Spinal Corticosteroid Injections
A structured guide for general practitioners on the diagnostic and therapeutic utility of spinal corticosteroid injections, and key triggers for neurosurgical referral.
Clinical Injection & Triage Matrix
Spinal injections serve a vital dual role as both highly localized diagnostic blocks and therapeutic tools to facilitate active physical rehabilitation.
| Injection Type | Primary Clinical Indications | Diagnostic Utility | Therapeutic Duration | Neurosurgical Referral Triggers |
|---|---|---|---|---|
| Facet Joint Injections | Localised mechanical back or neck pain, facet arthropathy, extension/rotation pain, osteoarthritis. | Excellent. Confirmation of target level if local anaesthetic blocks >80% of pain for 1 to 2 hours. | Muted. Typically provides 1 to 3 months of mild inflammatory reduction. Rarely curative. | Only if facet hypertrophy causes severe secondary spinal canal stenosis or instability requiring fusion. |
| Epidural Steroid Injections (ESI) | Multi-level radiculopathy, central lumbar spinal stenosis, sciatica with broad disc bulge, discitis. | Low. Diffusion of steroid across multiple levels prevents precise isolation of a single nerve root. | High. Reduces surrounding nerve root oedema and inflammation. Resolves sciatica in up to 70% of acute cases. | Refer urgently if progressive neurological deficits (weakness, bowel/bladder changes) occur, or if pain is refractory after 2 injections. |
| Selective Nerve Root Blocks (SNRB) | Focal foraminal stenosis, single-level disc herniation with severe dermatomal radiating pain. | Gold Standard. Crucial for surgical mapping of single-level radiculopathy (e.g., L5 vs. S1) in complex revision cases. | High. Meticulous local delivery of corticosteroid provides fast, targeted relief for 2 to 6 months. | Refer for neurosurgical opinion if arm/leg weakness is progressive, or if radicular pain recurs within 4 weeks of the block. |
| Sacroiliac (SI) Joint Injections | Localised buttock and groin pain, positive Fortin finger test, pain walking or climbing stairs, SI joint arthropathy. | Excellent. Immediate post-injection block of local pain confirms SI joint as the primary generator. | Moderate. Provides relief lasting 2 to 6 months to facilitate active core physical rehabilitation. | Refer if pain remains refractory after comprehensive conservative therapy and targeted injections, for SI joint fusion consideration. |
Best Practices for Spinal Injections
Ensure patient safety and maximize diagnostic accuracy by adhering to these core clinical principles:
Image Guidance is Mandatory
All spinal injections must be performed under fluoroscopic (X-ray) or CT guidance with contrast confirmation. Blind, anatomical landmark-guided injections are clinically unacceptable and carry elevated risks of neurovascular injury.
The Pain Diary Concept
Instruct patients to complete a hourly pain diary for 24 hours post-injection. Documenting the immediate, short-term anesthetic block is the single most valuable diagnostic signal for isolating a surgical level.
Tapering and Volume Limits
Limit injections to a maximum of 3 per level within a 12-month period. Repeated local corticosteroid infiltration accelerates tendon and cartilage wear, and may mask progressive neurological deficits.