What is Suprascapular Nerve Injury?
There’s a growing interest in studying the symptoms and signs of injuries to a nerve known as the suprascapular nerve (SSN). Although we’re not entirely sure what causes damage to this nerve, experts believe it could be due to things like pressure, stretching or inflammation. These conditions are often closely associated with other symptoms of SSN damage and are sometimes classified as ‘idiopathic’, which simply means we don’t know the cause.
The SSN is a nerve that travels through some critical areas in your shoulder, making it prone to direct pressure at the suprascapular and spinoglenoid notches – areas in your shoulder joint. Variations in the way this nerve travels in different people, or overuse due to someone’s job or sports, especially overhead athletes, can make the SSN more vulnerable to different levels of damage.
What Causes Suprascapular Nerve Injury?
Suprascapular nerve (SSN) discomfort, first identified in French literature in 1936 and English literature in 1959, is involved in about 1% to 2% of shoulder pain cases and up to 33% in athletes who perform a lot of overhead activities, like baseball or tennis players. The pain is often caused by SSN damage which can happen in a number of ways.
In some cases, the injury originates from the physical entrapment (or getting ‘stuck’) of the SSN along its path or from the strain of repetitive movements such as those seen in overhead sports players. Common areas of entrapment for the SSN include the suprascapular notch, spinoglenoid notch, and the superior transverse scapular ligament.
Other causes of SSN dysfunction can include scapulothoracic dyskinesia (a fancy term for shoulder blade movement dysfunction), traumatic injuries near the nerve, or even injuries that happen during shoulder surgeries. Some injuries can also happen because of space-occupying lesions, like cysts or tumors, that grow near the nerve.
Certain systemic conditions, which are disorders that affect multiple parts or systems in the body, like lupus or rheumatoid arthritis can also lead to SSN dysfunction.
While the SSN issue isn’t a common injury, it does frequently occur among those who use their arms for overhead activities repetitively such as athletes or workers who have to frequently lift their arms overhead. This group includes baseball players, tennis players, weight lifters, swimmers, and volleyball players.
Risk Factors and Frequency for Suprascapular Nerve Injury
Suprascapular nerve (SSN) dysfunction is a medical condition related to the shoulder with varying effects and diagnosis rates. Information about this condition’s prevalence is often contradictory and not entirely clear, partly due to improvements in diagnostic imaging technology. Some patients with SSN dysfunction don’t experience any symptoms and only discover they have it during unrelated medical procedures. Others, however, can experience varying degrees of shoulder pain and issues related to deterioration of certain shoulder muscles.
Estimates suggest that between 0.4% and 2% of cases of shoulder pain are due to elements like nerve damage in the shoulder, repetitive strain, or trapped nerves. It’s generally agreed that SSN dysfunction commonly appears alongside specific roles in sports and high-performance athletes.
One particular sign, known as infraspinatus muscle atrophy, can often be detected through physical exams or other methods like ultrasound, electromyographic studies, or magnetic resonance imaging (MRI). While some patients with this sign don’t experience any symptoms or change in shoulder function, the condition is commonly found in athletes who frequently use overhead movements. Rates of this occur in anywhere from 4% to 52% of these athletes, and it was particularly noted in a 2015 study of professional female tennis players. Interestingly, these same players showed no accompanying shoulder disorders.
- Suprascapular nerve (SSN) dysfunction is a condition whose incidence is not well-known due to varying data.
- Some people are asymptomatic, while others experience shoulder pain and degradation of shoulder muscles.
- It is estimated to cause 0.4% to 2% of shoulder pain cases, and is often associated with certain sports or high-performance activities.
- One symptom, infraspinatus muscle atrophy (muscle deterioration in the shoulder), can be checked with physical exams, ultrasound, electromyographic studies, or MRI.
- This muscle deterioration is common yet not necessarily harmful in athletes who frequently make overhead movements.
Signs and Symptoms of Suprascapular Nerve Injury
SSN (suprascapular nerve) injuries are often related to repetitive overhead actions, like those performed by athletes in baseball, tennis, weightlifting, swimming, or volleyball, or by laborers. The injury often presents as a dull, aching pain in the shoulder which can sometimes run down into the arm or neck. This pain might not be present if the injury is distal to the spinoglenoid notch. Additionally, patients may feel as if their shoulder is unstable, particularly if they also have a related shoulder condition such as a tear in the labrum or rotator cuff. The symptoms tend to develop slowly and irregularly, sometimes increasing in severity over time. However, almost half of the cases reported also indicated a traumatic event as the initial cause of the injury.
