What is Cluneal Neuralgia (Entrapment of the Cluneal Nerve)?
In the US, about 20.4% of adults experience chronic pain, according to data from the 2016 National Health Interview Survey. Of these, many suffer from lower back pain, which affects up to 84% of people at some point in their life. Lower back pain significantly impacts quality of life, accounting for a major portion of disability-related life impacts, according to the Global Burden of Disease Study from 2010. The causes of lower back pain can vary widely, with no specific cause identified in up to 85% of cases.
There are three main nerve groups in the lower back and buttocks area: the superior, middle, and inferior cluneal nerves. Sometimes, pain in the lower back and one side of the buttock can be due to the superior cluneal nerves getting trapped, causing a condition known as cluneal neuralgia (CN). CN usually results in pain and changes in sensation in the lower back and buttock area. It’s important to consider this as a potential cause when assessing patients with lower back pain. These cluneal nerves are responsible for sensation in the buttocks and the area at the back of the hip bones.
What Causes Cluneal Neuralgia (Entrapment of the Cluneal Nerve)?
Understanding the structure and function of the superior cluneal nerve (SCN) is crucial for diagnosing and treating cluneal neuralgia (CN), a nerve condition. Originally, it was believed that certain nerve roots in the spine (L1-L3) were connected to the SCN. Recent studies, however, have discovered that this can actually vary quite a bit, with roots ranging from T11-L5 being involved.
The way these spinal nerve roots travel is quite interesting. They break through a large muscle in the back (the psoas major) and other muscles alongside the spine, then they move behind a muscle called the quadratus lumborum.
These nerve roots then travel through a layer of connective tissue near the spine (the thoracolumbar fascia) towards the top ridge of the hip bone (the iliac crest). The nerve roots can sometimes pass through a bony tunnel on their way, which could be a spot where they get trapped.
There are three types of SCNs: medial (inner), intermediate (middle), and lateral (outer). One study identified their average distances from a point on the top line of the hip bone, measuring at about 5 cm, 6.5 cm, and 7.3 cm respectively.
Middle cluneal nerves (MCN) might be a cause of pain in the lower back, buttocks, and legs. However, most scientific articles focus on SCN entrapment. MCNs, which stem from certain roots in the lower spine (S1-S3), deal with sensation in the buttocks area. The ligament along the back of the sacroiliac joint (where the spine and hip connect) is a common spot where MCNs can get trapped, but it’s usually tricky to tell this condition apart from issues with the sacroiliac joint itself.
Also considered are inferior cluneal nerves (ICN), which are part of a group of nerves related to chronic pain in the pelvic area. These nerves run around the lower edge of the major buttocks muscle (the gluteus maximus) and send sensory information from the lower, outer area of the buttocks.
Risk Factors and Frequency for Cluneal Neuralgia (Entrapment of the Cluneal Nerve)
SCN entrapment is a condition that affects 14% of people with low back pain, according to research. In a Japanese study, out of 34 patients suspected to have SCN entrapment and who underwent surgery, 13 of them had the condition on one side (unilateral) while 21 had it on both sides (bilateral). Determining the incidence of entrapped MCN and ICN, conditions that can also lead to CN, can be challenging.
Other research suggests a range of 1.6 to 14% for SCN entrapment, 13% for MCN entrapment among those with low back pain, and 0.73% for generalized temporary cluneal nerve pain in women after childbirth. SCN entrapment is particularly high among those who have had vertebral fractures. Mainly, women and older individuals tend to have SCN entrapment, with the average age being around 64.
Signs and Symptoms of Cluneal Neuralgia (Entrapment of the Cluneal Nerve)
If you have pain in your lower back and gluteal area, you might have a condition called Cluneal Nerve (CN) entrapment. About half of people with this condition also experience leg symptoms, which can feel similar to pain caused by conditions affecting the lower back. No particular physical exam technique is perfect for identifying CN, but it’s generally agreed that the pain gets worse when you move your lower back in different directions. Doctors might tap (“Tinel-like sign”) along the path of the SCN over the iliac crest (the curved ridge at the top of your hip bone).
According to studies, the medial SCN (one of the cluneal nerves) passes through a narrow tunnel about 2.6 inches from the center line over the hip bone. If this area is pressed, you might experience pain from your lower back to your buttock and back of your thigh, following the course of the SCN, and even down to the back of your leg, a sensation referred to as “pseudo-sciatica”. It’s essential that a complete neurological exam is done, which includes testing strength and sensation, checking deep tendon reflexes, and looking for any signs of issues in the upper neural pathways.
CN is often a diagnosis of exclusion, meaning doctors will rule out all other possible causes first. Many people with chronic pain, like CN, have undergone evaluations to identify other potential causes, but these past assessments might not have been adequate, thorough, or corresponding with the patient’s condition at the time of assessment. However, some aspects of history and physical examination can indeed be helpful in diagnosing low back pain with or without leg pain.
- Pain localized in the lower back between the bottom of the buttock folds and back rib cage
- Tenderness at the rim of the hip bone
- Decreased sensation below the hip bone at the buttocks
- If SCN and MCN nerves are involved, usually leg pain with radiation to the same side leg
- Pain may increase when walking, sitting for a long time, extending, bending, or rotating the lower back, or any movement of the lower back area.
If CN affects the ICN (another cluneal nerve), it usually causes painful and/or burning sensations in the inner and lower part of the buttocks, upper/back side of the thigh, skin of the major lip area or scrotum, and/or side of the anal margin. Sitting, especially on hard surfaces, would worsen the pain, which should be reduced when standing or lying on your side. Activities like bicycle, motorcycle, or horseback riding could significantly increase the pain.
