Effect of the Stellate Ganglion Block on the Retinal Microcirculation

Effect of the Stellate Ganglion Block on the Retinal Microcirculation: A Pilot Study

Surges in the sympathetic nervous system occur at the ictus of a variety of neurological critical illnesses including intracranial hemorrhage and ischemic stroke. It is hypothesized that these exaggerated increases in sympathetic nervous activity produce maladaptations that promote secondary brain injury. One of these possible mechanisms include diffuse vasospasm that cause cerebral ischemia. Hence, methods to abrogate the sympathetic nervous system in this context are under active investigation. One possible method is the regional anesthesia technique of the stellate ganglion nerve block, which is ordinarily used for complex regional pain syndrome, but has been shown to reduce cerebral sympathetic activity and reduces vasospasm in patients with subarachnoid hemorrhage. However, its effect on the microcirculation is not clear. Hence, we propose to study patients receiving the stellate ganglion nerve block as part of their standard medical care and to image their retinal microcirculation before and after the procedure using Optical Coherence Tomography Angiography (OCTA).

Study Overview

• Status: Recruiting
• Conditions: Subarachnoid Hemorrhage; Intracerebral Hemorrhage; Severe Brain Injury; OCTA
• Intervention / Treatment: Device: OCTA Scan

• Study Type: Observational
• Enrollment (Estimated): 50

Contacts and Locations

• Study Contact: Name: Noah Jouett, DO, PhD; Phone Number: 214-645-7011; Email: noah.jouett@utsouthwestern.edu

Study Locations

• United States
  • Texas
    • Dallas, Texas, United States, 75235
      • Recruiting
      • UT Southwestern Medical Center
      • Contact: Noah Jouett, DO, PhD; Phone Number: 214-645-7011; Email: noah.jouett@utsouthwestern.edu
      • Principal Investigator: Noah Jouett, DO, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients receiving the stellate ganglion block

Description

Inclusion Criteria:

• Age 18 years or older
• Patients receiving the stellate ganglion nerve block for an approved indication, e.g. complex regional pain syndrome

Exclusion Criteria:

• Pregnancy
• Non-English speaking
• Temporary or permanent physical limitation that renders the patient unable to sit up and look inside OCTA device

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Intervention Group; Patients receiving the stellate ganglion block	Device: OCTA Scan; Optical Coherence Tomography Angiography before and after receiving the stellate ganglion nerve block.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vascular and Perfusion Density	Quantitative measure of retinal microperfusion	One day

Collaborators and Investigators

• Sponsor: University of Texas Southwestern Medical Center
• Investigators: Principal Investigator: Noah Jouett, DO, PhD, UT Southwestern Medical Center

Publications and helpful links

General Publications

• Patton N, Aslam T, Macgillivray T, Pattie A, Deary IJ, Dhillon B. Retinal vascular image analysis as a potential screening tool for cerebrovascular disease: a rationale based on homology between cerebral and retinal microvasculatures. J Anat. 2005 Apr;206(4):319-48. doi: 10.1111/j.1469-7580.2005.00395.x.

Study record dates

Study Major Dates

• Study Start (Actual): October 7, 2024
• Primary Completion (Estimated): October 7, 2026
• Study Completion (Estimated): October 7, 2026

Study Registration Dates

• First Submitted: December 21, 2024
• First Submitted That Met QC Criteria: January 27, 2025
• First Posted (Actual): January 28, 2025

Study Record Updates

• Last Update Posted (Actual): November 19, 2025
• Last Update Submitted That Met QC Criteria: November 15, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Wounds and Injuries; Pathologic Processes; Hemorrhage; Craniocerebral Trauma; Trauma, Nervous System; Intracranial Hemorrhages; Pathological Conditions, Signs and Symptoms; Brain Injuries; Cerebral Hemorrhage; Subarachnoid Hemorrhage
• Other Study ID Numbers: STU-2024-1027

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Pilot study

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No