Carpal Tunnel Syndrome

1
Carpal Tunnel Syndrome

• Daniel Robbins

2
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.
3
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).
4
Tests for symptoms
A common test for nerve entrapment is Tinels
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.
5
Tests for symptoms

• Durkans 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.

6
Tests for symptoms

• Phalens 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.

7
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.

8
How Does this Affect the nerve?
9
Nerves as a Pressure Vessel (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.
10
Implications 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

11
Vascular 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).

12
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.

13
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.

14
Other options(1,2)

• 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.

15
Carpal Tunnel Release 1
Open 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).
16
Carpal 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.

17
Outcome

• 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.

18
Splints
19
Possible post surgery problems

• General
• PO palmer discomfort
• Scar tenderness
• Weakness
• Taken from (6)

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).
Taken from (10)
20
Refs/Further Reading

• 1.)http//www.aurorahealthcare.org/yourhealth/heal
  thgate/getcontent.asp?URLhealthgate2214786.html
  22
• 2.)http//hcd2.bupa.co.uk/fact_sheets/html/carpal_
  tunnel.html
• 3.) Bland,J. (2007) Carpal tunnel syndrome. BMJ
  August 2007
• 4.) 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
  24 299-304
• 6.) 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) Tinels sign and Phalens
  maneuver Physical signs of carpal tunnel
  syndrome. Hospital physician July 2000
• 9.) Durkan, J.A. (1991) A new diagnostic test for
  carpal tunnel syndrome. Journal of bone and joint
  suregry Vol.73-A No4 April
• 10.) Palmer, A.K. Toivonen, D.A. (1999)
  Complications of Endoscopic and Open Carpal
  Tunnel Release. The journal of hand surgery Vol.
  24A No.3

21
Any Questions???