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A. Introduction

  1. Carpal Tunnel Anatomy
    1. Ventral aspect border is inelastic transverse carpal ligament
    2. Dorsal aspect by carpal bones (pisiform, triquetral, lunate, scaphoid, trapezium)
    3. Ten components in tunnel: 8 tendons, flexor pollicis longus and median nerve
  2. CTS is due to compression of the median nerve [2]
  3. CTS is then most common peripheral entrapment neuropathy [3]
  4. Epidemiology
    1. About 15% of general adult population have symptoms
    2. On clinical exam, prevalence is ~4% of general population
    3. Thus, of symptomatic persons, ~25% have clinical signs of CTS
    4. Electrophysiology (nerve conduction studies, NCS) used to confirm diagnosis
    5. Prevalence of NCS confirmed CTS is ~3% among women, ~2% among men
    6. However, NCS median nerve abnormalities occur in 18% of asymptomatic persons
    7. Both clinical and NCS evidence of CTS present in ~20% of sympatomic persons
  5. Considered one of the repetitive strain injuries [4]
    1. CTS has possible association with occupational / vibrational exposures
    2. Other repetitive strain juries include:
    3. cubital tunnel syndrome
    4. Guyon canal syndrome
    5. Lateral epicondylitis
    6. Tendinitis of the wrist or hand
  6. Appears not to be associated with computer use [5]
  7. About 1/3 of cases are associated with underlying, undiagnosed, medical diseases

B. Symptoms

  1. Pain in distal arm or wrist
  2. Radiation to first three digits, exacerbated by wrist motions
  3. Nocturnal pain: ~95% of patients awaken in middle of night with hand pain and numbness
  4. More severe disease includes loss of grip strength
  5. When pain comes on, patient will try to flick their wrist for relief
  6. Underlying, clinically silent diseases are present in about 1/3 of patients
    1. Hypothyroidism
    2. Diabetes mellitus
    3. Inflammatory arthropathies
    4. A variety of other diseases are associated with CTS

C. Signs [2]

  1. Thenar wasting - late in course of disease
  2. Tinel's Sign
    1. Tapping over carpal tunnel causes pain, numbness, dysesthesias in median nn area
    2. 60% sensitivity, 67% specificity (based on EMG)
  3. Phalen's Test
    1. Flex wrist at 90° for 1 minute: positive test is pain and numbness in median nerve area
    2. 75% sensitivity, 47% specificity (based on EMG)
  4. In a review, thenar wasting, Phalen's and Tinel's signs are not helpful for CTS [6]
  5. Carpal Compression Test
    1. Press on carpal tunnel for 30 seconds
    2. Positive test means that symptoms typical of CTS occur with this compression
    3. Hyperalgesia specifically in median nerve distribution is a good test for CTS [6]
  6. Loss of Two Point Descrimination
    1. Inability to distinguish between one and two sharp points on fingertip
    2. Occurs late in course
  7. Katz hand diagram results with median nerve pain demonstrated is a good test for CTS [6]
  8. Physical exam has low predictive value in absence of clear symptoms and circumstances

D. Causes [7]

  1. Increased Canal Volume
    1. Fluid overload - heart failure, renal failure, low albumin, hypothyroidism, pregnancy
    2. Rheumatoid Tenosynovitis, Nonspecific Synovial Cell Proliferation
    3. Postinjury
    4. Acromegaly - due to increased median nerve edema, not extrinsic canal effects [8]
    5. Thrombosis of Median Artery
    6. Obesity may presdispose to CTS
  2. Abnormal Anatomy
  3. Mass Lesion
    1. Gouty Tophus
    2. Calcium deposition (especially in pseudogout)
    3. Amyloidosis, multiple myeloma, other dysglobulinemias
    4. Malignant and Benign (lipoma) Tumors
    5. Hematoma
  4. Sick Nerve with Minimal Compression
    1. Cervical Radiculopathy
    2. Thoracic Outlet Syndrome
    3. Proximal Median Neuropathy
  5. Consider reflex sympathetic dystrophy in atypical cases
  6. Patients should be evaluated for common underlying medical causes