As the symptoms of SSN injury can overlap with other shoulder conditions and sometimes there may be no pain, diagnosing an SSN injury based solely on patient history can be challenging. A thorough physical examination, including a detailed evaluation of the shoulder and cervical spine, is crucial to exclude other potential causes. One of the most common findings in an SSN injury is muscle wasting, or atrophy, particularly in the infraspinatus or supraspinatus muscles. Nearly 80% of patients with confirmed suprascapular neuropathy were found to have atrophy in one or both of these muscle groups.
Patients might feel pain when the area behind the acromioclavicular joint, the posterosuperior joint line, or both are touched. The pain might worsen when the shoulder is moved across the body and rotated inward. Signs of weakness can be noted specifically in the movements of shoulder rotation and lifting. Despite this, if the nerve injury is at or beyond the spinoglenoid notch, and only affects the infraspinatus muscle, the weakness may not be as marked because other muscles (the deltoid, supraspinatus, and teres minor) can help with movement and strength. To help with diagnosis, a specific test called the “SSN stretch test” has been described. In this test, the patient’s painful shoulder is retracted, while their neck and head are moved to the side. The test is marked positive if these movements result in pain at the back of the shoulder.
Testing for Suprascapular Nerve Injury
Suprascapular neuropathy, a nerve condition that affects the shoulder region, is complicated to diagnose. It’s often hard to identify through just a medical history check and a physical examination. So, doctors often have to use tests and imaging techniques to make a clear diagnosis.
The initial step typically involves basic X-rays to check for any bone abnormalities that might be pressing on the nerve or other shoulder problems like arthritis or dislocation. X-rays are particularly crucial for patients who have suffered an acute or sudden injury, as this step helps rule out fractures or dislocations in the shoulder area.
If the doctor suspects that bone abnormalities are the main cause of the nerve condition, a computed tomography (CT) scan can be used. A CT scan is a type of X-ray that can produce detailed images, which can help pinpoint precisely where the nerve is being compressed.
Magnetic resonance imaging (MRI) scans can also be quite valuable for this nerve condition. This kind of scan lets doctors check for signs of nerve injury, such as areas where soft tissue might be compressing the nerve. It also enables them to evaluate the health of shoulder muscles to check if muscle wasting or ‘infiltration’ of fat is present (which can also indicate nerve problems). MRI can also help rule out other potential causes of shoulder pain, like tears in the shoulder’s labrum or rotator cuff muscles.
Musculoskeletal ultrasound is helpful in diagnosing suprascapular neuropathy too. It provides a real-time, ‘moving’ image of the nerve’s path and can also guide injections into the nerve. It’s best used to see the nerve near the collarbone where the nerve is most superficial (closest to the skin). This technique helps the doctor see how certain movements can affect the nerve or how certain disease areas can press on the nerve. Like an MRI, ultrasound can also examine the condition of the rotator cuff muscles to look for signs of nerve problems.
Injections of a numbing medicine into the shoulder can also support the diagnosis. If the injection relieves pain, it’s likely that you have suprascapular neuropathy. Using ultrasound guidance during the injection helps doctors precisely deliver the treatment and avoid potential complications.
Finally, doctors may perform electrodiagnostic evaluations, which include nerve conduction studies and electromyography. These are considered the ‘gold standard’ for diagnosing and confirming suprascapular neuropathy, meaning that they provide the most reliable information. These tests can help the doctor assess if the nerve is being compressed and if it’s not working correctly. Additionally, these tests help the doctor rule out other conditions that pretense similar symptoms to suprascapular neuropathy.
Treatment Options for Suprascapular Nerve Injury
Diagnosing suprascapular neuropathy, a condition that affects a nerve in your shoulder, can be challenging. This difficulty might mean you’ve been living with persistent pain and weakness for several months without knowing why, or you may have been treated for other conditions but haven’t seen any improvement.
Some of these other conditions might include strains to your rotator cuff (the group of muscles that stabilize your shoulder), osteoarthritis (a type of arthritis that typically affects older people), or labral pathology (problems with a piece of cartilage in your shoulder). However, once your doctor confirms you have a suprascapular neuropathy injury, you can start effective treatment.
Non-surgical management can effectively treat patients who only have suprascapular neuropathy without any other shoulder conditions. Most studies indicate that patients see benefits within 6 to 12 months with this conservative treatment.
Management without surgery typically involves using anti-inflammatory medications, modifying your behaviours to avoid any activities that induce pain, doing physical therapy, and getting ultrasound-guided injections. This type of care is particularly crucial for athletes, as their issues often come from repetitive small injuries to their shoulder.
