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Injection with methylprednisolone proximal to the carpal tunnel: randomised double blind trial

BMJ 1999; 319 doi: (Published 02 October 1999) Cite this as: BMJ 1999;319:884
  1. J W H H Dammers, neurologist (J.Dammers{at},
  2. M M Veering, neurologista,
  3. M Vermeulen, professor of neurologyb
  1. a Department of Neurology, Medical Centre Alkmaar, PO Box 501, 1800 AM Alkmaar, Netherlands
  2. b Department of Neurology, Academic Medical Centre, University of Amsterdam, PO Box 22700, Amsterdam, Netherlands
  1. Correspondence to: Dr Dammers
  • Accepted 10 June 1999


Objective: To assess the effect of a 40 mg methylprednisolone injection proximal to the carpal tunnel in patients with the carpal tunnel syndrome.

Design: Randomised double blind placebo controlled trial.

Fig 1.
Fig 1.

Site for injecting corticosteroid to treat carpal tunnel syndrome

Setting: Outpatient neurology clinic in a district general hospital.

Participants: Patients with symptoms of the carpal tunnel syndrome for more than 3 months, confirmed by electrophysiological tests and aged over 18 years.

Intervention: Injection with 10 mg lignocaine (lidocaine) or 10 mg lignocaine and 40 mg methylprednisolone Non-responders who had received lignocaine received 40 mg methylprednisolone and 10 mg lignocaine and were followed in an open study.

Main outcome measures: Participants were scored as having improved or not improved. Improved was defined as no symptoms or minor symptoms requiring no further treatment.

Results: At 1 month 6 (20%) of 30 patients in the control group had improved compared with 23 (77%) of 30 patients the intervention group (difference 57% (95% confidence interval 36% to 77%)). After 1 year, 2 of 6 improved patients in the control group did not need a second treatment, compared with 15 of 23 improved patients in the intervention group (difference 43% (23% to 63%). Of the 28 non-responders in the control group, 24 (86%) improved after methylprednisolone. Of these 24 patients, 12 needed surgical treatment within one year.

Conclusion: A single injection with steroids close to the carpal tunnel may result in long term improvement and should be considered before surgical decompression.

Key messages

  • Corticosteroid injections into the carpal tunnel may damage the nerve, and any treatment benefits may be of short duration

  • A single injection with steroids proximal to the carpal tunnel improves 77% of patients with the carpal tunnel syndrome at one month after treatment

  • This single injection is still effective at one year in half of the patients

  • Injections proximal to the carpal tunnel have no side effects and are easier to carry out than injections into the carpal tunnel


  • Funding None.

  • Competing interests None declared.

  • Accepted 10 June 1999
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