Comparison of ambulatory versus video urodynamics in patients with spinal cord injury

Wireless intravesical device for real-time bladder pressure measurement: Study of consecutive voiding in awake minipigs

Traditional urodynamics have poor correlation with urological symptoms. Ambulatory urodynamics may improve this correlation but the need for a transurethral catheter and the time-consuming nature of this examination limits its use. Therefore, the objective of this study was to develop a wireless real-time bladder pressure measurement device for repeated and prolonged-term measurement of bladder behavior in awake pigs. The Bladder Pill is an intravesical device with a pressure microsensor and a 3-dimensional inductive coupling coil for energy supply. A corresponding external coil provides wireless power transmission and real-time communication of bladder pressure data. To test the correlation between the pressure data measured by the device and by standard methods, we compared static water column pressures with this device and water-filled urodynamic catheter systems. In vivo assessment of awake voiding by the pill was done by introducing the bladder pill into the bladder of Göttingen minipigs. An air-charged urodynamic catheter was introduced transurethrally as control for pressure measurements. The optimal physical configuration of the pill was investigated to maximize the containment in the bladder. We used two versions of external signal receivers (one waistband and one rectangular frame) to test the optimal external signal capture. Next to that, we performed short-term and medium-term comparative pressure studies. The in vitro static pressure measurement demonstrated a mean difference of less than 1 cm H₂O between the methods. The optimal design of the pill for maximal retainment in the bladder proved to be a pigtail configuration. The bending of the device during bladder contractions caused offset of 2.7 +/- 1.4 cm H₂O (mean +/- SD) on the pressure measurements. The rectangular frame performed signal capture during 5 consecutive voids with a good correlation of the pressure measurements. The device can be inserted through the urethra and is retrieved using string or endoscopic extraction. In conclusion, wireless long-term measurement of bladder pressure is demonstrated and yields comparable results to current available catheter methods of measurement in a pig model.

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.

When should video be added to conventional urodynamics in adults and is it justified by the evidence? ICI-RS 2014

AIMS

To debate and evaluate the evidence base regarding the added value of video to urodynamics in adults and to define research questions.

METHODS

In the ICI-RS Meeting 2014 a Think Tank analyzed the current guidelines recommending video urodynamics (VUD) and performed a literature search to determine the level of evidence for the additional value of the imaging with urodynamic assessment of both neurogenic and non-neurogenic lower urinary tract dysfunction.

RESULTS

Current guidelines do not specify the added value of imaging to urodynamics. Recommendations are based on single center series and expert opinion. Standard imaging protocols are not available and evidence regarding the balance between number and timing of pictures, patient positioning, and exposure time on the one hand and diagnosis on the other hand is lacking. On the basis of expert consensus VUD is relevant in the follow-up of patients with spinal dysraphism. Evidence for the value of VUD in non-neurogenic lower urinary tract dysfunction is sparse. There is some evidence that VUD is not necessary in uncomplicated female SUI, but expert opinion suggests it might improve the evaluation of patients with recurrent SUI.

CONCLUSIONS

There is only low level evidence for the addition of video to urodynamics. The ICI-RS Think Tank encourages better reporting of results of imaging and systematic reporting of X-ray doses. Specific research hypotheses regarding the added value of imaging are recommended. The panel suggests the development of standards for technically optimal VUD that is practically achievable with machines that are on the market.