Testing for Cluneal Neuralgia (Entrapment of the Cluneal Nerve)
After a detailed discussion of your medical history and a physical exam, nerve block tests are usually the next step in the check-up process for a condition known as CN. According to research by Isu et al., there are five key signs to look out for in cases of SCN entrapment. These include lower back pain that also affects the area around the hip bone and buttocks, pain that gets worse with back movement, tenderness over the back part of the hip bone where the nerve might be trapped, experiencing intense pain or a ‘pins and needles’ sensation when pressure is applied to the area where the nerve is trapped, and a noticeable reduction in your symptoms after a diagnostic nerve block is performed.
The same diagnostic procedure is also described for MCN entrapment, with specific consideration given to the unique anatomy associated with MCN.
If you might have ICN entrapment, your doctor might use the Nantes criteria to make a diagnosis. Sometimes, ICN entrapment occurs together with another nerve-related condition known as pudendal neuralgia, and that can also help to know if ICN might be affecting you.
In all these cases, it’s vital to make sure all possible causes of pain have been thought through and investigated properly, and to keep in mind the possible role of SCN, MCN, or ICN involvement in your symptoms. This way, treatment can be better directed towards the most likely causes rather than other less plausible sources of the pain.
Treatment Options for Cluneal Neuralgia (Entrapment of the Cluneal Nerve)
The treatment for Cluneal Nerve (CN) pain often involves multiple steps, starting with non-invasive methods like physical therapy, moving on to medicine, and ultimately surgery if other options are not effective.
Pain relievers that are often used for nerve pain, like gabapentin and pregabalin, are common treatment options. Other medicines, such as Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs), tricyclic antidepressants, and non-steroidal anti-inflammatory drugs (NSAIDs), can also be used. However, these medicines can have side effects and might not be tolerated by some individuals.
Recent years have seen an increase in popularity of focused treatments for CN pain. These include interventions targeting the specific spot where the pain is occurring.
One such treatment is nerve blocks, where an anesthetic is applied directly to the affected nerve, sometimes in combination with corticosteroids. This treatment can provide pain relief that lasts for several months. It can be performed using simply feeling the area of the pain, ultrasound, or through the use of X-Ray.
Heat treatments, known as Radiofrequency Ablation (RFA), can be used after successful nerve blocks to try and further relieve symptoms. This form of treatment involves heating the nerve to decrease pain signals but can have risks such as abnormal skin sensations and nerve lesions.
Neuromodulation is another treatment option that uses targeted nerve stimulation after a successful diagnostic nerve block. This approach has been known to significantly reduce pain.
Finally, surgical decompression may be considered as a last resort when all other treatment options have failed. This might involve relieving pressure on the affected nerve, although its effectiveness varies and is not always successful. Surgical intervention is less common now because our understanding of CN has improved, and treatments like RFA and nerve stimulation have gotten better.
What else can Cluneal Neuralgia (Entrapment of the Cluneal Nerve) be?
When diagnosing CN (cluneal neuritis), medical professionals need to consider a range of other conditions that can cause similar symptoms. These include issues with the main part of the lower spine, as well as conditions affecting the surrounding muscles or nerves. For example, one possibility could be a painful condition called lumbar radiculopathy, which can be caused by a slipped disc in the spine. Other reasons for lumbar radiculopathy, such as narrowing of the spinal canal due to arthritis of the spine, must also be considered.
These conditions can produce symptoms similar to CN, like pain and numbness in the lower body. In addition, some other disorders outside the spine, like piriformis syndrome (which can press on the sciatic nerve) and muscle pain in the lower back and buttocks, can feel like CN too.
Finally, doctors must consider sacroiliac joint dysfunction, a common condition that causes pain in the lower back, buttocks and hip area. It’s a key part of diagnosing CN to be able to distinguish it from these other conditions. One way doctors can do this is by using a procedure called a cluneal nerve block.
What to expect with Cluneal Neuralgia (Entrapment of the Cluneal Nerve)
There isn’t much information available on the future outcomes of CN, or chronic nerve pain. One potential treatment involves using local anesthetics to block the nerves causing pain, providing short-term relief. Adding corticosteroids to this procedure could potentially make the relief last longer.
Neuromodulation, a new method, also presents a promising opportunity. It could potentially provide relief from symptoms for more than a year. However, since this is a relatively recent development, long-term data on its effectiveness is still being gathered.
Possible Complications When Diagnosed with Cluneal Neuralgia (Entrapment of the Cluneal Nerve)
While they don’t happen often, there are potential complications to the treatment of cranial nerves (CN). Procedures like radiofrequency ablation (RFA), percutaneous nerve stimulation (PNS), and surgical decompression can carry more risks than simpler nerve block procedures. However, a study looking into PNS as a way to manage chronic pain resulting from peripheral nerves did not find any serious side effects associated with the device in a group of 94 individuals observed over a year.
Pharmaceutical treatments, including common medications for nerve pain like gabapentin and pregabalin, can also come with their own side effects. The ones observed most frequently with these drugs are:
- Dizziness
- Drowsiness
- Nausea
Preventing Cluneal Neuralgia (Entrapment of the Cluneal Nerve)
Because back problems can be complicated and varied, it’s really important for doctors to talk clearly with their patients throughout the whole process of diagnosis and treatment. That includes explaining in everyday language what the images from scans mean, what medicines to try, and how different procedures might help. This can enable patients to better grasp the treatment plan.
Also, when a patient is in pain, it’s crucial that the doctor and the patient work together to make decisions about care with a focus on improving the patient’s daily activities and overall quality of life. This way, treatments don’t just focus on the problem itself, but also how well the patient can live with or without the pain.
