AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

Carpal tunnel syndrome (CTS) is a collection of characteristic symptoms and signs that occurs following entrapment of the median nerve within the carpal tunnel. Usual symptoms include numbness, paresthesias, and pain in the median nerve distribution. These symptoms may or may not be accompanied by objective changes in sensation and strength of median-innervated structures in the hand.

Pathophysiology

Until the advent of electrophysiological testing in the 1940s, this syndrome commonly was thought to be the result of compression of the brachial plexus by cervical ribs and other structures in the anterior neck region. Now, it is known that the median nerve is damaged within the rigid confines of the carpal tunnel, initially undergoing demyelination followed by axonal degeneration. Sensory fibers often are affected first, followed by motor fibers. Autonomic nerve fibers carried in the median nerve also may be affected.

The cause of the damage is subject to some debate; however, it seems likely that abnormally high carpal tunnel pressures exist in patients with CTS. This pressure causes obstruction to venous outflow, back pressure, edema formation, and, ultimately, ischemia in the nerve.

The risk of development of CTS appears to be associated, at least in part, with a number of different epidemiological factors, including genetic, medical, social, vocational, avocational, and demographic. A complex interaction probably exists between some or all these factors, eventually leading to the development of CTS. Definite causative factors, however, are far from clear.

Frequency

United States

Incidence is 1-3 cases per 1000 subjects per year; prevalence is approximately 50 cases per 1000 subjects in the general population. Incidence may rise as high as 150 cases per 1000 subjects per year, with prevalence rates greater than 500 cases per 1000 subjects in certain high-risk groups.

International

A paucity of population-based studies exists; however, the incidence and prevalence in developed countries seems similar to the United States (eg, incidence in the Netherlands is approximately 2.5 cases per 1000 subjects per year; prevalence in the United Kingdom is from 70-160 cases per 1000 subjects). CTS is almost unheard of in some developing countries (eg, among nonwhite South Africans).

Mortality/Morbidity

The syndrome is not fatal, but it can lead to complete irreversible median nerve damage with consequent severe loss of hand function if left untreated.

Race

Whites are probably at highest risk. The syndrome appears to be very rare in some racial groups (eg, nonwhite South Africans). In North America, white US Navy personnel have CTS at a rate 2-3 times that of black personnel.

Sex

The female-to-male ratio is 3-10:1.

Age

The peak age of development of CTS is from 45-60 years. Only 10% of CTS patients are younger than 31 years.

CLINICAL

Section 3 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

The patient's history often is more important than the physical examination in making the diagnosis of CTS.

• Numbness and tingling
• • The most common complaints include that the hands fall asleep or things slip from the fingers without the person's noticing (loss of grip, dropping things), as well as numbness and tingling.
  • Symptoms are usually intermittent and are associated with certain activities (eg, driving, reading the newspaper, crocheting, painting). Nighttime symptoms that wake the individual are more specific of CTS, especially if the patient relieves symptoms by shaking the hand/wrist. Bilateral CTS is common, although the dominant hand is usually affected first and more severely than the other hand.
  • Complaints should be localized to the palmar aspect of the first to the fourth fingers and the distal palm (ie, the sensory distribution of the median nerve at the wrist). Numbness predominantly in the fifth finger or extending to the thenar eminence or dorsum of the hand should suggest other diagnoses. A surprising number of CTS patients are unable to localize their symptoms further (eg, whole hand/arm feeling dead). This generalized numbness may indicate autonomic fiber involvement and does not exclude CTS from the diagnosis.
• Pain
• • The sensory symptoms above commonly are accompanied by an aching sensation over the ventral aspect of the wrist. This pain can radiate distally to the palm and fingers or, more commonly, extend proximally along the ventral forearm.
  • Pain in the epicondylar region of the elbow, upper arm, shoulder, or neck is more likely to be due to other musculoskeletal diagnoses (eg, epicondylitis) with which CTS commonly is associated. This more proximal pain also should prompt a careful search for other neurologic diagnoses (eg, cervical radiculopathy).
• Autonomic symptoms
• • Not infrequently, patients report symptoms in the whole hand. Many patients with CTS also complain of a tight or swollen feeling in the hands and/or temperature changes (eg, hands being cold/hot all the time).
  • Many patients also report sensitivity to changes in temperature (particularly cold) and a difference in skin color. In rare cases, there are complaints of changes in sweating. In all likelihood, these symptoms are due to autonomic nerve fiber involvement (the median nerve carries most autonomic fibers to the whole hand).
• Weakness/clumsiness: Loss of power in the hand (particularly for precision grips involving the thumb) does occur; however, in practice, loss of sensory feedback and pain is often a more important cause of weakness and clumsiness than loss of motor power per se.

