70 patients with mild to moderate Carpal tunnel Syndrome (CTS) including 24 patients with unilateral CTS were randomized to treatment with ipsilateral cutaneous forearm deafferentation with an anesthetic cream (EMLA®) or placebo during 8 weeks. Patient-rated outcomes was assessed using the symptom severity scale from the Boston carpal tunnel syndrome questionnaire (BCTQ) and the disability of arm, shoulder and hand questionnaire(Quick-DASH). Clinically patients were assessed for tactile discrimination and dexterity and nerve conduction studies (NCS). Cortical activation during sensory stimulation was evaluated with functional magnetic resonance imaging (fMRI) at 3T. Assessments were performed at baseline, after 90 min of initial treatment, and after 8 weeks.

Inclusion Criteria:

• symptoms of CTS for more than 3 months
• classic or probable CTS according to Katz' hand diagram (2, 27)
• clinical signs of unilateral CTS with a positive Tinel's and Phalen's test
• age between 18 and 70 years
• nerve conduction studies (NCS) with a fractionated sensory nerve conduction velocity for the median nerve across the wrist of 40 m/s or less on the affected side and of more than 43 m/s on the contralateral side
• no contraindications for MR examinations.

Exclusion Criteria:

• bilateral symptoms
• having been operated for CTS previously
• prior wrist or carpal fracture
• diabetes
• thyroid disease
• rheumatoid arthritis
• neurological disease
• drug abuse
• complete conduction block on electroneurography or prior regular exposure to hand-held vibrating tools.

data can be shared upon reasonable demand after personal contact.