carpal tunnel news, research + Iyengar yoga

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BioMechanics January 2004 Cover Story http://www.biomech.com

Wristoration: Alleviating the pain of carpal tunnel syndrome

Researchers remain focused on cost-effective, conservative management

and careful selection of surgical candidates.

By: Barbara Boughton

Perhaps because it is frequently categorized as an occupational

injury-the sort that workers' compensation nightmares are made

of-researchers who study carpal tunnel

syndrome remain focused on cost-effective, conservative management and

careful

selection of surgical candidates.

And although a recent Cochrane Review article cited scientific support

for a few new-fangled therapies, including yoga and carpal bone

mobilization, the authors also

found that one of the most reliable nonsurgical treatment options is

still good

old-fashioned wrist splinting.

The pain of carpal tunnel syndrome arises when the median nerve that

passes through

the wrist bones becomes pinched by swollen tendons and membranes.

Symptoms are usually associated with repetitive work-related or

hobby-related tasks that put pressure

on the tendons. The classic example is the person who types for hours

each day on a

computer keyboard; another example is the bicyclist who rides with his

palms resting on

the handlebars, which puts unrelieved pressure on the membranes and

tendons

surrounding the wrist.

Practitioners find that splinting at night can give the median nerve

time to rest and relieves pressure that can cause further symptoms in

some patients. Splinting also helps protect tissue during repetitive

tasks during the day, but to maintain a neutral position the wrist has

to be held at 5º to 10º of dorsiflexion, said Herb , MD, an

orthopedic surgeon who practices in Sun Valley, ID.

In a 2003 Cochrane Review article on conservative options for treating

carpal tunnel syndrome, researchers from the University of South

Australia cited a study from Chieti, Italy, published in Muscle and

Nerve in August 2001, which found that a hand brace

significantly improved symptoms and function after four weeks.

In a study published in the Journal of Neurology, Neurosurgery and

Psychiatry in September, researchers from Vrije University Medical

Center in Amsterdam, the

Netherlands, identified prognostic indicators for splints that improved

outcomes.

In the study, patients had to wear splints at night for at least six

weeks. At 12 months, 60 of the 83 patients who received splints and

attended follow-up visits reported improvement. However, 34 of the 83

had received one or more additional types of treatment during the

follow-up period, and thus were considered treatment failures for

splints. The final success rate for splinting was 31%.

Only two prognostic indicators could be found that contributed to

success-a short

duration of carpal tunnel syndrome complaints (less than one year) and a

score of 6 or

less on a scale of 0 to 10 for severity of nighttime paresthesia at

baseline. For patients to whom both factors applied, the probability of

treatment success with

splints was 62%.

But because the benefits of conservative management, including splints,

have generally

been limited to patients with mild to moderate symptoms, the critical

factor for most

practitioners is determining which patients really do need surgery.

" The first task is to establish the reason for the carpal tunnel

symptoms, " said.

Carpal tunnel symptoms that arise during pregnancy often disappear after

delivery and

conservative treatment. Pain and inflammation in the wrist caused by

thyroid problems

and rheumatoid arthritis is also considered carpal tunnel syndrome, but

in such cases

treatment should first be directed to the underlying condition, after

which symptoms

often resolve, according to .

If a patient has been symptomatic for six to eight months and wasting of

muscles around the base of the thumb is evident, conservative therapy

may not work, said,

because of the likelihood of damage to the nerve or surrounding tissues.

A high positive score on the Tinel test or the Phalen test can also

indicate that a patient needs surgery. In the Tinel test, the

practitioner taps over the wrist

crease-and the median nerve-with a finger or a reflex hammer. If the

patient has

serious carpal tunnel syndrome, he or she will feel tingling or burning

along the course of the nerve. In the Phalen test, the wrists are flexed

and held in position for a minute. Those who experience symptoms within

15 to 45 seconds afterward may be candidates for surgery. Persistent

numbness may also indicate a need for surgery. The Tinel test has a

sensitivity of 60% to 67% and a specificity of 67%; the Phalen test has

a sensitivity of 75% to 85% and a specificity of 47% to 89%.1,2

If a patient has pain but no numbness, he or she may fare well with

conservative

treatment, said Nadler, DO, a physiatrist and the director of

physical medicine and rehabilitation at the University of Medicine and

Dentistry of New Jersey.

