carpal tunnel syndrome (CTS)

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carpal tunnel syndrome (CTS)

• Rachel M Schutz

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CTS Overview

• The most frequently encountered peripheral
  compressive neuropathy .
• Caused by compression of the median nerve at
  wrist.
• The median nerve enters the hand from the wrist
  by traveling through the narrow passage in
  between the transverse carpal ligament and carpal
  bones (carpal tunnel).

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The Median Nerve

• Formed by the medial (C5-C7) and lateral (C8-T1)
  cords of the brachial plexus.
• Runs through carpal tunnel along with 9
  extrasynovial flexor tendons.
• Travels superficial to other structures.

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The Median Nerve

• The median nerve provides motor and sensory
  stimulation in the hand.
• Sensory palm and the 1st, 2nd, 3rd, and radial ½
  of 4th fingers.
• Motor opponens pollicis, flexor pollicis brevis,
  abductor pollicis brevis, and two radial
  lumbrical muscles in the hand.

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CTS Symptomology

• Swelling in the tunnel can pinch the nerve and
  cause pain, numbness, tingling or weakness.
• Symptoms usually worse at night and can cause
  sleep disturbances.
• This may be related to the flexed-wrist sleeping
  position and/or fluid accumulating around the
  wrist and hand during sleep.
• CTS may be a temporary condition that resolves
  itself (acute) or can persist and be progressive
  (chronic).
• Chronic is more common.

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Progressive CTS

• As the disease progresses, patients may develop a
  burning sensation, cramping, and/or weakness of
  the hand.
• Loss of grip strength can lead to frequent
  dropping of objects from the hand.
• Occasionally, sharp shooting pains can be felt in
  the forearm or even up to the shoulder.
• Chronic carpal tunnel syndrome can also lead to
  wasting (atrophy) of the hand muscles,
  particularly those near the base of the thumb in
  the palm of the hand.

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Causes of CTS

• Local causes

• Regional causes

• Inflammation
• Tenosynovitis, histoplasma, fungal infection,
  hypertrophic synovium
• Trauma
• Colles fracture, dislocation of one of the
  carpal bones
• Tumors
• Haemangioma, cyst, ganglion, lipoma, neuroma
• Anatomical anomalies
• Thickened transverse carpal ligament, bony
  abnormalities, abnormal muscle bellies,
  persistent median artery

• Osteoarthritis
• Rheumatoid arthritis
• Amyloidosis
• Gout

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Causes of CTS Cont.

• Systemic causes

• Diabetes
• Obesity
• Hypothyroidism
• Pregnancy
• Menopause
• Systemic lupus erythematosus
• Scleroderma
• Dermatomyositis

• Renal failure
• Long-term haemodialysis
• Acromegaly
• Multiple myeloma
• Sarcoidosis
• Leukemia
• Alcoholism
• Haemophilia

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Demographics

• http//www.nlm.nih.gov/medlineplus/carpaltunnelsyn
  drome.htmlcat59

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Diagnosis of CTS

• To exclude other conditions that may mimic carpal
  tunnel syndrome examination of the neck,
  shoulder, elbow by pulses, and reflexes may be
  performed.
• The wrist can be examined for swelling, warmth,
  tenderness, deformity, and discoloration.

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Diagnosis of CTS Cont.

• Tinel's sign of carpal tunnel syndrome.
• Tapping the front of the wrist can reproduce
  tingling of the hand.
• Phalen's maneuver.
• Symptoms reproduced by bending the wrist forward.
  
• Median nerve compression test.
• Squeezing down on the wrist just before it enters
  the palm may reproduce the symptoms.
• A nerve conduction study (NCS) is a test to
  evaluate the function, especially the ability of
  electrical conduction, of the motor and sensory
  nerves of the median nerve.
• Nerve conduction velocity used to mean the actual
  test.

