CUBITAL TUNNEL SYNDROME

1. What is cubital tunnel syndrome?

Cubital tunnel syndrome is a medical condition that results from pressure or pinching of a nerve as it goes by the elbow to the hand. The nerve (which is called the ulnar nerve) provides for muscle action to the fingers and sensation in the little and one-half of the ring fingers. This nerve travels on the inside (medial side) of the elbow and through a long tunnel at that area call the cubital tunnel. Bone surrounds this canal on one side while a thick ligament covers the medial side.

Pressure of the nerve within the cubital tunnel may result from two basic causes. One is an injury directly to the nerve which is softer than its surrounding structures. The second and most common cause is irritation of the nerve, sometimes producing a thickening or swelling around the nerve due to repetitious use of the arm, forearm and/or elbow.

The symptoms associated with cubital tunnel syndrome are generally a numbness which may or may not be painful and which intermittently occurs in the ring and small fingers. The condition usually worsens at night. The characteristic symptoms of tingling or numbness or sleepiness in the hand results. Occasionally when the nerve pressure occurs at the elbow there may be associated sensa-tions of pain and numbness up the forearm which can extend into the arm, shoulder and even into the neck. Generally the hand symptoms are worst.

During the daytime, any repetitive or heavy use of the elbow which might tend to increase the irritation of the musculature may also aggravate it. For unknown reasons, the condition has been associated with utilization of oral birth control pills. Generally these are discontinued if the condition occurs. The condition may also result from any deformity of the elbow joint, due to injury and/or arthritis, producing delayed symptoms, called "tardy ulnar palsy".

2. What Causes Cubital Tunnel Syndrome?

In the majority of instances, cubital tunnel syndrome occurs without known cause. A few disease conditions such as gout and rheumatoid arthritis produce excessive thickening of joint capsules and result in cubital tunnel syndrome. People with diabetes may be more susceptible to the condition because of nerve damage from the diabetes. The vast majority of patients, however, probably have a constitutional predisposition or an inborn predisposition to develop irritation of their nerves with heavy use. The condition is extremely common and perhaps occurs to some degree in one out of 50 patients in the population. Persons involved in heavy lifting or occupations requiring repetitive motions of the hand, elbows, and forearms may aggravate their condition at work. In the majority of instances, this situation is purely an overuse of tendons occurring in certain job activities, but there are persons prone to develop these overuse syndromes in their hands and other parts of their bodies.

3. What are the Dangers of Cubital Tunnel Syndrome?

As mentioned above, the condition is very common in the population and many people who have this problem will not require any treatment. They simply find it an occasional annoyance or inconvenience. If the nerve pressure increases, it may interfere with the patient's comfortable life and cause permanent damage to the nerve. When symptoms reach the point that a patient is awakened frequently at night or has almost constant numbness, a need is present for medical or surgical treatment. If advanced damage does occur to the nerve, it is probable that medical treatment may not result in correction of the numbness and that surgical treatment is required. Additionally, weakness of the muscles that spread or extend the fingers or which control pinch may occur and not be recoverable. For this reason the physician utilizes tests to determine whether or not treatment is indicated.

4. What are the Clinical Findings and Tests that the Physician Uses to Diagnose Cubital Tunnel Syndrome?

The history of the problem of cubital tunnel syndrome as described above is typical. In general, the symptoms of nocturnal or night-time numbness and tingling with certain positions of the elbow make the physician suspect cubital tunnel syndrome. There are other locations where nerve pressure can cause similar symptoms but there are some very specific tests which will localize the nerve pressure to the elbow. Specifically, the physician may position your elbow to cause aggravation of the nerve pressure or he may "tap" on the nerve at the level of the elbow. Tingling produced by this maneuver indicates that this is the probable location of the pressure. A very specific laboratory test, an electromyogram may be performed to confirm that nerve pressure is present at the elbow. In some patients, this test will be done, although it is not mandatory to establish the diagnosis in a classical clinical situation. A very sensitive test is a thermogram which also can determine the presence of nerve compression, and sometimes the severity.

5. What is an Electromyogram?

An electromyogram is a nerve conduction test which studies the ability of a nerve to transmit electrical impulses from the areas of sensation in your fingers and into the muscles. The test which is mildly uncomfortable usually confirms the diagnosis of cubital tunnel syndrome. It utilizes mild electrical impulses or stimuli of the nerves. During the test the speed of conduction of the nerve impulses is measured by electronic devices and, if it is slowed across the elbow, it is indicative of pressure at this level. The amount of slowing will usually give an indication of the severity of the nerve compression. Additionally the muscles are tested and stimulated to determine if the nerve fibers to the muscles are impaired or slowed.

As mentioned above, this test may tell your physician not only if the nerve pressure is present, but how severe it is. With the help of this information he may elect to select medical or surgical treatment. In a percentage of patients, nerve pressure may exist in the presence of a normal electrical test but if it is normal your physician has other methods of determining whether or not nerve pressure is likely to be present, i.e. the thermogram.

6. What is a thermogram?

Thermography is a non-invasive (painless and harmless) study of heat changes of skin dermatomes throughout the body. Thermography can be done either electronically or by liquid crystal. Your exam will be done with the liquid crystal, using Flexi-Therm contact, utilizing a unique elastomeric ther- mally-sensitive film that can be readily contoured to display the t hermovascular patterns of the body.

During the procedure the technologist will change "cassettes" for different body parts. The reason for this is that each cassette is a precalibrated representation of temperature difference or Delta T between each color. The temperature difference or Delta T with liquid crystal will vary from cassette to cassette. These cassettes are a highly sophisticated, new, innovative and precisely calibrated pieces of equipment that are extremely sensitive to heat changes. What does it involve on the part of the patient to pre-pare for this exam? First of all, this exam is painless, so you can relax. You will need to do a few things before the exam can be done: A) You cannot smoke for at least 8 hours prior to the exam, B) You can take any medicine that you are presently taking and C) You will need to bathe well before the exam, as dirt and oil will affect the exam.

