Cluneal Nerve Block for Chronic Low Back and Buttock Pain: Procedure, Benefits, and Recovery

Chronic low back pain is often blamed on the discs, facet joints, sacroiliac joint, or muscles of the lower back. But sometimes the source of pain is much smaller and easier to overlook: a group of sensory nerves known as the cluneal nerves.

When one of these nerves becomes irritated, compressed, or entrapped, it can produce persistent pain over the lower back, top of the buttock, or along the iliac crest—the upper edge of the pelvic bone. In some people, the pain may even spread farther into the buttock or leg, making the condition resemble sciatica.

A cluneal nerve block is an injection performed around the affected nerve. It can serve two purposes. First, it can help determine whether the cluneal nerve is actually responsible for the pain. Second, it may provide temporary or sometimes more prolonged pain relief.

Cluneal nerve problems are particularly important because they can mimic several much more familiar causes of back pain. Studies and clinical reviews have increasingly recognized superior and middle cluneal nerve entrapment as potentially overlooked causes of chronic low back and buttock pain.

The cluneal nerves are small sensory nerves that supply sensation to portions of the lower back, buttocks, and surrounding skin. Unlike major nerves that control muscles as well as sensation, the cluneal nerves are primarily sensory.

There are three main groups:

• Superior cluneal nerves
• Middle cluneal nerves
• Inferior cluneal nerves

Of these, the superior cluneal nerves are the most frequently discussed in relation to chronic low back pain.

The superior cluneal nerves travel toward the upper buttock and cross over the back of the iliac crest. Some branches pass through a tight space formed between the bone and surrounding connective tissue. This anatomical location can make the nerve vulnerable to irritation or entrapment.

The middle cluneal nerves supply portions of the buttock closer to the sacrum and sacroiliac region. Their symptoms can sometimes be difficult to distinguish from sacroiliac joint pain.

Inferior cluneal nerves supply areas farther down the buttock and may contribute to pain around the lower gluteal region, particularly pain associated with prolonged sitting.

Cluneal nerve entrapment occurs when a cluneal nerve becomes compressed or irritated as it travels through nearby tissue.

Superior cluneal nerve entrapment commonly occurs where the nerve crosses the posterior iliac crest and passes through the thoracolumbar fascia. Because this area moves whenever a person bends, twists, stands, or walks, irritation of the nerve can lead to recurring or persistent symptoms.

In some patients, the problem develops without an obvious injury. In others, symptoms may occur after trauma, surgery, changes in spinal mechanics, or conditions affecting the surrounding tissues.

Cluneal nerve entrapment has also been described in patients who continue to experience low back pain after lumbar spine surgery. This does not mean persistent pain after spine surgery is necessarily caused by a cluneal nerve problem, but it is one potential pain generator physicians may consider when the symptoms and examination findings fit.

Cluneal nerve pain can vary considerably from person to person.

A common feature is localized low back pain near the upper buttock or iliac crest. The pain may occur on one side or occasionally on both sides.

Patients may describe the sensation as:

• Burning
• Aching
• Sharp
• Stabbing
• Tingling
• Electric or shooting
• Tender to touch
• Numb or unusually sensitive

A particularly important finding is a small area of pronounced tenderness along the posterior iliac crest. Pressing this area may reproduce the person’s usual pain or cause the discomfort to radiate into the buttock.

Symptoms may worsen with activities such as walking, prolonged sitting, standing, bending forward, extending the back, twisting, or changing positions.

Because cluneal nerve irritation can sometimes cause pain extending into the buttock or leg, it can resemble lumbar radiculopathy or sciatica. However, cluneal nerves are sensory nerves, so isolated cluneal nerve entrapment would not normally be expected to produce true muscle weakness caused by nerve root compression.

Pain traveling from the lower back into the buttock immediately raises suspicion for a spinal problem in many patients.

Lumbar disc herniation, spinal stenosis, lumbar nerve root irritation, sacroiliac joint dysfunction, piriformis-related pain, facet joint pain, and muscle disorders can all produce symptoms in similar regions.

Cluneal nerve pain can overlap with these conditions.

In particular, some patients with superior cluneal nerve entrapment develop radiating symptoms extending from the iliac crest into the buttock and leg. This has sometimes been described as a form of “pseudo-sciatica.”

