> Table of Contents > Carpal Tunnel Syndrome
Carpal Tunnel Syndrome
Philip H. Aurigemma, MD
Marci D. Jones, MD
image BASICS
  • Carpal tunnel syndrome (CTS) is a symptomatic compression neuropathy of the median nerve.
  • Increased pressure within the carpal tunnel leads to compression of the median nerve and characteristic of motor-sensory findings.
  • The dorsal element of the carpal tunnel is composed of the carpal bones. The transverse carpal ligament defines the palmar boundary:
    • The carpal tunnel contains nine flexor tendons in addition to the median nerve.
  • Symptoms most commonly affect the dominant hand; >50% of patients will experience bilateral symptoms.
  • System(s) affected: musculoskeletal, nervous
  • Predominant age: 40 to 60 years
  • Predominant sex: female > male (3:1 to 10:1)
  • Two peaks: late 50s (women), late 70s (both genders)
  • Incidence up to 276/100,000 has been reported.
  • Incidence increases with age.
  • 9% in women and 6% in men; 50 cases per 1,000 individuals per year in United States (1)[C]
  • 14% in diabetics without neuropathy and 30% in patients with diabetic neuropathy
  • Rising prevalence may be the result of increasing lifespan and increasing prevalence of diabetes.
  • Combination of mechanical trauma, inflammation, increased pressure, and ischemic injury to the median nerve within the carpal tunnel
  • Acute CTS caused by rapid and sustained pressure in carpal tunnel, usually secondary to trauma, may require urgent surgical decompression.
  • Chronic CTS divided into four categories (1)[C]:
    • Idiopathic: combination of edema and fibrous hypertrophy without inflammation
    • Anatomic: persistent median artery, ganglion cyst, infection, space-occupying lesion in carpal tunnel
    • Systemic: associated with conditions such as obesity, diabetes, hypothyroidism, rheumatoid arthritis, amyloidosis, scleroderma, renal failure, and drug toxicity
    • Exertional: repetitive use of hands and wrists, repeated palmar impact, use of vibratory tools. Repetitive use is an objective cause of CTS.
Unknown; however, a familial type has been reported.
  • Prolonged postures in extremes of wrist flexion and extension; repetitive exposure to vibration
  • Alterations of fluid balance: pregnancy, menopause, obesity, renal failure, hypothyroidism, congestive heart failure (CHF), and oral contraceptive use
  • Neuropathic factors, such as diabetes, alcoholism, vitamin deficiency, or exposure to toxins, can elicit CTS symptoms.
There is no known prevention for CTS. It is recommended to take occasional (hourly) breaks when doing repetitive work involving hands.
  • Diabetes, obesity; pregnancy; hypothyroidism
  • Osteoarthritis of small joints of hand and wrist
  • Hyperparathyroidism, hypocalcemia
  • Miscellaneous associations include the following:
    • Acromegaly; lupus erythematosus; leukemia
    • Pyogenic infections; sarcoidosis
    • Primary amyloidosis; Paget disease
    • Hormone replacement therapy
  • Positive Tinel sign: Tapping over the palmar surface of the wrist proximal to the carpal tunnel may produce an electric sensation along the distribution of the median nerve (50% sensitivity; 77% specificity).
  • Positive Phalen sign: Holding the wrist in fullly flexed position for 60 seconds precipitates paresthesias (68% sensitivity; 73% specificity).
  • Durkan compression test: Direct compression of median nerve at carpal tunnel for 30 seconds elicits symptoms (87% sensitivity; 90% specificity) (1)[C].
  • Wasting of thenar musculature is a late sign.
  • Loss of 2-point discrimination
  • Ulceration of tips of fingers is associated with loss of protective sensation.
  • Cervical spondylosis (carpal tunnel may also occur with cervical spine disease; “double crush”)
  • Generalized peripheral neuropathy
  • Brachial plexopathy, in particular upper trunk
  • CNS disorders (multiple sclerosis, cerebral infarction)
  • Thoracic outlet syndrome
  • Pronator syndrome
  • Anterior interosseous syndrome
  • Musculoskeletal disorders of the wrist:
    • Trauma or distal radius fracture
    • Degenerative joint disease
    • Rheumatoid arthritis
    • Ganglion cyst
  • Scleroderma
No laboratory test is diagnostic.
