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Carpal Tunnel Syndrome

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Ovid: 5-Minute Sports Medicine Consult, The


Carpal Tunnel Syndrome
Anne S. Boyd
Adam Abdulally
Stacey L. Brown Brocklehurst
Basics
Description
  • Clinical condition caused by entrapment of the median nerve in the carpal tunnel at the wrist
  • Classically presents as pain, weakness, and paresthesias on the palmar surface on the first 3½ digits
  • Can be acute or chronic (idiopathic)
Epidemiology
  • Carpal tunnel syndrome (CTS) accounts for ∼90% of all entrapment neuropathies (1).
  • Predominant gender: Female > Male (from 3:1 to as high as 10:1).
  • Predominant age: Peak prevalence is among women aged 55 yrs and older; prevalence increases with age.
  • More likely to occur in the dominant extremity and is bilateral up to 50% of the time.
Pregnancy Considerations
Common during pregnancy; usually in the 3rd trimester and often bilateral; usually symptoms will resolve spontaneously after delivery or with conservative treatment during pregnancy.
Incidence
  • Lifetime incidence is ∼10%.
  • It is estimated that 1 million adults annually in the U.S. require medical treatment (1).
Prevalence
Prevalence is 1–16% of the population depending on the criteria for diagnosis.
Risk Factors
  • Repetitive wrist motion is the most widely recognized risk factor for occupational CTS.
  • Narrow bony measurements of the wrist, elevated body mass index, increased age, female gender, and pregnancy are other common risk factors.
Etiology
  • Exact pathogenesis of CTS is not clear. Most popular theories are mechanical compression, microvascular insufficiency, and vibration.
  • Acute:
    • Uncommon and caused by rise in pressure in carpal tunnel
    • Most commonly with radial fracture
    • Also with burns, coagulopathy, local infection, and injections
  • Chronic:
    • Idiopathic: Only 50% of cases have an identifiable cause, which can be local, regional, or systemic in origin.
    • Local: Inflammation, trauma, tumors, and anatomic anomalies
    • Regional: Osteoarthritis, rheumatoid arthritis, amyloidosis, and gout
    • Systemic: Diabetes, obesity, hypothyroidism, pregnancy, menopause, systemic lupus erythematosus (SLE), scleroderma, dermatomyositis, renal failure, long-term hemodialysis, acromegaly, multiple myeloma, sarcoidosis, leukemia, alcoholism, and hemophilia (1)
Commonly Associated Conditions
  • Diabetes, thyroid disease, advancing age, and rheumatoid arthritis all have been associated with the development of CTS.
  • Activities involving repetitive wrist motion, vibration, and excessive forces through the wrist
  • Traumatic carpal bone dislocation or wrist fracture can disrupt the median nerve through the carpal tunnel.
  • Lipomas, ganglion cysts, and other anatomic anomalies can grow and directly compress the median nerve.
  • Proximal upper extremity nerve entrapment or nerve root compression—the “double crush” syndrome
Diagnosis
History
  • Complaints of pain, weakness, and paresthesias on the palmar surface on the 1st 3.5 digits
  • Exacerbated by specific wrist motion in sport, occupational task, sleeping, driving, etc.
  • Nighttime symptoms
  • Improved with “shaking of the hands” (aka flick sign)
  • Consider cervical root pathology or radiculopathy if complaint of “shooting pain” down arm.
  • Consider generalized peripheral polyneuropathy if complaint of “sock and glove” distribution of pain in upper and lower extremities.
Physical Exam
  • Classically presents as pain, weakness, and paresthesias on the palmar surface on the first 3½ digits; however, there can be variations.
  • Nocturnal acroparesthesia (ie, extremity numbness, tingling, or other abnormal sensation) is the symptom most characteristic of CTS (2).
  • Flick sign, in which a patient may demonstrate vigorous shaking of the hand and wrist in order to relieve symptoms, may be present.