Physical

Clinical examination is important to rule out other neurologic and musculoskeletal diagnoses; however, the examination often contributes little to the confirmation of the diagnosis of CTS.

• Sensory examination
• • Abnormalities in sensory modalities may be present on the palmar aspect of the first 3 digits and radial one half of the fourth digit. Semmes-Weinstein monofilament testing or 2-point discrimination may be more sensitive in picking this up; however, in the author's experience, pinprick sensation is as good as any test.
  • Sensory examination is most useful in confirming that areas outside the distal median nerve territory are normal (eg, thenar eminence, hypothenar eminence, dorsum of first web space).
• Motor examination: Wasting and weakness of the median-innervated hand muscles (LOAF muscles) may be detectable.
• • L - First and second lumbricals
  • O - Opponens pollicis
  • A - Abductor pollicis brevis
  • F - Flexor pollicis brevis
• Special tests: No good clinical test exists to support diagnosis of CTS.
• • Hoffmann-Tinel sign
    • Gentle tapping over the median nerve in the carpal tunnel region elicits tingling in the nerve's distribution.
    • This sign still is commonly looked for despite the low sensitivity and specificity.
  • Phalen sign
    • Tingling in the median nerve distribution is induced by full flexion (or full extension for reverse Phalen) of the wrists for up to 60 seconds
    • This test has 80% specificity but lower sensitivity.
  • The carpal compression test
    • This test involves applying firm pressure directly over the carpal tunnel, usually with the thumbs, for up to 30 seconds to reproduce symptoms.
    • Reports indicate that this test has a sensitivity of up to 89% and a specificity of 96%.
  • Palpatory diagnosis
    • This test involves examining the soft tissues directly overlying the median nerve at the wrist for mechanical restriction.
    • This palpatory test has been noted to have a sensitivity over 90% and a specificity of 75% or greater.
  • The square wrist sign
    • The ratio of the wrist thickness to wrist width is greater than 0.7.
    • This test has a modest sensitivity/specificity of 70%.
• Several other tests have been advocated but rarely provide additional information beyond what the Phalen and square wrist signs provide.

Causes

Note that CTS is associated with many different factors. In particular, the more the hand and wrist are used, the greater the symptoms. This observation does not necessarily mean that using the hand and wrist causes the syndrome or that more median nerve damage ensues. Association should not be assumed to signify causation.

• Demographics
  • Increasing age
  • Female sex
  • Increased body mass index (BMI), especially recent increases
  • Square-shaped wrist
  • Short stature
  • Dominant hand
  • Race (white)
• Genetics
• • A strong family susceptibility exists, probably related to multiple inherited characteristics (eg, square wrist, thickened transverse ligament, stature).
  • A number of inherited medical conditions also are associated with CTS (eg, diabetes, thyroid disease, hereditary neuropathy with liability to pressure palsies).
• Medical conditions
• • Wrist fracture (Colles)
  • Acute severe flexion/extension injury of wrist
  • Space-occupying lesions within the carpal tunnel (eg, flexor tenosynovitis, ganglions, hemorrhage, aneurysms, anomalous muscles, various tumors, edema)
  • Diabetes
  • Thyroid disorders (usually myxoedema)
  • Rheumatoid arthritis and other inflammatory arthritides of the wrist
  • Recent menopause (including post-oophorectomy)
  • Renal dialysis
  • Acromegaly
  • Amyloidosis
• Vocational/avocational¹: Activities involving (1) prolonged severe force through the wrist, (2) prolonged extreme posture of the wrist, (3) high amounts of repetitive movements, and (4) exposure to vibration and/or cold may be associated with CTS (particularly in combination).
• Other factors
• • Lack of aerobic exercise
  • Pregnancy and breastfeeding
  • Use of wheelchairs and/or walking aids

DIFFERENTIALS

Section 4 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Other Problems to Be Considered

Focal CNS pathology (multiple sclerosis, tumor, stroke)
Proximal median nerve mononeuropathy (eg, pronator teres syndrome)
Polyneuropathies
Compartment syndrome
Reflex sympathetic dystrophy
Raynaud syndrome
Degenerative arthritis in hand and wrist
Lyme disease
Leprosy

WORKUP

Section 5 of 11  

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• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• No blood tests exist for the diagnosis of CTS; however, laboratory testing for associated conditions (eg, diabetes) may be performed when clinically indicated.

