A simple screening tool for an unfavorable bladder in children with myelomeningocele: Is the height to width ratio of the cystogram useful to predict high-pressure bladder?
INTRODUCTION
Videourodynamics is the key follow-up examination of children with myelomeningocele. However, it has been performed in specific institutions focused on the urological management of children due to the difficulty in its interpretation. Although a neurogenic bladder frequently appears elongated vertically and trabeculated, no objective study has clearly shown the relationship between bladder shape on the cystogram and urodynamic parameters in children with myelomeningocele.


OBJECTIVES
The aim of this study was to investigate the usefulness of the height to width ratio of cystogram (HWR) as a screening tool for finding high-pressure bladder in children with myelomeningocele.Study design the medical records of children with myelomeningocele aged less than 13 years who underwent videourodynamics were reviewed. Maximum detrusor pressure (MDP) was defined as the maximum detrusor pressure at end-filling or at leak. HWR was calculated by the maximum height/maximum width of the cystogram appearance at maximum cystometric capacity (Figure) The children were categorized into two groups: children with high-pressure bladder (MDP≥40 cmH2O) and low-pressure bladder (MDP<40 cm H2O). Age, sex, videourodynamics variables, and HWR were compared between the 2 groups. Using the results of the above, receiver-operating characteristic (ROC) curves were constructed.


RESULTS
A total of 81 children who were on clean intermittent catheterization met the study criteria. All children were on CIC, and their median age was 81 months (IQR 54-128 months). The HWR was significantly higher for high-pressure bladders than for low-pressure bladders (median 1.50 vs 1.37, p = 0.004). The sensitivity and specificity of the HWR for discriminating children with high-pressure bladder from all children were 87% and 56.9%, respectively. The area under the curve (AUC) was 0.71 with a cutoff score of 1.40.


DISCUSSION
Bladder deformity was objectively evaluated by the HWR, and measurement of the HWR was straightforward. The main drawback of this evaluation method for bladder shape is to disregard the presence or absence of bladder trabeculation, which has been considered a key finding of an unfavorable bladder in this population. Based on the HWR ROC curves, the AUC was 0.71, which meant that the HWR would be considered to be fair at screening for high-pressure bladder.


CONCLUSION
The height to width ratio of the cystogram was a useful tool for objectively evaluating bladder shape in children with myelomeningocele, and a cut-off point of 1.40 could be used as a simple screening tool for high-pressure bladder in this population.