Carpal Tunnel Syndrome

Carpal Tunnel Syndrome is the most common upper extremity compression neuropathy that results from median nerve compression within the carpal tunnel. It was first described by Paget in 1854.

The carpal tunnel syndrome occupational disease occurs most often in patients 30 to 60 years old, and is more common in women than in men.

Carpal Tunnel Anatomy

The carpal tunnel is bound by the carpal bones arching dorsally. The hook of the hamate and the pisiform medially; and the scaphoid tubercle and trapezial ridge laterally.

The palmar aspect, or “roof,” of the carpal tunnel is formed by the flexor retinaculum, consisting of:

• The deep forearm fascia proximally
• The transverse carpal ligament over the wrist.
• The aponeurosis between the thenar and hypothenar muscles distally.

The most palmar structure in the carpal tunnel is the median nerve.

Lying dorsal (deep) to the median nerve in the carpal tunnel are the nine flexor tendons of the finger and the flexor policies longus tendon FPL.

See Also: Tarsal Tunnel Syndrome

Risk Factors:

Risk factors for Carpal Tunnel Syndrome include:

1. Female sex
2. Obesity
3. Cigarette smoking
4. Vibrations associated with job tasks.
5. Physically inactive individuals.

Carpal Tunnel Syndrome Causes:

Decrease in Size of Carpal Tunnel	■ Bony abnormalities of the carpal bones ■ Acromegaly ■ Flexion or extension of wrist
Increase in Contents of Canal	■ Forearm and wrist fractures (Colles fracture, scaphoid fracture) ■ Dislocations and subluxations (scaphoid rotary subluxation, lunate volar dislocation) ■ Posttraumatic arthritis (osteophytes) ■ Musculotendinous variants ■ Aberrant muscles (lumbrical, palmaris longus, palmaris profundus) ■ Local tumors (neuroma, lipoma, multiple myeloma, ganglion cysts) ■ Persistent medial artery (thrombosed or patent) ■ Hypertrophic synovium ■ Hematoma (hemophilia, anticoagulation therapy, trauma)
Neuropathic Conditions	■ Diabetes mellitus ■ Alcoholism ■ Double-crush syndrome ■ Exposure to industrial solvents
Inflammatory Conditions	■ Rheumatoid arthritis ■ Gout ■ Nonspecific tenosynovitis ■ Infection
Alterations of Fluid Balance	■ Pregnancy ■ Menopause ■ Eclampsia ■ Thyroid disorders (especially hypothyroidism) ■ Renal failure ■ Long-term hemodialysis ■ Raynaud disease ■ Obesity ■ Lupus erythematosus ■ Scleroderma ■ Amyloidosis ■ Paget disease
External Forces	■ Vibration ■ Direct pressure

Clinical Evaluation

1. Tingling and numbness in the typical median nerve distribution (thumb, index, long, and radial side of ring).
2. Pain: aching, or throbbing, occurs diffusely in the hand and may radiate up the forearm.
3. Thenar muscle atrophy usually is seen in late-stage nerve compression.

Physical Examination:

• Tinel sign
• Phalen test
• Durkan test
• Application of a blood pressure cuff on the upper arm sufficient to produce venous distention may initiate the symptoms (not recommended because of its insensitivity and nonspecificity).

See Also: Wrist and Hand Special Tests

Studies:

Electrodiagnostic studies including Nerve Conduction Velocities (NCV) and Electromyography (EMG) are reliable confirmatory tests.

Carpal Tunnel Syndrome in Children:

Carpal tunnel syndrome in children is unusual. Predisposing factors may include:

1. Macrodactyly
2. Lysosomal storage diseases
3. A strong family history of carpal tunnel syndrome

Symptoms in children may be confusing and include decreased dexterity and diffuse pain.

Findings such as thenar muscle atrophy and weakness suggest that the condition is severe by the time of presentation.

The Phalen test and Tinel sign may be absent if the nerve compression has been present for a long time.

Carpal Tunnel Syndrome Treatment:

Nonoperative Treatment:

Nonoperative Treatment of Carpal Tunnel Syndrome is indicated as a first line of treatment and for mild cases.

1. NSAIDS, night splints, activity modifications.
2. Steroid injections: Second line of treatment. Care should be taken not to inject directly into the nerve. It maybe used as diagnostic study.

Kaplan, Glickel, and Eaton identify 5 risk factors to fail of non-operative CTS therapy: ¹

1. Age older than 50 years.
2. Duration of the disease is longer than 10 months.
3. Constant paresthesia.
4. Stenosing flexor tenosynovitis.
5. A positive Phalen test result in less than 30 seconds.
6. When none of these factors was present, two-thirds of patients were cured by medical therapy.

Operative Treatment:

Carpal tunnel syndrome surgery is indicated if nonoperative treatment is failed or in sever cases.

Carpal Tunnel Surgery Release:

• If signs and symptoms are persistent and progressive, especially if they include thenar atrophy.
• When median nerve palsy develops after a radial fracture and has not improved after positional change.

Carpal Tunnel Syndrome Severity Score

The following questions refer to your symptoms for a typical 24-hour period during the past 2 weeks:

How severe is the hand or wrist pain you have at night?

1. No pain
2. Mild pain
3. Moderate pain
4. Severe pain
5. Very severe pain

How often did hand or wrist pain wake you up during a typical night in the past 2 weeks?

1. Never
2. 1 time
3. 2–3 times
4. 4–5 times
5. More than 5 times

Do you typically have pain in your hand or wrist during the daytime?

1. No pain
2. Mild pain
3. Moderate pain
4. Severe pain
5. Very severe pain

How often do you have hand or wrist pain during the daytime?

1. Never
2. 1 time
3. 2–3 times
4. 4–5 times
5. More than 5 times

How long, on average, does an episode of pain last during the daytime?

1. Never have pain
2. Less than 10 minutes
3. 10–60 minutes
4. More than 60 minutes
5. Constantly

Do you have numbness (loss of sensation) in your hand?

1. No numbness
2. Mild numbness
3. Moderate numbness
4. Severe numbness
5. Very severe numbness

Do you have weakness in your hand or wrist?

1. No weakness
2. Mild weakness
3. Moderate weakness
4. Severe weakness
5. Very severe weakness

Do you have tingling sensation in your hand?

1. No tingling
2. Mild tingling
3. Moderate tingling
4. Severe tingling
5. Very severe tingling

How severe is the numbness or tingling at night?

1. No numbness/tingling
2. Mild numbness/tingling
3. Moderate numbness/ tingling
4. Severe numbness/tingling
5. Very severe numbness/ tingling

How often did hand numbness or tingling wake you up during a typical night in the past 2 weeks?

1. Never
2. 1 time
3. 2–3 times
4. 4–5 times
5. More than 5 times

Do you have difficulty with the grasping & use of small objects, such as keys or pencils?

1. No difficulty
2. Mild difficulty
3. Moderate difficulty
4. Severe difficulty
5. Very severe difficulty

Scoring: Summate the scores and divide by 11. The higher the mean score, the more severe the impairment.

References

1. Campbel’s Operative Orthopaedics 12th edition Book.
2. Millers Review of Orthopaedics -7th Edition Book.
3. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
4. Levine DW, Simmons BP, Koris MJ, Daltroy LH, Hohl GG, Fossel AH, Katz JN. A self-administered questionnaire for the assessment of severity of symptoms and functional status in carpal tunnel syndrome. J Bone Joint Surg Am. 1993 Nov;75(11):1585-92. doi: 10.2106/00004623-199311000-00002. PMID: 8245050.