Use of non-invasive uroflowmetry with simultaneous electromyography to monitor patient response to treatment for lower urinary tract conditions

A comparative study between EMG uroflowmetry with and without a catheter in children

OBJECTIVES

To evaluate the effect of urethral catheterization on the accuracy of EMG uroflowmetry in children with non-neurogenic voiding disorders during pressure-flow (PF) studies compared to the non-invasive EMG uroflowmetry test.

METHODS

A retrospective study of children undergoing a urodynamic evaluation at our institution between 8/2018 and 7/2022 was employed. Urination curves and pelvic floor muscle activity were compared between PF studies and non-invasive EMG uroflowmetry test. The non-invasive test was selected as the standard benchmark.

RESULTS

104 children were tested, with 34 children (33%) being able to urinate only in a non-invasive EMG uroflowmetry. The percentage of boys unable to urinate with a catheter was significantly higher than girls (54% vs. 13%, p-value < 0.001). In 70 children, a normal bell-shaped urination curve was found in 13 compared to 33 children in the PF studies and non-invasive uroflowmetry, respectively. PF studies demonstrated a specificity of 39% (95% CI 23-57) and a positive predictive value (PPV) of 61% (95% CI 53-67) in finding non-bell-shaped curves. Relaxation of pelvic muscles was found in 21 (30%) as opposed to 39 (55%) of children in invasive and non-invasive EMG uroflowmetry, respectively (p-value = 0.5).

CONCLUSION

The accuracy of PF studies in children, primarily in boys, compared to the non-invasive uroflowmetry, was poor. This may pose potential errors in diagnosis and subsequent treatment. We recommend completing a non-invasive EMG uroflowmetry in cases where the child refused to urinate, or pathology was found, requiring a modification in treatment.

Is it time to reconsider how we document pediatric uroflow studies?: A study from the SPU Voiding Dysfunction task force

BACKGROUND

Uroflowmetry is a non-invasive study used in the diagnosis and monitoring of treatment response for lower urinary tract disorders. For optimal clinical utility, uroflow studies rely on careful clinical interpretation by a trained provider, but currently there is a lack of accepted standardized normal values for the measured uroflow parameters in children. The International Children's Continence Society proposed standardizing the terminology for uroflow curve shapes. However, the patterning of curves is largely at the physician's subjective discretion.

OBJECTIVES

The aims of this study were to understand inter-rater reliability in interpreting uroflow curves and to define characteristics of uroflow curves that could be used to provide definitive criteria for uroflowmetry parameters.

METHODS

All members of the SPU Voiding dysfunction Task Force were invited to contribute deidentified uroflows to a centralized HIPAA complaint receiving database. All studies were then distributed to all raters for review. Each observer's findings were recorded according to ICCS criteria (ICCS), additional readings were done using a previously reported system which defined curves as smooth or fractionated (SF) and whether the shape resembled a bell, tower, or plateau (BTP). Flow indexes (Qact/Qest) (FI) for Qmax and Qavg were generated using formulas previously reported for children 4-12 and for patients≥12 years.

RESULTS

A total of 119 uroflow studies were read by 7 raters and curves were contributed from 5 sites. Kappa scores for the 5 readers from different institutions were 0.34 and 0.28 for the ICCS and BTP methods, respectively (both considered fair agreement). Kappa for smooth and fractionated curves was 0.70 (for each; considered substantial agreement), which were the two highest agreement scores obtained throughout the study. Discriminant analysis (DA) revealed that the FI Qmax was the dominant vector, and that the ICCS uroflow parameters have a total of 42.8% prediction rate in the training sample. Using DA of a smooth/fractionated system, the total prediction rates were 72% and 65.5% for smooth and fractionated, respectively.

DISCUSSION

Given the poor inter-rater agreement for analyzing uroflow curve pattern based on ICCS criteria in this study and others, one may find it reasonable to consider alternative approaches to describing and characterizing uroflow curves. Our study is limited by lack of EMG and post-void residual data.

CONCLUSIONS

For a more objective uroflow interpretation and comparison of studies among different centers, we recommend using our proposed system (based on FI, and smooth vs. fractionated curve pattern), which is more reliable.

Relationship between maximum voided volume obtained by bladder diary compared to contemporaneous uroflowmetry in men and women

INTRODUCTION

The 24-hour bladder diary is considered to be the gold standard for evaluating maximum voided volume (MVV). However, we observed that patients often have a greater MVV during office uroflowmetry than that seen in the bladder diary. The purpose of this study is to compare these two non-invasive methods by which MVV can be determined - at the time of uroflowmetry (Q-MVV), or by 24hour bladder diary (BD-MVV).

