Clinical significance of urodynamic study parameters in maintenance of renal function in spinal cord injury patients

Duration of detrusor overactivity as an independent predictive factor of upper urinary tract deterioration in patients with traumatic spinal cord injury: results of a retrospective cohort study

OBJECTIVE

To determine whether duration of detrusor overactivity (DO) during a cystometric study is an independent predictive factor of upper urinary tract deterioration (UUTD) in patients with traumatic spinal cord injury (TSCI).

STUDY DESIGN

Retrospective cohort study.

SETTING

A rehabilitation facility in Chiang Mai, Thailand.

METHODS

Data were obtained from medical records of patients who underwent cystometric evaluation at 6-12 months after TSCI. The independent predictor of interest is the duration of DO, which was evaluated by the DO/cystometry ratio (DOratio). Other conventional urodynamic parameters (maximum detrusor pressure, cystometric capacity, bladder compliance, and detrusor-sphincter dyssynergia) and clinical parameters (age, sex, level and severity of injury, comorbidities, bladder emptying method, and history of urinary tract infection) were determined. The outcome was UUTD, which is indicated by chronic kidney disease (GFR < 60 ml/min/1.73 m2), hydronephrosis, and/or vesicoureteral reflux. Multivariable Cox regression analysis was used to determine the independent associations between DOratio and UUTD by adjusting with all other parameters.

RESULTS

Medical records of 194 patients with TSCI were included in the study. During a combined total of 1260 follow-up years of those patients, 34 UUTD events were identified, indicating an incidence rate of 27.0 cases per 1000 person-years. After adjusting for all other parameters, a high DOratio (≥0.33) was significantly associated with UUTD (hazard ratio = 3.00 [95% CI: 1.12-7.99], p = 0.025).

CONCLUSION

DOratio may be an independent cystometric predictor of UUTD in patients with TSCI. However, further prospective study is needed prior to applying DOratio as a predictor of UUTD in clinical settings.

CLINICAL TRIAL REGISTRATION

There was no clinical trial registration since this study is not a clinical trial.

Urologic surveillance of persons with spinal cord injuries - a scoping review

STUDY DESIGN

Scoping review - standardized according to the Equator-network and the Prisma-Statement guidelines with PRISMA-ScR.

OBJECTIVES

Review the literature concerning surveillance of the urinary- and renal systems in persons with spinal cord injuries (SCI). Specifically, to assess: #1 the usability of non-invasive and non-ultrasound methods, #2 the usage of systematic ultrasound surveillance #3 patient characteristics which predispose to urinary tract abnormalities (UTA) or renal function deterioration.

METHODS

The literature assessed was collected from PubMed by creating a search string comprised of three main phrases: #1 persons with SCI, #2 kidney function and #3 surveillance program. The final search resulted in 685 studies. Eligibility criteria were defined prior to the search to assess the studies systematically.

RESULTS

Four studies found serum cystatin C (s-cysC) to be accurate in estimating the glomerular filtration rate in persons with SCI. One study found no difference in UTA between surveillance adherent and surveillance non-adherent persons up to 30 years post injury. UTA and especially renal function deterioration seems rare the first 15 years post-injury. Non-traumatic SCI, time since injury, high detrusor pressure, upper urinary tract dilation, vesicourethral reflux, trabeculated bladder, history of calculi removal are significant risk factors for developing UTA or renal function deterioration.

CONCLUSION

Measurements of S-cysC should be considered to replace serum creatinine in most cases. Surveillance non-adherent persons are not at higher risk of developing UTA. A selective surveillance based on a baseline risk profile may be beneficial for patients and caretakers.

Urodynamics Are Essential to Predict the Risk for Upper Urinary Tract Damage after Acute Spinal Cord Injury

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.

