Supinator tunnel syndrome is a rarely occurring narrowing syndrome. It results from damage to the radial nerve within the forearm supinator ligament.
What is supinator tunnel syndrome?
In medicine, supinator tunnel syndrome also goes by the names supinator ligament syndrome, inferior radialis palsy, or interosseus posterior syndrome. This refers to a nerve compression syndrome that appears on the forearm near the elbow. This is where the radial nerve, which is one of the important arm nerves, takes its course. It passes through the supinator muscle. If compression of the radial nerve occurs in this region, this results in supinator tunnel syndrome. This affects the branch of the radial nerve, resulting in the weakening or paralysis of some muscles. However, there is no fear of a complete loss of function. The radial nerve is also known as the radial nerve. It is one of the mixed nerves and has both sensitive and motor fibers. At the elbow, it is divided into a sensitive and a motor section. While the sensitive part extends towards the back of the hand, the motor part runs through the supinator muscle. There it supplies the muscles for hand extension. The symptoms of supinator tunnel syndrome depend on the area in which damage occurs. If the damage takes place in the upper section, the affected person suffers from sensory disturbances. If the damage occurs in the motor area, on the other hand, the patient may suffer from muscular dysfunction. If damage occurs in the upper arm region, both sets of symptoms may also exist.
Causes
The causes of supinator tunnel syndrome vary. In all cases, however, the motor branch of the radial nerve is constricted and affected. Not infrequently, a fracture of the radius or ulna at the elbow is responsible. In this case, a bruise or bone displacement causes a nerve contusion, which in turn is responsible for nerve damage. Another possible cause is the dislocation of the radial head from its ligamentous guide. As a result, there is a risk of constriction at the entry point to the supinator muscle. In some cases, fatty growths, inflammations or tumors at the nerve passage are also possible causes of supinator tunnel syndrome. The same applies to a muscular proliferation in the supinator muscle. It is mostly formed by constant repetitive activities such as playing tennis or piano. Another reason for the development of supinator ligament syndrome is permanent external pressure. This is usually triggered by carrying heavy loads on one side.
Symptoms, complaints and signs
Supinator tunnel syndrome is noticeable by feelings of weakness when stretching the fingers. Sometimes the weakness is so intense that the fingers cannot be stretched at all. Because only the motor part of the radial nerve is affected, only the motor part is affected. In contrast, the sensitive part of the nerve is not affected, so that there are no sensory disturbances in the arm or fingers. The third and fourth fingers are particularly affected by extensor weakness. Furthermore, the affected person suffers from a dull spontaneous pain in the forearm near the elbow. When pressure is applied, the pain worsens. Most often, the painful symptoms appear when the patient moves the surface of his hand in the upper direction. Sometimes, after several rotational movements of the forearm, signs of fatigue of the muscle are also felt. In some cases, the pain radiates into the wrist.
Diagnosis and course of the disease
To diagnose supinator tunnel syndrome, the physician first looks at the patient’s medical history (anamnesis). The next step is a physical examination. A neurologist can also determine the performance rate of the damaged nerve. For example, if the nerve and nerve sheath are impaired, there is usually a significant reduction in the nerve conduction velocity. Other important examination procedures include sonography (ultrasound examination), taking X-rays, and performing magnetic resonance imaging (MRI).While an X-ray examination can find fatty growths or benign soft tissue tumors such as ganglia, an X-ray examination can detect bone fractures of the radius and ulna. With magnetic resonance imaging, it is possible to image the constricting structures. How supinator tunnel syndrome will progress is difficult to predict. For example, the prognosis depends on the extent and duration of nerve damage. Sometimes it even takes months for a nerve that was already pre-damaged and led to paralysis to heal completely, even though there is no longer any pressure effect.
Complications
Due to supinator tunnel syndrome, patients primarily suffer from severe movement restrictions. These occur mainly in the fingers, so that the fingers can no longer be stretched properly. In severe cases, movement of the fingers is completely restricted. Furthermore, the neighboring areas may also be affected by paralysis or sensory disturbances. Due to these restrictions, the patient’s everyday life becomes significantly more difficult, so that many affected persons suffer from depression or other psychological upsets. Pain in the fingers or hand can also occur and in some cases radiate to the wrist. Since the pain often occurs at night, supinator tunnel syndrome can also cause sleep disturbances and thus irritability in the affected person. In children, supinator tunnel syndrome leads to restricted and delayed development. Treatment of the syndrome depends on the cause. First and foremost, the strain that is responsible for the paralysis is discontinued. Various medications and therapies can also be used to limit the other symptoms and pain. Surgical interventions are rarely necessary. In most cases, this results in a positive course of the disease and the patient’s life expectancy is not reduced by the disease.
