Ulnar Tunnel Syndrome of the Wrist
The ulnar nerve is one of the three primary nerves that control feeling and movement in the hand. This nerve comes from the spinal cord and travels from the neck to the arm and hand. If there is compression of this nerve, it may cause weakness, tingling, and numbness in the hand and fingers. Ulnar tunnel syndrome is when this nerve is compressed at the wrist. The most common cause of this compression is a soft tissue mass pushing against the nerve. These tumors, called ganglion cysts, are usually benign and can change in size. They may even come and go with conservative management. The nerve may also be compressed by a narrow tunnel (Guyon’s Tunnel) where the nerve enters the hand from the wrist. Sometimes chronic pressure or injury to the wrist can cause ulnar tunnel syndrome.
Patients with ulnar tunnel syndrome may experience tingling or numbness in the ring and pinky fingers. They may have weakness with gripping or pinching. It may be difficult to separate or bring the fingers together. Symptoms tend to start gradually and worsen with time.
How Is Ulnar Tunnel Syndrome Diagnosed
When you visit an orthopedic specialist, the provider will perform a physical examination. They will test sensation and your ability to feel something on your skin. They will evaluate for weakened muscles by looking for reduced muscle bulk. They may ask you to perform several movements to test for weakness. Inability to pull the pinky finger in to touch the ring finger is a sign of weakness, called Wartenberg’s sign. Your provider may tap over your nerve at the wrist to see if this causes a tingling sensation (Tinel sign). They may tap over the elbow, and the ulnar nerve may be compressed in this area and cause similar symptoms.
Some tests may be ordered:
- A nerve conduction study/electromyography (NCS/EMG) may be performed to check for nerve function.
- A computed tomography (CT) scan, magnetic resonance image (MRI) scan, or ultrasound (US) may be used to identify whether something is putting pressure on the nerve, like a cyst or other mass.
- X-rays may be used to identify whether bone is pressing on the nerve. This can be from a fracture or other bone abnormality.
Depending on what is causing the compression, non-operative treatment may be very effective. For example, if a cyclist has experienced chronic pressure on the wrist from his handlebars, she may try changing hand position or increasing padding in the area. A temporary wrist splint may allow the wrist to rest, decreasing inflammation. Non-steroidal anti-inflammatory medications may be effective as well.
If ulnar tunnel syndrome is caused by growth at the wrist or a narrow ulnar tunnel as the nerve runs from the wrist into the hand, surgery is usually needed to remove the growth or open up the tunnel.
An experienced surgeon can remove growths, scar tissue, and other causes of compression and open up the ulnar tunnel. This can restore normal blood flow to the nerve and allow for recovery of nerve function. These can be done in an outpatient setting.
Surgery complications are rare but may include infection, wound issues, or damage to nearby structures such as nerves, vessels, and tendons. Before proceeding, you should discuss the surgery’s risks and benefits with your surgeon.
It is important to note that it may take several months to a year for the nerve to recover completely. It is possible to not completely recover if the patient is older with long-standing symptoms. Some muscle wasting that has already occurred may not return with surgery. Even in cases with severe and prolonged symptoms, surgery may still be helpful to prevent the worsening of the condition even if full recovery cannot be reached. Post-operative rehabilitation or home exercises may help in conjunction with surgery.