Detrusor underactivity (DU) is one of the etiologic factors of female LUTS, even though no standardized urodynamics (UDS) criteria for DU have been defined in women. UDS including a pressure flow study is invasive-nature and give discomfort for the patients during UDS. Therefore, UDS is not a routine method for evaluation of LUTS. However, a pressure flow study is still a key procedure  because a pressure flow study may be only a method to discriminate BOO and DU from LUTS. Patients with DU or BOO usually have similar voiding symptoms. To establish the refined UDS criterion for DU, we tried to examine the criteria already published for DU. The aim of this study is to investigate and compare the four major UDS criteria for DU.

Retrospectively female patients with DU were selected from our pooled UDS database. DU was diagnosed if at least one of the following four criteria for DU was met. The 4 UDS criteria for DU were as follows; A) Pdet@Qmax≦10 and Qmax≦12(Jeong2012), B) Pdet@Qmax ≦ 30 and Qmax≦10 (Abarbanel2007), C) Pdet@Qmax≦20, Qmax≦15, and BVE<90% (Gammie2016), D) PIP1 (Pdet@Qmax+Qmax) <30 (Griffiths 2004). To investigate the presence of BOO in these DU patients, we used the following UDS criterion for BOO (Pdet@Qmax≧21 and Qmax≦11) (Lemack 2000).

Hundred-five patients (mean age 69.8±10.7) were selected using 4 UDS criteria from our female UDS database(N=365). The ages and UDS parameters of DU patients stratified according to the 4 UDS criteria is shown in table 1.The symptoms of these DU patients are as follows; a feeling of pressure in the pelvic area (pelvic organ prolapse) 34, stress urinary incontinence 33, difficulty on urination 14, pollakisuria 10, urgency urinary incontinence 8 and others 2. The Venn diagram (Figure 1) demonstrates the distribution and overlap of DU patients’ groups by 4 UDS criteria. No DU patients were selected by only A criterion.  Detrusor overactivity was found in 19 patients (18%:19/105) out of 105 DU patients. The number of patients diagnosed by D criterion Griffiths, which is PIP1, was 2 to 4 times as large as those diagnosed with other three criteria. Thirteen (28%, 13/46) out of the DU patients diagnosed using B criterion had BOO based on Lemack’s BOO criterion.

The reason for larger number of DU patients in D criterion, Griffiths’ PIP1, may be, not the simple combination of cutoff values of Qmax and Pdet@Qmax, but, different concept, Qmax+PdetQmax values. 
Some (28%) of DU patients diagnosed using B criterion (Abarbanel) had BOO  because high Pdet@Qmax value(=30cmH2O) in B criterion  may suggest  BOO (low flow and high pressure). B criterion may have weak power to discriminate between DU and BOO.

The diagnosis of detrusor underactivity were dependent on the DU criterion used. Some criteria may be difficult to discriminate between DU and BOO.  UDS criterion for DU should be carefully used with its limitation. We need more refined UDS criterion for female DU.

Continence 2S2 (2022) 100302
DOI: 10.1016/j.cont.2022.100302