Carpal Tunnel Syndrome

Aka: Carpal Tunnel Syndrome, Median Neuropathy, Carpal Tunnel

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II. Epidemiology

  1. Most common Entrapment Neuropathy of the arm
    1. Prevalence: 3% of U.S. general population
    2. Incidence: 3.8 per 1000 person-years (increasing with age)
  2. Women outnumber men affected by 3 fold
  3. Bilateral in 50% of cases
  4. Associated with workplace repetitive hand activities
  5. Hand Paresthesias occur in 30% of computer users
    1. Only 10% of these meet criteria for Carpal Tunnel
    2. Only 3.5% of these have abnormal EMGs
    3. Stevens (2001) Neurology 56:1568-70 [PubMed]

III. Pathophysiology

  1. Compression of Median Nerve
    1. Occurs between transverse carpal ligament and underlying Carpal Bones
    2. Median Nerve adjacent to 9 flexor tendons whose synovial lining may become inflamed and enlarged
  2. Sensory deficits predominate
    1. Motor Nerves are much less susceptible than Sensory Nerves to compression

IV. Risk Factors: General

  1. Repetitive motion of hand and wrist
    1. Most common cause, and typically work related
    2. More common if significant force applied or hand-operated vibratory tool
  2. Local wrist or Hand Trauma
  3. Many predisposing conditions (see below)

V. Risk Factors: Predisposing Medical Conditions

  1. Obesity
  2. Hypothyroidism
  3. Diabetes Mellitus
  4. Acromegaly
  5. Rheumatoid Arthritis
  6. Gouty Arthritis
  7. Lyme Disease
  8. Amyloidosis
  9. Multiple Myeloma
  10. Double-Crush Syndrome
  11. Edematous condition
    1. Third trimester of Pregnancy
      1. Symptoms subside after delivery
    2. Congestive Heart Failure
    3. Renal Failure
  12. Aberrant or Anomalous Muscles in wrist
    1. Proximal lumbrical insertion
    2. Distal extension of flexor superficialis Muscle
    3. Persistent thrombosed median artery
    4. Abnormal palmaris longus tendon
    5. Ganglion Cyst
    6. Lipoma

VI. Symptoms

  1. Image: Median Nerve Sensory Innervation
    1. NeuroMedianNerve.jpg
  2. Pain and Paresthesias along Median Nerve course (palmar/volar surface)
    1. Electrical Sensation or Dysesthesias
    2. Radiation from the volar wrist into the thumb, index and middle finger
    3. Commonly involves only palmar/volar aspect of Index and Middle fingers
      1. May affect palmar aspect of all Median Nerve innervated 3.5 fingers (thumb to fourth finger)
  3. Radiation
    1. Proximal radiation into Forearm (may rarely radiate proximally into Shoulder and neck)
    2. May even present as Chest Pain (has resulted in ED Chest Pain cardiac work-ups)
    3. Radiation from the neck may occur with double crush injury (especially with bilateral involvement)
  4. Gradually increasing night pain (95% of patients)
    1. Increase in wrist swelling with inactivity
    2. Wrist flexion at night (may awaken patient)
  5. Numbness
    1. Describes "poor circulation" and "Stiffness"
    2. Despite which hand feels warm
  6. Weakness and Clumsiness of hand (severe cases)
    1. Decreased grip strength, with weak thumb abduction and opposition
  7. Timing
    1. Spontaneous onset
    2. Often interferes with sleep
  8. Provocative of Sensory and Motor Symptoms
    1. Repetitive wrist flexion or hand elevation
    2. Precipitated by Typing, holding phone, driving, painting, and wrist motion
  9. Palliative
    1. Shaking or moving hand
    2. Allow hand to hang down
    3. Flick Sign
      1. Flicking wrist as if shaking down Thermometer (often after night-time awakening)
      2. Test Sensitivity 93%, Test Specificity 96%

