C5-C6 Epidural Neck Injection: What Is the Success Rate?

Roughly 50 to 70 percent of people who receive a cervical epidural steroid injection at the C5-C6 level experience at least a 50 percent reduction in arm pain within the first few months, though the exact number depends on what “success” means, how long you follow patients, and which injection technique is used. C5-C6 and C6-C7 are the most commonly treated disc levels because they’re the most common sites of cervical disc herniation.¹ The success rate story, though, is more layered than a single percentage can capture.

What the Success Rate Numbers Actually Look Like

One of the better prospective studies tracking cervical transforaminal epidural steroid injections over a full year found that about 58 percent of patients achieved at least a 50 percent drop in arm pain at one month. That number climbed to roughly 72 percent at three months, then settled to about 65 percent at both six and twelve months.² The fact that the three-month mark looked slightly better than one month and that the improvements then held steady through a year is encouraging: it suggests the benefit isn’t just a brief honeymoon period that steadily fades.

An older but frequently cited study from 1989 followed 58 patients for six months after cervical epidural steroid injection and classified outcomes more strictly. Patients who maintained at least 90 percent pain relief for the entire six months were counted as “excellent.” By that high bar, about 41 percent qualified.³ A separate study looking at longer follow-up found roughly 79 to 80 percent of patients achieved meaningful pain relief from a single injection, with the benefit remaining stable over a mean follow-up of about 43 months.⁴ The wide spread between these numbers (41 percent to 80 percent) largely reflects how “success” was defined and how patients were selected. Studies that set a stricter threshold or include patients with spinal stenosis tend to report lower numbers than those focused on disc herniations with a more generous improvement cutoff.

For functional improvement rather than just pain relief, the picture looks similar. About 61 to 71 percent of patients in the prospective cohort showed at least a 30 percent improvement in a neck disability index at various time points through one year.² In a randomized trial comparing two injection techniques, roughly half to two-thirds of patients reported feeling “much improved” or “very much improved” at six months regardless of method.⁵

How the Injection Approach Changes Results

There are two main routes a needle can take to reach the cervical epidural space. The interlaminar approach enters between the bony arches of the vertebrae from the back, while the transforaminal approach enters through the neural foramen, the small opening where the nerve root exits the spine. Your doctor’s choice between these can influence your odds.

A retrospective analysis comparing the two found a meaningful trend favoring the interlaminar route: about 59 percent of patients achieved at least 50 percent pain relief with the interlaminar approach compared to 46 percent with the transforaminal technique. The gap was even wider for dramatic relief, with 37 percent of interlaminar patients hitting at least 80 percent pain reduction versus 17 percent in the transforaminal group.⁶ However, a different study looking specifically at patients with axial neck pain from cervical disc herniation found no significant difference between approaches: about 73 versus 67 percent success at two weeks and roughly 48 percent for both at eight weeks.⁷ That study noted the transforaminal route carries a higher risk of serious complications, making the interlaminar approach preferable when both perform similarly.

The type of imaging used to guide the needle also matters less than you might think. A randomized trial comparing ultrasound guidance with fluoroscopy (real-time X-ray) found both achieved accuracy rates around 89 to 90 percent, with no significant differences in pain or disability scores at one, three, or six months. The ultrasound group had the added benefit of shorter procedure times and no radiation exposure.⁸ Another trial found treatment success around 50 to 57 percent with either guidance method, again with no significant difference.⁹

Who Is Most Likely to Benefit

The cause of your neck pain is one of the strongest predictors of how well an injection will work. If your pain stems from a herniated disc compressing a nerve root, your odds are considerably better than if the cause is spinal stenosis, which is a more generalized narrowing of the spinal canal. Multiple regression analysis has confirmed that the underlying cause of pain is the single most significant factor associated with outcome.¹⁰ A separate study found that the presence of spinal stenosis dropped the odds of a good short-term response dramatically. Patients who had been symptomatic for more than about six months also had substantially lower odds of responding well.¹¹

MRI findings alone, however, aren’t a reliable crystal ball. One study specifically tried to use clinical and radiological features to predict who would respond to cervical transforaminal injections and concluded that prediction wasn’t possible from imaging alone.¹² That said, there’s some evidence that the severity of foraminal stenosis and the level of herniation do correlate with treatment success when examined as specific variables.¹³ The tension between these findings likely reflects the fact that pain is a whole-person experience and no single scan finding captures enough of what’s happening to reliably forecast your outcome.

What Happens If the First Injection Only Partly Works

A partial response to the first injection doesn’t mean you should give up on the approach. Research suggests that patients who get some but not enough relief from a first injection can benefit from a timely repeat. Scheduling a second injection within two to three weeks of the first, rather than waiting until pain flares back up unpredictably, appears to produce better overall outcomes with fewer total injections needed.¹⁴

For the small fraction of patients who need a second injection as a “salvage” procedure, the news is generally good. In one study, about 16 percent of cervical herniation patients required a second injection, typically about seven weeks after the first. Nearly all of them responded well, with very low pain scores and improved function sustained at one year after the second injection.¹⁵ So a disappointing first result isn’t necessarily the end of the road.