MATERIALS AND METHODS

This was an Institutional Review Board approved retrospective study of patients evaluated for LUTS who completed a 24hour bladder diary and contemporaneous uroflowmetry. For Q-MVV, the patient was instructed to wait to void until their bladder felt full. Sample means were compared, and Pearson's correlations were calculated between the Q-MVV and BD-MVV data across the total sample, women, and men.

RESULTS

Seven hundred seventy one patients with LUTS completed bladder diaries. Of these, 400 patients, 205 women and 195 men, had contemporaneous Q-MVV. Mean BD-MVV was greater than mean Q-MVV. However, Q-MVV was larger in a sizable minority of patients. There was a weak correlation between BD-MVV and Q-MVV. Furthermore, there was a difference ≥50% between Q-MVV and BD-MVV in 165 patients (41%).

CONCLUSIONS

The data suggest that there is a difference between the two measurement tools, and that the BD-MVV was greater than Q-MVV. For a more reliable assessment of MVV, this study suggests that both Q-MVV and BD-MVV should be assessed and that the larger of the two values is a more reliable assessment of MVV.

Is there a unique symptom in lower urinary tract dysfunction in children?

OBJECTIVES

Lower urinary tract symptoms (LUTS), particularly urgency, incontinence and intermittency are common in children and it is suggested that the specific symptoms may be used for definite diagnosis for LUT dysfunction (LUTD). This study was performed to investigate the relationship between each LUTD and its associated symptoms, using uroflowmetry/electromyography (UF/EMG) as a diagnostic tool.

METHODS

Each patient was categorized into one of four LUT conditions which were overactive bladder (OAB), dysfunctional voiding (DV), underactive bladder and primary bladder neck dysfunction (PBND), according to UF/EMG results. Patients' complaints and findings were documented by using voiding dysfunction symptom score, bladder diary, urine analysis and ultrasonography. In addition, a detailed history of bowel habits (including use of Rome III criteria) was obtained.

RESULTS

There were 189 children of which 106 were female. The OAB was the largest group including 91 patients, followed by the DV group which had 61 patients. The symptoms specific to any LUTD group were constipation and hesitancy (P < .05). Hesitancy was present in 89.4% with PBND and constipation was present in 78.6% of patients with DV. None of other symptoms were able to differentiate any LUTD group from the other.

CONCLUSIONS

While certain symptoms are often presumed by clinicians to imply specific diagnoses, the main outcome of this study is that there is a generally weak correlation between the specificity of symptoms and LUTD. Symptoms-based approach may lead to misdiagnosis in LUTD. Thus, it may be essential to focus on the underlying pathologies and UF/EMG test may help this.

Evaluation of Functional Bladder Capacity in Children with Nocturnal Enuresis According to Type and Treatment Outcome

Purpose

This study aimed to identify whether functional bladder capacity (FBC) differs among subgroups of nocturnal enuresis (NE) patients and can be used to predict treatment response.

Methods

A total of 69 children with NE were included in this study between July 2017 and February 2019 according to medical chart review, retrospectively. All patients completed a questionnaire about voiding symptoms and 48-hour frequency/volume (48-h F/V) charts. FBC was obtained from the 48-h F/V charts and uroflowmetry (UFM) with post-void residual volume (PVR). All patients were primarily treated with standard urotherapy and pharmacological therapy. The response rate was analyzed at 3 months after treatment.

Results

The mean age of the 69 patients (42 male, 27 female) was 83.3 ± 22.4 months (range, 5–13 years) at the first visit. The percentages of children with monosymptomatic NE (MNE) and non-monosymptomatic NE (NMNE) on the questionnaire were 40.6% (28/69) and 59.4% (41/69), respectively. FBC of all patients was lower than the normal range of expected bladder capacity, and there were no significant differences between measurement methods, NE types (MNE vs NMNE), or response rates (p > 0.05).

Conclusion

Children with NE had diminished FBC in both 48-h F/V charts and UFM with PVR. We found no difference in FBC by NE type or treatment outcome. Therefore, FBC cannot be used to distinguish between NE types or predict treatment responses.

Does small voided volume influence uroflowmetry curve patterns in Japanese children with daytime urinary incontinence?

BACKGROUND

A voided volume (VV) of <50% of the expected bladder capacity for age is considered small VV. It was recommended that a VV ≥50% of expected bladder capacity for age is required to assess uroflowmetry (UFM) curves because a small VV causes changes in UFM curve characteristics. However, no clear consensus has been reached on the criterion for evaluating UFM curve patterns.

OBJECTIVE

The aim of the study was to evaluate the reproducibility and characteristics of UFM curve patterns in children with daytime urinary incontinence (DUI) and with a variety of VVs.

