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A prospective crossover study comparing ICCS-recommended and Palmer-adjusted filling rates in children with spina
Arzu Canmemiş1, Cigdem Ulukaya Durakbasa2, Mustafa Yağız2
1Department of Pediatric Urology, Göztepe Prof. Dr. Süleyman Yalçın City Hospital, Istanbul, Türkiye.
Insights
Slower bladder filling rates in children with spina bifida (SB) more accurately estimate maximal cystometric capacity (MCC) and improve bladder compliance measurements. These findings suggest optimized urodynamic assessment strategies for pediatric SB patients.
Area of Science:
- Pediatric Urology
- Urodynamics
- Spina Bifida Research
Background:
- Maximal cystometric capacity (MCC) is a key urodynamic parameter in managing spina bifida (SB).
- The Palmer formula predicts lower MCC, but its clinical utility and the impact of filling rates require further investigation.
Purpose of the Study:
- To determine if the Palmer formula accurately predicts MCC in children with SB.
- To assess how varying bladder filling rates affect urodynamic parameters during cystometry.
Main Methods:
- A prospective, randomized crossover study involving 70 children (3-18 years) with SB.
- Bladder filling rates were varied: ICCS-recommended rate versus 75% of that rate (Palmer formula).
- Key urodynamic parameters including MCC, compliance, and detrusor leak point pressure (DLPP) were analyzed.
Main Results:
- Bladder filling at the Palmer-adjusted rate (slower) resulted in higher measured MCC compared to the ICCS-recommended rate.
- Reduced bladder compliance was significantly less frequent with slower filling in one group.
- A positive correlation was found between expected bladder capacity (EBC) and measured MCC, with best agreement at the Palmer rate.
Conclusions:
- Bladder filling rate significantly influences cystometric capacity and compliance measurements in pediatric SB patients.
- Slower filling rates, aligned with the Palmer formula, yield MCC values closer to expected norms and improve consistency.
- While slower filling appears beneficial for measurement consistency, clinical impact requires cautious interpretation due to potential sequence effects.
Objective:
This study aimed to investigate whether the maximal cystometric capacity (MCC) in children with spina bifida (SB) is indeed lower, as predicted by the Palmer formula, and to evaluate the impact of different bladder filling rates on urodynamic parameters.
Materials And Methods:
This prospective, randomized, two-sequence crossover-controlled study included 70 children aged 3-18 years with spina bifida under regular follow-up. In Group 1, the first two bladder fillings were performed at the ICCS-recommended rate, and the third at 75% of that rate (Palmer formula). In Group 2, the sequence was reversed. Urodynamic parameters, including maximal cystometric capacity (MCC), bladder compliance, detrusor activity, filling pressures, and detrusor leak point pressure (DLPP), were analyzed across fillings.
Results:
Cystometric bladder capacity was lower during fillings performed at the Palmer-adjusted rate compared with those at the ICCS-recommended rate. The proportion of reduced compliance significantly decreased in Group 1 (p = 0.046) but remained unchanged in Group 2. A significant positive correlation was observed between expected bladder capacity (EBC) and measured MCC in both groups (ρ ≈ 0.5-0.6). The highest correlation and agreement were found in Group 1 during the third filling at the Palmer rate (ICC = 0.606). No significant intra- or intergroup differences were observed in detrusor pressure, end-filling pressure, DLPP, or overactive bladder prevalence.
Conclusion:
Bladder filling rate was associated with differences in both cystometric capacity and bladder compliance in children with spina bifida. Fillings performed according to the Palmer formula (approximately 75% of the ICCS-recommended rate) were associated with capacities that more closely approximated age-expected values and with modest differences in bladder compliance. Conversely, faster filling rates did not produce similar benefits. These findings suggest that slower filling strategies may improve measurement consistency and agreement with expected bladder capacity estimates. However, the magnitude and direct clinical impact of these differences should be interpreted cautiously, particularly in light of the potential influence of sequence-related effects.