  • Pain or paresthesia evoked by hand grip
  • Observe and palpate region of thenar muscle mass for atrophy (late finding).
  • Usually normal ROM
  • Strength testing of the abductor pollicis brevis muscle
  • Sensory testing, especially in median nerve distribution
  • Provocative tests:
    • Tinel sign: Percuss over the region of the carpal tunnel at wrist to elicit paresthesias in the distribution of the nerve; 38–100% sensitive and 80% specific (2)[A].
    • Phalen test: Position wrists adjacent to each other in complete flexion for at least 60 sec to elicit paresthesias; 42–85% sensitive and 80% specific (2)[A].
    • Carpal compression test: Press with thumbs over the carpal tunnel for 30 sec to elicit symptoms; reported 87% sensitivity and 90% specificity for CTS (2)[A].
    • Other tests: Square wrist sign, tethered median nerve stress test, pressure provocation test, and tourniquet test
Diagnostic Tests & Interpretation
Diagnosis usually can be made on history and physical examination alone.
Imaging
  • Indicated when the classic defining features of CTS are not present
  • Plain films generally are normal. Occasionally, carpal tunnel views may be helpful to rule out anatomic variants, fractures with trauma, and narrowing or calcification in the carpal tunnel.
  • US of the wrist depicts structural abnormalities of nerve swelling.
    • A recent study showed that a change in cross-sectional area of the nerve as it travels distally through the carpal tunnel is more useful than just one measurement of the nerve.
    • Sensitivity of diagnosis may increase with use of nerve conduction velocity (NCV) together with US.
    • US is painless, noninvasive, and inexpensive. The sensitivity and specificity of US vary among studies (3)[B].
  • MRI has been used to visualize structural abnormalities in and around the nerve.
    • There are few studies examining the sensitivity and specificity of MRI for this purpose.
    • One small study showed no difference in diagnostic accuracy between MRI and US.
    • MRI is costly and cumbersome.
    • MRI cannot assess the physiologic integrity of the median nerve across the carpal tunnel segment.

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Diagnostic Procedures/Surgery
  • Electrodiagnostic examinations can confirm/support the diagnosis of CTS.
  • Nerve conduction studies provide a highly sensitive (>85%) and specific (>95%) means for assessing the physiologic integrity of the median nerve across the carpal tunnel segment (2)[A].
  • Can be used to classify severity of CTS and to monitor progression of median nerve entrapment
  • Needle electromyography is useful for documenting the presence of axonal loss to intrinsic hand muscles innervated by the median nerve distal to the carpal tunnel segment and, if the study includes structures proximal to the carpal tunnel, identifying other or coexisting neuromuscular pathology (eg, cervical radiculopathy).
  • Clinical prediction rule (CPR): One recent prospective diagnostic study evaluated a developed CPR for the diagnosis of CTS.
  • CPR: Shaking hand for symptom relief, wrist ratio index of 0.67, symptom severity scale >1.9, reduced median sensory field of digit 1, and age >45 yrs (LR = 18.3)
Differential Diagnosis
  • de Quervain tenosynovitis
  • Cervical radiculopathy, C6–7
  • Proximal median nerve entrapment, pronator teres syndrome, or anterior interosseous syndrome
  • Ulnar neuropathy at the elbow or wrist
  • Brachial plexus neuropathy
  • Wrist arthritis or other lesions in the wrist
  • Colles fracture, lunate dislocation
  • Generalized peripheral polyneuropathy
  • Angina pectoris
  • Upper motor neuron pathology
  • Syringomyelia
  • Mononeuritis multiplex
  • Multiple sclerosis
Treatment
  • Conservative treatment:
    • Splinting:
      • Splinting the wrist at a neutral angle helps to decrease repetitive flexion and rotation, thus relieving mild soft tissue swelling or flexor tenosynovitis.
      • Compared with nighttime-only splint use, full-time use has been shown to provide greater improvement of symptoms and electrophysiologic measures; however, compliance with full-time use is more difficult (4)[B].
