A review of the fundamentals and evidence-basedtreatment options.

In carpal tunnel syndrome (CTS), the median nerve is irritated in the carpal tunnel. The cause is thought to be compression, which directly damages the nerves and can decrease the blood supply to the nerve.1 Symptoms of CTS include pain in the wrist and hand, which can spread to the forearm; and paresthesia in the thumb, index, middle, and radial half of the ring finger.2 Advanced CTS can result in thenar muscle weakness and atrophy.1

The course of CTS is not predictable. Some patients progress from intermittent paresthesia to more constant paresthesia and eventual thenar atrophy, while others experience intermittent exacerbation of sensory symptoms, with no symptoms in-between, over many years.3,4 

Median nerve compression in the carpal tunnel is the most commonly occurring nerve compression in the body.5 CTS is said to affect 1% of the population.6 Middle-age women develop CTS four times more often than men.2 Those with medical conditions such as renal disease, metabolic disorders, and diabetes are more likely to develop CTS.6 CTS occurs more frequently in professions where there is frequent grasping, forceful grasping, and flexed-wrist postures.

Diagnosis of CTS

CTS is a clinical condition, and it is diagnosed by a combination of symptoms, signs, and tests. Questionnaires such as the Boston Questionnaire7 may be used to serially assess the symptoms of CTS. There are a number of provocative tests for the diagnosis of CTS, including Tinel’s sign, Phalen’s maneuver, and the carpal compression test, which do not have ideal sensitivity or specificity.8 There also are sensory assessments such as the Semmes-Weinstein monofilaments, the vibrometer, current perception threshold, and two-point discrimination, which are applied in the sensory distribution of the median nerve.9–13 Nerve-conduction studies are used to test the sensory and motor-transmission speed of the large, myelinated median nerve fibers in the carpal tunnel.14

Treatment Options

Treatment of CTS is either surgical or nonsurgical. However ,carpal tunnel release surgery is now the most common procedure in the United States, with more than 400,000 performed annually.15 Surgical treatment is usually offered to those with advanced CTS who have constant symptoms, severe sensory disturbance, and/or thenar motor weakness. Nonsurgical treatments are offered to those who cannot undergo surgery, or have intermittent symptoms of mild to moderate CTS.

Surgery involves open or endoscopic release of the flexor retinaculum to allow more space for the structures within the carpal canal. Studies have shown that division of the flexor retinaculum relieves CTS in most cases, and that endoscopic surgery has shorter recovery times and less scar sensitivity than does open surgery. Also reported is a low instance of incomplete division of the flexor retinaculum during endoscopic surgery.15 

Nonsurgical treatments for CTS include injection of anti-inflammatories into the carpal canal, wrist splinting, exercises, yoga, therapeutic ultrasound, activity, ergonomic modification, oral medication, and vitamins. In Table 1 below, the efficacy of these treatments has been summarized from a systematic review of randomized controlled trials (RCT). In the table, evidence is defined as:

• strong—provided by generally consistent findings in multiple RCTs with low bias ratings;

• moderate—provided by generally consistent findings in one RCT with low bias and one or more RCTs with moderate or high bias ratings, or by generally consistent findings in multiple RCTs with moderate or high bias ratings;

• limited—provided by only one RCT (any bias rating); and

• none—no RCTs are provided.

Further research is needed into the long-term effects (more than 3 months) of conservative treatment for CTS, and the efficacy of these treatments in patients with different levels of severity in their condition.

Nicola Massy-Westropp, OTR, CHT, PhD, is a practicing occupational therapist and lectures for the University of South Australia. She can be reached at mwestropp@picknowl.com.au.

References

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2. 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.

3. Bessette L, Keller RB, Lew RA, et al. Prognostic value of a hand symptom diagram in surgery for carpal tunnel syndrome. J Rheumatol. April 1997;24(4):726–34.

4. Braun RM, Davidson K, Doehr S. Provocative testing in the diagnosis of dynamic carpal tunnel syndrome. J Hand Surg [Am]. Mar 1989;14(2 Pt 1):195–7.

5. Rosenthal EA. Tenosynovitis: tendon and nerve entrapment. Hand Clin. November 1987;3(4):585–609.

6. Gerr F, Marcus M. Risk factors for carpal tunnel syndrome. Arch Intern Med. May 10, 1999;159(9):1008–10.

7. Reale F, Ginanneschi F, Sicurelli F, et al. Protocol of outcome evaluation for surgical release of carpal tunnel syndrome. Neurosurgery. August 2003;53(2):343–50; discussion 350–1.

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9. Ghavanini MR, Haghighat M. Carpal tunnel syndrome: reappraisal of five clinical tests. Electromyogr Clin Neurophysiol. October–November 1998;38(7):437–41.

10. Jetzer T, Dellon LA, Mitterhauser MD. The use of PSSD testing in comparison to vibrotactile testing of vibration exposed workers. Cent Eur J Public Health. 1995;Suppl 3:49–51.

11. Jetzer TC. Use of vibration testing in the early evaluation of workers with carpal tunnel syndrome. J Occup Med. February 1991;33(2):117–20.

12. Kamon M. Quantitative measurement of vibratory perception threshold using a new vibrometer. J Occup Med. September 1994;36(9):989–96.

13. Katims JJ, Rouvelas P, Sadler B, et al. Current perception threshold. Reproducibility and comparison with nerve conduction in evaluation of carpal tunnel syndrome. ASAIO Trans. July–September 1989;35(3):280–4.

14. Jablecki CK, Andary MT, So YT, Wilkins DE, Williams FH. Literature review of the usefulness of nerve conduction studies and electromyography for the evaluation of patients with carpal tunnel syndrome. AAEM Quality Assurance Committee. Muscle Nerve. December 1993;16(12):1392–414.

15. Concannon MJ, Brownfield ML, Puckett CL. The incidence of recurrence after endoscopic carpal tunnel release. Plast Reconstr Surg. April 2000;105(5):1662–5.

16. O’ Connor D, Marshall S, Massey-Westropp N. Nonsurgical treatment (other than steroid injection) for carpal tunnel syndrome. Cochrane Database Syst Rev. 2003;(1): CD003219.