When should one go to the doctor?
In supinator tunnel syndrome, the affected person is dependent on a visit to a doctor. Since self-healing is also not possible with this disease, treatment by a doctor is inevitable. As a rule, early diagnosis also has a positive effect on the further course of the supinator tunnel syndrome and can prevent further complications and also a worsening of the symptoms. The doctor should be consulted in the case of supinator tunnel syndrome if the affected person can no longer extend his fingers properly. As a rule, stretching out is associated with severe pain and is hardly possible anymore. Sensory disturbances in the arm of the affected person can also indicate this disease and should also be examined by a doctor. Severe pain can also occur in the arms. These can occur without any particular reason and, above all, permanently and have a very negative effect on the quality of life of the affected person. At the first signs of supinator tunnel syndrome, a general practitioner or an orthopedist can be consulted. Further treatment depends on the exact cause of the syndrome. As a rule, this disease does not reduce the life expectancy of the affected person.
Treatment and therapy
Treatment of supinator tunnel syndrome can be either conservative or surgical. If an unusual strain is responsible for the syndrome and it is stopped, the radial nerve often recovers on its own, causing the symptoms to subside. For the treatment of acute pain, analgesics such as ibuprofen or diclofenac are suitable. In addition to relieving the pain, these preparations also combat inflammation. Physiotherapeutic exercises as well as heat or cold applications are also considered helpful measures. If the conservative therapeutic measures do not lead to an improvement in the symptoms, surgery may be advisable. If paralysis is present, surgery must be performed as soon as possible. During surgery, the surgeon exposes the deep motor branch of the radial nerve. However, special care must be taken during this procedure due to the delicacy of the nerve. In addition, the entry point of the radial nerve into the muscle is widened because it is covered by connective tissue fibers that can cause its entrapment. Confining structures such as connective tissue or fibrous tracts are cut.
Prevention
Preventive measures against supinator tunnel syndrome are not known.After surgery, full baths are recommended to prevent movement disorders of the elbow.
Aftercare
For successful aftercare, abstaining from weight-bearing is the first line of treatment. If intraoperative findings are present, immobilization is accomplished with an upper arm cast in a 120-degree position. The cast remains in place for 10 to 14 days. During this time, the shoulder and fingers can be moved. In the further course, the arm may only be lightly loaded. Everyday activities can be carried out without any problems. Physiotherapy can be prescribed to support this. Alternatively, underwater weight-bearing therapy is an option. The algetic supinator syndrome is accompanied by medication during follow-up care. Low doses of ibuprofen and diclofenac are prescribed for a maximum period of three weeks. Permanent stress disorders can be ruled out if the treatment is carried out properly. However, recurrence of supinator tunnel syndrome is possible. If CRPS (Sudeck’s disease) occurs during follow-up, occupational therapy and physiotherapy are prescribed. CRPS (Sudeck’s disease) occurs as a result of tissue injury, or surgical procedures. It occurs several weeks after the surgical procedure and causes severe pain in the operated area. The stitches are removed from the 12th day after the surgery if the healing process is positive. The removal is painless and of a few minutes duration.
What you can do yourself
If supinator tunnel syndrome is treated conservatively or surgically, it is important to avoid heavy exertion. Pain-relieving medications, such as diclofenac or ibuprofen, are recommended for moderate to severe pain to prevent the pain from becoming chronic. If the bottleneck syndrome is due to excessive stress on the radial nerve, it usually recovers on its own if the stress is not applied. Heavy physical stress should be avoided for this reason. Physiotherapy is another way to reduce the symptoms in everyday life. The controlled movements in the therapy relieve the radial nerve and in this way it can regenerate better. Cold and heat therapy can also help reduce the pain and cure the bottleneck syndrome. Typically, cold therapy is used when inflammation is present and heat therapy is used for pain in the muscles and joints. Muscle and joint pain is common in the bottleneck syndrome due to adopting the gentle posture. Red light lamp is popular in heat therapy and is ideal for home use. Hot air and the use of the hot roller also provide relief for radial nerve pain. To reduce the pain in everyday life, wraps, packs and natural moor also help. Which variant helps the affected person the most depends on the individual case and should be tested out.