Assessing Neurogenic Lower Urinary Tract Dysfunction after Spinal Cord Injury: Animal Models in Preclinical Neuro-Urology Research

Neurogenic bladder dysfunction is a condition that affects both bladder storage and voiding function and remains one of the leading causes of morbidity after spinal cord injury (SCI). The vast majority of individuals with severe SCI develop neurogenic lower urinary tract dysfunction (NLUTD), with symptoms ranging from neurogenic detrusor overactivity, detrusor sphincter dyssynergia, or sphincter underactivity depending on the location and extent of the spinal lesion. Animal models are critical to our fundamental understanding of lower urinary tract function and its dysfunction after SCI, in addition to providing a platform for the assessment of potential therapies. Given the need to develop and evaluate novel assessment tools, as well as therapeutic approaches in animal models of SCI prior to human translation, urodynamics assessment techniques have been implemented to measure NLUTD function in a variety of animals, including rats, mice, cats, dogs and pigs. In this narrative review, we summarize the literature on the use of animal models for cystometry testing in the assessment of SCI-related NLUTD. We also discuss the advantages and disadvantages of various animal models, and opportunities for future research.

The Utility of Urodynamic Studies in Neuro-Urological Patients

INTRODUCTION

The utility of a clinical tool lies in its clinical performance evaluation and describes the relevance and usefulness of that tool in a medical setting. The utility of urodynamic and video-urodynamic studies in the management of specific urodynamic profiles in the diagnosis, treatment, and prognostic approach in neuro-urological patients is the focus of the current review.

METHODS

For this narrative review, a PubMed^® search was performed by cross-referencing the keywords "urodynamics", "neurogenic bladder", "utility", "clinical utility" and "clinical performance" with various terms related to the management of neurogenic lower urinary tract dysfunction. Clinical practice guidelines and landmark reviews from the most renowned experts in the field were also used.

ANALYSIS

Assessment of the utility of urodynamic study was performed during the diagnostic, therapeutic and prognostic steps of the neuro-urological patients' management. We focused on its clinical performance in the identification and evaluation of several unfavorable events, such as neurogenic detrusor overactivity, detrusor-sphincter dyssynergia, elevated detrusor leak point pressure and the presence of vesico-ureteral reflux, which may be indicators for a higher risk for the development of urological comorbidities.

CONCLUSION

Despite the paucity of existing literature assessing the utility of urodynamic study-specifically video-urodynamic study-in neuro-urological patients, it does remain the gold standard to assess lower urinary tract function precisely in this patient category. With regard to its utility, it is associated with high clinical performance at every step of management. The feedback on possible unfavorable events allows for prognostic assessment and may lead us to question current recommendations.

Temporal development of unfavourable urodynamic parameters during the first year after spinal cord injury

OBJECTIVES

To describe the temporal development of and risk factors for the occurrence of unfavourable urodynamic parameters during the first year after spinal cord injury (SCI).

PATIENTS AND METHODS

This population-based longitudinal study used data from 97 adult patients with a single-event traumatic or ischaemic SCI who underwent video-urodynamic investigation (UDI) at a university SCI centre. The first occurrences of unfavourable urodynamic parameters (detrusor overactivity combined with detrusor sphincter dyssynergia [DO-DSD], maximum storage detrusor pressure ≥40 cmH₂ O, bladder compliance <20 mL/cmH₂ O, vesico-ureteric reflux [VUR] and any unfavourable parameter [composite outcome]) were evaluated using time-to-event analysis.

RESULTS

The majority of the population (87/97 [90%]) had at least one unfavourable urodynamic parameter. Most unfavourable urodynamic parameters were initially identified during the 1- or 3-month UDI, including 92% of the DO-DSD (78/85), 82% of the maximum storage pressure ≥40 cmH₂ O (31/38), and 100% of the VUR (seven of seven) observations. No low bladder compliance was observed. The risk of DO-DSD was elevated in patients with thoracic SCI compared to those with lumbar SCI (adjusted hazard ratio [aHR] 2.38, 95% confidence interval [CI] 1.16-4.89). Risk of maximum storage detrusor pressure ≥40 cmH₂ O was higher in males than females (aHR 8.33, 95% CI 2.51-27.66), in patients with a cervical SCI compared to those with lumbar SCI (aHR 14.89, 95% CI 3.28-67.55), and in patients with AIS Grade B or C compared to AIS Grade D SCI (aHR 6.17, 95% CI 1.78-21.39). No risk factors were identified for the composite outcome of any unfavourable urodynamic parameter.

CONCLUSIONS

The first UDI should take place within 3 months after SCI as to facilitate early diagnosis of unfavourable urodynamic parameters and timely treatment. Neuro-urological guidelines and individualised management strategies for patients with SCI may be strengthened by considering sex and SCI characteristics in the scheduling of UDIs.

