Predictors of Treatment Response to Stellate Ganglion Block in Cervical Radicular Pain

Cervical Multifidus Fatty Degeneration and Bony Foraminal Stenosis Predict Unsuccessful Response to Stellate Ganglion Block in Cervical Radicular Pain: a Retrospective Study

Purpose: Stellate ganglion block (SGB) is a procedure that uses ultrasound to guide a needle near a group of nerves in the neck called the stellate ganglion. A local anesthetic is then injected to block pain signals. This procedure has recently shown promise as a treatment for cervical radicular pain - pain that travels from the neck down into the arm, usually caused by a pinched nerve in the spine.

While SGB appears to be effective for many patients, not all patients respond equally well. Currently, there is no way to predict before the procedure which patients are likely to benefit and which are not. Identifying such predictors would help doctors select the right patients for this treatment and avoid unnecessary procedures.

Study Question: This study aimed to determine whether specific clinical characteristics or imaging findings on MRI could predict whether a patient would have a successful pain response after receiving SGB for cervical radicular pain.

Methods: This was a retrospective study that reviewed the medical records of patients who received ultrasound-guided SGB at a single medical center between October 2018 and April 2023. Patients were included if they had one-sided arm pain caused by a pinched nerve confirmed on MRI and had not improved after at least one month of standard treatments such as medication and physical therapy.

Information collected from medical records included patient age, sex, body mass index, presence of diabetes or hypertension, pain severity (measured on a 0-to-10 scale), duration of symptoms, and neck disability scores. Imaging findings from cervical MRI were also evaluated, including the degree of nerve compression, the cause of the compression (soft disc herniation versus bony overgrowth), the condition of the spinal canal, disc degeneration, and the amount of fatty changes in the small muscles along the back of the neck (called the multifidus muscles).

Hypothesis: The study hypothesized that certain imaging-based factors - specifically, significant fatty degeneration of the cervical multifidus muscles and bony overgrowth as the main cause of nerve compression - would be associated with a poorer response to SGB at 3 months after the procedure.

Study Overview

• Status: Completed
• Conditions: Radiculopathy, Cervical Region
• Intervention / Treatment: Other: Cervical multifidus fatty degeneration; Other: Primary etiology of foraminal stenosis; Drug: Steroid use during stellate ganglion block; Other: Other collected data

• Study Type: Observational
• Enrollment (Actual): 90

Contacts and Locations

Study Locations

• South Korea
  • Seoul, South Korea, 05505
    • Asan Medical Center

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

Patients aged 19 years or older with unilateral cervical radicular pain who underwent ultrasound-guided stellate ganglion block at the pain clinic of Asan Medical Center, Seoul, Korea, between October 2018 and April 2023. All patients had MRI-confirmed cervical foraminal stenosis consistent with their symptoms and had failed at least 1 month of conservative treatment including medication and physical therapy. Patients were excluded if they had a history of cervical spine surgery, bilateral or multi-segment involvement, neck pain exceeding arm pain, other contributing pain conditions, or insufficient medical records.

Description

Inclusion Criteria:

• Unilateral cervical radicular pain
• Evidence of cervical foraminal stenosis on magnetic resonance imaging (MRI) consistent with radicular pain
• Age ≥ 19 years
• Symptoms unresponsive to at least 1 month of conservative treatment, including medication and physical therapy

Exclusion Criteria:

• History of cervical spine surgery
• Bilateral symptoms or involvement of three or more segments
• Neck pain intensity greater than arm-pain intensity
• Other conditions, such as facet joint syndrome or myofascial pain syndrome, contributing to the symptoms
• Insufficient documentation in the electronic medical records