After you get here: A) You will be asked to fill out a form of history, pain, medications, etc., B) You will be placed in an exam room. You will need to put on a gown, especially designed for the exam, C) You will need to stay seated in the exam room for about 15 minutes before the exam actually begins so that your body temperature can stabilize and adjust to the room temperature, D) Several views will be taken of the dermatome paths including both extremities. These views will be repeated every 15 minutes. The exam takes about 1½ to 2 hours per patient. Approximately 40-50 pictures will be taken during the exam. The reason for the time interval is to rule out any "artifacts" and/or to compare persistent abnormalities, E) Dr. Herrick will interpret your thermograms and dictate a report that will be filed in your chart, F) Occa-sionally your exam may need to be repeated or follow-up exam may be necessary to further evaluate either a suspected abnormality or to check on progressive improvement.

7. What is the Treatment for Cubital Tunnel Syndrome?

Medical Treatment. Some physicians may prescribe use of a splint to be worn on the forearm to treat mild cubital tunnel syndrome. This will prevent the elbow from getting into the flexed position and may decrease the amount of numbness that occurs in the hand at night (it does not change the condition per se). The major form of nonsurgical treatment for cubital tunnel syndrome is rest and the use of Non-Steroidal Anti-Inflammatories and high doses of Vitamins B6, C and E. If the changes are felt to be minor on the testing, and improve with this type of treatment, surgical consideration may be delayed and/or avoided.

Surgical Treatment. The surgical procedure for cubital tunnel syndrome involves enlarging the canal through which the tendons and the nerve pass at the elbow. This is generally done through an incision approximately 4 inches long centered at the elbow and curved to decrease scar contracture. After the skin is divided, the deep ligament which forms the roof of the tunnel is divided. This separates allowing the canal to enlarge. At the time of surgery the nerve is inspected for evidence of compression. Sometimes the nerve will be transposed or moved anteriorly to prevent direct injury in the future.

The surgery is most often done under axillary block anesthesia which provides minimal discomfort for the patient and rapid recovery without the associated dangers and potentially significant side effects of general anesthesia. The operation is performed in a regular operating room usually at the hospital, under sterile conditions. After the surgery is performed, the skin is closed with stitches and a small plastic tube may be placed along the incision to prevent accumulation of blood. A large dressing is applied to the arm and forearm to hold the elbow and wrist in a stationary position . This dressing is sometimes removed at two to four days and replaced with a small dressing. Usually a splint is used for a few days only.

At 10 days to 2 weeks following surgery, the dressing and the sutures are removed. The hand is then allowed to be used freely without the use of dressings but it is necessary to avoid strenuous heavy use of the hand for four to six weeks following surgery. At this time some patients are able to return to full activities. Occasionally discomfort and soreness in the incision develops as the healing occurs and will take approximately three to four months to go away. The symptoms of numbness and tingling, however, are generally relieved immediately following surgery. Some discomfort and occasional tingling are expected to occur for three to four months. The presence of burning redness and tender lumps about the incision is common for the first three to four months following surgery but resolve spontaneously by that time.

8. How Painful is Cubital Tunnel Surgery?

Most patients undergoing cubital tunnel surgery feel better the night after surgery. Occasionally mild oral narcotic pain medications are necessary but the majority of people require nothing other than occasional Tylenol (acetaminophen) and/or aspirin. Fingers are free imme- diately after surgery for handling such items as coffee cups and light spoons but the wrist and elbow cannot bend. Therefore, there can be problems with personal hygiene for several days if both elbows are done at the same time. With some help, even the patient who has had both elbows operated on at the same time may carry on all the daily functional activities of living. Frequently cubital tunnel syndrome occurs simultaneously with carpal tunnel syndrome. Also, both can be operated on at the same time.

The decision to operate on both arms is generally left to the patient. If the condition occurs in both arms and is severe, it is probably wisest to proceed with decompression of the nerve on both sides. In most patients the condition is severe on one side and either non-existent or mild on the other. In these cases generally the involved side only is done. Having the condition on one side does not necessarily mean that it will become severe on the other side although this is commonly the case.

9. When Can I Return to Work and Will I Return to Normal?

As mentioned previously, patients doing heavy work activities are not allowed to return to these activities until six weeks following surgery. At this time their incisions will be well healed but they may still be sore and there will be some aching and swelling in the elbows. In these instances the patients are allowed to return to light work as no damage will be done to their hands by using them, but is may be three to four months before they feel quite comfortable and it may be a year before the hands feel totally normal. If the condition is occupationally aggravated or caused, a permanent impairment of 5 percent of the arm is a standard impairment rating for this problem. The patient may be advised not to return to the aggravating employment.

In general this procedure is 95 percent successful in relieving compression and relieving symptoms caused by nerve pressure at the elbow. In a very small percentage of cases there is a recurrence but this is probably less than 5 percent of the time.

NOTE: During the first three to four months following surgery, there commonly is a development of a firm and modular ridge on either side of the incision. This may be associated with a sensation of burning or heat and occasional tingling-shooting to the fingers with stretching of the incision. This is a normal response as the scar tissue forms at the site of surgery. With use of local massage of this tissue it generally resolves in three to four months as the scar underneath matures and softens as does the skin scar itself. In approximately two years in most patients the scar is nearly invisible although approximately 10 percent of patients may develop stretching and separating of their scars because of the nature and elasticity of their tissue.

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