VII. Signs

  1. Precautions
    1. In addition to wrist and Hand Exam, also examine elbow, Shoulder and neck for referred pain source
  2. Observation
    1. Square-shaped wrist (depth dimensions approaches wrist width, esp in Obesity, OR 4.56)
      1. Shiri (2015) Muscle Nerve 52(5): 709-13 [PubMed]
  3. Modifying factors
    1. Pain not worse with resisted motion
    2. Flick Test (see above)
    3. Carpal Compression Test (64-90% sensitive, 83-90% specific)
      1. Direct pressure applied over the transverse carpal ligament for 30 seconds
      2. Positive for sensory symptoms within first 30 seconds
    4. Classic exam findings have individual poor predictive value (but combined 80% sensitivity, 92% Specificity)
      1. Tinel's Sign (44-70% sensitive, 94% specific, LR+ 1.3)
      2. Phalen's Maneuver (70-80% sensitive, 80% specific, LR+ 1.4)
    5. Hand elevation test
      1. Hands raised overhead for one minute
      2. Positive test if Median Neuropathy symptoms are reproduced in the first minute
      3. Differentiate from Thoracic Outlet Syndrome provoked with overhead arm (Elevated Arm Stress Test or EAST Test)
      4. Ahn (2001) Ann Plast Surg 46(2): 120-4 [PubMed]
    6. Tourniquet Test (not recommended as not sensitive and not specific)
      1. Inflate Blood Pressure Cuff on upper arm above systolic Blood Pressure
      2. Positive if Paresthesias and Numbness after inflation in first 60 seconds
  4. Sensory deficit over Median Nerve
    1. Sensory deficit predominates as Sensory Nerves are more susceptible to compression than Motor Nerves
    2. Hyperalgesia in classic Median Nerve distribution has high Likelihood Ratio
      1. Patient draws areas of pain or numbness on hand diagram
    3. Loss of Two Point Discrimination <=5 mm with caliper (33% Sensitive, 100% Specific)
    4. Resolution of pain with persistent numbness suggests permanent sensory loss
    5. DIP joint Sensation of the index and middle finger (anterior interosseous nerve) is often spared in Carpal Tunnel
  5. Motor deficits (late finding in severe Median Neuropathy)
    1. Weak thumb abduction and weakness
      1. Weak on grasping items, opening jars, buttoning clothing
    2. Thenar Muscle atrophy
      1. Associated with decreased grip strength
      2. Only present in severe, long-standing disease
      3. Other hand and wrist neuropathies will cause this as well
    3. Abductor pollicis brevis weakness
      1. Abduct thumb perpendicular to palm against examiner's resistance
  6. Findings suggestive of alternative diagnosis
    1. Findings of Cervical Radiculopathy
    2. Wrist and hand with reduced range of motion (ROM should be unaffected in Carpal Tunnel)
    3. Thenar eminence with reduced Sensation
      1. Innervated by Median Nerve's palmar cutaneous branch (origin is proximal to Median Nerve)
      2. Suggests a Median Nerve injury in the neck or proximal arm

VIII. Diagnosis

  1. Carpal Tunnel Syndrome Six Item Evaluation Tool (CTS-6 Evaluation Tool)
    1. Positive result (>=12, LR+ 4.5) is suffiicient evidence for diagnosis (without further diagnostics)
  2. Findings with highest predictive value
    1. Classic hand symptoms in median distribution
    2. Decreased Pain Sensation at index palmar surface
    3. Weak thumb abduction
    4. Thenar atrophy (99% Test Specificity)
  3. References
    1. D'Arcy (2000) JAMA 283:3110-7 [PubMed]

IX. Differential Diagnosis

  1. Tenosynovitis
    1. Flexor carpi radialis tenosynovitis
      1. Extends from proximal 1st Metacarpal to medial epicondyle
    2. De Quervain's Tenosynovitis
      1. Affects extensor pollicis brevis, abductor pollicis longus
  2. Other Neuropathy
    1. Cervical Radiculopathy (C6 nerve)
    2. Median Nerve compression at elbow (Pronator Syndrome)
    3. Ulnar Tunnel (or Cubital Tunnel)
    4. Peripheral Neuropathy (e.g. Diabetes Mellitus)
  3. Degenerative Joint Disease
    1. Wrist Osteoarthritis
    2. Thumb carpometacarpal Osteoarthritis
  4. Vascular conditions
    1. Raynaud Syndrome
    2. Vibration white finger (occurs with vibratory hand tools)

X. Imaging

  1. Ultrasound
    1. See Median Nerve Measurement on Ultrasound
    2. Not needed for Carpal Tunnel diagnosis if CTS-6 Evaluation Tool is positive
    3. Highest efficacy when wrist Median Nerve cross sectional area is compared with Forearm measurement
    4. Noninvasive, painless test with high efficacy (for experienced operators) and evaluates other wrist structures
  2. Wrist XRay (only if indicated)
    1. Consider Wrist XRay if bone or joint disorders are suspected
    2. Evaluate for local bony abnormality
  3. Other diagnostic studies (CT, MRI)
    1. Not typically indicated
    2. May consider Cervical Spine MRI if double crush injury is suspected (or suggested by Nerve Conduction Study)

