Carpal Tunnel SyndromeCarpal Tunnel Syndrome

Daniel Robbins

What… is it?What… is it?Carpal tunnel syndrome is a nerve compression syndrome where the median nerve gets compressed at the wrists

The carpal tunnel is formed between the carpal bones of the wrist and the transverse carpal ligament. The ligament is an unyielding thick fibrous tissue which does not allow for changes in volume within the carpal tunnel.

What are the symptoms?What are the symptoms?

The typical primary symptoms are pain and numbness and tingling the areas innervated by the median nerve. Symptoms are often worse at night and can be brought on by various activities that increase the pressure in the carpal tunnel (i.e. involving wrist flexion).

Tests for symptomsTests for symptoms

Tinel’s sign(8)

A common test for nerve entrapment is Tinel’s sign. Tapping or ‘percussing’ is performed on the surface of the skin along the nerve pathway over the suspected area of the lesion. If this produces a tingling sensation then the test is positive.

• Durkan’s test or the pressure provocation test is performed by applying firm pressure to the palm over the nerve for up to 30 seconds to elicit symptoms.

• The pressure is either applied by hand approximately or with a pressure gauge held at 150mmHg.

Tests for symptomsTests for symptoms

Durkan’s test (9)

• Phalen’s maneuever is performed by positioning the patient with their wrists in flexion and placed together in front of them.

• The position is held for up to 2 minutes, if the position induces symptoms the test is positive.

Tests for symptomsTests for symptoms

Phalen’s maneuver (8)

Why do we get it? Why do we get it?

• Genetic predisposition…?(3)

• You may also get carpal tunnel syndrome if you:

– start doing a something you aren't used to, such as house painting, guitar, knitting etc. – have rheumatoid arthritis in your wrist joint have osteoarthritis in your wrist as a result of an

old fracture – are pregnant – have thyroid problems – have acromegaly, a condition caused by too much growth hormone (a chemical produced

naturally by your body) – have diabetes – have cysts in your carpal tunnel – take certain medicines, such as the oral contraceptive

• For many people, it isn't known why carpal tunnel syndrome develops. Other nerve and tendon disorders may produce similar symptoms.

How Does this Affect the nerve?How Does this Affect the nerve?

Nerve’s as a Pressure Vessel Nerve’s as a Pressure Vessel (5)(5)

If nerves are considered as a cylinder they can be modelled as pressure vessels. Pressure applied at a set point can therefore be modelled across the whole nerve.

The pressure at one end causes increases in length and both decreases and increases in diameter.

These changes can be quantified. Note that the denominator in each equation is the radius. The implication of this is that large nerves are affected before small nerves by the same amount of pressure.

Implications of pressureImplications of pressure• Large fibres are affected by pressure more than small fibres

– as large fibres carry signals for tactile sensation this could account for the loss of sensation prior to loss of pain and temperature sensation(5).

• The loss/reduction of tactile sensation signals could limit presynaptic inhibition at the spine, therefore increasing pain sensations (following gate theory)(5).

• Observations of longitudinal sliding suggest that shearing forces deforming the nerve in a proximal direction are more severe than those deforming it towards the fingers(4).

• Axoplasmic transport effects?? In theory this would suggest extracellular pathways would be affected before intracellular pathways (axoplasmic transport). However, there is no conclusive evidence as of yet…

Vascular effectsVascular effects

• Reduced vascular return – increased pressure restricts flow through oblique blood vessels (7).

• Currently it is unclear if symptoms are a result of mechanical compression or relative ischemia (6).

Image taken from Butler, Mobilisation of the nervous system (1991)

What… can be done?(1,2)

• Self-help

– If your condition is linked to the way you use your hands, it's important to try to change how you do things. Changing the way you make repetitive movements, reducing how often you do them, and increasing the amount of rest between periods of activity should help.

– Stretching exercises can help to relieve your symptoms and keep the area mobile. Some studies indicate that special hand exercises - called nerve &/or tendon and gliding exercises - can help.

– Mild symptoms can be relieved by resting your hands and wrists regularly and by applying a cold compress, such as ice or a bag of frozen peas, wrapped in a towel. You shouldn't apply ice directly to your skin as it can damage your skin.

• Medicines

– Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen don't seem to have much effect on carpal tunnel syndrome symptoms unless it's caused by an inflammatory condition. Diuretics (water tablets) have also been prescribed for carpal tunnel syndrome but recent studies don't show any benefit.

– Corticosteroid tablets (for example prednisolone) for two to four weeks can provide relief of your symptoms in the short term but they have side-effects if you take them for a long time.

– Steroid injections (for example hydrocortisone) into the carpal tunnel. Your pain may get a little worse for a couple of days after the injection, but symptoms should improve after that.

What happens after the injection? What happens after the injection? (1,2)

• I had a steroid injection for my carpal tunnel syndrome. How long will the effects of the injection last? Can I just have another one if this wears off?