  • Normal serum thyrotropin (thyroid-stimulating hormone [TSH]) and normal serum can exclude secondary conditions associated with CTS.
Initial Tests (lab, imaging)
  • Special tests
    • Electrodiagnostic studies
      • Sensitivity 85%; specificity 95%
      • Nerve conduction studies compare latency and amplitude of median nerve across the carpal tunnel.
      • Prolonged distal latency of the median motor and/or sensory fibers may be seen. Axon loss is suggested with decreased amplitudes.
      • The most sensitive indicator is median sensory distal latency, which is prolonged in CTS. Sensory nerve action potentials may be reduced or unobtainable.
      • Electromyographic changes are indicative of long-standing or severe nerve dysfunction.
  • Ulnar nerve stimulation should be performed to exclude generalized polyneuropathy.
  • Standard radiographs of the wrist evaluate bony anatomy and degenerative joint disease.
  • Special radiographic views of the carpal tunnel are of limited use.
  • Magnetic resonance imaging and ultrasound are of limited benefit in diagnosis of CTS.
  • Splinting of the wrist in a neutral position while sleeping may provide significant symptom relief:
    • Limited evidence indicates that splints worn at night are more effective than no treatment in the short term. Insufficient evidence to recommend a specific splint design or wearing regimen (2)[A].
  • Splinting (sometimes prolonged) typically promotes symptom resolution.
  • Corticosteroid injections are effective for up to 3 months compared with placebo (3)[A].
  • Outcomes at 1 year show no benefit for local steroid injections compared to placebo (3)[A].

First Line
NSAIDs, such as ibuprofen or naproxen sodium, are commonly used. There is insufficient evidence to determine their routine efficacy:
  • Contraindications: GI intolerance
  • Precautions: GI side effects of NSAIDs may preclude their use in selected patients.
Second Line
  • Local steroid injection: Methylprednisolone injections are more effective than systemic steroids or placebo at 1 and 3 months and more effective than splinting at 6 months (4)[A].
  • Response to injections can help confirm diagnosis of CTS and predict a better response to surgery.
  • Side effects include reduction of collagen and proteoglycan synthesis, limiting tenocytes, and reducing mechanical strength of tendon, leading to further degeneration and risk for rupture.
  • Oral steroids may provide a short-term improvement (2 to 8 weeks) in symptoms.
  • The long-term risks of even a short course of steroids should be balanced with the limited potential benefit of symptom improvement.
Preoperative electrodiagnostic studies are generally obtained prior to any surgical intervention.
  • Completely dividing the transverse carpal ligament provides symptom relief in >95% of patients.
  • Surgical decompression is an outpatient procedure performed under local or regional anesthesia.
  • Healing of the incision generally takes 2 weeks; an additional 2 weeks may be required before using the affected hand for tasks requiring strength.
  • Long-term results of open carpal tunnel release are excellent. Patients experience consistent pain relief for 10 to 15 years (5)[B].
  • Recent randomized, controlled studies indicate that surgery leads to better functional improvements at 1 year compared with nonoperative management.
  • Open versus endoscopic surgical procedures produce similar outcomes at 6 months. The approach should be based on surgeon and patient preference.
  • Endoscopic carpal tunnel release allows a faster return to work.
  • Risk of transient nerve injuries is higher with endoscopic release (6)[A].
  • Therapeutic ultrasound, exercise, and mobilization techniques have limited benefit compared with other nonsurgical interventions. Poor quality evidence shows ultrasound may be more effective than placebo (7,8)[A].
No trial data support the use of vitamin B6 in the prevention or treatment of CTS.
Admission Criteria/Initial Stabilization
Patient Monitoring
  • Patients treated nonoperatively (splinting, injections) require follow-up over 4 to 12 weeks to ensure adequate progress.
  • There is only limited, low-quality evidence to suggest that rehabilitation exercises such as wrist immobilization, ice therapy, and multimodal hand rehabilitation are beneficial.
  • 7-20% of patients treated surgically may experience recurrence.
  • American Society for Surgery of the Hand: http://www.assh.org/Public/HandConditions/Pages/CarpalTunnelSyndrome.aspx
  • For patient education materials, contact: American Academy of Family Physicians Foundation, P.O. Box 8418, Kansas City, MO 64114 (800) 274-2237, Ext. 4400.
