Anatomy of the Hand
Guyon’s Canal Syndrome is a common nerve compression affecting the ulnar nerve as it passes through a tunnel in the wrist called Guyon’s canal. The ulnar nerve begins at the side of the neck, travels behind the elbow and ends in the hand at the little and ring fingers. At the wrist, the ulnar nerve and artery run through the tunnel known as Guyon’s Canal. The canal is formed by two bones, the pisform and hamate and the ligament that connects them. After passing through the canal, the ulnar nerve branches out to supply feeling to the little finger and half the ring finger. Branches of this nerve also supply the small muscles of the hand. This syndrome is much less common than Carpal Tunnel Syndrome (CTS), but may be present along with CTS. The ulnar nerve supplies sensation to the little finger and half of the ring finger, and if these fingers are involved in any symptoms of numbness, compression of the ulnar nerve in Guyon’s canal may be present. It is critical that the area of compression be localized to either the wrist (Guyon’s canal), or the elbow (cubital tunnel), by physical examination and electrical studies prior to embarking on a treatment regimen.
Causes of Guyon’s Canal Syndrome
Guyon’s canal syndrome can be caused by:
• acute or repetitive trauma – Overuse of the wrist, especially in tasks bending the wrist down (flexing) and out, or put constant pressure on the palm.
• anomalous muscles
• arthritis – arthritis of the wrist bones
• ganglion cysts are the most common non-traumatic cause
• blood clots in the ulnar artery
In some cases the symptoms may be caused by a fracture of the bony process called the hook of the hamate bone. These fractures sometimes occur in golfers from hitting the ground instead of the golf ball, or in baseball player’s while batting.
Symptoms of Guyon’s Canal Syndrome
Symptoms start with a pins and needles feeling in ring and little fingers, starting in the early morning before waking. This progresses to a burning pain in the wrist and hand, followed by a decrease or loss of feeling in the hand that causes clumsiness in the hand. The ulnar nerve also supplies many of the small muscles of the hand.
Diagnosis of Guyon’s Canal Syndrome
The diagnosis of Guyon’s Canal Syndrome begins with a history and physical examination by your doctor. Compression can occur at several areas along the ulnar nerve, and your doctor will try to find exactly where the nerve is being compressed. If it’s unclear on physical examination where the point of compression is, electrical studies can be. The Nerve Conduction Velocity test (NCV) measures how fast nerve impulses travel along the nerve.
Preventing Guyon’s Canal Syndrome
Take frequent breaks or limit the amount of time you do tasks that require flexing and turning out the wrist, or place constant pressure on the palm. A wrist splint can be worn at night to reduce the feeling of pins and needles. Keyboard operators may find that a wrist rest reduces symptoms.
Treatment of Guyon’s Canal Syndrome
Anti-inflammatory medications (such as ibuprofen or aspirin) may help reduce inflammation and pain.
If conservative treatment fails to control your symptoms, surgery may be needed to relieve pressure on the ulnar nerve. Surgery involves making a small incision along the ulnar nerve in the palm of the hand. The ligament that forms the roof of Guyon’s canal is cut to relieve the pressure on the ulnar nerve. Once the ligament is cut the pressure on the nerve is relieved. The skin is then sewn back together. The ligament heals by forming scar tissue.
Immediately after surgery, you should keep the arm raised above the level of your heart. For seven to ten days after surgery (until the wound is healed), keep the incision clean and dry to reduce chances of a post-operative infection. If the bandage gets dirty, very bloody or wet, remove it immediately and put on a clean, dry bandage. When you take off the bandage, you’ll see stitches at the incision site. Do not try to remove the stitches even it the skin looks healed, the stitches hold the skin’s edges together while the skin heals. The sutures and the bandage will be removed at your first post-operative visit about ten days after surgery. If you develop a fever while the wound is healing, or if the incision gets red, swollen, or starts to drain, call your doctor right away.
During your short stay in the hospital, you’ll be given either pills or injections to control pain. At home all pain medicine will be by pills. It’s important to remember that pain medication be only taken when needed and only as prescribed so it controls your pain as it should and does not become habit-forming.