– About three-quarters of people who have a steroid injection find that their symptoms improve. However, symptoms come back for some people after a few months. You may be able to have repeat injections.

• Explanation

– It has been shown that about seven out of 10 of people feel their symptoms get better after a single steroid injection but the effects don't last for everybody. Some studies have suggested that about nine out of 10 people will feel their symptoms returning within two years whereas in other studies about half the people treated with steroid injections are still free of symptoms after seven years.

– You can only take steroids for a short time because of side-effects. Although this is true for steroid tablets, it doesn't apply to steroid injections. You may be able to have a second or third injection if your symptoms return and the first injection worked for you for a while.

– You should see your GP and ask his or her advice if you feel your symptoms are getting worse again.

• Complementary therapies

– You may have heard that acupuncture helps to relieve symptoms of carpal tunnel syndrome, but there is no scientific evidence to back this up. Also there is no evidence to suggest that vitamin B6 (pyroxidine) tablets help.

– There is some evidence that performing yoga reduces pain in people with carpal tunnel syndrome.

• Non-surgical treatments

– Wrist splints are often recommended for you to use either at night, or both day and night although you may find they get in the way when you're doing daily activities. These help to keep your wrist straight and reduce pressure on the compressed nerve.

– Research indicates that ultrasound treatment can help reduce the symptoms of carpal tunnel syndrome.

Other optionsOther options(1,2)

Carpal Tunnel Release 1Carpal Tunnel Release 1Open Carpal Tunnel Release

The surgeon makes a 2-5 inch incision in the lower palm and wrist area. The carpal ligament is opened. This frees the median nerve. The incision is closed with stitches. A bulky bandage is applied to the wound, with care taken to ensure that digit movement is NOT restricted.

Effective release of TCL has been shown to increase carpal tunnel volume by 24% (6).

Carpal Tunnel Release 2Carpal Tunnel Release 2• Endoscopic Carpal Tunnel Release

• A tiny, ½-inch incision is made on the palm side of the wrist. A miniature fiber optic camera is passed through. This camera allows the surgeon to view the inside of the carpal tunnel. Another tiny incision is made. Surgical tools are passed in. While looking at the monitor, these instruments are used to release the carpal ligament and free the median nerve. After the camera and instruments are removed, a few stitches are necessary to close the incisions. A bulky bandage is placed over the wounds.

OutcomeOutcome

• You may have to wear a brace or splint for several weeks after surgery.

• Complete recovery may take 4-6 weeks or longer. The numbness or tingling in your hand and fingers usually improves rather quickly. Your grasp strength will very slowly begin to improve. You may be given special exercises or be advised to attend physical therapy. This will further improve the strength and mobility of your hand and fingers.

SplintsSplints

Possible post surgery problemsPossible post surgery problems

• General

• PO palmer discomfort

• Scar tenderness

• Weakness• Taken from (6)

Complications

Lacerations ECTR(708 surgeons)

OCTR(616 surgeons)

Median 100 147

Ulnar 88 29

Digital 77 54

Vessel 121 34

Tendon 69 19

Taken from (10)

Reference 10 details questionnaires sent to American

surgeon who perform carpal tunnel releases. The following

table is a summary of surgeons who encountered complications

at some point (though not detailing out of how many

releases performed).

Ref’s/Further ReadingRef’s/Further Reading1.)

http://www.aurorahealthcare.org/yourhealth/healthgate/getcontent.asp?URLhealthgate=%2214786.html%22

2.)http://hcd2.bupa.co.uk/fact_sheets/html/carpal_tunnel.html3.) Bland,J. (2007) Carpal tunnel syndrome. BMJ August 20074.) McLellan, D,L. and Swash, M. (1976) Longitudinal sliding movements of the upper

limb. Journal of Neurology, Neurosurgery and Psychiatry 39, 566-570 5.) Macgregor, R.J. Sharpless, S.K. and Luttges, M,W. (1975) A pressure vessel model

for nerve compression. Journal of the neurological sciences 24: 299-3046.) Rodner, C,M. and Katarincic, J. (2006) Open carpal tunnel release. Techniques in

orthopaedics 21(1): 3-11 7.) Butler, D. (1991) Mobilisation of the Nervous System, Churchill Livingstone 8.) Urbano, F.L. (2000) Tinel’s sign and Phalen’s maneuver: Physical signs of carpal

tunnel syndrome. Hospital physician July 20009.) Durkan, J.A. (1991) A new diagnostic test for carpal tunnel syndrome. Journal of bone

and joint suregry Vol.73-A No:4 April10.) Palmer, A.K. Toivonen, D.A. (1999) Complications of Endoscopic and Open Carpal

Tunnel Release. The journal of hand surgery Vol. 24A No.3

Any Questions???