Imaging Studies

• No imaging studies are considered routine in diagnosing CTS.
• • MRI of the carpal tunnel is particularly useful preoperatively if a space-occupying lesion in the carpal tunnel is suggested. Signal abnormality can be detected in the median nerve in some cases of CTS, but how these abnormalities correlate to diagnosis and physiological severity is not clear. MRI does not rule out the multitude of other differential diagnoses and is time consuming and resource intensive.
  • Ultrasound potentially can pick up some space-occupying lesions in the carpal tunnel. Problems differentiating the median nerve from surrounding soft tissue (particularly distally) severely limit its role in diagnosis at present.

Other Tests

• Electrodiagnosis²
• • Electrophysiologic (EDX) studies, including electromyography (EMG) and nerve conductions studies (NCS), are the first-line investigations in suggested CTS. Abnormalities on EDX testing, in association with specific symptoms and signs, are considered the criterion standard for CTS diagnosis. In addition, other neurologic diagnoses can be excluded with these test results.
  • EDX also can provide an accurate assessment of how severe the damage to the nerve is, thereby directing management and providing objective criteria for determination of prognosis. CTS is usually divided into mild, moderate, and severe; however, criteria for this assessment usually vary from lab to lab. In general, patients with mild CTS have sensory abnormalities alone on EDX testing, and patients with sensory plus motor abnormalities have moderate CTS. Any evidence of axonal loss (eg, decreased or absent sensory or motor responses distal to the carpal tunnel or neuropathic abnormalities on needle EMG), however, is classified as severe CTS.
  • Changes in EDX results over time can be used to assess the success of various treatment modalities.
• The American Association of Electrodiagnostic Medicine has published standards and guidelines that govern the minimum number of studies that should be performed to diagnose CTS.
• Other quantitative tests, such as thermography and vibrometry, have been shown to be inferior to EDX and are not recommended, as they have not been supported by controlled studies.

TREATMENT

Section 6 of 11  

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Rehabilitation Program

Physical Therapy

Given that CTS is associated with low aerobic fitness (and increased BMI), it makes inherent sense to provide the patient with an aerobic fitness program. Stationary biking, cycling, or any other exercise that puts strain on the wrists probably should be avoided.

The use of modalities (eg, ultrasound, phonophoresis, iontophoresis) may provide relief in some patients. Interestingly, it may be possible to enlarge the carpal tunnel by specific stretching techniques. Such an exercise program may provide a new noninvasive treatment for CTS in the future.

Occupational Therapy

Work site ergonomic assessment may help to reduce potentially exacerbating factors (eg, poor posture, excessive force). Manufacture of a wrist-hand orthosis with wrist joint in neutral (to be worn at nighttime for a minimum of 3-4 weeks) is one of the best evidence-based conservative treatments for CTS. A specific stretching/strengthening program for the hand and wrist may be useful in improving strength and dexterity (particularly following surgical treatment), although it can exacerbate symptoms. Massage and/or nerve glide techniques offer no proven benefit.

Medical Issues/Complications

Most individuals with mild-to-moderate CTS (according to EDX data) respond to conservative management, usually consisting of splinting the wrist at nighttime for a minimum of 3 weeks. Many off-the-shelf wrist splints seem to work well, although, theoretically, a custom-made splint in neutral is probably the best choice. Nonsteroidal anti-inflammatory drugs (NSAIDs) and/or diuretics may be of benefit. Steroid injection into the carpal tunnel is of benefit, as is oral prednisone (although injection rarely is used in practice). Vitamin B-6 or B-12 supplements are of no proven benefit. Lack of aerobic exercise (along with increased BMI) is a risk factor for development of CTS and should be addressed. Overuse of legal drugs (eg, caffeine, nicotine, alcohol) can contribute to CTS and, therefore, should be reduced.

