Ulrich Mehnert

Urodynamic investigation (UDI) is the gold standard for evaluating refractory lower urinary tract symptoms but may cause pain, emotional discomfort, and adverse events, particularly urinary tract infections. In this secondary analysis of a randomized controlled trial, adults undergoing UDI for neurogenic lower urinary tract dysfunction rated pain and emotional discomfort on an 11-point numeric rating scale (0–10), with ≥ 4 defining moderate-to-severe burden; a structured telephone interview at 7–14 days assessed post-procedural adverse events. Among 490 patients, most reported low pain and emotional discomfort (median 2, IQR 0–4 and 0–5). Pain did not differ by sex, whereas emotional discomfort was higher in females (median 2.5 vs 1; p = 0.004). Post-procedural symptoms included pain (30%), worsening lower urinary tract symptoms (18%), and macrohematuria (8%); 99% were transient. Urinary tract infection occurred in 6% and was associated with pre-procedural bacteriuria (OR 6.69; 95% CI 2.15–20.81). Assuming risk equalization, the number needed to treat to prevent one infection was 15 (95% CI 9.6–38.6). In conclusion, UDI is generally well tolerated, although approximately one-third of patients experience moderate-to-severe pain or emotional discomfort. Pre-procedural bacteriuria increases infection risk, but the number needed to treat does not support antibiotic prophylaxis.

Objectives: To evaluate if bladder washing cytology (BWC) provides a diagnostic benefit in the initial evaluation of patients with neuro‐urological disorders. Patients and Methods: This prospective cross‐sectional study investigated a consecutive series of patients with lower urinary tract symptoms referred for neuro‐urological evaluation at our department of neuro‐urology who underwent urethro‐cystoscopy (UC) and BWC from 2018 to 2023. Results: Among 581 neurological patients, 274 (47.2%) were females. Tumour‐suspicious findings leading to surgical intervention were detected in 17 (2.9%) by UC alone and in three (0.5%) by BWC but unsuspicious UC, respectively. Overall, relevant histological findings after transurethral bladder surgery (TUBS) were detected in eight (1.4%, 95% confidence interval [CI] 0.6–2.7%) patients: keratinising squamous metaplasia (two) and non‐muscle‐invasive urothelial carcinoma (six), all were initially identified by UC. Three patients refused surgery, two of whom had positive BWC without suspicious lesion in UC. Sensitivity and specificity of BWC referenced to UC alone were 0% (95% CI 0.0–36.9%) and 99.7% (95% CI 98.7–99.9%), respectively. Adding BWC to UC increased costs by 22.8% without improving tumour detection. The main study limitation was the lack of true positives in BWC. Conclusions: Bladder washing cytology in addition to UC is not justified in the initial evaluation of patients with neuro‐urological disorders as decision making regarding TUBS is based on UC findings. Moreover, omission of BWC saves relevant costs without compromising patient safety.

Objective: To evaluate sex differences in maximum storage detrusor pressure (Pdet _max storage), focusing on Pdet _max storage ≥40 cmH ₂ O, an established risk factor for upper urinary tract damage, within the first year after spinal cord injury (SCI). Patients and Methods: A cohort of patients with neurogenic lower urinary tract dysfunction due to acute traumatic or ischaemic SCI, managed according to the European Association of Urology Guidelines on Neuro‐Urology, prospectively underwent urodynamic investigations at 1, 3, 6 and 12 months after SCI at a university SCI centre. Pearson's chi‐squared tests and multivariable regression analyses were used to compare outcomes between females and males. Results: Of 97 patients, 34% were female. Within the first year after SCI, 9% of females presented with a Pdet _max storage ≥40 cmH ₂ O, compared to 55% of males ( P < 0.001). Females had lower Pdet _max storage than males, with a grand mean (standard deviation [SD]) of 13 (9) vs 30 (20) cmH ₂ O (coefficient = 18 cmH ₂ O, 95% confidence interval [CI] 13–24 cmH ₂ O; P < 0.001). Females also had lower detrusor overactivity leak‐point pressure (DOLPP) than males, with a grand mean (SD) of 15 (4) vs 35 (21) cmH ₂ O (coefficient = 20 cmH ₂ O, 95% CI 11–29 cmH ₂ O; P < 0.001). The cumulative incidence of antimuscarinic therapy and reported urinary incontinence was similar between sexes (female vs male: 55% vs 70%, P = 0.12; 53% vs 43%, P = 0.42, respectively). Conclusions: Females rarely reached a Pdet _max storage ≥40 cmH ₂ O during the first year after SCI and had lower Pdet _max storage and DOLPP than males. However, the prevalence of urinary incontinence was similar between the sexes, suggesting the need for a more sex‐tailored approach to patient management.