" But if symptoms persist after conservative treatment, or the patient's

constantly uncomfortable and unable to perform daily tasks, then we may

look at surgery, " Nadler

said.

An abnormal electromyogram may also send a patient to surgery. EMG

results are graded

as mild (a slowing of the nerve conduction across the carpal tunnel, or

increased

latency), moderate (severely prolonged latency and/or decreased

amplitude of the

impulse), or severe (findings include denervation potentials in the

abductor pollicis muscle or an action potential across the carpal tunnel

can't be found), according to Goitz, MD, assistant professor and

chief of hand surgery at the University of

Pittsburgh. Those patients whose EMG results are graded as severe are

often sent to

surgery. Those with mild or moderate EMGs may benefit from conservative

treatments,

especially if they don't have sensory symptoms, according to Teri

Bielefeld, PT, a hand and wrist specialist at the VA Hospital in

Milwaukee.

" In the EMG test, we look for a loss in amplitude or latency to indicate

carpal tunnel

syndrome. A positive needle electrode test, showing spontaneous

discharge, indicates

nerve damage, " said Sheila Dugan, MD, a physiatrist and assistant

professor of physical

medicine at Rush University in Chicago.

That's frequently an indication of damage to the myelin sheath of the

nerve. A significant loss of height on the EMG in response to the

current often shows that

the nerve itself is damaged, according to Dugan.

In surgery for carpal tunnel syndrome, the transverse carpal ligament is

cut to relieve pressure on the nerve. If the nerve is pinched or

strangled by ligaments or tendons and is untreated for too long-longer

than a year-there can be irreversible nerve damage caused by lack of

sufficient blood supply. Surgery, however, can prevent further nerve

damage.

The techniques for carpal tunnel surgery are standard open, limited

open, and endoscopic. Though patients can return to work earlier with

endoscopic surgery (in about

two weeks), all three surgeries have similar efficacy, according to

Goitz. The recurrence rate is less than 5%, he said.

In a study published in the Journal of Hand Surgery in September,

University of Utah

researchers found that patients who underwent bilateral simultaneous

open carpal tunnel

release returned to work in an average of 2.6 weeks. Average patient

satisfaction with

the surgery was 9.6 out of 10.

In less than 1% of cases scar tissue from the surgery can adhere to

other structures in the wrist afterward, limiting mobility of the nerve

and causing symptoms to return. In

those cases, more surgery will be necessary.

" Problems with scar tissue are pretty rare. Some people just make more

exuberant scar tissue than others, " Goitz said.

In studies comparing surgery and conservative treatments, researchers

have found that

surgery can be more effective. But it is also more expensive than

conservative

treatments, and it often takes patients at least six weeks to fully

recover.

In a September 2002 study published in the Journal of the American

Medical Association

by researchers from the same Dutch group mentioned earlier, 89 patients

with carpal

tunnel syndrome were assigned to either wrist splinting at night for at

least six weeks or open carpal tunnel release. The patients were

examined by a physiotherapist at three,

six, and 12 months after randomization. They scored the severity of

carpal tunnel

syndrome complaints on an 11-point scale with 0 equaling no complaints

and 10 equaling

very severe complaints.

The subjects filled out questionnaires at three, six, 12, and 18 months

after

randomization. General improvement was self-reported by the patient on a

six-point

scale, ranging from " completely recovered " to " much worse. " Treatment

success was

defined as " completely recovered " or " much improved. " The two other

outcomes measured

were the number of nights that the patient had awakened due to the

symptoms during

the past week and severity of pain, paresthesia, or hypoesthesia.

The researchers found better general improvement scores in patients who

underwent

surgery. The success rate after three months was 80% for the surgery

group versus 54%

for the splinting group. After 18 months, the success rates increased to

90% for the

surgery group and 75% for the splinting group. However, by that time 41%

of patients in

the splinting group had also undergone surgery.

Those who had surgery had fewer complaints in general and less severe

pain, paresthesia, and hypoesthesia. They also woke up less during the

night.

In the Cochrane Review article, which analyzed 21 trials of 884

patients, other common

methods of treating mild to moderate carpal tunnel syndrome were

associated with mixed

results. Ultrasound was associated with no benefit after two weeks in

two trials, but in

another trial was associated with significant improvement after both

seven weeks and six

months.