Efficacy, according to urodynamics, of OnabotulinumtoxinA compared with antimuscarinic drugs, for neurogenic detrusor overactivity: a systematic review and network meta-analysis

To summarize the differences in urodynamic outcomes between oral antimuscarinic drugs and OnabotulinumtoxinA, and finding a therapy that maintains good urodynamics in neurogenic detrusor overactivity (NDO). We conducted a literature search of EMBASE and PubMed, with the language limited to English. In the analysis, all of the published randomized trials of OnabotulinumtoxinA or antimuscarinic drugs used to treat NDO were found and the results were finally obtained through Bayesian model analysis. A total of 12 RCTs and 2208 patients were included. OnabotulinumtoxinA 300U was superior to other drugs in terms of MCC, volume at IDC, and Pdet_max endpoints. OnabotulinumtoxinA 200U was more effective on the urodynamic endpoint of BC than other drugs or doses of OnabotulinumtoxinA. According to the MCC urodynamic results, oxybutynin, solifenacin 10 mg, and tolterodine 4 mg also had positive effects. OnabotulinumtoxinA 300U, 200U and 100U were better in improving the urodynamic results of NDO, and the current evidence also shows that selective injection of onabotulinumtoxinA can effectively improve the urodynamic results.

Clinical utility of the maximum area of detrusor tracing measurement in the urodynamic studies in pediatric population diagnosed with neuropathic bladder: A pilot study

INTRODUCTION

Neuropathic bladder (NB) is a lower urinary tract dysfunction (LUTD) that may lead to kidney failure. Urodynamic study is the gold standard for its diagnosis and follow-up. A classic prognostic parameter to predict the risk of upper urinary tract damage (UUTD) is the detrusor leak point pressure (DLPP) ≥  40 cmH2O, although this factor alone may lack prognostic value. The area under the curve (AUC) of the detrusor pressure tracing has been recently described as a prognostic factor.

AIM

To analyze the clinical utility of the AUC of the detrusor pressure tracing in the pediatric population (<15 years).

METHODS

Retrospective study of urodynamic recordings in pediatric population with NB from 2011 to 2020. The following variables were evaluated: detrusor leak point pressure ≥ 40 cmH2O, voiding dysfunction, bladder compliance and overactivity. The sample is classified according to clinical-radiological findings at the time of the UD. AUC is calculated using Newton-Cotes rules (trapezium, Simpson's rule) and its indexes are calculated according to bladder capacity (TI: Trapezium Index, SI: Simpson Index). Statistical significance: P < .05.

RESULTS

Fifty-five recordings are analyzed. Unfavorable clinical condition was identified in 41.8% (n = 23) patients. Voiding dysfunction, low compliance and both indexes were associated with an unfavorable clinical condition (P < .05). ROC analysis showed the following AUC for the new indexes: TI (0.736, P = 0.0006), SI (0.755, P = .0001) with a cut-off value of 10,69 and 8 cmH2O·s/cc, respectively. We did not find differences in the diagnostic performance between them (P > .05).

CONCLUSIONS

The analyzed indexes are useful in the diagnosis of patients with NB and unfavorable clinical condition.

The Stockholm Spinal Cord Uro Study: 3. Urodynamic characteristics in a regional prevalence group of persons with spinal cord injury and indications for improved follow-up

AIMS

Examine the outcome of urodynamic studies in a regional prevalence group of patients with traumatic spinal cord injury (SCI), explore relationships between urodynamic parameters and renal complications/other SCI-related dysfunctions, assess the role of urodynamics in SCI follow-up.

METHODS

In a cross-sectional study, 211 patients were included, who attended a yearly check-up and had urodynamics performed as part of the follow-up in addition to S-creatinine, S-cystatin-C, renal ultrasound, and a questionnaire regarding complications. Relationships between urodynamic parameters and renal complications/other SCI-related dysfunctions were explored by descriptive and comparative statistics.