Unlike typical lumbar radiculopathy, however, imaging may not reveal a spinal abnormality that adequately explains the symptoms. Even when degenerative changes are visible on magnetic resonance imaging, those findings may not necessarily be the source of pain.

This is one reason a careful physical examination and, in selected cases, a diagnostic cluneal nerve block can be valuable.

A cluneal nerve block is a targeted injection of medication near one or more cluneal nerves.

The injection usually contains a local anesthetic. Depending on the physician, patient’s condition, and purpose of the procedure, a corticosteroid may sometimes be added.

The local anesthetic temporarily interrupts pain signals traveling through the nerve. If the patient’s familiar low back or buttock pain decreases significantly after the injection, it provides evidence that the targeted cluneal nerve may be contributing to the pain.

For this reason, a cluneal nerve block can function as both:

A diagnostic procedure: It helps identify whether the cluneal nerve is a significant source of pain.

A therapeutic procedure: It may reduce pain and improve function for a period after treatment.

Local anesthetic alone usually has a relatively short pharmacological duration, although the benefit experienced by a patient does not always correspond exactly to the duration of the medication. When corticosteroid is used, some patients may experience longer-lasting relief, although evidence regarding the ideal medication combination, dose, and technique remains limited.

A physician may consider a cluneal nerve block when a patient’s symptoms suggest that the cluneal nerves could be contributing to chronic low back or buttock pain.

Possible clues include:

• Pain centered around the posterior iliac crest
• Pain over the upper buttock
• A distinct tender or trigger point along the iliac crest
• Burning, tingling, or altered sensation in the buttock
• Pain reproduced by pressing over the suspected nerve
• Pain aggravated by lumbar movement
• Persistent pain despite treatment for more common causes of low back pain
• Buttock or leg pain without clear evidence of lumbar nerve root compression
• Persistent low back pain following lumbar surgery when other causes have been evaluated

A cluneal nerve block is not appropriate for every person with back pain. The examination is important because many other conditions can produce almost identical symptoms.

The goal is not simply to inject the painful area. The physician tries to determine whether the location and behavior of the pain correspond to the anatomy of a particular cluneal nerve.

There is no single magnetic resonance imaging scan, blood test, or physical examination maneuver that definitively diagnoses cluneal nerve entrapment.

Diagnosis typically involves several pieces of information.

Pain often involves the lower back near the iliac crest and extends into the upper buttock.

With superior cluneal nerve entrapment, a particularly tender point may be found over the posterior iliac crest.

The medial branches of the superior cluneal nerve commonly cross the iliac crest several centimeters away from the midline. Anatomical variation exists, so the precise location differs between individuals.

Pressing over the suspected nerve may reproduce the patient’s usual pain, sometimes accompanied by tingling or radiating discomfort.

A substantial temporary reduction in pain following injection around the suspected nerve supports the diagnosis.

Published studies have used different thresholds when interpreting diagnostic blocks. Some reports have used pain reductions of more than 50 percent, while others have used thresholds around 75 percent. There is therefore no single response percentage that should automatically be applied to every patient. The result needs to be interpreted together with the history, examination, and other possible causes of pain.

Routine magnetic resonance imaging may help physicians evaluate other potential causes of low back pain, such as a herniated disc, spinal stenosis, arthritis, or other structural abnormalities.

However, standard imaging is often less useful for directly demonstrating small cluneal nerve entrapment.

Ultrasound can sometimes identify portions of the superior cluneal nerve and can also be used to guide injections. The diagnosis remains largely clinical and may be strengthened by a positive response to a diagnostic nerve block.

The exact technique depends on the nerve being targeted and the physician performing the procedure.

For a superior cluneal nerve block, the patient is generally positioned so the physician has easy access to the posterior iliac crest. Depending on the technique, this may involve lying face down or on the side.

The skin is cleaned, and the physician identifies the intended injection site.

The nerve may be targeted using anatomical landmarks, ultrasound guidance, or fluoroscopic imaging.

Ultrasound has become increasingly useful because it allows the physician to visualize the tissue layers, iliac crest, nearby muscles, and structures through which the superior cluneal nerve travels.

