The aims of this study are

• to confirm whether detrusor after-contraction (DAC) is a true contraction or not with a new approach
• and to understand clinical implication of DAC

The definition of detrusor after-contraction (DAC) is usually accepted as the increase of detrusor pressure (Pdet), whether it is sudden or not, after cessation of urinary flow. The amount of increase in Pdet is sometimes included in the definition of DAC (14, 15, 20 cmH2O or at least two times the level of the maximal Pdet during the voiding phase). However, it is clear that the lack of a well-established definition may induce much bias in the interpretation of the clinical implication of DAC. The previous studies showed a wide range of prevalence.1-4 DAC seemed to occur more frequently in children and the occurrence rate usually decreased with age in urodynamic studies.

Inclusion Criteria:

• Indications and selection of patients for conduction of urodynamic studies (UDS) were followed as the recommendation of ICS (international continence society).

Exclusion Criteria:

• Patients with indwelling catheters, urinary tract infection and urinary stones were excluded from this study

2,309 patients more than 18 years old with neurogenic or non-neurogenic voiding dysfunction who performed urodynamic studies