Surgical Intervention

Patients whose condition does not improve following conservative treatment and patients who initially are in the severe CTS category (as defined by EDX) should be considered for surgery. Surgical release of the transverse ligament provides high initial success rates (greater than 90%) with low rates of complication; however, it has been suggested recently that the long-term success rate may be much lower than previously thought (approximately 60% at 5 y). Success rates also are considerably lower for individuals with normal EDX studies.³

Consultations

Refer patients with suggested CTS to a specialist trained in clinical neurophysiology (usually a neurologist, physiatrist, or physical medicine and rehabilitation specialist) for possible EDX studies. These test results are important for diagnosis, instigation of appropriate treatment, determination of prognosis, and long-term follow-up.

Other Treatment

Steroid injection into the carpal tunnel has been shown to be of long-term benefit and may be worthwhile prior to surgical management or in those individuals where surgery is relatively contraindicated (eg, because of pregnancy).⁴ Techniques and devices to stretch or manipulate the carpal tunnel have shown some promise but still are not accepted widely. Laser therapy also has shown some early promise.

MEDICATION

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• References

Short (1-2 wk) courses of regular NSAIDs can be of benefit, particularly if there is any suggestion of inflammation in the wrist region (eg, flexor tenosynovitis, rheumatoid arthritis). Likewise, if edema is thought to be prominent, then a short course of a mild diuretic may be of benefit.

Drug Category: Nonsteroidal anti-inflammatory drugs

Provide pain relief and reduction of inflammation. Reducing inflammation in the structures passing through the carpal tunnel decreases pressure and provides some relief to the compressed nerve.

Drug Category: Cyclooxygenase-2 inhibitors

Although increased cost can be a negative factor, the incidence of costly and potentially fatal GI bleeds is clearly less with COX-2 inhibitors than with traditional NSAIDs. Ongoing analysis of cost avoidance of GI bleeds will further define the populations that will find COX-2 inhibitors the most beneficial.

Drug Category: Diuretic agents

Conditions that cause edema may increase pressure in the carpal tunnel. Diuretics may be beneficial in reducing edema.

FOLLOW-UP

Section 8 of 11  

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• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Further Outpatient Care

• Individuals treated conservatively should follow up in 4-6 weeks to assess the success of treatment interventions. Patients who do not achieve desired results from conservative treatment should be referred for a surgical opinion.
• Continued symptoms following carpal tunnel release should prompt referral for repeat EDX studies.

Deterrence

• No conclusive evidence exists of any intervention that can prevent CTS.

Complications

• The condition may continue to increase median nerve damage leading to permanent impairment and disability.
• Some individuals can develop chronic wrist and hand pain (with or without reflex sympathetic dystrophy).

Prognosis

• CTS appears to be progressive over time (though with considerable fluctuations week to week) and can lead to permanent median nerve damage. Whether any conservative management can prevent progression is unclear. Even with surgical release, it appears the syndrome reoccurs to some degree in a significant number (possibly up to one third after 5 years).
• Initially, approximately 90% of mild-to-moderate CTS cases respond to conservative management. Over time, a number progress to requiring surgery.
• Patients with CTS secondary to underlying pathology (eg, diabetes, wrist fracture) tend to have a less favorable prognosis than those with no apparent underlying cause.
• Patients with normal EDX studies consistently have much less favorable operative outcomes (and more complications) than those with abnormalities on EDX. Axonal loss on EDX indicates less favorable prognosis.

Patient Education

• Association versus cause: Association of 2 phenomena does not imply a causal relationship. Using the hands frequently brings on symptoms of CTS, just like exercise brings on angina in patients with coronary artery disease. This association, however, does not necessarily mean that the median nerve damage is caused by use or that it will get worse. Exercise, in fact, is good for coronary artery disease.
• Avoid extremes: If a patient's vocation/avocation involves extreme force/repetition/posture/vibration through the wrist, then it seems prudent to seek ways of avoiding factors that cause or aggravate CTS.
• Reduce caffeine, alcohol, and/or nicotine intake because all these substances are associated with development of CTS.
• Exercise: BMI and poor fitness levels do appear to be related to the development of CTS.
• For excellent patient education resources, visit eMedicine's Hand, Wrist, Elbow, and Shoulder Center and Arthritis Center. Also, see eMedicine's patient education article Carpal Tunnel Syndrome.

