Carpal Tunnel Syndrome / Nerve Compression Syndromes
Carpal Tunnel Syndrome - what is it ?
CARPAL TUNNEL SYNDROME:
This condition previously occurred most commonly in women, 30 to 60 years of age. With the increased use of computers, men as well as women are affected. The age of onset has also become lower.
Carpal Tunnel Syndrome is due to compression of the median nerve as it passes through the carpal tunnel leads to signs and symptoms in the distribution of the median nerve such as numbness in the thumb, index and long fingers, awakening at night with numbness, pain, and/or burning.
Compression of the nerve occurs in the area under the transverse carpal ligament.
Occupations that require chronic repetitive wrist motion in flexion, extension, and gripping are prone to develop carpal tunnel syndrome. Common occupations include typists, computer operators, grocery checkers, dental hygienists, and packing house workers.
Carpal tunnel syndrome may also be result of a motor vehical accident.
Another factor in the development of carpal tunnel syndrome is any activity that results in chronic trauma to the volar side of the wrist.
Carpal tunnel syndrome that develops as a result of repetitive vibrational injury may have a worse prognosis as the nerve may be injured both by compression as well as recurrent mechanical trauma. Assembly line, construction workers involved in repetitive hammering, carpenters, and electrical workers are also prone to develop carpal tunnel syndrome.
Many times it is helpful if patients can perform different types of activities during an 8-hour shift (part of time assembly line, part of time another job within same factory).
Not all cases of carpal tunnel syndrome are due to repetitve trauma. Premenstrual fluid retention, early rheumatoid arthritis with synovial tendon sheath thickening, distal radius or carpal fractures may be responsible as they restrict the space left for the nerve in the carpal tunnel.
The condition is sometimes seen in association with thyroid disease, acromegaly, and pregnancy Diabetic patients are also at increased risk.
Often, however, no obvious cause can be found.
Patients complain of paresthesias in the hand and weakness in handling objects. Often they claim that all the fingers are involved and, although theoretically the little finger should be spared, approximately 30% of patients also have paresthesias in the ulnar nerve distribution.
Pain may radiate proximally to the elbow or shoulder. Weakness of grip is also common. The symptoms often become most marked at night, often awakening the patient (called nocturnal paresthesias).
Typically the patient will shake the hand or hang it over the side of the bed. In some cases the history and clinical examination are unequivocal.
In others it may be difficult to differentiate the patient's symptoms from those produced by compression of the sixth cervical root in the neck, pronator syndrome, or diabetic peripheral neuropathy; indeed both conditions may
be present at the same time as carpal tunnel syndrome.
Two-point discrimination testing is useful when screening for carpal tunnel syndrome. The test is performed by checking to see of the patient can feel two separate points of a small paper clip so that there is a 6 mm distance between the tips.
Both hands should always be tested as bilateral carpal tunnel syndrome is common.
On physical examination two-point discrimination may be abnormal (greater than 6 mm), grip strength diminished, and thenar (thumb muscle) atrophy is present.
This test is performed by having the examiner gently tap the area over the median nerve at the wrist. While this can be done with a reflex hammer it is better done using the examiner's long finger bent 90 degrees as this joint is more sensitive. The test result is considered positive if this produces tingling in the fingers.
Phalen's (Wrist-Flexion) Test:
The patient actively places the wrist in complete but unforced flexion. If numbness and tingling are produced or exaggerated in the median nerve distribution of the hand (thumb, index and long fingers) within 60 seconds, the
test result is considered positive (abnormal).
In patients with limited wrist motion gentle compression over the median nerve may produce the same result.
NERVE CONDUCTION TESTING:
electrodiagnostic testing (EMG, NCV) is useful when contemplating surgery or trying to rule out another etiology.
For patients seen early, before the development of abnormal two-point discrimination or thenar atrophy, splinting of the wrist with or without injection of steroids into the carpal canal may prove successful.If conservative treatment does not relieve the symptoms -
If, there is either thenar atrophy (muscle wasting) or abnormal two-point discrimination in the distribution of the median nerve then surgical release of the transverse carpal ligament is the best treatment ..
This can be done either using the traditional open approach or using the newer endoscopic technique. The endoscopic technique gives a quicker return to work and activity and has less post-operative pain in most patients.
Postoperatively, patients are protected in a removable volar resting wrist splint for 2 to 3 weeks.
During this time finger motion is encouraged. After the splint is removed wrist range of motion exercises and grip
strengthening are started.
Most patients will return to their preoperative level of grip strength and wrist motion by 3 months.
Not all patients will require therapy after surgery but if progress appears slow, referral to an Occupational or hand therapist should be made.
Patients are usually ready to return to work between 3 and 6 weeks postoperatively.
Treatment Options for Carpal Tunnel Syndrome
Swelling in the carpal tunnel may compress the median nerve, causing CTS. Surgical treatments cut the transverse carpal ligament to make room for the nerve. Eventually new tissue will fill the gap where the ligament was cut.
Non-surgical treatments may include behavioral changes such as reducing or eliminating repetitive hand motion, wearing wrist splints at night or receiving anti-inflammatory medication taken orally or injected into the carpal tunnel.
Surgical treatments vary, but the two most common are Open Surgery and Endoscopic Surgery. Both procedures share the goal of easing pressure on the median nerve by surgically cutting the transverse ligament and thereby enlarging the carpal tunnel to make more room for the nerve. Both procedures are effective, but Endoscopic Surgery results in faster recovery time, less post-operative pain and a smaller, less-noticeable scar.1
During Open Surgery, an incision is made from the crease of the wrist toward the center of the palm, through layers of skin, fat and connective tissue. Once the transverse ligament is exposed, the surgeon cuts the ligament with a blade to release pressure on the nerve. The surgeon then closes the incision with sutures and dresses the hand.
This procedure is effective; but it may not be the best option for some patients because it leaves a scar from the wrist to the center of the palm; and recovery and rehabilitation can take several weeks due to post-operative pain, the deep cutting of the hand and a longer incision.
During single-portal Endoscopic Surgery, a small incision is made in the crease of the wrist, where the surgeon inserts a small camera mounted to a surgical instrument called a SmartRelease™ ECTR. This device allows the surgeon to see inside the carpal tunnel using a video monitor. The surgeon then precisely cuts the ligament using a retractable blade within the SmartRelease™ ECTR, without opening the entire palm. Once the ligament is fully released, the blade is retracted, the instrument is withdrawn and the small incision is sutured and dressed.
The guiding principle of this minimally invasive procedure is to minimize post-operative pain by avoiding an open incision extending from the wrist across to the palm. Endoscopic Surgery is highly effective and has been used for more than 20 years. It results in less post-operative pain, a minimal scar concealed by a wrist crease, and generally allows patients to resume some normal activities in a short period of time.1
Endoscopic Carpal Tunnel Release
MicroAire’s patented single-portal endoscopic carpal tunnel release system uses a small incision at the base of the wrist as the entry point for a disposable blade assembly. Once inside, an endoscope provides a clear view of the underside of the transverse carpal ligament and surrounding anatomy. With the disposable blade assembly accurately positioned beneath the transverse carpal ligament, the retractable blade is elevated by a trigger, and the ligament is incised with a few strokes.