Objectives: To determine whether air‐filled systems (AFS) provide comparable urodynamic investigation (UDI) trace quality to water‐filled systems (WFS), the recommended standard by the International Continence Society. Patients and Methods: A total of 490 patients undergoing UDI from April 2021 to January 2022 were included in this non‐inferiority randomised controlled trial. Eligible patients were female and male adults with neurogenic lower urinary tract dysfunction (NLUTD). Patients were allocated by block randomisation in a 1:1 ratio to undergo UDI using a WFS ( n = 244) or an AFS ( n = 246). The primary endpoint was artefact susceptibility evaluated by a ‘blinded’ assessor using a modified ‘Bristol UTraQ’ quality scoring scale ranging from 0 to 18, with higher scores indicating a better quality. A clinically meaningful non‐inferiority margin was pre‐specified as −2 points on the quality scoring scale (AFS‐WFS). Results: The median (interquartile range [IQR]) overall quality score was 14.5 (13.5–15.5) points for the WFS and 15.5 (14.5–16.5) points for the AFS. Inferiority of AFS could be rejected at the pre‐specified non‐inferiority margin (0.96, 95% confidence interval 0.68–1.25; P < 0.001). Artefacts were more frequent in WFS. Typical artefacts consisted of repeat rectal contractions, poor pressure transmission during cough test at empty bladder, and detrusor resting pressure outside of the physiological range at empty bladder. Conclusions: Our results indicate that AFS are non‐inferior to WFS regarding overall urodynamic trace quality in patients with NLUTD.

Objective: To characterize structural integrity of the lumbosacral enlargement and conus medullaris within one month after spinal cord injury (SCI).Methods: Lumbosacral cord MRI data were acquired in patients with sudden onset (<7 days) SCI at the cervical or thoracic level approximately one month after injury and in healthy controls. Tissue integrity and loss were evaluated through diffusion tensor (DTI) and T2*‐weighted imaging (cross‐sectional area [CSA] measurements). Associations with the degree of neurological impairment were assessed using linear mixed‐effects models.Results: Twenty‐one patients with SCI showed lower white matter (WM) fractional anisotropy (FA) (≤−13.3%) and higher WM radial diffusivity (≤14.6%) compared to 27 healthy controls. Differences were most pronounced in the lateral columns of WM. CSA measurements revealed no group differences. For the lateral columns, lower FA values were associated with lower motor scores and lower amplitudes of motor evoked potentials. For the dorsal columns, lower FA values were associated with lower amplitudes of somatosensory evoked potentials from the lower extremities.Interpretation: One month after SCI, first signs of WM degeneration were apparent, without indication of tissue loss. The more pronounced differences observed in the lateral column could be attributed to anterograde degeneration of the motor tracts. The variability among DTI measurements remote from the lesion site can be partially explained by the degree of the SCI‐induced neurological impairment. Together with previous studies, our findings indicate that impaired tissue integrity precedes tissue loss. The presented techniques have potential applications in monitoring the progression of various neurological diseases.

Background: Patients with neurogenic lower urinary tract dysfunction (NLUTD) often rely on some type of catheterization for bladder emptying. Intermittent catheterization (IC) is considered the gold standard and is preferred over continuous catheterization, since it is considered to cause fewer urinary tract infections (UTIs) than indwelling catheterization. The main objective of our study was to describe UTI prevalence (at visit) and incidence (within the last 12 months) and urine culture characteristics between patients using an indwelling catheter versus (vs) those performing IC. Methods: In this cross-sectional study, we prospectively evaluated from 02/2020 to 01/2021 patients with NLUTD undergoing urine cultures for prophylactic reasons or due to UTI symptoms. At visit, all patients underwent a standardized interview on current UTI symptoms as well as UTI history and antibiotic consumption within the past year. Patients using an indwelling catheter (n = 206) or IC (n = 299) were included in the analysis. The main outcome was between-group differences regarding UTI characteristics. Results: Patients using an indwelling catheter were older (indwelling catheter vs IC: median 66 (Q1-Q3: 55—77) vs 55 (42—67) years of age) and showed a higher Charlson comorbidity index (indwelling catheter vs IC: median 4 (Q1-Q3: 2–6) vs 2 (1–4) (both p < 0·001). A total of 40 patients from both groups were diagnosed with a UTI at visit (indwelling catheters vs IC: 8% (16/206) vs 8% (24/299); p = 0·782), and the number of UTIs within the past 12 months was not significantly different between groups. Overall, Escherichia coli (21%), Enterococcus faecalis (17%), and Klebsiella spp. (12%) were the most frequently detected bacteria. Conclusions: In this cohort of patients with NLUTD, we did not find relevant differences in UTI frequency between groups. These results suggest that UTI-related concerns should not be given undue emphasis when counseling patients for catheter-related bladder emptying methods.

