Health: Watch Your Wrists

First, you might feel some tingling in the thumb.

You might think it’s normal and chalk it up to a long bike ride or a day climbing and bouldering. And it could be just that. However, with time, your hands may become weak and drop objects.

If that’s the case, it could be that you have an onset of one of two conditions that often plague athletes: carpal tunnel or Guyon’s syndromes.

Many will have symptoms at night especially when the wrist is flexed. Initially, symptoms may be relieved with simply extending the wrist.

However, if the symptoms progress, they can be debilitating making everyday activities very challenging. Early diagnosis and treatment is critical to prevent permanent damage to the median nerve. Here’s what you need to know.

How the Wrist Works

First, a quick anatomy lesson: The wrist consists of 8 small bones that are in two separate rows of four. These bones (called the “carpal” bones) allow for a wide array of motions and help us position our hands for desired tasks. Nerves from our neck are responsible for the sensation and motor function in our upper extremity. Three nerves make it all the way to the hand and two of them can be compressed or pinched at the wrist causing pain, numbness and loss of function.

The median nerve is the nerve that runs through the carpal tunnel and the ulnar nerve passes through Guyon’s canal. The median nerve allows us to bring our thumb across our hand and gives us sensation from the thumb, index, middle and the inner half of the ring finger. The ulnar nerve allows us to spread our fingers out and gives us sensation to the little finger and the outer half of the ring finger.

Carpal Tunnel Syndrome

The carpal tunnel lies on the palmar or volar aspect of the wrist (the side opposite the face of your watch). The carpal bones make up the floor of the carpal tunnel and a thick sheet of tissue forms the roof. This is just beneath the skin at the base of our palm. Several ligaments pass through the carpal tunnel along with the median nerve. These ligaments help us flex our fingers when we grip, shake hands or type.

For some, the volume of the carpal tunnel is small to begin with (women tend to have smaller carpal tunnels) and for others, the volume is sufficient. However, with increased activities, especially cycling or climbing where there’s added pressure on your hands, the sheaths around the ligaments that help them move freely begin to swell. This causes compression of the median nerve. Further, fluid retention such as during pregnancy may lead to narrowing of the carpal tunnel.

To help confirm the diagnosis, a health care provider may order a special test called a nerve conduction study (NCS) to determine the severity of the nerve compression. Initial treatment for carpal tunnel syndrome is the use of a cock up wrist splint at night to prevent flexion at the wrist.

Work space ergonomics or bike fit may also help. Eliminating temporarily the activities that cause symptoms may also be necessary. Other treatments involve taking non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or a corticosteroid injection into the carpal tunnel to help relieve inflammation and swelling.   If you’ve tried all your options, including a comprehensive course of hand physical therapy, surgery may be necessary.

The surgery involves releasing the carpal tunnel which is accomplished either with open surgery (an incision over the palm to cut the sheet of tissue that makes the roof of the carpal tunnel) or endoscopic surgery (two smaller incisions are made for a small camera on a tube that allows the surgeon to visualize and cut the sheet of tissue without making one larger incision).

Typical recovery from surgery for carpal tunnel release may take weeks to months. However, often patients are able to use their hand quite soon after surgery and the success rates for surgery is high.

Guyon canal syndrome (or Handle bar palsy)

On the other side of the palm from where the thumb lies is where the ulnar nerve passes over the wrist and into the little and ring fingers. The ulnar nerve actually travels through a small canal called Guyon’s canal. Guyon’s canal has a bony border on one side from one of the bones in the wrist. This bone is called the hamate bone and the hamate has a small hook on it. The hook of the hamate bone is where several ligaments attach.

Although much rarer than carpal tunnel syndrome, Guyon canal syndrome involves compression of the ulnar nerve as it passes through the Guyon canal. A very common cause of this syndrome is compression of the nerve against the handlebars of a bicycle giving this an alternate name, handlebar palsy. A palsy is when a nerve is pinched causing numbness, tingling and weakness.

Avid cyclists will often put a significant amount of pressure on the outer part of the wrist and hand for long periods of time. This may lead to numbness and tingling to the little finger and the outer (ulnar) aspect of the ring finger. Other causes involve fracture of the hamate bone or simply overusing the wrist with repetitive tasks. For instance, it’s not uncommon for baseball players to fracture the hook of the hamate during the batting motion. The butt of the bat can press against the hamate with enough force while batting that the hook may break causing compression of the ulnar nerve.

Many of the initial evaluations and treatments for Guyon canal syndrome are similar to those for carpal tunnel syndrome. Wrist bracing, anti-inflammatory medications, physical therapy, work station modifications or handlebar adjustments can help eliminate symptoms. If these are not helpful, a surgery similar to carpal tunnel release may be performed to release or cut the small ligament running on the roof of Guyon’s canal. If the symptoms are caused by a fracture of the hook of the hamate, this fractured hook is often simply removed altogether to prevent further issues.

Keep in mind: repetitive use of the hand and wrist may lead to nerve compression of either the median (carpal tunnel syndrome) or ulnar (Guyon canal syndrome). Prompt evaluation, diagnosis and treatment can help prevent permanent problems.

Dr. David Lisle is a sports medicine physician in Burlington, Vermont. He holds dual appointments as assistant professor in the Department of Orthopaedics and the Department of Family Medicine at the University of Vermont College of Medicine. He is the director for the sports medicine curriculum in the University of Vermont Family Medicine residency program. Dr. Lisle serves as the team physician for St. Michael’s College, the Vermont Lake Monsters Single A baseball affiliate and several Burlington-area high schools. He is also an assistant team physician for University of Vermont athletics.