RESULTS

Neurogenic detrusor overactivity (NDO) was found in 150, underactive/acontractile detrusor in 44, normal detrusor function in 17 patients. Maximum detrusor pressures during filling/voiding in NDO attained mean levels of >40 cm H₂O in 68% of patients and >25 cm H₂O in 83%. Reduced compliance of the bladder wall, cystometric bladder capacity <250 mL, and detrusor overactivity leakage during filling were associated with higher detrusor pressures. Detrusor overactivity during more than one-third of the filling phase was significantly related to signs of renal complications among patients with SCI duration 11-20 years. No significant relationships were found between other urodynamic parameters and renal/other SCI-related complications. Renal complications in underactive/acontractile and normal detrusor function co-varied with evidence of previous NDO and other co-morbidities which may negatively influence kidney function.

CONCLUSIONS

Maximum detrusor pressures during the filling/voiding phases attained high levels in a majority of patients. Detrusor overactivity during more than one-third of the filling phase was significantly related to signs of renal complications.

Testing of a New Portable Device for Dynamic Bladder Pressure Monitoring

OBJECTIVE

To develop a portable dynamic bladder pressure monitoring device for facilitating the monitoring of bladder detrusor pressure in patients with neurogenic bladder (NB) caused by spinal cord injury and further compared the effect with traditional urodynamics devices.

METHODS

Portable dynamic bladder pressure monitoring device was implemented by software and hardware. The hardware was mainly composed of seven parts, such as micro liquid pressure sensor, electric bridge amplifying circuit, clock module, SD card storage circuit, liquid crystal display circuit, touch circuit, controller circuit and so on. The main program of the software included system initialization, data acquisition, storage, display, alarm, etc. A total of 45 patients with neurogenic bladder caused by spinal cord injury were enrolled in the study. Detrusor pressure was measured with the portable device and traditional urodynamics device.

RESULTS

The test-retest reliability of the portable device was modest in two times test (intra-class correlation coefficient (ICC) = 0.852), no significant difference was found in the results of volume perfusion evaluation between our device and conventional urodynamic (each P > 0.05).

CONCLUSION

The portable dynamic bladder pressure monitoring device is conducive to the dynamic monitoring of bladder pressure in patients with neurogenic bladder caused by spinal cord injury.

Value of urodynamic findings in predicting upper urinary tract damage in neuro-urological patients: A systematic review

AIM

The main goals of neurogenic lower urinary tract dysfunction (NLUTD) management are preventing upper urinary tract damage (UUTD), improving continence, and quality of life. Here, we aimed to systematically assess all available evidence on urodynamics predicting UUTD in patients with NLUTD.

METHODS

A systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement was performed in March 2017. Only neuro-urological patients assessed by urodynamics were included. Any outcome of upper urinary tract function were evaluated.

RESULTS

Forty-nine studies (1 randomized controlled trial, 9 prospective, and 39 retrospective case series) reported urodynamic data on 4930 neuro-urological patients. Of those, 2828 (98%) were spina bifida (SB) children. The total number of adults was 2044, mainly having spinal cord injury (SCI) (60%). A low bladder compliance was found in 568 (46.3%) and 341 (29.3%) of the paediatric and adult population, respectively. Hydronephrosis (HDN) was detected in 557 children (27.8%) in 19/28 studies and 178 adults (14.6%), mainly SCI, in 14/21 studies. Nine out of 30 multiple sclerosis (MS) patients affected by HDN (16.8%) showed low compliance in 4/14 studies.

CONCLUSIONS

Patients with SB and SCI have a higher risk of developing UUTD (mainly reported as HDN) compared to those with MS. Reduced compliance and high DLPP were major risk factors for UUTD. Although our findings clarify the mandatory role of urodynamics in the management of NLUTD, standardization and better implementation of assessments in daily practice may further improve outcomes of neuro-urological patients based on objective measurements, that is, urodynamics.

Follow-up urodynamics in patients with neurogenic bladder

INTRODUCTION

Neurogenic bladder patients are at long-term risk of secondary upper urinary tract damage. Symptoms are unreliable and follow-up urodynamics is the only method of ascertaining safety of bladder pressures. This review examines the recommendations, shortcomings and utilization of existing guidelines. The evidence with regard to follow-up urodynamics in different settings relevant to neurogenic bladder is evaluated and an algorithm is proposed.

METHODS

A pubmed search was conducted for studies on follow-up urodynamics in patients with neurogenic bladder. Additional search was made of secondary sources including reviews and guidelines.

