Carpal

• Most common entrapment neuropathy (90% of all cases) [1]

• The prevalence and yearly incidence of CTS may change according to several occupational and nonoccupational factors.

• CTS is caused by compression of the median nerve in the carpal tunnel, under the transverse carpal ligament. [2]

  Risk factors [2][3][4]

  • Previous fracture of the wrist

  • Traumatic dislocation of the lunate [5]

  • Manual work: increased risk in workers using vibrating tools or prolonged, forceful, and repetitive flexion/extension of the wrist [6]

  • Rheumatoid arthritis and other types of chronic inflammation of the tendon sheaths [3]

  • Pregnancy and puerperium [7]

  • Obesity

  • Osteoarthritis

  • Systemic amyloidosis

  • Renal failure and dialysis-associated deposition of amyloid [4][8]

  • Diabetes mellitus

  • Hypothyroidism [9]

  • Acromegaly

• The carpal tunnel is a narrow fibro-osseous structure at the level of the palmar aspect of the wrist, delimited by the carpal bones and the transverse carpal ligament, which contains flexor tendons and the median nerve.

• Pressure increase within the carpal tunnel → compression of contained structures → impaired blood flow and altered microvascular structure of the median nerve → inflammatory reaction → edema and hypoxia → axonal degeneration

• Develop in the areas innervated by the median nerve: palmar surface of the thumb, index, and middle fingers, and radial half of the ring finger.

  • Paresthesia: burning sensation, tingling

  • Loss of sensation/numbness

  • Pain

• Typically worsen at night

• Patients often report that symptoms improve by shaking the hand (flick sign). [12]

• Severely affected patients may report:

  • Dropping objects and difficulty with fine motor skills (e.g., buttoning up clothing) secondary to weakened finger pinch and grip strength

  • Disappearance of pain

• Mild disease: Initial examination is often normal; symptoms only develop with provocative tests for CTS.

• Severe disease: Findings of both sensory and motor deficits may be seen.

• Examination of the sensory system

  • May show decreased sensation in the area innervated by the median nerve distal to the carpal tunnel

  • Usually, there is no loss of sensation of the palmar surface of the thenar eminence because it is innervated by the superficial branch of the median nerve, which arises 5–7 cm proximal to the carpal tunnel and is, therefore, not compressed.

• Examination of the motor system: may show weakness in thumb abduction and opposition as well as thenar atrophy

Sensory innervation of the thenar eminence is not affected in CTS.

The "pope's blessing" (inability to flex the first three digits when making a fist) is not a symptom of CTS. It is only seen in proximal lesions of the median nerve

• Usually a clinical diagnosis, based on classic clinical features of CTS combined with positive provocative tests for CTS [2]

• Consider additional testing (e.g., electrodiagnostic studies) in:

  • Diagnostic uncertainty

  • Severe cases (e.g., those that may require surgical intervention)

• Overview

  • Considered positive when sensory symptoms (e.g., pain, paresthesias) are elicited along the distribution of the median nerve distal to the carpal tunnel [12]

  • Usually performed in combination as use of a single provocative test has low sensitivity and specificity [2][12]

• Commonly used provocation tests

  • Phalen test: The patient's wrist is held in full flexion (90°) for one minute. [13]

  • Tinel sign: The examiner percusses or taps with the fingertips over the carpal tunnel.

  • Hand elevation test: The patient holds both hands above their head for one minute.

  • Carpal compression test: The examiner uses a finger to apply moderate pressure directly over the carpal tunnel for 30 seconds.

• Indications

  • Diagnostic uncertainty or atypical presentation

  • To rule out alternative diagnoses (e.g., polyneuropathy, radiculopathy)

  • Presurgical evaluation

• Modalities

  • Nerve conduction studies (confirmatory test): show impaired median nerve conduction along the carpal tunnel

    • Prolonged sensory and distal motor latency

    • May be normal in patients with mild disease

  • Electromyogram

    • Usually ordered to rule out alternative diagnoses

    • May show abnormal spontaneous activity (e.g., fibrillation potentials) or altered action potential morphology

Electrodiagnostic studies are not necessary to confirm a clinical diagnosis of CTS but should be ordered when the diagnosis is uncertain and for patients scheduled to have surgery.

• Carpometacarpal arthritis of the thumb

• Arthritis of the wrist

• Cervical radiculopathy (C6)

• De Quervain tendinopathy

• Peripheral neuropathy

• Pronator syndrome

• Raynaud phenomenon

• Ulnar neuropathy

• Vibration white finger

• Mild to moderate disease

  • Trial immobilization or glucocorticoid injection.

  • No response after 6 weeks

    • Assess for adherence.

    • Trial alternate conservative methods.

• Severe or refractory disease: Refer to a hand specialist for possible surgery.

• Treatment of underlying comorbidities

• Immobilization: splinting of the wrist in a neutral position.

• Glucocorticoids

  • First-line: steroid injection, e.g., methylprednisolone

  • Alternative: oral glucocorticoids, e.g., prednisone

• Physical therapy and exercise: e.g., nerve glide exercises, therapeutic ultrasound, and carpal bone mobilization

Oral analgesia (e.g., NSAIDs, gabapentin) is not effective in managing CTS

• Indications: severe disease or refractory symptoms

• Method

  • Open or endoscopic release of the transverse carpal ligament

  • The transverse carpal ligament is divided to increase space for the median nerve in the carpal tunnel.