Once the target area has been identified, a small needle is advanced toward the nerve under real-time ultrasound visualization.

A small amount of local anesthetic is then deposited around the nerve. In some situations, corticosteroid may be included.

Ultrasound guidance may help improve precision and allows the physician to observe the spread of medication around the target area. Several ultrasound-guided approaches have been described, reflecting variations in anatomy and clinical technique.

Most patients experience some discomfort when the needle passes through the skin and deeper tissues.

There may be a brief pinch, pressure, burning sensation, or reproduction of the patient’s familiar pain as the needle approaches the irritated nerve.

The procedure itself is generally brief.

Because the injection contains local anesthetic, the treated area may begin feeling numb shortly after the medication is administered.

Pain tolerance varies substantially between patients, so an injection that feels mild to one person may be uncomfortable for another.

After the injection, the physician may ask the patient to reassess the pain that was present before the procedure.

This is especially important when the block is being performed for diagnostic purposes.

For example, a patient who normally develops severe pain when standing, walking, bending, or pressing over the iliac crest may be asked whether that same activity feels different after the injection.

A meaningful reduction in the patient’s usual pain provides important information.

Patients should pay attention not only to their numerical pain score but also to changes in function.

Questions worth considering include:

• Can I walk more comfortably?
• Can I bend or turn with less pain?
• Is the painful spot over the iliac crest less sensitive?
• Can I sit longer?
• Has the burning or shooting pain decreased?
• Is the buttock pain different from before the injection?

Keeping a simple pain diary for the hours or days following the procedure can sometimes help the treating physician understand the response.

There is no standard duration of relief after a cluneal nerve block.

A diagnostic injection containing local anesthetic may provide relief primarily during the period when the anesthetic is working. In some patients, relief persists longer.

When corticosteroid is used, the therapeutic effect may potentially last weeks or months in some individuals, but the response is unpredictable.

Some patients obtain substantial improvement after one injection. Others undergo repeated blocks. Some experience only short-term relief.

Clinical studies have reported meaningful improvement after cluneal nerve blocks in selected patients, but results vary substantially between published series. The available research also includes relatively small studies, case series, and observational evidence rather than large numbers of high-quality randomized trials.

This means a cluneal nerve block should not be presented as a guaranteed or permanent solution for chronic back pain.

One of the major advantages of a cluneal nerve block is that it can provide diagnostic information and treatment during the same procedure.

Potential benefits include:

• Reduction in localized low back pain
• Reduction in upper buttock pain
• Decreased burning or nerve-type discomfort
• Improved walking tolerance
• Improved ability to sit, stand, bend, or perform daily activities
• Reduced tenderness around the iliac crest
• Identification of a previously overlooked source of chronic pain
• Guidance for further treatment when the diagnostic block is successful

For some people who have undergone multiple tests or treatments without a clear explanation for their pain, identifying a peripheral nerve as a possible pain generator can significantly change the treatment strategy.

Cluneal nerve blocks are generally considered minimally invasive, but no injection is completely without risk.

Possible side effects or complications can include:

• Temporary soreness at the injection site
• Bruising
• Bleeding
• Infection
• Temporary numbness
• Temporary worsening of pain
• Allergic reaction to medication
• Injury to a nearby blood vessel
• Irritation or injury of the nerve
• Local anesthetic toxicity if medication unintentionally enters the bloodstream or an excessive dose is administered

Serious complications appear to be uncommon in the published literature, but available research on cluneal nerve blocks is still relatively limited.

Ultrasound guidance allows the physician to visualize the needle and surrounding anatomy during the procedure and may help with accurate medication placement. Proper technique, aspiration before injection, appropriate local anesthetic dosing, and patient monitoring are also important safety measures.

Recovery is generally relatively quick.

Patients may experience tenderness around the injection site for a short period. The buttock or lower back may also temporarily feel numb because of the local anesthetic.

Specific post-procedure instructions vary between physicians and facilities.

Patients are commonly advised to avoid unusually strenuous activity immediately after the injection and to follow the treating physician’s instructions regarding driving, exercise, bathing, medications, and return to work.

If corticosteroid was administered, immediate pain relief is usually related primarily to the local anesthetic rather than the steroid. Any effect attributable to the corticosteroid may develop later.