    • Corticosteroids:
      • Oral corticosteroids have been shown to be more effective than NSAIDs or diuretics in short-term treatment (4).
      • Corticosteroid injection into or proximal to the carpal tunnel provides greater clinical improvement at 1 mo than placebo (4)[A].
      • Surgery should be considered if patient needs more than 2 injections.
    • Other conservative treatments and their evidence:
      • Level 1 (strong evidence of efficacy): Local and oral steroids (5)[A]
      • Level 2 (moderate evidence of efficacy): Splints are effective; vitamin B6 is ineffective (5)[A].
      • Level 3 (limited/conflicting evidence of efficacy): NSAIDs, diuretics, yoga, laser, and US are effective. Botulinum toxin B injection is ineffective (5)[A].
    • ∼80% of patients with CTS respond initially to conservative treatment; however, symptoms recur in 80% after 1 yr (4).
  • Surgical treatment:
    • Patients who fail conservative therapy or who have severe symptoms (eg, nerve entrapment on nerve conduction studies, thenar atrophy, or motor weakness)
    • Surgical decompression of the carpal tunnel segment by sectioning of the transverse carpal ligament has been reported to result in good symptomatic improvement in 80–90% of patients and may prevent further median nerve axon loss.
    • Both open and endoscopic carpal tunnel surgical procedures currently are used.
    • Recent Cochrane database review did not show a difference in postoperative complications and early return to work between the 2 techniques (1)[A].
    • Complications of surgery include injury to median nerve, scar tenderness, hypotrophic scarring, loss of grip strength, pillar pain (ie, tenderness on the base of the palm), reflex sympathetic dystrophy, and bow stringing of flexor tendons.
Geriatric Considerations
In the geriatric population, surgery has been found to provide better symptom relief, functional status, and general satisfaction than nonoperative therapy.
Additional Treatment
Restriction of precipitating activities may relieve symptoms.
Ongoing Care
Patient Education
  • Use of wrist wraps and taping may minimize forces through the carpal tunnel by limiting excessive motion through the wrist in upper extremity weight-bearing sports such as gymnastics and weight lifting.
  • Improvements in wrist pain and paresthesias may be noted within a few weeks after CTS surgery, but maximal improvements in thenar strength and numbness may take as long as 9 mos.
References
1. Aroori S, Spence RA. Carpal tunnel syndrome. Ulster Med J. 2008;77:6–17.
2. Wilder-Smith EP, Seet RC, Lim EC. Diagnosing carpal tunnel syndrome-clinical criteria and ancillary tests. Nat Clin Pract Neurol. 2006;2:366–374.
3. Klauser AS, Halpern EJ, De Zordo T, et al. Carpal tunnel syndrome assessment with US: value of additional cross-sectional area measurements of the median nerve in patients versus healthy volunteers. Radiology. 2009;250:171–177.
4. Viera AJ. Management of carpal tunnel syndrome. Am Fam Physician. 2003;68:265–272.
5. Piazzini DB, Aprile I, Ferrara PE, et al. A systematic review of conservative treatment of carpal tunnel syndrome. Clin Rehabil. 2007;21:299–314.
Additional Reading
Wainner RS, et al. Development of a clinical predition rule for the diagnosis of carpal tunnel syndrome. Arch Phys Med Rehabil. 2005;86:609–617.
Gerritsen AAM, et al. Splinting vs surgery in the treatment of carpal tunnel syndrome. JAMA. 2002;288:1245–1251.
Codes
ICD9
354.0 Carpal tunnel syndrome
Clinical Pearls
  • CTS is a very common compressive neuropathy of the upper extremity.
  • It classically presents as pain, weakness, and paresthesias on the palmar surface on the 1st 3½ digits.
  • Patients also complain of nighttime symptoms and needing to shake their hands to help the pain.
  • Diagnosis often can be made based on history and physical examination findings alone.
  • Corticosteroids (oral and injection), splinting, and surgery have the best evidence for treatment.


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