METHODS

This study investigated 119 children (79 boys and 40 girls) with primary DUI who underwent UFM 3 times on the same day and were classified into two groups: small VV (<50% of expected bladder capacity for age) in 0-1 of the 3 UFM measurements (group 1; normal VV) or in 2-3 of the 3 UFM measurements (group 2; small VV). The authors then evaluated the agreement of UFM curve patterns among the 3 measurements, classifying complete, partial, or no agreement according to the number of identical curve patterns. The authors also evaluated the most characteristic patterns of UFM curve patterns for each group.

RESULTS

Group 1 comprised 45 children, and group 2 comprised 74 children. Rates of complete agreement (group 1, 24/45; group 2, 30/74), partial agreement (group 1, 19/45; group 2, 35/74), and no agreement (group 1, 2/45; group 2, 9/74) did not differ significantly between groups (p = 0.226). Bell curve patterns were significantly more common in group 1 than in group 2 (p = 0.025). Frequency of the tower pattern was significantly higher in group 2 than in group 1 (p = 0.006) (Summary table).

DISCUSSION

No differences in agreement rates of UFM curve patterns were seen between two groups (small and normal VV). The authors thus suggest that UFM curve patterns can be validly assessed in children with DUI and with small VV. It was found that the bell pattern was significantly more common among children with normal VV, whereas the tower pattern was significantly more common among children with small VV. The tower pattern reflects an overactive bladder. The present results suggest that some children have DUI that is not attributable to urgency.

CONCLUSION

Reproducibility of UFM curve patterns might be properly assessed even in children with DUI and with small VV. This result suggests the presence of various pathological conditions other than the conditions with urgency underlying DUI.

Uroflow measurement combined with electromyography testing of the pelvic floor in healthy children

AIMS

To investigate if the standard protocol for uroflowmetry, recommended by the International Children's Continence Society, remains accurate when integrating EMG measurement by means of superficial electrodes.

METHODS

A cross-sectional study was conducted including healthy children. Group A performed two direct repetitions of uroflowmetry in combination with electromyography (uroflow/EMG). Group B performed a preceding measurement of isolated uroflowmetry, followed by two randomized measurements of uroflowmetry with and without EMG. Interpretation of uroflow curve was assessor blinded by a pediatric urologist and secondly performed using the flow index methodology. Statistical analysis compared different voids within each group and between group A and B.

RESULTS

Eighty-three children were included and 206 uroflow measurements were obtained. In both groups statistical findings confirmed the hypothesis that it is preferable to perform an additional measurement before the use of uroflow/EMG. Although both groups showed improvement between voids, the group with initial uroflow measurement followed by uroflow/EMG measurement showed more improvement in concern of curve pattern. An initially better first void in group A, but no statistical difference between the second void in group A and uroflow/EMG testing in group B further demonstrates a higher improvement in group B. This suggests the use of a precedent uroflowmetry without EMG is preferable to immediate testing with EMG.

CONCLUSIONS

It should be mandatory to perform one measurement in advance to ensure the reliability of the results. It is suggested to initiate the procedure with a single uroflowmetry measurement followed by one measurement of uroflow with EMG testing.

Time Course of Treatment for Primary Enuresis With Overactive Bladder

PURPOSE

To characterize the course of treatment for nonmonosymptomatic enuresis with overactive bladder (OAB) in a real clinical setting.

METHODS

Data from 111 OAB patients with moderate to severe enuresis were analyzed. The baseline analysis included a questionnaire, voiding diary, uroflowmetry with postvoid residual urine measurement, and plain abdominal radiography of the kidneys, ureters, and bladder (KUB). Following standard urotherapy for 1 month, anticholinergic medication was administered with or without laxatives. Desmopressin was added if there was a partial response to OAB. Patients were followed every 3 months to evaluate the status of OAB and enuresis. Multivariate analysis was performed to identify predictors associated with the lack of complete response (CR) in enuresis at 12 months.

RESULTS

Following 12 months of treatment, 64% and 88% of patients experienced at least partial response in enuresis and OAB, respectively. Urgency improved more quickly than enuresis, supporting the need to address daytime symptoms before enuresis. Seventy-nine patients (71%) had fecal impaction on KUB and/or subjective constipation. The combination of anticholinergics with either laxatives or desmopressin fared better than anticholinergics alone. Daytime incontinence and anticholinergics- only treatment were associated with a lack of CR during 12 months of treatment.

Conclusions

The data confirmed the validity of addressing OAB before treating enuresis. The results of this study also highlight the need to address fecal impaction. Patients should be counseled about the need for a prolonged course of treatment before starting treatment. Anticholinergics should be accompanied with either desmopressin or laxatives for better control of enuresis.

