Radial Tunnel Syndrome
What is radial tunnel syndrome?
Radial tunnel syndrome is a set of symptoms that include fatigue or a dull, aching pain at the top of the forearm with use. Although less common, symptoms can also occur at the back of the hand or wrist.
The symptoms are caused by pressure on the radial nerve, usually at the elbow. The radial nerve is one of the three main nerves in the arm. It runs from the neck to the back of the upper arm. Next, it crosses the outside of the elbow and goes down to the forearm and hand. At the elbow, the radial nerve enters a narrow tunnel formed by muscles, tendon, and bone. This is called the radial tunnel.
Symptoms and Causes
What are the symptoms of radial tunnel syndrome?
Radial tunnel syndrome causes dull aching pain at the top of the forearm, to the outside of the elbow, or the back of the hand. Patients less often describe the pain as cutting, piercing, or stabbing. It happens most often when the person straightens his or her wrist or fingers.
Radial tunnel syndrome can cause fatigue and weakness in the forearm muscles and weakness in the wrist.
Radial tunnel syndrome affects the muscles, not the nerves, so it does not cause tingling or numbness in the arm, wrist, or fingers.
What causes radial tunnel syndrome?
Any time the radial nerve is pinched anywhere along its length, it can cause pain. The tunnel at the elbow is one of the most common spots the nerve gets pinched or squeezed because it travels between muscle bellies and under facial bands. (Facial bands are tissue fibers that enclose, separate, or bind together muscle, organs, or other soft structures of the body.)
Overuse of the arm to push or pull and overuse of the hand by gripping, pinching, or bending the wrist can irritate the nerve and cause pain. Repeating the same movement, such as twisting the arm or wrist on the job or playing sports, squeezes the radial nerve. Over time, this can cause radial tunnel syndrome.
Diagnosis and Tests
How is radial tunnel syndrome diagnosed?
Pain in the forearm and hand are usually the symptoms that send a person to the doctor. However, there are no tests to prove a person has radial tunnel syndrome. This makes the diagnosis difficult. The doctor must depend on the patient’s physical exam and the type and location of the pain. As part of the exam, the patient is asked to turn his or her palm up with a straight elbow while the doctor restricts arm and hand movement. If the patient feels pain while trying to move the arm or hands against resistance; it is a sign of radial tunnel syndrome. In another test, the patient is asked to point with his or her middle finger against resistance. Pain with this movement is another sign of radial tunnel syndrome.
Management and Treatment
How is radial tunnel syndrome treated?
Treatment begins with resting the arm from the activity that is causing the symptoms. For most patients, rest combined with medical treatment for 3 to 6 weeks will relieve symptoms.
- Over-the-counter medications to reduce swelling
- Steroid injections to relieve inflammation and pressure on the radial nerve
- Wrist and/or elbow splints to reduce irritation of the radial nerve
- Exercise, techniques to reduce the effects of repetitive motion stress, ultrasound, heat and cold
The goal of treatment is to prevent the return of symptoms. If the job is causing the problem, the work site may need to be changed. More breaks may be needed during the workday and heavy pulling and pushing should be avoided if possible.
For sports injuries, strength and flexibility exercises and adequate warm-up time before playing or practicing are important.
Wearing an arm splint at night can keep the arm in a position that prevents pinching the nerve.
Is there a surgical treatment for radial tunnel syndrome?
The results of surgery for radial tunnel syndrome vary. Doctors recommend surgery only when time and non-operative therapy fails.
Radial tunnel surgery is uncommon, and usually is done as an outpatient surgery (the patient does not stay in the hospital overnight). It can be done with total anesthesia (the patient is asleep) or a partial anesthesia. Partial anesthesia blocks the feeling only in the arm being operated on. The patient is awake if partial anesthesia is used.
The operation to treat radial tunnel syndrome is called radial tunnel release. In this operation, the surgeon divides all compressive sites within the radial tunnel. This makes the radial tunnel bigger so the radial nerve has more space. After the operation, new tissue grows across the split, and builds a permanently larger tunnel.
What happens after surgery for radial tunnel syndrome?
After surgery, patients wear an elbow splint with the arm wrapped. One week after surgery, the patient will start on a gentle exercise program. Patients use ice packs, soft-tissue massage, and stretching to improve patients’ range of motion.
After 6 weeks, patients begin strength-building exercises for the forearm and hand under a therapist’s supervision. During recovery, lifting and other activities that require bending the arm at the elbow are not allowed. In the final stage, the therapist adds exercises to stabilize and strengthen the wrist, elbow, and shoulder, and improve fine motor control in the hand.
Full recovery after surgery can take 6 to 8 months or longer. How long it takes to recover depends on the amount of damage to the nerve before surgery.
Who is at risk for developing radial tunnel syndrome?
Risk factors for developing radial tunnel syndrome include:
- Sports or jobs that require a constant wrist twisting motion
- Poor physical arm and wrist strength and flexibility
- Lack of adequate warm-up time before playing sports
- Underactive thyroid gland
- Tumors or ganglion cysts (mass or lump) in the arm that cause pressure on the nerve
- Swelling or fluid in the arm that squeezes the nerve
- Inflammation of the radial nerve
- A hard blow to the forearm
Outlook / Prognosis
What is the outlook (prognosis) after treatment for radial tunnel syndrome?
Most patients recover completely with medical treatment if they follow instructions carefully and avoid future injury to the nerve. Surgery improves symptoms for patients who did not respond to medical treatment, but some patients continue to have mild pain after surgery.
Preventing re-injury to the radial nerve is the most important goal after recovery.