E. Nerve Conduction Studies (NCS)

  1. NCS are the diagnostic modalities of choice
  2. CTS usually involves both large sensory and motor nerves
  3. Peripheral neuropathy must be ruled out by doing NCS on non-median nerves
  4. Ulnar nerve is often used as control
  5. Electromyography (EMG) may also be performed in some cases

F. Differential Diagnosis: Hand and Wrist Discomfort [1]

  1. CTS
  2. Ulnar Nerve Entrapment
  3. Cervical Radiculopathy
  4. Tendon Disorders
  5. Overuse of muscles
  6. Nonspecific Pain Syndromes
  7. Reflex Sympathetic Dystrophy (RSD)
  8. Other less common disorders

G. Nonsurgical Therapy

  1. Indications
    1. Symptoms for <1 year
    2. Absence of muscle weakness or atrophy
    3. Absence of denervation on NCS or electromyography (EMG)
  2. Physical Therapy
    1. Wrist brace to improve positioning
    2. Palmer wrist splints worn at night
    3. Unclear if modifying patient's activities is beneficial
    4. Activity modification for 2-6 weeks has been suggested
  3. Medications
    1. Nonsteroidal anti-inflammatory drugs (NSAIDs) - minimal value (trial for 2-6 weeks)
    2. Glucocorticoid (Steroid) Injections are the most effective of all treatments
    3. Glucocorticoid oral - prednisolone 20mg qd x 2 weeks then 10mg qd x 2 weeks [1]
    4. Diuretics have not been effective
    5. Pyridoxine (Vitamin B6) 50mg qd - tid no more effective than placebo
  4. Glucocorticoid Injections [2,9]
    1. 10-30mg of triamcinolone or + 0.5-1mL of 1-2% (10-20mg) lidocaine
    2. Alternatively, methylprednisolone 20-40mg DepoMedrol® instead of triamcinolone
    3. 22-25ga needle placed 1cm proximal to distal wrist flexion crease
    4. Position just ulnar to the palmaris longus tendon (middle of hand)
    5. Insert needle to 1-1.5cm at 45° angle facing distal
    6. Provides long term (>12 month) benefits in >50-70% of patients
  5. Conservative treatment may be preferred for mild nerve impairment
  6. Ultrasound therapy may be beneficial in longer term treatment (controversial)
  7. Surgery superior to splinting for patients with NCS/EMG confirmed CTS with pain [10]

H. Carpal Tunnel Release Surgery [10]

  1. Indicated for muscular atrophy or clear sensory (pinpoint descrimination) damage
  2. Superior to splinting for patients with objectively confirmed nerve damage
  3. Carpal tunnel release surgery leads to decompression of transverse carpal ligament
  4. Current open procedure requires 2-2.5cm incision
  5. Endoscopic techniques are being developed but increased risk of median nerve damage
  6. >70% of patients are completely or very satisfied with surgery
  7. ~80% are free of nocturnal pain after surgery
  8. 15-20% have failure to achieve satisfactory results

References

  1. Katz JN and Simons BP. 2002. NEJM. 346(23):1807 abstract
  2. Viera AJ. 2003. Am Fam Phys. 68(2):265 abstract
  3. Atroshi I, Gummesson C, Johnsson R, et al. 1999. JAMA. 282(2):153 abstract
  4. Van Tulder M, Malmivaara A, Koes B. 2007. Lancet. 369(9575):1815 abstract
  5. Andersen JH, Thomsen JF, Overgaard E, et al. 2003. JAMA. 289(22):2963 abstract
  6. D'Arcy CA and McGee S. 2000. JAMA. 283(23):3110 abstract
  7. Stevens JC, Beard CM, O'Fallon WM, Kurland LT. 1992. Mayo Clin Proc. 67(6):541 abstract
  8. Jenkins PJ, Sohaib SA, Akker S, et al. 2000. Ann Intern Med. 133(3):197 abstract
  9. Dammers JW, Veering MM, Vermeulen M. 1999. Brit Med J. 319:884 abstract
  10. Gerritsen AAM, de Vet HCW, Scholten RJPM, et al. 2002. JAMA. 288(10):1245 abstract