and maintained sinus rhythm after receiving a left stellate ganglion block (LSGB) using a lidocaine and bupivacaine solution.

The LSGB procedure appears to be a safe and effective method for controlling refractory VT, suggesting its potential as a rescue therapy before more invasive treatments like catheter ablation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Left stellate ganglion block, a rescue treatment for ventricular arrhythmia refractory to radiofrequency catheter ablation: A care-compliant case report. Yang, SC., Wu, CC., Hsieh, YJ.[2022]

Stellate ganglion block (SGB) has been found effective for non-pain indications such as reducing cardiovascular sympathetic stimulation and improving blood flow in limbs, with moderate to low certainty based on 24 studies including 19 randomized controlled trials.

SGB is also recommended for alleviating menopausal symptoms like hot flashes, particularly in cases where conventional treatments have failed, although evidence for other non-pain uses remains insufficient.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Stellate ganglion block for non-pain indications: a scoping review. Feigin, G., Velasco Figueroa, S., Englesakis, MF., et al.[2023]

Ultrasonographic guidance for stellate ganglion block (SGB) resulted in a complete block in all patients, compared to 11 out of 12 with the blind technique, indicating improved efficacy.

The use of ultrasound significantly reduced complications, as no hematomas occurred with the imaging technique, while three patients experienced hematomas with the blind method, highlighting enhanced safety.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Ultrasound imaging for stellate ganglion block: direct visualization of puncture site and local anesthetic spread. A pilot study. Kapral, S., Krafft, P., Gosch, M., et al.[2022]

This clinical trial aims to evaluate whether a single-shot stellate ganglion block (SGB) can reduce the incidence of myocardial injury after non-cardiac surgery (MINS) in high-risk patients undergoing laparoscopic colorectal cancer surgery, involving 950 participants aged over 45 with at least one risk factor for MINS.

The study will assess multiple outcomes, including pain levels, recovery quality, and serious cardiovascular complications, providing a comprehensive evaluation of SGB's efficacy and safety in improving postoperative recovery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Postoperative stellate ganglion block to reduce myocardial injury after laparoscopic radical resection for colorectal cancer: protocol for a randomised trial. Hu, Z., Li, W., Zhao, G., et al.[2023]

Stellate ganglion block (SGB) is generally a safe procedure, but it can lead to serious complications like retropharyngeal hematomas (RPH) and local anesthetic toxicity in rare cases.

Management of these complications includes emergency airway management for RPH and the use of higher doses of intravenous lipid emulsions to improve outcomes in cases of local anesthetic toxicity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Complication and Anesthetics-induced Toxicity of Stellate Ganglion Block]. Okuda, Y., Suzuki, H., Saima, S.[2018]

Stellate ganglion block (SGB) significantly reduced facial pain in patients, with a mean visual analog scale (VAS) score dropping from 8.89 to 0.2 after treatment, and this relief was maintained for at least 12 months.

In contrast, patients who received oral medications (tramadol and gabapentin) showed only a moderate reduction in pain, indicating that early administration of SGB is crucial for optimal efficacy in treating facial pain.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Facial pain: a possible therapy with stellate ganglion block. Salvaggio, I., Adducci, E., Dell'Aquila, L., et al.[2022]

In a study of 60 patients with complex regional pain syndrome type II undergoing surgery, stellate ganglion block (SGB) significantly reduced the need for intraoperative propofol and fentanyl, indicating its efficacy in managing acute pain during surgery.

Patients receiving SGB also experienced a longer time before needing their first analgesic and required less fentanyl in the 24 hours post-surgery, suggesting that SGB can effectively decrease opioid consumption after surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of Stellate Ganglion Block on Intraoperative Propofol and Fentanyl Consumption in Patients with Complex Regional Pain Syndrome Undergoing Surgical Repair of Brachial Plexus Injury: A Randomized, Double-blind, Placebo-controlled Trial. Rajagopalan, V., Chouhan, RS., Pandia, MP., et al.[2022]

Stellate Ganglion Block (SGB) is an effective treatment for upper extremity pain due to Chronic Regional Pain Syndrome (CRPS), and this study compared the effectiveness of ultrasound-guided SGB versus fluoroscopy-guided SGB in 14 patients.

The results indicated that ultrasound guidance for SGB is safer and leads to better improvements in patient disability indexes compared to fluoroscopic guidance, with significant reductions in pain intensity observed over six months.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effectiveness of Stellate Ganglion Block Under Fuoroscopy or Ultrasound Guidance in Upper Extremity CRPS. Imani, F., Hemati, K., Rahimzadeh, P., et al.[2022]

Citations

1. clinicaltrials.gov clinicaltrials.gov/study/NCT05107752

Stellate Ganglion Block to Augment Trauma-focused ... The primary objective of this project is to examine if stellate ganglion block (SGB) improves outcomes among military personnel and veterans receiving cognitive ...

2. nature.com nature.com/articles/s41598-024-76663-9

Efficacy of stellate ganglion block in treatment of electrical ... The in-hospital or 30-day mortality was 22% and escalation of therapy including MCS (7%), deep sedation with mechanical ventilation (15%) and ...

3. frontiersin.org frontiersin.org/journals/medicine/articles/10.3389/fmed.2025.1625121/full

Retrospective efficacy analysis of stellate ganglion block ... Results: The SGB+GA group demonstrated superior hemodynamic stability (P < 0.001) and markedly lower pain scores postoperatively (P < 0.001). Opioid-induced ...

4. ncbi.nlm.nih.gov ncbi.nlm.nih.gov/books/NBK442253/

Evidence Brief: Effectiveness of Stellate Ganglion Block for ... In the RCT, the range of mean percent PTSD improvement after one round of SGB was 5.4% to 14.7%, and was 12.1% to 21.2% after the second round, which was no ...

5. jamanetwork.com jamanetwork.com/journals/jamapsychiatry/fullarticle/2753810

Effect of Stellate Ganglion Block Treatment on ... 2 stellate ganglion block treatments 2 weeks apart were effective in reducing Clinician-Administered PTSD Scale for DSM-5 total symptom severity scores over 8 ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC4601906/

Safety and Patient Acceptability of Stellate Ganglion ... The SGB procedure for PTSD is a safe, well-tolerated, and acceptable treatment adjunct in the management of severe symptoms associated with chronic treatment- ...

7. nature.com nature.com/articles/s41598-025-91847-7

Effectiveness and safety of stellate ganglion block with ... Clinical practice and literature have demonstrated that SGB is safe and effective for PHN. However, some patients do not experience satisfactory ...

8. wjgnet.com wjgnet.com/2307-8960/full/v11/i10/2160.htm

Treatment of stellate ganglion block in diseases SGB is a minimally invasive injection that aims to inject low-concentration local anesthetics to induce a broad sympathetic blocking effect near the SG.

9. sciencedirect.com sciencedirect.com/science/article/pii/S2405500X24000082

A Multicenter Study of Stellate Ganglion Block as ... Safety data. There were 2 complications, both in the Duke patient cohort. There was 1 recurrent laryngeal nerve block with resultant hoarseness and 1 ...

10. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/39263197/

The Effectiveness and Safety of Stellate Ganglion Block in the ... Stellate ganglion block is a safe, low-risk, minimally invasive, and effective procedure in the treatment of symptoms for long COVID.