RESULTS

The need for follow-up urodynamics should be considered in all patients undergoing an initial assessment and weighed against the risks. Existing guidelines, while unanimous in their recommendation of its utilization, give scant details regarding its incorporation in clinical management. Follow-up urodynamics can document efficacy and identify the need for escalation of therapy in patients on intermittent catheterization and antimuscarinics. Patients with spinal injury, spinal dysraphism and anorectal malformations are at higher risk for upper tract damage. Follow-up urodynamics can help identify patients suitable for intravesical botulinum and mark those destined for failure. Patients undergoing augmentation cystoplasty may be candidates for less aggressive urodynamic follow-up.

CONCLUSIONS

Neurogenic bladder is managed by a broad cross-section of physicians. Clear recommendations and a management algorithm are important for improving patient care. Follow-up urodynamics can identify patients at risk, prevent renal dysfunction and improve the quality of life. There is an urgent need for more evidence on this important subject.

Renal deterioration after spinal cord injury is associated with length of detrusor contractions during cystometry-A study with a median of 41 years follow-up

AIMS

To investigate which urodynamic parameters are associated with renal deterioration over a median of 41 years follow-up after traumatic spinal cord injury.

METHODS

Medical records of patients with a traumatic spinal cord injury sustained 1944-1975 were reviewed from time of injury until 2012. Patients who attended regular renography and/or renal clearance examinations and had minimum one cystometry and pressure-flow study were included. Renal deterioration was diagnosed as split renal function ≤30% in one kidney or relative glomerular filtration rate ≤51% of expected according to age and gender. Detrusor function, presence of detrusor sphincter dyssynergia, maximum detrusor pressure, post-void residual volume, and cystometric bladder capacity were obtained. In patients with detrusor overactivity, a detrusor overactivity/cystometry ratio was calculated using duration of detrusor contraction(s) during filling cystometry divided by total duration of filling cystometry.

RESULTS

A total of 73 patients were included in the study, and the median follow-up time was 41 years after injury (range 24-56). Sixty-four patients (88%) used reflex triggering or bladder expression as bladder emptying method for the longest period after injury. During follow-up 60% changed to clean intermittent catheterization. The majority of the patients (68%) had neurogenic detrusor overactivity. In 35 patients, a detrusor-overactivity/cystometry ratio could be calculated and a detrusor overactivity/cystometry ratio > 0.33 was significantly associated with renal deterioration (P < 0.02). No significant association was found between maximum detrusor pressure or other urodynamic parameters and renal deterioration.

CONCLUSIONS

Duration of detrusor overactivity longer than one third of the duration of cystometry is associated with renal deterioration after spinal cord injury.

The use of urologic investigations among patients with traumatic spinal cord injuries

Objective

To assess the use of urologic investigations among traumatic spinal cord injury (TSCI) patients.

Methods

This is a retrospective cohort study from Ontario, Canada. We included all adult TSCI patients injured between 2002 and 2012. The primary outcome was the frequency of urodynamic testing, renal imaging, and cystoscopy. Primary exposure was the year of injury. The impact of age, sex, comorbidity, socioeconomic status, and lesion level was assessed with Cox regression models.

Results

One thousand five hundred and fifty one incident TSCI patients were discharged from a rehabilitation hospital. The median follow-up time of this cohort was 5.0 years (interquartile range =2.9–7.5). At least one urodynamics, renal imaging, or cystoscopy was performed during follow-up for 50%, 80%, and 48% of the cohort, respectively. The overall rate of these tests was 0.22, 0.60, and 0.22 per person-year of follow-up. The proportion of patients who had regular, yearly urodynamics (<2%), renal imaging (6%), or cystoscopy (<2%) was low. There were no significant linear trends in the use of these tests over the 10-year study period. Urodynamics were significantly less likely to be performed in patients over 65 years of age (hazard ratio [HR] =0.63, P<0.01) and those with a higher level of comorbidity (HR =0.72, P<0.01). Patients with quadriplegia were significantly less likely to receive any of the investigations compared to those with paraplegia.

Conclusion

Renal imaging is done at least once for the majority of patients with TSCI; however, only half undergo urodynamics or cystoscopy. Few patients have regular urologic testing. The reality of urologic testing after TSCI is very different from urologist’s ideals and practice guidelines.