Selective Nerve Root Injections

A selective nerve root block shows which spinal nerve is causing your pain and calms the swelling around it. Guided by live X-ray and given by our board-certified pain doctors at Remix Medical in Houston, TX.

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By Raju Mantena, DO · Pain Medicine PhysicianReviewed Jul 9, 20262 min read

Key takeaways

A selective nerve root block (transforaminal injection) places a small, deliberate volume of local anesthetic and corticosteroid directly onto a single spinal nerve root where it exits the spine.
It does two jobs at once: diagnostically, it identifies which specific root is causing pain when imaging implicates several levels; therapeutically, the steroid reduces inflammation around that root.
The deliberately small injectate volume is what makes it selective — larger volumes spread to adjacent levels and destroy the diagnostic value, so recording pain relief during the anesthetic window is essential.
It's especially useful when an MRI shows multiple possible pain generators, helping determine whether and where to operate and often improving surgical success.
Evidence supports lumbar transforaminal steroid injection as effective for radicular pain from disc herniation, and for many patients it provides weeks-to-months of relief that avoids the need for surgical decompression.

Selective Nerve Root Block in Houston, Texas

An MRI of a degenerating spine often shows several levels that could plausibly be causing pain. Surgery based on that ambiguity is a gamble. A selective nerve root block resolves it by anesthetizing one nerve root at a time and asking a simple question: did your pain stop?

What is a Selective Nerve Root Injection?

A selective nerve root block — also called a transforaminal injection — delivers a very small volume of local anesthetic, usually with corticosteroid, directly onto a single spinal nerve root as it exits the spine through its foramen.

The deliberately small volume is what makes it selective. Larger volumes spread to adjacent levels and destroy the diagnostic value.

Stage	What happens
Before	You're positioned, the skin is cleaned and numbed, and live imaging (fluoroscopy or ultrasound) guides the needle
During	The medication is placed precisely at the specific irritated nerve root; most people feel pressure more than sharp pain
After	You rest briefly and go home the same day — arrange a driver if you received sedation

Two Jobs at Once

Diagnostic. When imaging implicates multiple levels, or when the pain pattern does not match the imaging, blocking one root at a time identifies which one is symptomatic. This directly informs whether and where to operate.

Therapeutic. The corticosteroid reduces inflammation around the root, and many patients get durable relief without ever proceeding to surgery.

Who It Helps

Radiculopathy from a herniated or bulging disc, with pain following a nerve distribution
Foraminal stenosis narrowing the exit of a specific nerve root
Multi-level degenerative disease where the symptomatic level is unclear
Sciatica unresponsive to conservative treatment
Post-surgical radicular pain at an adjacent or recurrent level
Pre-surgical planning , to confirm the target before committing to decompression

Precision Before Intervention at Remix Medical

The most important thing a pain physician can give you is an accurate diagnosis. Everything downstream depends on it.

How it's performed

Under live fluoroscopic guidance, a needle is advanced toward the neural foramen at the target level until it lies adjacent to the exiting nerve root. Contrast is injected to confirm the characteristic outline of the nerve root and to exclude vascular uptake. A small, deliberately limited volume of local anesthetic and corticosteroid is then deposited onto that single root.

How to prepare

Avoid pain medication immediately beforehand, as it can obscure the diagnostic result. Arrange a driver. Hold anticoagulants only as directed by the prescribing physician. Bring recent MRI or CT imaging. Be prepared to record pain scores for several hours afterward.

What to expect after

Record pain scores hourly for 6 to 8 hours — the anesthetic phase carries the diagnostic information. Ice the site 20 minutes every 2 to 3 hours on the first day. Avoid heavy lifting and driving for 24 hours. Temporary numbness or heaviness in the limb is expected and resolves. Report fever, severe headache, or progressive weakness immediately.

Outcome

Substantial relief of familiar radicular pain during the anesthetic phase identifies the symptomatic nerve root with high confidence. The corticosteroid component frequently provides weeks to months of relief, and in many patients avoids the need for surgical decompression.

Frequently asked

Selective Nerve Root Injections questions, answered

What is a selective nerve root block?

It's a precise injection around a specific spinal nerve root to both relieve pain and identify which nerve is causing your symptoms. It targets one nerve rather than the whole area.

Is it a diagnostic or treatment injection?

It's often both: relief after the injection points to that nerve as the source, and the medication also calms the inflammation. That information guides next steps.

What does a nerve root block treat?

It's used for pain, numbness, or tingling traveling down an arm or leg from an irritated spinal nerve, such as with a herniated disc. Your doctor decides if it fits.

Does a nerve root block hurt?

The skin is numbed and imaging guides the needle, so you'll mostly feel pressure. Some soreness afterward is normal.

What should I expect after the injection?

Take it easy that day and note how your pain responds, which helps your doctor. Call for fever, severe pain, or new weakness.

Sources

References

Manchikanti L, Knezevic NN, Knezevic E, et al. Epidural Interventions in the Management of Chronic Spinal Pain: ASIPP Comprehensive Evidence-Based Guidelines. Pain Physician 2021;24(S1):S27–S208 — https://www.painphysicianjournal.com/current/pdf?article=NzIwNg%3D%3D
Patel VB, Wasserman R, Imani F. Interventional Therapies for Chronic Low Back Pain: Transforaminal Epidural Steroid Injections — A Systematic Review. Pain Physician 2021 — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11891702/
Barreto MdM, et al. Epidural Steroids for Cervical and Lumbar Radicular Pain and Spinal Stenosis: Systematic Review Summary — Report of the AAN Guidelines Subcommittee. Neurology 2025 — https://pubmed.ncbi.nlm.nih.gov/39938000/
Kreiner DS, Hwang SW, Easa JE, et al. Diagnosis and treatment of lumbar disc herniation with radiculopathy (NASS). Spine J 2014;14(1):180–191 — https://pubmed.ncbi.nlm.nih.gov/24239490/
Bhatia A, Flamer D, Shah PS, Cohen SP. Transforaminal Epidural Steroid Injections for Treating Lumbosacral Radicular Pain from Herniated Intervertebral Discs. Anesth Analg 2016;122(3):857–870 — https://pubmed.ncbi.nlm.nih.gov/26580836/
National Institute of Neurological Disorders and Stroke: Low Back Pain — https://www.ninds.nih.gov/health-information/disorders/back-pain

SpecialtyPain ManagementTypeProcedureBody locationCervical nerve roots, thoracic nerve roots, lumbar nerve roots, neural foramen, dorsal root ganglionCPT code64479 (transforaminal, cervical/thoracic, single level), 64480 (each additional level); 64483 (transforaminal, lumbar/sacral, single level), 64484 (each additional level); 77003 (fluoroscopic guidance, when reported separately)

Also called Selective Nerve Root Injection, SNRB, Transforaminal Injection, Nerve Root Block, Transforaminal Epidural Steroid Injection

This page is for general education and is not a substitute for medical advice. Whether a given procedure is appropriate depends on your individual evaluation. Contact a Remix Medical clinician to discuss your care.

Updated July 9, 2026. Medically reviewed by Raju Mantena, DO.