Reported incidences for paraesthesia vary widely between about 0.2% and 50% in different articles, depending on the catheter (catheter material, soft-tipped or firm-tipped catheter), the applied technique (lumbar or thoracic epidural anesthesia, depth of catheter insertion), the approach (midline or paramedian) and the included patients (obstetrical or non-obstetrical). Furthermore, the inconsistent definition of "paraesthesia" makes it difficult to compare the results of different studies. Paraesthesia are not supposed to lead to permanent neurological sequelea, but are unpleasant and perturbing sensations for the patient.