MISCELLANEOUS

Section 9 of 11  

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• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• The textbook case of CTS is quite rare, and the range of symptoms is large and varied. Missing the diagnosis potentially could lead to permanent median nerve damage, with consequent severe loss of hand function. Incorrect diagnosis could lead to unnecessary surgery (or other treatments) with potentially severe complications and delay in making the true diagnosis may be detrimental to the patient. Clinical examination is not good for diagnosing CTS and rarely is useful or accurate in determining severity. Therefore, early use of EDX studies (completed by certified electrodiagnosticians in an accredited laboratory) is advocated strongly.
• CTS is common and often can coexist with other potentially more serious conditions (eg, radiculopathy). In patients with preexisting polyneuropathy, a superimposed CTS rapidly can become severe. Likewise, CTS potentially is more severe if associated with a more proximal injury to the peripheral nervous system (eg, double crush injury), although some have debated this connection hotly.
• Assess the reliability of the EDX laboratory and the electrodiagnostician producing the report. Poor technique and poor lab standards easily can lead to very high false-positive and false-negative rates.

MULTIMEDIA

Section 10 of 11  

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• Multimedia
• References

Media file 1:  The hands of an 80-year-old woman with a several-year history of numbness and weakness are shown in this photo. Note severe thenar muscle (abductor pollicis brevis, opponens pollicis) wasting of right hand with preservation of hypothenar eminence.
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Media type:  Photo

Media file 2:  Sensory nerve conduction studies from the left hand of the patient in Picture 1 (responses from the median nerve in the right hand were completely absent). Note marked slowing of the conduction velocity (CV) to 29.8 and 25.5 m/s for digit 3 and 1, respectively (normal >50 m/s). The amplitude for both also is reduced markedly (normal >10). These findings are consistent with carpal tunnel syndrome.
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Media type:  Photo

Media file 3:  Motor nerve conduction studies from the left hand of the patient in Picture 1 (responses from the median nerve in the right hand were completely absent). Note the conduction velocity across the carpal tunnel segment slows severely to 18.3 m/s (normal >50 m/s), and the distal motor latency is prolonged at 6.3 ms (normal <4.2 ms). Amplitudes are low for the wrist and elbow stimulus sites at 4.7 mV (normal >5 mV) but are 31% higher distal to the carpal tunnel (at the palm). This discrepancy may represent conduction block (neurapraxia) at the level of the carpal tunnel or coactivation of the ulnar branch to adductor pollicis. Needle electromyography is required to determine whether axonal loss is present.
	View Full Size Image
Media type:  Photo

