[11] Carpal Tunnel Syndrome

Question 1

What is carpal tunnel syndrome?

Answer 1

A collection of symptoms and signs caused by compression of the median nerve in the carpal tunnel

Question 2

What is the carpal tunnel?

Answer 2

An anatomical compartment at the base of the palm

Question 3

What forms the postero-lateral boundary of the carpal tunnel?

Answer 3

Scaphoid and trapezium

Question 4

What forms the postero-medial boundary of the carpal tunnel?

Answer 4

Hook of the hamate and the pisiform

Question 5

What forms the anterior boundary of the carpal tunnel?

Answer 5

The flexor retinaculum

Question 6

What is the contents of the carpal tunnel?

Answer 6

• 9 flexor tendons in synovial sheaths

- Median nerve

Question 7

What are the 9 flexor tendons in the carpal tunnel?

Answer 7

• 4 of flexor digitorum profundus
• 4 of flexor digitorum superficialis
• Flexor pollicis longus

Question 8

What happens to the median nerve before entering the carpal tunnel?

Answer 8

It gives of the palmar cutaneous branch

Question 9

What is the role of the palmar cutaneous branch of the median nerve?

Answer 9

It provides sensation to the lateral palm of the hand

Question 10

What is true of the palmar cutaneous branch in carpal tunnel syndrome?

Answer 10

It does not travel through the carpal tunnel and so there is often sparing of the lateral palm in carpal tunnel syndrome

Question 11

Once it has passed through the carpal tunnel what branches are given off by the median nerve?

Answer 11

• Recurrent motor branch

- Palmar digital nerves

Question 12

What is the role of the recurrent motor branch of the median nerve?

Answer 12

Supplies the thenar muscle group

Question 13

What is the role of the palmar digital nerve of the median nerve?

Answer 13

• Sensory innervation to the palmar skin and dorsal nail beds of the lateral 3and 1/2 digits
• Motor innervation of the lateral 2 lumbricals

Question 14

What can lead to compression of the median nerve within the carpal tunnel?

Answer 14

• Decrease in size of the tunnel
• Increase in size of the contents
• Both

Question 15

Why does increased tunnel pressure lead to compression of the median nerve?

Answer 15

The boundaries of the carpal tunnel are rigid

Question 16

What are the risk factors for carpal tunnel syndrome?

Answer 16

• Obesity
• Repetitive wrist work
• Pregnancy
• Genetics
• Rheumatoid arthritis

Question 17

What repetitive wrist work can lead to increased risk of carpal tunnel syndrome?

Answer 17

• Computer work
• Work with vibrating tools
• Work that requires a strong grip

Question 18

Wha tis carpal tunnel syndrome characterised by?

Answer 18

Tingling, numbness or pain in the distribution of the affected median nerve branches

Question 19

What are the areas affected by carpal tunnel syndrome?

Answer 19

• Thumb
• Index and middles fingers
• Medial half of the ring finger on the palmar aspect

Question 20

When is carpal tunnel syndrome pain often worse?

Answer 20

At night

Question 21

How can symptoms of carpal tunnel syndrome develop?

Answer 21

They can become more persistent and radiate to the forearm, elbow, arm and shoulder

Question 22

What clinical sign may be present in later carpal tunnel syndrome?

Answer 22

Wasting of the thenar muscles

Question 23

How can carpal tunnel syndrome be clinically identified?

Answer 23

• Positive Phalen’s test
• Positive Tinel’s sign
• Positive carpal tunnel compression test

Question 24

What is a positive Phalen’s test?

Answer 24

Flexing the wrist for 60 seconds causes pain or paraesthesia in the median nerve distribution

Question 25

What is a positive Tinel's sign?

Answer 25

Tapping lightly over the median nerve at the wrist causes distal paraesthesia in the median nerve distribution

Question 26

What is a positive carpal tunnel compression test?

Answer 26

Pressure over the proximal edge of the carpal ligament (proximal wrist crease) causes paraesthesia to develop or increase in median nerve distribution

Question 27

When are investigations for carpal tunnel syndrome needed?

Answer 27

When there is diagnostic doubt or before surgery

Question 28

What investigations can be used for carpal tunnel syndrome?

Answer 28

Electroneurography (ENG)

Question 29

What happens in ENG for carpal tunnel syndrome?

Answer 29

The median nerve is stimulated proximal to the carpal ligament and compound muscle action potential is picked up over the thenar eminence

Question 30

What are the differentials for carpal tunnel syndrome?

Answer 30

- Other median nerve compression - Cervical radiculopathy - Thoracic outlet syndrome - Tendonitis - Ulner neuropathy - MS

Question 31

Over what period may carpal tunnel syndrome spontaneously resolve?

Answer 31

6 months

Question 32

When is spontaneous resolution of carpal tunnel syndrome most likely?

Answer 32

- Under 30's - Unilateral - Short duration - In women who were precipitated by pregnancy

Question 33

What conservative management can be used for carpal tunnel syndrome?

Answer 33

- Minimise exacerbating activities | - Splinting

Question 34

When should referral be made for patients with carpal tunnel syndrome?

Answer 34

- Diagnosis is uncertain - Treatments have failed after 3 months - Severe, persisting symptoms, especially if thumb weakness

Question 35

What may treatment for carpal tunnel syndrome involve?

Answer 35

- Local corticosteroid injections - Surgical treatment - Physiotherapy

Question 36

What does surgical treatment for carpal tunnel syndrome involve?

Answer 36

Release of the nerve by cutting the transverse carpal ligament

Question 37

What are the disadvantages of surgical treatment of carpal tunnel syndrome?

Answer 37

- Surgery related pain - Hand weakness - Complications of surgery

Question 38

What physiotherapy techniques can be used in carpal tunnel syndrome?

Answer 38

- Stretching of the wrist to improve blood flow | - Exercises to improve strength and flexibility