Transcutaneous tibial nerve stimulation (TTNS) is a promising treatment for neurogenic lower urinary tract symptoms. However, the evidence is limited due to a general lack of randomised controlled trials (RCTs) and, also, inconsistency in the sham and blinding conditions. In the context of much-needed RCTs, we aimed to develop a suitable sham-control protocol for a clinical setting to maintain blinding but avoid meaningful stimulation of the tibial nerve. Three potential electrode positions (lateral malleolus/5th metatarsal/plantar calcaneus) and two electrode sizes (diameter: 2.5 cm/3.2 cm) were tested to determine which combination provided the optimal sham configuration for a TTNS approach, based on a visible motor response. Sixteen healthy volunteers underwent sensory and motor assessments for each sham configuration. Eight out of them came back for an extra TTNS visit. Sensory thresholds were present for all sham configurations, with linear regression models revealing a significant effect regarding electrode position (highest at plantar calcaneus) but not size. In addition, motor thresholds varied with the position—lowest for the 5th metatarsal. Only using this position and 3.2 cm electrodes attained a 100% response rate. Compared to TTNS, sensory and motor thresholds were generally higher for the sham configurations; meanwhile, perceived pain was only higher at the lateral malleolus. In conclusion, using the 5th metatarsal position and 3.2 cm electrodes proved to be the most suitable sham configuration. Implemented as a four-electrode setup with standardized procedures, this appears to be a suitable RCT protocol for maintaining blinding and controlling for nonspecific TTNS effects in a clinical setting.

We used clinical parameters to develop a prediction model for the occurrence of urodynamic risk factors for upper urinary tract (UUT) damage during the first year after acute spinal cord injury (SCI). A total of 97 patients underwent urodynamic investigation at 1, 3, 6, and 12 months after acute SCI, within the framework of a population-based longitudinal study at a single university SCI center. Candidate predictors included demographic characteristics and neurological and functional statuses 1 month after SCI. Outcomes included urodynamic risk factors for UUT damage: detrusor overactivity combined with detrusor sphincter dyssynergia, maximum storage detrusor pressure (pDetmax) ≥ 40 cmH₂O, bladder compliance < 20 mL/cmH₂O, and vesicoureteral reflux. Multivariable logistic regression was used for the prediction model development and internal validation, using the area under the receiver operating curve (aROC) to assess model discrimination. Two models showed fair discrimination for pDetmax ≥ 40 cmH₂O: (i) upper extremity motor score and sex, aROC 0.79 (95% CI: 0.69–0.89), C-statistic 0.78 (95% CI: 0.69–0.87), and (ii) neurological level, American Spinal Injury Association Impairment Scale grade, and sex, aROC 0.78 (95% CI: 0.68–0.89), C-statistic 0.76 (95% CI: 0.68–0.85). We identified two models that provided fair predictive values for urodynamic risk factors of UUT damage during the first year after SCI. Pending external validation, these models may be useful for clinical trial planning, although less so for individual-level patient management. Therefore, urodynamics remains essential for reliably identifying patients at risk of UUT damage.

Objective: To present the protocol for a randomized controlled trial (RCT) evaluating the efficacy and safety of transcutaneous tibial nerve stimulation (TTNS) for refractory neurogenic lower urinary tract dysfunction (NLUTD). Study Design and Results: bTUNED (bladder and TranscUtaneous tibial Nerve stimulation for nEurogenic lower urinary tract Dysfunction) is an international multicentre, sham‐controlled, double‐blind RCT investigating the efficacy and safety of TTNS. The primary outcome is success of TTNS, defined as improvements in key bladder diary variables at study end compared to baseline values. The focus of the treatment is defined by the Self‐Assessment Goal Achievement (SAGA) questionnaire. Secondary outcomes are the effect of TTNS on urodynamic, neurophysiological, and bowel function outcome measures, as well as the safety of TTNS. Conclusions: A total of 240 patients with refractory NLUTD will be included and randomized 1:1 into the verum or sham TTNS group from March 2020 until August 2026. TTNS will be performed twice a week for 30 min during 6 weeks. The patients will attend baseline assessments, 12 treatment visits and follow‐up assessments at the study end.