Why Does My Back Still Hurt After a Nerve Block?
Nerve blocks and nerve injections reduce pain by calming inflammation and swelling around the nerve. But causes such as adhesions, weakened muscles, and ingrained movement habits remain. That is why pain returns over time, and the effect often gets shorter with each repeat.
What Do Nerve Blocks and Nerve Injections Actually Do?
A nerve block injects medication around the nerve to calm inflammation and swelling and temporarily interrupt pain signals. It plays a useful role when severe pain makes examination and treatment difficult.
There are also clear limits to what an injection cannot do.
1. It Does Not Open the Compressed Space
Where tissue has become stuck together, the space around the nerve stays narrow. Medication calms irritation but does not separate adhered tissue.
2. It Cannot Strengthen Weak Muscles
When weak core muscles fail to support the lower back and pelvis, the same spot gets compressed again. Injections have no role in restoring muscle function.
3. It Cannot Change Movement Habits
As long as bending and twisting patterns stay the same, the conditions for pain are rebuilt every day. This lies outside what an injection can reach.
If the Effect Fades Quickly, a Cause Remains
① There May Be Several Layers of Cause
Peripheral nerves can be trapped in the buttocks or pelvis, separate from the disc. Research found cutaneous nerve entrapment in about 27% of patients with persistent post-surgical pain. If the injection targets the spine, causes like these are not addressed.
② What Shows on MRI May Not Be the Cause
Disc herniation findings appear in 30-40% of people without any pain. If injection targets are chosen based on imaging alone, results fall short. Imaging and the actual painful site need to be checked against each other.
③ A Shortening Effect Is Also a Clue
If the same injection at the same spot lasts less and less, something other than inflammation is likely driving the pain. Adhesions and muscle imbalance do not disappear with medication.
④ Numbness Outlasts Pain
When a nerve has been compressed for a long time, sensory symptoms do not resolve immediately even after inflammation settles. Before adding more injections, it is worth re-examining where the compression actually is.
Signs It Is Time to Revisit the Treatment Direction
- Pain improved right after the injection but returned within days or weeks
- The number of procedures keeps rising while each one lasts shorter
- A painful spot in the buttock or pelvis can be pointed to with one finger
- Pain worsens in specific positions regardless of coughing or sneezing
- Ankle strength and knee reflexes are normal while numbness remains
- MRI findings do not match where the pain actually is
Our Approach at Yonsei SM Pain Clinic
Before repeating an injection in the same spot, change why the area keeps getting compressed. Circulation Therapy addresses three things injections cannot reach, in order.
Stage 1: We bring the swelling down
Circulation HD uses ultrasound-guided fluid injection around nerves and fascia to physically separate adhered tissue. It creates space without steroids, which makes its role different from a standard nerve block.
Stage 2: We wake the muscles up
Circulation PT awakens weakened transverse abdominis, multifidus, and gluteal muscles so the back and pelvis regain their own support. This reduces the force that compresses the nerve again.
Stage 3: We make the movement stick
Sitting, standing, and lifting patterns are corrected so the conditions for pain are not rebuilt in daily life.
Diagnostic Blocks Serve as a Compass
An ultrasound-guided diagnostic block uses a small amount of anesthetic to confirm whether a suspected site is the true source of pain. We use it to decide the direction of treatment rather than as a therapy to keep repeating.
※ Responses to treatment vary by individual. An accurate diagnosis and treatment plan are determined after consultation.
Related Questions
References
- Friedly JL, Comstock BA, Turner JA, et al. A randomized trial of epidural glucocorticoid injections for spinal stenosis. N Engl J Med. 2014;371(1):11-19. PMID 24988555
- Cass SP. Ultrasound-guided nerve hydrodissection: what is it? A review of the literature. Curr Sports Med Rep. 2016;15(1):20-22. PMID 26745165
- Lam KHS et al. Ultrasound-guided nerve hydrodissection for pain management: rationale, methods, current literature, and theoretical mechanisms. J Pain Res. 2020;13:1957-1968. DOI 10.2147/JPR.S247208
- Daniell JR, Osti OL. Failed back surgery syndrome: a review article. Asian Spine J. 2018;12(2):372-379.
Still in Pain Despite Repeated Injections?
Let us look for causes beyond the injection site.
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