Compression of the median nerve in the carpal tunnel can be produced by a variety of factors, including fractures, metabolic disturbances, rheumatoid arthritis or anatomical anomalies. When it is not possible to identify a specific cause, the term 'idiopathic carpal tunnel syndrome' is used. Although this disease is very common, its pathophysiology is still unclear. In the past, the presence of a chronic non-specific tenosynovitis around the flexor tendons was postulated but several investigations failed to show any inflammatory reaction in the carpal synovium. In this study, the histology of the flexor tendon sheaths in a group of 50 patients surgically treated for idiopathic carpal tunnel syndrome (ICTS) have been investigated both from the qualitative (histopathology) and quantitative (micrometric evaluation) points of view. Lack of acute or chronic inflammatory cells, connective disorganization, and vascular modifications are the main histological findings which are present in all the specimens, regardless of the patient's age, the duration of the sensory symptomatology or the severity of the neurological lesion on EMG exam. The carpal synovium in these patients appeared thickened when compared to the specimens obtained from the control group. However, on micrometric evaluation a relationship between synovial thickness and severity of the symptomatology or of the EMG data was not observed. The carpal synovium in ICTS has a consistent histological appearance and is increased in thickness when compared with normal specimens.
- Carpal tunnel syndrome
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