The Role of Non-invasive Testing in Evaluation and Diagnosis of Pediatric Lower Urinary Tract Dysfunction

PURPOSE OF REVIEW

The symptoms of lower urinary tract dysfunction (LUTD) including urinary incontinence, frequency, and urgency are among the most common reasons children are referred to pediatric urologists. Despite this, the workup for LUTD is often time consuming and a source of frustration for patients, parents, and clinicians alike. In the current review, we summarize the important role non-invasive testing plays in the diagnosis and management of children with LUTD and to show how use of these tests can help avoid the need for more invasive testing in the majority of children.

RECENT FINDINGS

Non-invasive tests such urine studies, uroflowmetry ± simultaneous electromyography, assessment of post-void residual, renal/bladder ultrasound, and pelvic ultrasound when used appropriately can provide valuable information to facilitate decision making during the evaluation of children with LUTD. While these tests should be employed prior to more invasive testing such as urodynamic studies, they can often act as a surrogate for the more invasive tests. Non-invasive tests can help us in our goal of improving diagnostic ability to better classify the child's LUTD into an actual condition which allows targeted treatment in the hope of better outcomes and more satisfied patients and families.

How can we maximize the diagnostic utility of uroflow?: ICI-RS 2017

AIMS

To gauge the current level of diagnostic utility of uroflowmetry and to suggest areas needing research to improve this.

METHODS

A summary of the debate held at the 2017 meeting of the International Consultation on Incontinence Research Society, with subsequent analysis by the authors.

RESULTS

Limited diagnostic sensitivity and specificity exist for maximum flow rates, multiple uroflow measurements, and flow-volume nomograms. There is a lack of clarity in flow rate curve shape description and uroflow time measurement.

CONCLUSIONS

There is a need for research to combine uroflowmetry with other non-invasive indicators. Better standardizations of test technique, flow-volume nomograms, uroflow shape descriptions, and time measurements are required.

Evaluation of bladder capacity in children with lower urinary tract symptoms: Comparison of 48-hour frequency/volume charts and uroflowmetry measurements

INTRODUCTION

Objective evaluation of bladder capacity (BC) in children with lower urinary tract symptoms (LUTS) is important for recognizing types of bladder dysfunction. Bladder capacity is evaluated from 48-hour frequency/volume (48-h F/V) charts or by uroflowmetry with ultrasound post-void assessment. There are limited data on the reliability of both methods of assessment in children.

OBJECTIVE

The aim of the study was to compare two modalities of assessment, (F/V chart and uroflowmetry) in cohorts of children with bladder dysfunctions.

STUDY DESIGN

Maximum bladder capacity (MBC) obtained from 48-h F/V charts was compared with volumes calculated from uroflowmetry in a cohort of 86 children with different bladder dysfunctions. The BC obtained by the two modalities was compared for the three most frequent subtypes of bladder dysfunction: monosymptomatic nocturnal enuresis (MNE), overactive bladder (OAB), and dysfunctional voiding (DV). Considering a 48-h F/V chart as standard, the sensitivity, specificity, negative and positive predictive values of uroflowmetry measurements were calculated for detecting low bladder capacity.

RESULTS

The mean maximal bladder capacity (188 ± 99.42 ml) obtained from home 48-h F/V chart measurement was 17 ml lower than the mean value obtained from uroflowmetry (205 ± 112.11 ml) (P = 0.58). The differences between bladder capacities estimated by 48-h F/V chart and uroflowmetry for subjects were not significant (Figure). Concordance between 48-h F/V chart and uroflowmetry categorization of BC was present in 64 (74%) subjects. The sensitivity and specificity of uroflowmetry, in comparison with 48-h F/V chart evaluation, for recognizing low bladder capacity were 75.5% and 73.17%. The sensitivity and specificity for the different types of LUTS achieved 68.42% and 58.83% for OAB, 80% and 83% for MNE, and 50% and 83.3% for DV.

DISCUSSION

According to the International Children's Continence Society, the management of MNE in children can be made without uroflowmetry. History and MBC evaluation by 48-h F/V charts yields sufficient information. Nevertheless, in situations where F/V charts are unreliable or unavailable, uroflowmetry can be used as an alternative method. The highest discrepancy between both methods of BC evaluation was found in DV; this was mainly due to the mean PVR of 31 ml.

CONCLUSION

For children with MNE, both 48-hour frequency/volume charts and triplicate urine flow measurement with PVR evaluation are reliable methods of maximum bladder capacity evaluation. For children with OAB or DV, both methods may be necessary for accurate evaluation of decreased BC, as F/V chart and uroflow results may not be comparable.