XI. Diagnostics

  1. Nerve Conduction Studies (Electromyography, EMG)
    1. Not needed for Carpal Tunnel diagnosis if CTS-6 Evaluation Tool is positive
    2. Indicated in severe Carpal Tunnel, unclear cases or in pre-surgical assessment of severity
    3. Delayed electrical conduction across wrist at the Median Nerve
    4. Axonal loss or Muscle denervation is an indication for surgery
    5. Efficacy: 56-85% sensitive, 94-99% specific
    6. Normal in up to one third of patients with mild Carpal Tunnel

XII. Grading: Severity

  1. Mild Carpal Tunnel
    1. Intermittent, occassional symptoms of pain and Paresthesias
  2. Moderate Carpal Tunnel
    1. Awakens with Carpal Tunnel pain frequently at night
    2. Activity provokes symptoms, but does not impair function
    3. No neurologic deficits on exam (motor or sensory)
  3. Severe Carpal Tunnel
    1. Thenar atrophy
    2. Weak thumb abduction or opposition
    3. Persistent sensory loss

XIII. Management: General Conservative Measures

  1. Precautions
    1. Severe Carpal Tunnel symptoms should prompt early EMG
    2. Early referral to surgery if EMG positive for axonal loss or Muscle denervation
  2. Efficacy
    1. Spontaneous resolution in non-severe CTS with Placebo, within 2 years: 50%
      1. Goodyear-Smith (2004) Ann Fam Med 2:267-73 [PubMed]
    2. Short-term: 80% respond
    3. Long-term: 80% of responders recur after one year
  3. Eliminate cause and modify work conditions
    1. Avoid repetitive Trauma (esp. high force, and with repeated hand gripping or pinching)
    2. Avoid the extremes of wrist flexion or extension
    3. Avoid vibratory tool use
    4. Employ ergonomics (wrist rest, adjust chair/desk, voice recognition software)
  4. Wrist Splint or Wrist brace (neutral position)
    1. Polypropylene occupational Wrist Splint
    2. Maintains wrist in neutral position
      1. Do NOT use a hyperextension (dorsiflexion) brace which may exacerbate symptoms
      2. Modify the cock-up (hyperextension) brace by straightening the aluminum bar inside the brace
    3. Most effective if started early (within 3 months)
    4. Use the splint for at least 1 to 2 months (up to 6 months) at nighttime
      1. Wearing splint only during the night appears as effective as continuous use (day and night)
        1. Walker (2000) Arch Phys Med Rehabil 81(4): 424-9 [PubMed]
      2. Original studies had best benefit when worn during both day and night (continuously)
        1. Burke (1994) Arch Phys Med Rehabil 75:1241-4 [PubMed]
        2. Sevim (2004) Neurol Sci 25:48-52 [PubMed]
  5. Wrist and Hand Exercises
    1. Brief (1 minute) Exercise performed intermittently (e.g. during or after work)
      1. May be taught by physical therapy, hand therapy or by online video
    2. Other Exercise and therapy interventions that may offer benefit
      1. Yoga may decrease pain and increase grip strength
        1. Garfinkel (1998) JAMA 280(18): 1601-3 [PubMed]
  6. Local or Systemic Corticosteroid
    1. Carpal Tunnel Steroid Injection (preferred)
      1. May repeat injection after 6 months
      2. Rare risk of Median Nerve injury, tendon rupture
      3. Improves symptoms and function for 3 to 6 months
        1. Less need for surgery (NNT 7) at one year
        2. Similar outcomes to night Splinting at 6 months (slightly better than Splinting at 6 weeks)
        3. Does not significantly reduce need for surgical intervention in the longterm (5 years)
        4. Ashworth (2023) Cochrane Database Syst Rev (2):CD015148 [PubMed]
        5. Chesterton (2018) Lancet 392(10156): 1423-33 [PubMed]
        6. Ly-Pen (2005) Arthritis Rheum 52:612-9 [PubMed]
    2. Consider Systemic Corticosteroids (NOT recommended)
      1. Less effective and more adverse effects than with local injection
      2. First: Prednisone 20 mg orally daily for 14 days
      3. Next: Prednisone 10 mg orally daily for 14 days
      4. Chang (1998) Neurology 51:390-3 [PubMed]
    3. Avoid ineffective injection strategies
      1. Platelet rich plasma injection is not effective
      2. Hydrodissection with prolotherapy is lacking evidence
  7. Analgesics: NSAIDs (e.g. Ibuprofen) or Acetaminophen
    1. Variable efficacy (unlikely to offer benefit beyond transient pain relief)
  8. Pyridoxine may be indicated in pregnancy
    1. Dose: Pyridoxine 25-50 mg PO tid
    2. Unproven benefit
    3. Reference
      1. (1993) Can Fam Physician, 39:2122-7 [PubMed]