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Nerve Conduction Velocity EMG

• Nerve conduction velocity tests (NCV) are often
  used along with an EMG to differentiate a nerve
  disorder from a muscle disorder.
• NCV detects a problem with the nerve whereas an
  EMG detects whether the muscle is functioning
  properly in response to the nerve's stimulus.
• Both procedures help to detect the presence,
  location, and extent of diseases that damage the
  nerves and muscles.

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Nerve Conduction Velocity Test

• Nerve Conduction Velocity test
• Application of sticky electrodes are placed over
  the muscles and nerves that are being tested. The
  nerve is electrically stimulated by a low
  intensity electric current of the first electrode
  (farthest up arm), thus generating nerve
  impulses while a second electrode detects the
  electrical impulse from the first.
• The resulting electrical activity is recorded by
  other electrodes. The distance between electrodes
  and the time it takes to travel between
  electrodes are used to calculate the speed of the
  impulses and is reported out as milliseconds.

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NCV Cont.

• Used to distinguish between true nerve disorders
  and conditions where muscles are affected by
  nerve injury.
• Differentiates between disorders of lower motor
  neurons, peripheral nerves, neuromuscular
  transmission, and muscle
• This test is used to diagnose nerve
• damage or dysfunction and confirm
• a particular diagnosis.

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NCV Cont.

• Decreased speed of transmission indicates nerve
  disease or dysfunction.
• Abnormal results (slowed velocity) may be caused
  by some sort of neuropathy resutling from a
  contusion or traumatic injury to a nerve. Various
  diseases can also cause the impulses to slow
  down.
• The velocity (or speed) of the propagated nerve
  impulse is directly related to the diameter of
  the nerve fiber and the presence of a myelin
  sheath.
• The fastest nerve fibers have large diameters
  are myelinated.
• Motor nerve fibers that supply skeletal muscles
  .
• The slowest nerve fibers have small diameters
  are unmyelinated.
• Sensory nerve fiber from the stomach.

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Electromyography (EMG)

• An electromyography (EMG) is a test that is used
  to record the electrical activity of muscles.
• This test helps to exclude other conditions that
  have similar abnormal muscle electrical impulses,
  as it will check for evidence of disorders of
  neuromuscular transmission or demyelination.
• Fibrillations, positive waves, fasciculations,
  and sometimes giant motor units, even in
  unaffected limbs.
• Muscular dystrophy, pinched nerves, ALS (i.e. Lou
  Gehrigs disease), disc herniation, diabetic
  neuropathy and others.

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Treatment

• Several levels of treatment
• Rest affected hand
• Splints
• Night splint keep wrist in neutral position
• Pain and anti-inflammatory medications
• Surgery
• Carpal Tunnel Release
• Endoscopic
• http//www.csa.com/discoveryguides/archives/carpal
  .php
• http//www.nlm.nih.gov/medlineplus/carpaltunnelsyn
  drome.htmlcat59

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Carpal Tunnel Release

• In carpal tunnel release surgery, the transverse
  carpal ligament is cut. This releases pressure on
  the median nerve, relieving carpal tunnel
  syndrome symptoms.

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Endoscopic Surgery

• Endoscopic surgery uses a thin, flexible tube
  with a camera attached (endoscope). The endoscope
  is guided through a small incision in the wrist
  (single-portal technique) or at the wrist and
  palm (two-portal technique). The endoscope lets
  the doctor see structures in the wrist without
  opening the entire area with a large incision.
• The cutting tools used are very tiny and are also
  inserted through the small incisions in the wrist
  or wrist and palm. In the single-portal
  technique, 1 small tube contains both
• the camera and cutting tool.
• The transverse carpal ligament is cut.
• This releases pressure on the median
• nerve, relieving CTS symptoms.

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Economic Effects

• CTS is the fastest growing occupational illness
  in the US.
• Musculoskeletal impairments are the most common
  causes for occupational disability and loss of
  work.
• In overall workers compensation 1 of every 3
  spent is in CTS settlements.
• 3,500-35,000 per settlement case
• 80 billion lost productivity annually
• http//www.lni.wa.gov/Safety/Research/OccHealth/Re
  ports/CtsBurden/default.asp