Carpal Tunnel Syndrome (CTS)

Summary

• Carpal Tunnel Syndrome (CTS) is a common acquired compressive neuropathy of the median nerve.
• Symptoms include numbness and tingling in the median nerve distribution of the hand.
• Diagnosis involves clinical evaluation, including night pain, hand weakness, numbness, and positive provocative tests or EMG/NCS studies.
• Treatment is mostly conservative with night splints and corticosteroid injections; surgery is for refractory cases.

Epidemiology

• Incidence: Affects 0.1-10% of the population, with up to 70% having bilateral CTS.
• Demographics:
  • Age: 40-60 years old
  • Gender: Female to Male ratio of 3:1
• Location: Carpal tunnel at the wrist
• Risk factors:
  • Female sex, obesity, pregnancy, hypothyroidism, rheumatoid arthritis
  • Trauma, repetitive motion activities, acromegaly, age, menopause
  • Chronic renal failure, space-occupying lesions, oral contraceptives, heart failure, diabetes, smoking, alcoholism, mucopolysaccharidosis

Etiology

• Pathophysiology: Increased pressure on the median nerve affects blood supply.
  • Normal pressure: 2.5mmHg at rest to 30mmHg with wrist flexion.
  • 20mmHg impedes venous flow, edema occurs; 60-80mmHg disrupts arteriolar flow.
• Mechanism: Repetitive vibratory exposure, certain sports (cycling, tennis), trauma.
• Pathoanatomy: Most common causes include inflamed synovium, repetitive motions, space occupying lesions.
• Associated conditions: Diabetes mellitus, hypothyroidism, rheumatoid arthritis, pregnancy, amyloidosis.

Anatomy

• Carpal Tunnel Borders:
  • Radially: Scaphoid tubercle and trapezium
  • Ulnarly: Hook of hamate and pisiform
  • Palmarly: Transverse carpal ligament
  • Dorsally: Proximal carpal row
• Contents: Median nerve, tendons of FDS, FDP, and FPL.
• Median Nerve:
  • Branches: AIN, Palmar cutaneous branch, recurrent motor branch.

Presentation

• History: Hand overuse, particularly with vibrating equipment or computer use.
• Symptoms:
  • Numbness and tingling in radial 3-1/2 digits
  • Clumsiness, pain, nocturnal paresthesias
• Physical Exam:
  • Inspection: Thenar atrophy
  • Provocative Tests: Durkan's test (most sensitive), Phalen test, Tinel's test, Semmes-Weinstein test, innervation density test.

Imaging & Studies

• Imaging:
  • Radiographs, MRI, CT not routinely indicated unless for space-occupying lesion.
  • Ultrasound can detect increased cross-sectional area of the median nerve.
• EMG and NCV: Provides evidence of compressive neuropathy.
• Diagnostic Criteria: Based on clinical symptoms and tests.

Treatment

• Nonoperative:
  • NSAIDS, night splints, activity modifications, steroid injections.
  • Indicated as first-line treatment.
• Operative:
  • Carpal tunnel release for nonresponsive cases or acute CTS.
  • Techniques: Open, endoscopic, ultrasound-guided percutaneous.
  • Outcomes: Pinch strength returns in 6 weeks, grip strength by 12 weeks.
  • Revision surgery for incomplete release.

Complications

• Common Complications: Scar tenderness, pillar pain, recurrence, nerve injuries.
• Prognosis: Positive indicators include relief with steroid injections and small incision surgeries.

Prognosis

• Generally good prognosis with appropriate treatment; surgery improves outcomes over conservative treatment.

Note: Information synthesized from Orthobullets' content on Carpal Tunnel Syndrome.