Carpal tunnel syndrome

Carpal tunnel syndrome is the most common nerve compression of the upper extremity. It is characterized because the median nerve is compressed at the level of a tunnel found in the wrist.

In most cases it affects middle-aged women and can also affect pregnant women.

Any cause that decreases the size or space of the carpal tunnel can cause compression of the median nerve. Common causes related to carpal tunnel syndrome can be:

Inflammation of the flexor tendons, intracanal tumors (cysts, lipomas…), pregnancy, diabetes and hormonal alterations secondary to a thyroid problem.

Carpal tunnel symptoms

The patient with carpal tunnel syndrome presents tingling or numbness of the first three fingers and the radial (lateral) half of the 4th finger of the hand. In addition, it is common for objects to fall out of their hands, or that they cannot open jars or turn lids.

Sometimes the symptoms worsen with activities that require repetitive movements, or also in situations in which the wrist remains bent or extended for a long time (talking on the phone, driving, combing your hair).

It is common in carpal tunnel for patients to wake up at night with their hand numb and have to shake and move it to make the symptoms go away.

When compression is severe, loss of finger sensation and muscle atrophy may be significant.

Physical examination of the carpal tunnel

In the physical examination of the carpal tunnel we can find:

• A decrease in thumb opposition strength.
• An important loss of muscles of the first finger of the hand.
• A decrease in the sensitivity of the first three fingers and the lateral half of the 4th finger.

Exploration maneuvers for carpal tunnel syndrome are:

• Phallen: very useful maneuver, the wrists are kept in flexion for 60 seconds, and if a dull pain and hypoaesthesia (decreased sensitivity) appear in the medium territory, the maneuver is positive.

• Tinel:  light tapping on the median nerve at the wrist level, causing a cramp in the first three fingers (median nerve).
• Durkan: is the compression of the median nerve by the thumb on the heel of the palm for a maximum of 30 seconds, which also reproduces the symptoms in the median territory.

Siagnosis of Carpal tunnel syndrome

• Clinic and examination are the fundamental basis for the diagnosis of carpal tunnel syndrome. The numbness of the first three fingers, especially at night, is quite significant.
• Electromyogram, is the most useful confirmation test. It cannot be interpreted in isolation, since between 5 and 10% of patients with symptoms have normal results.
• The surest confirmation diagnosis is the one that includes clinical history and examination, using electrophysiological tests as confirmation.
• Ultrasound today makes it possible to assess the compression of the median nerve inside the carpal tunnel, measure its caliber and plan possible surgical intervention.
• Always make a differential diagnosis with C6 cervical radiculopathy, and with double compression syndrome of the median nerve.
• The failure of carpal tunnel syndrome surgery is sometimes due to a diagnostic error.
• Proximal compression of the median nerve is a frequent cause of added compression that should always be ruled out by a peripheral nerve surgeon.

Differential diagnosis of Carpal tunnel

Carpal tunnel syndrome is frequently associated with:

• Osteoarthritis of the base of the thumb (associated in 40%)
• Diabetes with peripheral neuropathy
• Inflammation of the flexor carpi radialis tendon

Carpal tunnel treatment

In some situations, such as pregnancy, surgical treatment is not indicated as there is a hormonal imbalance that is usually resolved by having the baby.

In cases of mild carpal tunnel syndrome, the use of wrist splints in a neutral position (generally worn at night) and the use of analgesics is adequate. Antioxidant vitamin complexes (Alasod/Alaon) can also be taken.

Corticosteroid infiltration can be performed in mild and moderate carpal tunnel syndrome. I do not like to inject in severe cases, because it masks the symptoms and does not give good results due to the internal damage of the nerve secondary to compression.

Infiltration should be assessed based on clinical and neurophysiological findings to obtain the best results.

Ultrasound-guided infiltration of the carpal tunnel allows the injection to be safely and safely introduced, as well as ensuring that with a smaller amount of fluid we can obtain greater benefit for our patients.

Infiltration has a beneficial therapeutic effect and helps us know if the surgery will be effective. If the infiltration relieves the symptoms, we can guarantee that the surgery will provide a good clinical result. If not, look for other diagnoses.

When the Carpal Tunnel Syndrome has an occupational origin, it can improve with ergonomic modifications (use of keyboard supports, adjustment of the height of the computer keyboard and avoiding a forced flexion position as in dental hygienists.

When the splint and symptomatic treatment fail, or the neurophysiological record shows significant compression with low amplitudes, carpal tunnel surgery is the indication.

Surgery can be performed in two ways:

1. Conventional open carpal tunnel surgery

After approximately 10 days, the points are removed, and the approximate time off work is 4 weeks for jobs that do not require great effort or take weights, and 6 weeks for those workers who take weights.

The most important risks of surgery, although few, are injury to the median nerve, recurrence of carpal tunnel syndrome (approximately 10%), and painful scarring.

2. Ultrasound-Guided Carpal Tunnel Surgery (our preference)

It is undoubtedly the optimal surgical treatment for the treatment of carpal tunnel syndrome.

Ultrasound allows us to visualize all the anatomical relationships of the median nerve, and the anatomical variations that we can find during the surgical intervention.

With local anesthesia, without ischemia (tourniquet) and with opening of the annular carpal ligament through an incision of approximately 1 mm, we reduce the surgical aggressiveness of conventional surgery and obtain an earlier recovery.

This less surgical aggressiveness allows our patients to operate on both hands affected by carpal tunnel syndrome simultaneously (bilaterally), something unthinkable with a conventional open technique.

It has been an advance for our patients, who see their limitation greatly diminished in the postoperative period. Minimal wound without stitches, opening of the ligament without damaging the skin, and control of bleeding, allow this procedure to have revolutionized hand surgery.

Carpal tunnel syndrome frequently asked questions