Physical therapy exercises should keep your shoulder flexible to prevent the development of adhesive capsulitis, a condition that limits your shoulder movement (also known as a frozen shoulder). These exercises concentrate on stretching the back of your shoulder capsule and strengthening your rotator cuff and other shoulder muscles. Reducing tension on a ligament in your shoulder, the spinoglenoid ligament, through stretching the posterior capsule is especially significant for athletes. This tension reduction may minimize repetitive injury during sports. However, there is no definitive treatment protocol available yet.
Doctors may advise an ultrasound-guided injection at the location of the suspected trapped nerve to aid diagnosis and pain relief.
There’s promising evidence for the use of peripheral nerve stimulation devices primarily for patients with shoulder pain but no known compression at any specific location. These devices, which are temporarily implanted into the skin, target the suprascapular nerve as it travels through a notch in your shoulder. Some studies have reported that patients experienced significant relief from shoulder pain after the removal of these devices.
Doctors may recommend surgery if another condition is causing compression of the nerve or if your symptoms have not improved despite 6 to 12 months of non-surgical management. The exact surgical option used will vary depending on the cause and suspected location of the nerve injury.
For example, if the nerve injury is due to a paralabral cyst (a lump of fluid on the labrum, a piece of cartilage in your shoulder), a treatment option may include percutaneous cyst decompression – a procedure to remove fluid buildup using imaging guidance.
However, reports indicate that this technique may not be effective in up to 50% of cases due to the procedure’s inability to correct underlying conditions within your shoulder joint that may have contributed to the cyst. Post-surgery, most patients experience pain relief and improved muscle strength.
What else can Suprascapular Nerve Injury be?
Diagnosing a suprascapular nerve (SSN) injury can be tricky because it often has similar symptoms to other issues in the shoulder and neck region. The diagnosis process involves ruling out several other conditions that can cause similar symptoms. These may include but are not limited to:
- Neck nerve root disease (C5-6 cervical radiculopathy)
- Parsonage-Turner syndrome, a rare neurological disorder
- Nerve damage in the upper part of the arm (upper trunk brachial plexopathy)
- Different shoulder muscle injuries (rotator cuff pathology like tendinitis, bursitis, partial or complete strain or tear)
- Shoulder pain due to pressure on the rotator cuff (subacromial impingement syndrome)
- Abnormal movement of the shoulder blade (scapular dyskinesia)
- Damages to the ‘labrum’, a type of cartilage in the shoulder (labral pathology, such as a superior labral tear from anterior to posterior or SLAP tear)
- “Frozen shoulder” condition (adhesive capsulitis)
- Shoulder joint arthritis (glenohumeral arthritis)
- Pain caused by small joints in the spine (facet mediated pain)
Every patient is unique, so healthcare professionals must consider all these possibilities and carry out suitable tests to get the correct diagnosis.
What to expect with Suprascapular Nerve Injury
Suprascapular neuropathy, a condition impacting the suprascapular nerves in your shoulder, typically has a positive outlook. There was a study that showed 80% of patients saw a significant decrease in pain and better functionality.
Most people with this condition, whether they undergo surgery or receive non-surgical treatments, will notice a reduction in their pain and improved function. However, if there’s already considerable muscle wastage (atrophy), it’s unlikely that muscle size or strength will return to pre-injury levels.
Despite this, it’s important to note that even with persistent muscle wastage, most patients still observe an improvement in the strength of the supraspinatus and infraspinatus muscles, which are muscles located in the shoulder region. Interestingly, the supraspinatus muscle, a muscle on the upper part of the shoulder blade, shows a greater improvement in strength.
Possible Complications When Diagnosed with Suprascapular Nerve Injury
Both pain and weakness have been seen to lessen with non-surgical treatment or surgery to relieve nerve compression when deemed necessary. However, if the symptoms have been ongoing for a long time, the patient may continue to experience muscle shrinkage and weakness. These muscles are namely the supraspinatus and infraspinatus, both of which are controlled by the SSN (Suprascapular Nerve). Then again, as previously mentioned, the loss of strength in the infraspinatus muscle can be compensated by other muscles including the deltoid, supraspinatus, and teres minor.
- Pain and weakness can be treated with non-surgical methods or surgery for nerve decompression
- Long-term symptoms might lead to persistant muscle atrophy and weakness
- SSN controls the affected muscles, the supraspinatus and infraspinatus
- The loss of strength in the infraspinatus can be compensated by the deltoid, supraspinatus and teres minor muscles.
Preventing Suprascapular Nerve Injury
The key to managing this health issue is to first identify or diagnose it. It’s extremely important for patients to seek a professional medical check-up as soon as they notice any symptoms. When discussing treatment plans, it’s the doctor’s role to ensure that patients fully understand the process, the realistic expectations of improved muscle strength and function, as well as how long the recovery may take. The doctor should also be ready to answer any questions about what the future may hold in terms of the patient’s health condition.