Potential for Misdiagnosis of Detrusor Underactivity Due to Urodynamic Voiding Position and Seating Characteristics

Detrusor underactivity (DUA) is a lower urinary tract (LUT) diagnosis that is diagnosed with multichannel urodynamic studies (UDS). The effect of voiding position and DUA detection is unclear.

We investigated whether moving individuals from the UDS chair to their typical voiding position would more accurately assess detrusor function in cases of absent or nonrepresentative voiding. We hypothesized that patients unable to achieve a representative void while on the UDS chair may be misdiagnosed with DUA, and that changing position may reveal intact detrusor function.

We retrospectively studied patients who underwent UDS with a single provider over 2 years. Studies were included if a patient was moved to a new position after unsuccessful or unrepresentative void attempts on the UDS chair. Two neurourologists reanalyzed the studies and recorded: time spent attempting to void on UDS chair and after moving position, whether a bladder contraction occurred on UDS chair, pdet Q max and Q max when voiding occurred, presence of a bladder contraction in new position, and pdet Q max and Q max in new position, and Valsalva effort.

503 patients underwent UDS; 94/503 patients were moved to a new position and 81/94 studies were interpretable. 71% of patients without a bladder contraction on the UDS chair demonstrated contraction in new position.

UDS voiding position and surface can impact whether patients produce a bladder contraction and representative void during urodynamic testing. Positional change to more natural voiding positions and surfaces improves detection of intact detrusor function.