Carpal Tunnel Syndrome

January 15, 2021 | By : OrthoFixar | Hand Surgery
| Last updated on May 7, 2021


What is the 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.
  • It occurs most often in patients 30 to 60 years old, and is more common in women than in men

Anatomy of the carpal tunnel:

  • 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
Carpal Tunnel Syndrome causes

Symptoms of Carpal Tunnel Syndrome:

  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:
    • Macrodactyly
    • Lysosomal storage diseases
    • 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 nonoperative treatment: 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.
      • When none of these factors was present, two-thirds of patients were cured by medical therapy.

Operative Treatment:

Operative Treatment is indicated if nonoperative treatment is failed or in sever cases.

  • Carpal Tunnel 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.
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