The Place of Single Channel Cystometry for Evaluation of Bladder Dysfunction

Objectives: Complex urodynamic study (UDS) and single channel cystometry (SCC) each can be helpful in the assessment of bladder storage function, stress urinary incontinence (SUI) and detrusor overactivity (DO). Our objective is to evaluate correlation between these two tests, their accuracy, and whether there is any benefit if both tests are performed on the same patient.

Methods: We conducted a retrospective chart review of women aged >18 years who underwent both UDS and SCC from January 1, 2019, to December 31, 2022, at a University Hospital. After chart review, 609 consecutive women met the criteria for inclusion in the analysis. Data were extracted by manual chart review. Filling parameters including first sensation, first urge, second urge, and maximum capacity were compared, between the groups. Maximum capacity was capped at 300 cc for the SCC and at 900 cc for UDS testing. SUI for each testing method was defined as observation of leakage of urine during the cough stress test portion of each testing method. DO was defined by a provoked or unprovoked, involuntary detrusor contraction during the filling phase on UDS or a rise in fluid level in the syringe during the filling phase of SCC. For the sensitivity and specificity analysis for SUI and DO, UDS was used as the gold standard.

Results: Baseline demographics are listed as Table 1. Each patient served as their own control for each test. Filling capacity had a weak Pearson correlation (r) for first sensation r= 0.30 (p < 0.0001), first urge r=0.38 (p < 0.0001), second urge 0.40 (p < 0.0001) and max capacity r=0.43 (p < 0.0001). SCC DO detection had a sensitivity of 0.34 ± 0.05, specificity of 0.88 ± 0.02, positive predictive value (PPV) 0.38 ± 0.05, and negative predictive value (NPV) of 0.86 ± 0.02. SCC SUI detection had a sensitivity of 0.77 ± 0.02, specificity of 0.55 ± 0.04, PPV of 0.79 ±0.02 and NPV 0.53 ± 0.03. When UDS was performed in conjunction with SCC an additional 14% of patients (n=87) were found to have SUI. Additionally, SCC found 15% (n=92) patients with SUI who would have been missed if only UDS was performed (Figure 1).

Conclusions: Overall, correlation between SCC and UDS with respect to filling phase parameters is low. The SCC testing showed that it had a strong positive predictive value for SUI and might be useful to document SUI at initial new patient visits as it also had a strong negative predictive value. Ultimately, detection of SUI was increased by 30% by performing both tests, which may have significant clinical implications.