XIV. Management: Physical Therapy or Hand Therapy

  1. Hand therapy conservative measures are effective (see above),
    1. Splinting
    2. Work modifications
    3. Exercises
  2. Other specific therapies are NOT recommended and are NOT found to have longterm efficacy (or evidence)
    1. Avoid shock wave therapy, laser therapy, pulsed radiofrequency, massage therapy, kinesiology taping
    2. Local Therapeutic Ultrasound for 6 weeks may provide relief for up to 6 months
      1. Ebenbickler (1998) BMJ 316:731-5 [PubMed]
    3. Hand therapy Ultrasound and Carpal Bone mobilization have insufficient evidence
      1. Page (2012) Cochrane Database Syst Rev (6): CD009899 [PubMed]
    4. Nerve glide Exercises are NOT recommended
      1. Described for historical reasons
      2. May theoretically untether a compressed Median Nerve
        1. However in practice, does not improve outcomes when added to Splinting
        2. Abdrolrazaghi (2023) Hand 18(2): 222-9 [PubMed]
      3. Technique (repeated each for 10-15 repetitions)
        1. Hyperextend hand against wall
        2. Wrist rotation against wall
        3. Repeat wrist rotation with neck lateral bending to either side
        4. Alternate finger extension with clenched fist
      4. Video Resource
        1. https://www.youtube.com/watch?v=B5goXA9MqCA

XV. Management: Surgical Release Transverse Carpal Ligament

  1. Indications
    1. Early surgery for moderate to severe Median Nerve injury (by EMG)
    2. Persistent symptoms refractory to conservative therapy after 3-4 months
    3. Progressive or persistent motor weakness (grip strength) or thenar Muscle atrophy
  2. Efficacy
    1. General
      1. Results in prompt, permanent pain relief
      2. Very effective in 66% of patients (some studies report 70-90% of cases)
      3. May be effective even if EMG normal
    2. Longterm efficacy (>3 months after surgery)
      1. Mixed results in longterm studies of surgical versus non-surgical results
      2. Splinting and Corticosteroids injections may result in similar longterm outcomes to surgery
      3. Surgery may not lead to longterm significantly decreased symptoms or improved function
      4. Lusa (2024) Cochrane Database Syst Rev 1(1):CD001552 +PMID: 38189479 [PubMed]
    3. Open versus endoscopic repair
      1. Earlier return to work by 8 days with endoscopic repair
      2. Fewer complications (infection, scarring) with endoscopic repair
      3. Equivalent longterm outcomes with either endoscopic or open repair
    4. References
      1. Katz (2001) Arthritis Rheum 44:1184-93 [PubMed]
      2. Gerritsen (2001) Br J Surg 88:1285-95 [PubMed]
      3. Li (2020) BMC Musculoskelet Disord 21(1): 272 [PubMed]
      4. Vasiliadis (2014) Cochrane Database Syst Rev (1): CD008265 [PubMed]
  3. Course
    1. Sensory, Motor function improvement may take months
    2. Post-operative Splinting is NOT recommended
      1. Results in increased stiffness and does not improve outcomes
      2. Early mobilization results in better range of motion, strength and return to ADLs
    3. Postoperative rehabilitation is not typically recommended
      1. No evidence of benefit in outcomes
  4. Adverse affects
    1. No Disability from sectioning transverse ligament
    2. Residual discomfort may continue from tenosynovitis
  5. Complications (<2%)
    1. Median Nerve branch injury
    2. Hypertrophic, painful scar
    3. Superficial Palmar ArchLaceration
    4. Pillar pain adjacent to ligament release
    5. Incomplete transverse ligament division
      1. May result in refractory, persistent symptoms requiring repeat surgery (3% of patients)

XVI. References

  1. Alvarez (2024) Am Fam Physician 109(6): 571-2 [PubMed]
  2. D'Arcy (2000) JAMA 283(23): 3110-7 [PubMed]
  3. Katz (1994) Am Fam Physician 49(6):1371-9 [PubMed]
  4. Keith (2009) J Am Acad Orthop Surg 17(6): 389-96 [PubMed]
  5. Keith (2009) J Am Acad Orthop Surg 17(6): 397-405 [PubMed]
  6. LeBlanc (2011) Am Fam Physician 83(8): 952-8 [PubMed]
  7. Silver (2021) Am Fam Physician 103(5): 275-85 [PubMed]
  8. Shapiro (2025) J Am Acad Orthop Surg 33(7): e356-66 [PubMed]
  9. Viera (2003) Am Fam Physician 68(2):265-72 [PubMed]
  10. Wipperman (2016) Am Fam Physician 94(12): 993-9 [PubMed]
  11. Wipperman (2024) Am Fam Physician 110(1): 52-57 [PubMed]

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