The experimental group will receive 3 sessions (once per week) of ultrasound-guided Percutaneous Electrical Nerve Stimulation targeted the median nerve. Once the median nerve is ultrasound identified, the needles will be left in situ at the identified points connected to an electrostimulator (ES-160 ITO co.) applying a biphasic continuous waveform, at low frequency (2 Hz)19 and with 250 microseconds pulse duration for 30mins.

The surgical group will receive a surgical procedure consisting of the decompression and release of the median nerve at the carpal tunnel performed by an experienced surgeon according to standardized protocols.

Experimental: Percutaneous Electrical Nerve Stimulation The experimental group will receive 3 sessions (once per week) of ultrasound-guided Percutaneous Electrical Nerve Stimulation targeted the median nerve. Once the median nerve is ultrasound identified, the needles will be left in situ at the identified points connected to an electrostimulator (ES-160 ITO co.) applying a biphasic continuous waveform, at low frequency (2 Hz)19 and with 250 microseconds pulse duration for 30mins.

An 11-point Numerical Pain Rating Scale (NPRS, 0: no pain - 10: maximum pain) will be used to assess the patients' current level of hand pain and the worst and lowest level of pain experienced in the preceding week.

The Spanish version of the Boston Carpal Tunnel Questionnaire (BCTQ) will be used to assess function. This questionnaire evaluates 2 domains: 1) the functional status scale assesses ability to perform 8 common hand-related tasks; and, 2) the symptom severity scale includes 11 items assessing pain severity, numbness, and weakness at night and during the day. Each question is answered on a 5-point scale (1: no complaint; 5: severe complaint), with higher scores indicating greater severity.