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

1. Palmer KT, Harris EC, Coggon D. Carpal tunnel syndrome and its relation to occupation: a systematic literature review. Occup Med (Lond). Jan 2007;57(1):57-66. [Medline].
2. Robinson LR. Electrodiagnosis of carpal tunnel syndrome. Phys Med Rehabil Clin N Am. Nov 2007;18(4):733-46, vi. [Medline].
3. Scholten RJ, Mink van der Molen A, Uitdehaag BM, et al. Surgical treatment options for carpal tunnel syndrome. Cochrane Database Syst Rev. 2007;(4):CD003905. [Medline].
4. Marshall S, Tardif G, Ashworth N. Local corticosteroid injection for carpal tunnel syndrome. Cochrane Database Syst Rev. 2007;(2):CD001554. [Medline].
5. American Association of Electrodiagnostic Medicine, American Academy of Neurology, American Academy of Physical Medicine and Rehabilitation. Practice parameter for electrodiagnostic studies in carpal tunnel syndrome: summary statement. Muscle Nerve. Dec 1993;16(12):1390-1. [Medline].
6. Ashworth NL. Carpal tunnel syndrome. In: Clinical Evidence. Issue 13. BMJ Publishing: London, England; 2005:.
7. Atroshi I, Gummesson C, Johnsson R, et al. Prevalence of carpal tunnel syndrome in a general population. JAMA. Jul 14 1999;282(2):153-8. [Medline].
8. Banta CA. A prospective, nonrandomized study of iontophoresis, wrist splinting, and antiinflammatory medication in the treatment of early-mild carpal tunnel syndrome. J Occup Med. Feb 1994;36(2):166-8. [Medline].
9. de Krom MC, Kester AD, Knipschild PG, Spaans F. Risk factors for carpal tunnel syndrome. Am J Epidemiol. Dec 1990;132(6):1102-10. [Medline].
10. de Krom MC, Knipschild PG, Kester AD, et al. Carpal tunnel syndrome: prevalence in the general population. J Clin Epidemiol. Apr 1992;45(4):373-6. [Medline].
11. Dumitru D. Focal peripheral neuropathies. In: Dumitru D, ed. Electrodiagnostic Medicine. San Antonio, Tex: University of Texas Press; 1995:. 867-75.
12. Durkan JA. The carpal-compression test. An instrumented device for diagnosing carpal tunnel syndrome. Orthop Rev. Jun 1994;23(6):522-5. [Medline].
13. Garland FC, Garland CF, Doyle EJ Jr, et al. Carpal tunnel syndrome and occupation in U.S. Navy enlisted personnel. Arch Environ Health. Sep-Oct 1996;51(5):395-407. [Medline].
14. Goga IE. Carpal tunnel syndrome in black South Africans. J Hand Surg [Br]. Feb 1990;15(1):96-9. [Medline].
15. Goodyear-Smith F, Arroll B. What can family physicians offer patients with carpal tunnel syndrome other than surgery? A systematic review of nonsurgical management. Ann Fam Med. May-Jun 2004;2(3):267-73. [Medline].
16. Johnson EW, ed. Carpal tunnel syndrome. In: Physical Medicine & Rehabilitation Clinics of North America. Vol 8. Philadelphia, Pa: WB Saunders; 1997:. 3.
17. Kao SY. Carpal tunnel syndrome as an occupational disease. J Am Board Fam Pract. Nov-Dec 2003;16(6):533-42.
18. Lee D, van Holsbeeck MT, Janevski PK, et al. Diagnosis of carpal tunnel syndrome. Ultrasound versus electromyography. Radiol Clin North Am. Jul 1999;37(4):859-72, x. [Medline].
19. Nathan PA, Keniston RC. Carpal tunnel syndrome. In: Kasdan ML, ed. Occupational Hand & Upper Extremity Injuries & Diseases. St. Louis, Mo: Mosby-Year Book; 1991:. 129-39.
20. National Institute for Occupational Safety and Health (NIOSH). Musculoskeletal disorders and workplace factors: a critical review of epidemiologic evidence for work-related musculoskeletal disorders of neck, upper extremity and low back. 1999.
21. Nordstrom DL, DeStefano F, Vierkant RA, Layde PM. Incidence of diagnosed carpal tunnel syndrome in a general population. Epidemiology. May 1998;9(3):342-5. [Medline].
22. Nordstrom DL, Vierkant RA, DeStefano F, Layde PM. Risk factors for carpal tunnel syndrome in a general population. Occup Environ Med. Oct 1997;54(10):734-40. [Medline].
23. Rempel D, Evanoff B, Amadio PC, et al. Consensus criteria for the classification of carpal tunnel syndrome in epidemiologic studies. Am J Public Health. Oct 1998;88(10):1447-51. [Medline].
24. Rotman MB, Enkvetchakul BV, Megerian JT, Gozani SN. Time course and predictors of median nerve conduction after carpal tunnel release. J Hand Surg [Am]. May 2004;29(3):367-72.
25. Stevens JC. AAEM minimonograph #26: the electrodiagnosis of carpal tunnel syndrome. American Association of Electrodiagnostic Medicine. Muscle Nerve. Dec 1997;20(12):1477-86. [Medline].
26. Stevens JC, Sun S, Beard CM, et al. Carpal tunnel syndrome in Rochester, Minnesota, 1961 to 1980. Neurology. Jan 1988;38(1):134-8. [Medline].
27. Stewart JD. Compression and entrapment neuropathies. In: Dyck PJ, Thomas, PK, eds. Peripheral Neuropathy. 3rd ed. Philadelphia, Pa: WB Saunders; 1993:. 961-79.
28. Sucher BM. Palpatory diagnosis and manipulative management of carpal tunnel syndrome. J Am Osteopath Assoc. Aug 1994;94(8):647-63. [Medline].
29. Sucher BM, Glassman JH. Upper extremity syndromes. In: Stanton D, Mein E, eds. Manual Medicine. 1996:787-810.
30. Upton AR, McComas AJ. The double crush in nerve entrapment syndromes. Lancet. Aug 18 1973;2(7825):359-62. [Medline].
31. Zagnoli F, Andre V, Le Dreff P, et al. Idiopathic carpal tunnel syndrome. Clinical, electrodiagnostic, and magnetic resonance imaging correlations. Rev Rhum Engl Ed. Apr 1999;66(4):192-200. [Medline].

Article Last Updated: Nov 30, 2006