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Successful responder; Successful responders were defined as patients who demonstrated either a reduction of ≥4 points on the numerical rating scale or a ≥50% decrease in pain at 3 months post-procedure.	Other: Cervical multifidus fatty degeneration; Cervical multifidus fatty degeneration was assessed by evaluating the degree of fatty infiltration in the bilateral multifidus muscles at the C5-C6 level, which is a region noted for its high mechanical load and flexibility, rendering it susceptible to degenerative changes.T2-weighted axial MRI images were analyzed, and fatty infiltration of the cervical multifidus muscle was graded using the Goutallier classification as follows: grade 0 (no fat signal), grade 1 (minimal fat signal), grade 2 (more muscle than fat), grade 3 (equal amounts of fat and muscle), and grade 4 (more fat than muscle) (Fig. 1). For the analysis, cervical multifidus fatty degeneration was defined as minimal (Goutallier grades 0-1) or substantial (Goutallier grades 2-4).; Other: Primary etiology of foraminal stenosis; The primary etiology of foraminal stenosis was determined by differentiating between disc herniation and bony hypertrophy at the uncovertebral or facet joint, based on the more prominent lesion.; Drug: Steroid use during stellate ganglion block; Use of dexamethasone 5 mg added to 6 mL of 1% lidocaine versus 1% lidocaine alone during ultrasound-guided stellate ganglion block, based on the treating physician's clinical decision.; Other: Other collected data; Other collected data included patient demographics, such as age, sex, body mass index, and comorbidities, including diabetes and hypertension, pre-procedural symptoms such as radicular pain with or without neck pain, neck disability index, pain duration, cervical curvature types, central stenosis grade, foraminal stenosis grade, and disc degeneration.
Unsuccessful responder; Patients who did not achieve a successful response or who underwent additional interventional procedures within 3 months were classified as unsuccessful responders.	Other: Cervical multifidus fatty degeneration; Cervical multifidus fatty degeneration was assessed by evaluating the degree of fatty infiltration in the bilateral multifidus muscles at the C5-C6 level, which is a region noted for its high mechanical load and flexibility, rendering it susceptible to degenerative changes.T2-weighted axial MRI images were analyzed, and fatty infiltration of the cervical multifidus muscle was graded using the Goutallier classification as follows: grade 0 (no fat signal), grade 1 (minimal fat signal), grade 2 (more muscle than fat), grade 3 (equal amounts of fat and muscle), and grade 4 (more fat than muscle) (Fig. 1). For the analysis, cervical multifidus fatty degeneration was defined as minimal (Goutallier grades 0-1) or substantial (Goutallier grades 2-4).; Other: Primary etiology of foraminal stenosis; The primary etiology of foraminal stenosis was determined by differentiating between disc herniation and bony hypertrophy at the uncovertebral or facet joint, based on the more prominent lesion.; Drug: Steroid use during stellate ganglion block; Use of dexamethasone 5 mg added to 6 mL of 1% lidocaine versus 1% lidocaine alone during ultrasound-guided stellate ganglion block, based on the treating physician's clinical decision.; Other: Other collected data; Other collected data included patient demographics, such as age, sex, body mass index, and comorbidities, including diabetes and hypertension, pre-procedural symptoms such as radicular pain with or without neck pain, neck disability index, pain duration, cervical curvature types, central stenosis grade, foraminal stenosis grade, and disc degeneration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Successful response	Successful response was defined as either a reduction of ≥4 points on the numerical rating scale or a ≥50% decrease in pain intensity at 3 months post-procedure.	At 3 months post-procedure

Collaborators and Investigators

• Sponsor: Asan Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): October 8, 2024
• Primary Completion (Actual): September 15, 2025
• Study Completion (Actual): September 15, 2025

Study Registration Dates

• First Submitted: March 12, 2026
• First Submitted That Met QC Criteria: March 12, 2026
• First Posted (Actual): March 17, 2026

Study Record Updates

• Last Update Posted (Actual): March 18, 2026
• Last Update Submitted That Met QC Criteria: March 16, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Neuromuscular Diseases; Peripheral Nervous System Diseases; Radiculopathy
• Other Study ID Numbers: 2024-1179

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No