Guyon's Canal Syndrome -
Ulna Nerve Compression at the Wrist
Why Does it Occur?
The ulnar nerve runs through a small tunnel in the wrist called Guyon’s canal. Compression of the nerve within this canal sometimes occurs and can result from a mass, fracture of a nearby bone, and repetitive trauma seen in activities such as baseball, martial arts and cycling. Sometimes it occurs for no apparent reason.
Patients most commonly present with numbness, tingling, or pain of the pinkie finger and half of the ring finger. Symptoms will vary based on the severity and duration of compression. Hand weakness and functional issues can occur when the nerve is severely or chronically compressed.
X-ray may be considered upon initial evaluation, especially if symptoms were the results of trauma. A CT or MRI may be ordered to further evaluate an associated fracture or mass that may be causing the compression.
An Electromyogram (EMG) may be ordered to further evaluate ulnar nerve compression. This test provides details on the site and duration of compression. The EMG can also rule out other potential causes for your symptoms, including pathology coming from the neck.
A Doppler Ultrasound or Arteriogram may be ordered if compression from a vascular structure (thrombosis or aneurysm) is suspected.
Nonoperative treatment options include wearing a wrist splint. Prolonged flexion or extension of the wrist and leaning on the palm side of the wrist can worsen nerve compression and symptoms, hence the need for a wrist splint. Activity modifications will furthermore be discussed, especially if your compression is secondary to a specific activity such as martial arts or cycling.
Surgery is usually recommended if compression causes significant weakness of the fingers. It may also be recommended if your symptoms are related to a mass or fracture in the area. The aim of the surgery is merely to take pressure off of the nerve.
Surgery is often very successful if performed in a timely manner. It is important to know that the results of the surgery largely depend on how long and severely compressed the ulnar nerve is prior to surgery. Because compression commonly does not produce disabling symptoms until late in the progression of the disease, patients often put off having surgery performed until it is too late. Like a rock that is squashing a garden hose, the longer the rock is pressing on the garden hose, the more likely the hose can be permanently deformed after removing the rock. Therefore, if the nerve has been severely compressed for too long, the nerve may be permanently deformed upon decompression. The results after surgery for this patient may only be to keep the symptoms from getting worse, but may not necessarily get better. In the severest of cases, tendon transfers may be discussed to help correct and restore some function.
Dr. Steven J. Lee MD is the Chief of Hand and Upper Extremity at Lenox Hill hospital, and has extensive training in microsurgical techniques. He has successfully treated thousands nerve compression disorders such as Guyon canal compression.
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Patients will begin therapy immediately after your first post-op appointment. Most patients are able to return to normal activities after 4 weeks. It’s important to know that some patients may have some sensitivity at the incision site up to 4 weeks after surgery. This hypersensitivity is especially common with gripping and pushing activities. Therapy can help decrease this hypersensitivity and break up scar tissue.
Immediate Post-Operative Instructions
Please refer to the following pages for more information:
*It is important to note that all of the information above is not specific to anyone and is subject to change based on many different factors including but not limited to individual patient, diagnosis, and treatment specific variables. It is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopedic advice or assistance should consult Dr. Steven Lee or an orthopedic specialist of your choice.
*Dr. Steven Lee is a board certified orthopedic surgeon and is double fellowship trained in the areas of Hand and Upper Extremity Surgery, and Sports Medicine. He has offices in New York City, Scarsdale, and Westbury Long Island.