  • Patients with severe CTS may not recover completely after surgical release. Paresthesias and weakness may persist, but night symptoms generally resolve.
  • If untreated, more severe cases of CTS can lead to numbness and weakness in the hand, atrophy of the thenar muscles, and permanent loss of median nerve function.
1. Cranford CS, Ho JY, Kalainov DM, et al. Carpal tunnel syndrome. J Am Acad Orthop Surg. 2007;15(9):537-548.
2. Page MJ, Massy-Westropp N, O'Connor D, et al. Splinting for carpal tunnel syndrome. Cochrane Database Syst Rev. 2012;(7):CD010003.
3. Atroshi I, Flondell M, Hofer M, et al. Methylprednisolone injections for the carpal tunnel syndrome: a randomized, placebo-controlled trial. Ann Intern Med. 2013;159(5):309-317.
4. Marshall S, Tardif G, Ashworth N. Local corticosteroid injection for carpal tunnel syndrome. Cochrane Database Syst Rev. 2007;(2):CD001554.
5. Louie DL, Earp BE, Collins JE, et al. Outcomes of open carpal tunnel release at a minimum of ten years. J Bone Joint Surg Am. 2013;95(12):1067-1073.
6. Sayegh ET, Strauch RJ. Open versus endoscopic carpal tunnel release: a meta-analysis of randomized controlled trials. Clin Orthop Relate Res. 2015;473(3):1120-1132.
7. Page MJ, O'Connor D, Pitt V, et al. Exercise and mobilisation interventions for carpal tunnel syndrome. Cochrane Database Syst Rev. 2012;(6):CD009899.
8. Page MJ, O'Connor D, Pitt V, et al. Therapeutic ultrasound for carpal tunnel syndrome. Cochrane Database Syst Rev. 2013;(3):CD009601.
Additional Reading
  • Fowler JR, Gaughan JP, Ilyas AM. The sensitivity and specificity of ultrasound for the diagnosis of carpal tunnel syndrome: a meta-analysis. Clin Orthop Relat Res. 2011;469(4):1089-1094.
  • Graham B. Nonsurgical treatment of carpal tunnel syndrome. J Hand Surg Am. 2009;34(3):531-534.
  • Huisstede BM, Hoogvliet P, Randsdorp MS, et al. Carpal tunnel syndrome. Part I: effectiveness of nonsurgical treatments—a systematic review. Arch Phys Med Rehabil. 2010;91(7):981-1004.
  • Middleton SD, Anakwe RE. Carpal tunnel syndrome. BMJ. 2014; 349: g6437.
  • Peters S, Page MJ, Coppieters MW, et al. Rehabilitation following carpal tunnel release. Cochrane Database Syst Rev. 2013;(6):CD004158.
  • Shi Q, MacDermid JC. Is surgical intervention more effective than non-surgical treatment for carpal tunnel syndrome? A systematic review. J Orthop Surg Res. 2011;6:17.
  • Tai TW, Wu CY, Su FC, et al. Ultrasonography for diagnosing carpal tunnel syndrome: a meta-analysis of diagnostic test accuracy. Ultrasound Med Biol. 2012;38(7):1121-1128.
  • Vasiliadis HS, Georgoulas P, Shrier I, et al. Endoscopic release for carpal tunnel syndrome. Cochrane Database Syst Rev. 2014;(1):CD008265.
See Also
  • Arthritis, Rheumatoid (RA); Hypoparathyroidism; Scleroderma; Lupus Erythematosus, Systemic (SLE)
  • Algorithms: Carpal Tunnel Syndrome; Pain in Upper Extremity
  • G56.00 Carpal tunnel syndrome, unspecified upper limb
  • G56.01 Carpal tunnel syndrome, right upper limb
  • G56.02 Carpal tunnel syndrome, left upper limb
Clinical Pearls
  • Paresthesias associated with CTS are characteristically confined to the thumb, index, long, and radial 1/2 of the ring fingers of the affected hand.
  • Thenar atrophy is a late finding, indicating severe nerve damage.
  • Durkan (carpal compression) test is superior to Tinel sign (tapping on median nerve over carpal tunnel) and Phalen maneuver (holding wrists in flexion) for the clinical diagnosis of CTS.
  • Steroid injections offer short-term relief, but clinical outcomes at 1 year are no different than placebo.