The most useful part of the recovery period may actually be monitoring how the usual pain behaves once the block has been performed.

Patients should contact their healthcare provider if they develop symptoms that are unexpected, severe, or progressively worsening after the procedure.

Urgent medical evaluation may be required for symptoms such as significant new weakness, severe or increasing neurological symptoms, difficulty breathing, signs of a serious allergic reaction, high fever, progressive redness or drainage around the injection site, or other concerning symptoms.

New bowel or bladder dysfunction, severe leg weakness, numbness around the groin or saddle region, or rapidly worsening neurological symptoms should not simply be attributed to a cluneal nerve problem. These symptoms require prompt medical assessment for more serious causes of back pain.

Temporary relief from a correctly targeted cluneal nerve block can still be clinically valuable.

If the patient’s characteristic pain decreases substantially after the block but later returns, it strengthens the possibility that the targeted nerve is an important pain generator.

Depending on the circumstances, treatment options may include another cluneal nerve block, physical therapy, medication management, radiofrequency procedures, peripheral nerve stimulation, or surgical decompression.

The appropriate next step depends on the duration and degree of relief, the specific nerve involved, the patient’s overall condition, previous treatment, and whether other sources of pain are also present.

Radiofrequency treatment and peripheral nerve stimulation have been reported as options for persistent cluneal neuralgia after successful diagnostic blocks, while surgical decompression is generally reserved for carefully selected patients with persistent symptoms despite less invasive treatment.

Yes.

Finding degenerative disc disease, spinal arthritis, spinal stenosis, sacroiliac joint dysfunction, or another musculoskeletal abnormality does not automatically rule out cluneal nerve pain.

More than one source of pain can exist at the same time.

For example, a patient may have lumbar degenerative changes visible on imaging but also have very focal tenderness over the iliac crest with reproduction of buttock pain when the superior cluneal nerve is compressed.

This is why treatment decisions should not be based on imaging findings alone.

A successful diagnostic cluneal nerve block can sometimes help physicians separate one pain generator from another.

Cluneal nerve pain and sacroiliac joint pain can occur in nearby locations, but the injections target different anatomical structures.

A cluneal nerve block places medication around a sensory nerve thought to be causing the pain.

A sacroiliac joint injection places medication into or around the sacroiliac joint.

Middle cluneal nerve entrapment can be especially difficult to differentiate from sacroiliac joint dysfunction because of the close anatomical relationship between the nerve, surrounding ligaments, and sacroiliac region.

Physical examination, pain location, previous imaging, diagnostic injections, and the patient’s response to each procedure may help determine which structure is contributing to the symptoms.

There is encouraging evidence that cluneal nerve blocks can help appropriately selected patients, but the success rate should be interpreted carefully.

Published reports have shown substantial pain improvement in some patients after one or more superior cluneal nerve blocks. Other studies have found less consistent responses.

A recent systematic review examining treatments for cluneal neuropathy found generally favorable responder rates across several interventions, but it also emphasized that much of the available evidence is observational and that diagnostic criteria and treatment pathways vary considerably between studies.

This is an important distinction.

The evidence supports cluneal nerve entrapment as a legitimate and treatable source of pain, but it does not mean every patient with buttock or low back pain will benefit from a cluneal nerve block.

Careful patient selection remains essential.

Persistent pain across the lower back and upper buttock is not always coming from the spine.

For some patients, irritation or entrapment of the superior or middle cluneal nerves may be an overlooked source of pain—particularly when there is a highly tender area along the posterior iliac crest and pressing that area reproduces the patient’s familiar symptoms.

A cluneal nerve block for chronic low back and buttock pain is a relatively targeted procedure that can help answer an important question: Is this small sensory nerve contributing to the pain?

If pain decreases significantly after the injection, the result can help guide future treatment. In some patients, the block itself also provides meaningful therapeutic relief.

However, chronic low back pain frequently has more than one potential cause. A cluneal nerve block is therefore most useful when it is performed as part of a careful evaluation rather than simply as another injection for nonspecific back pain.

For patients who have persistent pain around the iliac crest or upper buttock despite treatment for more common back conditions, discussing cluneal nerve entrapment and diagnostic cluneal nerve block with a pain management physician may be worthwhile.