Does the Steroid Even Matter

This is one of the more surprising aspects of the cervical epidural injection literature. A systematic review and meta-analysis comparing epidural injections of local anesthetic alone versus local anesthetic combined with steroid found that both groups improved by roughly the same amount. At six months, pain scores dropped by about four and a half points in the local-anesthetic-only group and about four and a third points in the steroid group. Functional scores improved similarly. Those nearly identical results persisted at one-year and even two-year follow-up.¹⁶

A broader systematic review examining various spinal pain conditions reached a similar conclusion: local anesthetic with steroid and local anesthetic alone were equally effective for most types of chronic spinal pain. The one exception was disc herniation specifically, where steroids appeared to add some benefit over local anesthetic alone.¹⁷ This finding raises real questions about what’s driving the benefit. If the steroid’s anti-inflammatory effect were the main event, you’d expect a clear advantage over numbing medicine alone. The fact that local anesthetic alone performs nearly as well suggests that mechanical effects (the volume of fluid opening up space around the nerve), neuroplastic changes from temporarily interrupting the pain signal, or even the natural history of disc herniations resolving on their own are all contributing.

When steroids are used, the type doesn’t seem to make much difference either. A comparison of triamcinolone versus dexamethasone in cervical transforaminal injections found mean pain reductions of about 2.3 points on a 10-point scale for both, with no significant difference.¹⁸ Dexamethasone has gained favor in transforaminal cervical injections because it’s a non-particulate steroid, carrying a lower theoretical risk of vascular occlusion if inadvertently injected into a blood vessel.

How Injections Compare to Other Treatments

A multicenter randomized trial compared cervical epidural steroid injections alone, conservative care alone (physical therapy and medications), and the combination. At one month, no significant differences in arm pain scores were found between the three groups. Combination therapy did show slightly better improvement on some secondary measures, but the headline finding was that injections alone didn’t clearly outperform conservative care alone for the primary outcome.¹⁹

Meta-analyses of spinal epidural injections more broadly suggest that they provide better short-term and intermediate-term pain relief compared with conservative treatment, but this advantage fades at longer follow-up. Functional improvement didn’t consistently differ between injection and conservative groups at any time point.²⁰ This matters for setting expectations: injections tend to fast-track relief rather than fundamentally change your long-term trajectory. If your pain is recent and severe enough to interfere with daily life or prevent you from doing physical therapy, an injection can create a window of reduced pain that lets rehabilitation actually happen. That bridge-to-rehab framing is probably the most honest way to think about the role of these injections for many people.

One small pilot study found that adding an epidural steroid injection to conservative care was considerably more cost-effective over three months than conservative management alone, primarily because patients improved faster and required fewer visits and medications.²¹ But that’s a three-month window from a small sample, and the economic picture over a year or longer is less clear.

An Important Caveat for Myelopathy

There’s one scenario where cervical epidural injections don’t appear to help and may be associated with worse outcomes: degenerative cervical myelopathy, a condition where the spinal cord itself is compressed (rather than just a nerve root). A large database study found that epidural and transforaminal injections were actually associated with higher odds of eventually needing surgery at every time point examined, from one year through five years after diagnosis, compared to patients who didn’t receive injections at all.²² This doesn’t necessarily mean the injections made things worse. Patients selected for injections may have had more severe disease to begin with. But the finding is a reminder that myelopathy and radiculopathy are different conditions, and a procedure that helps one doesn’t automatically help the other.

How Depression and Mindset Affect Your Odds

Your psychological state going into the injection has a measurable impact on how well it works. In a study of patients with cervical spondylosis, only about 19 percent of those with comorbid depression achieved at least 50 percent arm pain improvement at three months, compared to roughly 56 percent of patients without depression. That’s a threefold difference. The gap was equally large for neck pain and for functional improvement.²³

Research on spinal injections more broadly echoes this pattern. Higher negative emotional states before the procedure predict greater pain at 12-week follow-up, while patients with higher cognitive resilience at baseline tend to report lower pain at six months, even after controlling for how much pain they started with.²⁴ A scoping review reinforced this, finding that poor psychosocial functioning was consistently associated with worse outcomes after epidural injections for back pain.²⁵

None of this means you should skip an injection if you have depression. It means that if you’re struggling with mood, sleep, or catastrophizing about your pain, addressing those issues in parallel could meaningfully improve how much the injection helps. The research suggests the needle is doing less than half the work. Your nervous system’s overall state is doing the rest.

Risks Worth Knowing About

Cervical epidural injections are generally safe, but the neck is an area where complications carry higher stakes than in the lower back. A review of adverse events found that serious complications, including epidural hematoma, new neurological deficits from inadvertent intramedullary injection, and strokes from intravascular injection affecting the spinal cord, brainstem, or cerebellum, are likely underreported in the literature.²⁶ These events are rare, but when they occur they can be devastating. This is why image guidance (fluoroscopy or ultrasound) is standard practice for cervical injections, and why many clinicians prefer the interlaminar approach in the cervical spine, since the transforaminal route places the needle closer to critical blood vessels that feed the spinal cord.

More common but far less serious side effects include temporary increases in pain at the injection site, transient headache, flushing, and brief spikes in blood sugar for people with diabetes. Some patients experience mild dizziness or lightheadedness during or immediately after the procedure. These typically resolve within hours to days. One retrospective study of patients who received cervical interlaminar injections under light sedation found high satisfaction rates and no major complications, with minor side effects described as transient.²⁷

Neuropathic Pain Screening and the Injection Response

One factor that doesn’t get discussed much outside pain clinics is whether your pain has neuropathic features, meaning the nerve itself has changed how it fires rather than just being pinched. The study examining predictors of injection response found that patients who screened positive on both the DN4 and painDETECT questionnaires (two short screening tools designed to detect neuropathic pain characteristics) had sharply reduced odds of a good short-term response to cervical interlaminar injections.¹¹ In practical terms, if your pain involves burning, tingling, or electric-shock sensations and you’ve had it for a long time, those features may signal that the nerve has developed its own pain-generating behavior that a steroid bath around it won’t easily fix. It doesn’t mean an injection is pointless, but it shifts the conversation toward managing expectations and potentially combining the injection with medications that target nerve pain directly.