Radical cystectomy (RC) is a standard treatment for patients with advanced or high-risk non-muscle invasive bladder cancer (NMIBC). Although orthotopic neobladder (ONB) generally improves quality of life (QoL), the frequent occurrence of voiding dysfunctions and lower urinary tract symptoms (LUTS) may significantly affect post-operative outcomes. Despite the possible importance of urodynamic studies (UDS) in assessing the functionality of ONB, there is limited evidence on standardized protocols for their execution, terminology and interpretation. The primary objective of this survey is to investigate how and when major Italian oncological centres perform UDS on patients with ONB, aiming to identify common practices and potential areas for standardization.

A survey consisting of 32 items was developed to investigate the terminology and procedures adopted in conducting UDS on ONB. This survey was distributed via email to Italian oncological centres between September 2024 and January 2025. Responses were collected using the Google Forms® platform. Descriptive statistics were used to report the survey results. Centres performing fewer than 10 RCs per year were excluded.

Approximately 37% of the contacted centres responded to the survey and most were general hospitals (63.6%). The most adopted techniques were the VIP (38.1%) and Studer (28.6%) neobladders. Only 13.6% conducted UDS systematically on all patients, regardless of LUTS. 
The timing of UDS varied with 31.8% performed it at 6 months post-surgery, 13.6% at 3 months, and 4.5% at 12 months. Antibiotic prophylaxis is administered by 71.4% of centres using different antibiotics.
All centres performed uroflowmetry before UDS and water-filled catheters were preferred over air-filled ones (13:1 ratio). Cystomanometry was performed with infusion rates ranging from 20 to 50 mL/min. The first sensation of filling was described as any abdominal change in 71.4% of cases. There was no consensus on normal ONB pressure values or thresholds for stopping filling. Valsalva and cough manoeuvres were performed at various filling stages in 42.8% of cases. 
During the pressure-flow study, 85.7% reported neobladder pressure at Qmax, with 92.9% including maximum pressure values in medical reports. Presence of obstruction was evaluated in 36.4% of cases using native bladder nomograms. The assessment of post-void residual (PVR) was conducted via ultrasound (49.5%) or catheterization (49.5%), with 1% using volume difference calculations showing significant heterogeneity. The acceptable threshold for PVR varying: 31.8% considered ≤ 100 ml acceptable, while others set the thresholds at ≤ 150 ml (13.6%) or ≤ 50 ml (13.6%).

A significant variation was observed in the timing of UDS assessments, ranging from 3 to 12 months post-surgery. There was also considerable variability in the definition of key filling parameters, such as the first sensation of bladder filling. Moreover, no consensus was found regarding normal neobladder pressure values or the thresholds for stopping the filling phase.
Notably, parameters originally designed for the intact native bladder are frequently applied to the ONB, raising concerns about their appropriateness. The results of this survey highlight substantial heterogeneity in the assessment and interpretation of functional outcomes, emphasizing the need for standardized protocols and guidelines.

Based on this Italian survey, while UDS is an essential tool for assessing neobladder function and evaluating patients' LUTS, only a minority of centres perform these studies systematically on all patients. This suggests that UDS is often reserved for patients exhibiting urinary symptoms, potentially leading to an underdiagnosis of functional impairments.
Appropriate guidelines are needed to standardize assessments and ensure the comparability of functional outcomes and improving the management of LUTS in ONB patients.