Four trials of 193 subjects examined oral medications-including

steroids, diuretics, and

nonsteroidal anti-inflammatory drugs-versus placebo. Oral steroids

provided significant

improvement after two and four weeks in two trials, but the other two

classes of drugs

did not demonstrate significant benefits.

Nerve and tendon-gliding exercises, when combined with wrist splints,

were found to improve static two-point discrimination after eight weeks

in three trials. But there was no effect on symptoms, hand function,

grip strength, or pinch strength. And finally, two trials involving 105

people using ergonomic keyboards versus controls using regular

keyboards demonstrated equivocal results for pain and function,

according to the

reviewers.

The Cochrane Review authors found limited evidence to suggest that

taking vitamin B6

for 12 weeks can reduce finger swelling and movement discomfort.

However, they found

no evidence that the vitamin relieved nighttime discomfort,

hand-coordination, Phalen's

sign, or Tinel's sign.

" There haven't been controlled studies that have convincingly

demonstrated its efficacy, " Bielefeld said.

The Cochrane Review article found chiropractic care, laser acupuncture,

and magnet therapy to have limited benefit for patients with carpal

tunnel syndrome, but did cite one study of 21 patients that found

symptom improvement after three weeks of carpal bone

mobilization. Similarly, a group of practitioners at Performance

Dynamics in Muncie, IN,

have found success using soft tissue manipulation on patients with

carpal tunnel

syndrome as well as other repetitive motion injuries. They theorize that

delivering a

controlled amount of microtrauma to specific areas of connective

tissue-through

augmented soft tissue mobilization (ASTYM), as they've named the

technique-leads to

the resorption of fibrosis and soft tissue regeneration.

After a lubricant is applied, the practitioner manipulates the angled

edge of patented,

specially designed acrylic polymer instruments to catch on the areas of

fibrosis, which

triggers a local inflammatory response. The devices are then moved in

longitudinal strokes above the affected soft tissues and in

multidirectional strokes around the bony prominences of the wrist.

In a study published in 2000 in Work: A Journal of Prevention,

Assessment and

Rehabilitation, researchers from Performance Dynamics examined

cumulative trauma

disorders in a large manufacturing plant and found that 68% of 28

extremity injuries

resolved within six to eight weeks with the ASTYM system. The criteria

utilized for

resolution were full return to preinjury activities and functional

ability, and a score of 3 or lower out of 10 for pain on a visual analog

scale.

The physician who invented the ASTYM method, Sevier, MD, an

internist and

sports medicine specialist, has now trained nearly 700 therapists in the

technique

throughout the U.S. He's embarking on a clinical trial of ASTYM compared

to NSAIDs in

patients with carpal tunnel syndrome.

" In carpal tunnel, ASTYM stimulates healing and the regeneration of

tendons that surround the median nerve, " he said.

Of the other alternative therapies the Cochrane Review article examined,

only yoga

showed a benefit for carpal tunnel syndrome. In 1998 n Garfinkel,

EdD, a clinical

investigator at the University of Pennsylvania published a study in JAMA

comparing yoga

to wrist splinting for carpal tunnel syndrome. The 42 patients in the

study were assigned to either a yoga group or a splint group for eight

weeks. The yoga protocol used the Iyengar style and consisted of 11

postures designed for strengthening,

stretching, and balancing each joint in the upper body, as well as

encouraging

relaxation. The participants practiced yoga twice weekly.

The results showed significant improvement in grip strength (from 162 to

187 mm Hg) and

pain reduction in the yoga group but not in the splint group. The number

of subjects with a positive Phalen sign in the yoga group also went down

significantly.

Garfinkel uses the Iyengar system of yoga because it emphasizes proper

alignment, range of motion, and increasing mobility.

" For many people in the study who took the yoga class, their awareness

of their entire body changed, " Garfinkel said. " They had better range of

motion and flexibility and their sleep disturbances decreased. Now I

have doctors referring patients to me with arthritis and repetitive

strain injury who can reap the benefits of yoga. "

Barbara Boughton is a freelance writer based in San Francisco.

References

1. Durkan JA. A new diagnostic test for carpal tunnel syndrome. J Bone

Joint Surg

1991;73-A(4):535-538.

2. Bruske J, Bednarski M, Grzelec H, Zyluk A. The usefulness of the

Phalen test and the

Hoffmann-Tinel sign in the diagnosis of carpal tunnel syndrome. Acta

Orthop Belg

2002;68(2):141-145.