Carpal tunnel syndrome (CTS) is a focal compressive neuropathy of the median 
nerve at the level of the wrist. CTS is the most common type of compressive 
neuropathy that occurs in the upper extremity. Typically, patients with CTS have 
paresthesia, pain, and numbness in the radial three and one-half digits. 
Nighttime symptoms are more common earlier in the disease process, with daytime 
symptoms becoming more frequent as CTS progresses. Electrodiagnostic studies may 
be performed to confirm a diagnosis of CTS or to obtain a baseline before 
surgical treatment; however, electrodiagnostic studies may be normal in a subset 
of patients who have CTS. Patients who have mild CTS should undergo an initial 
trial of nonsurgical treatment that includes lifestyle modifications, nighttime 
splinting, and corticosteroid injections. Carpal tunnel release should be 
performed in patients in whom nonsurgical treatment fails and patients who have 
acute CTS secondary to infection or trauma or have advanced symptoms. 
Recalcitrant CTS, which may occur in as many as 25% of patients who undergo 
carpal tunnel release, most commonly results from an incomplete transverse 
carpal ligament release or an incorrect initial diagnosis. Patients with 
recurrent symptoms often have perineural fibrosis that tethers the median nerve.