Determination of voiding pressure in infants with normal lower urinary tracts: Exploring the possible effect of sacral development.

Objective: To investigate the association between sacral underdevelopment, as defined by subnormal sacral ratio (SR) measurements, with increased maximum detrusor voiding pressure (P det. Max) in infants.

Methods: In this 2007-2015 retrospective cohort study, the medical records of all infants who underwent a pyeloplasty due to congenital ureteropelvic junction obstruction were added. Their P det. Max was evaluated through the suprapubic catheter utilized for urinary drainage intraoperatively, without imposing any additional risk of urethral catheterization on the infant. SR was calculated via the plain kidney, ureter, and bladder (KUB) radiography film obtained during the voiding cystourethrogram (VCUG) evaluation before the surgery. Participants were categorized into SR < 0.74 or SR ≥ 0.74. P det. Max was subsequently compared between these two groups.

Results: A total of 45 patients were included in our analysis. Twenty-eight (62.2%) patients had a (SR < 0.74), while 17 (37.8%) had a (SR ≥ 0.74). P det. Max was shown to be significantly higher in the SR < 0.74 compared to the SR ≥ 0.74 group (167.5 ± 60.8 vs. 55.7 ± 17.9 cmH₂O, p < 0.001). After adjusting for age and sex, SR remained a significant contributor to P det. Max (p < 0.001). Physiologic detrusor sphincter dyscoordination (PDSD) rate was significantly higher in the SR < 0.74 versus SR ≥ 0.74 group (100.0% vs. 70.6%, respectively; p = 0.005).

Conclusion: Lumbosacral underdevelopment, as indicated by subnormal sacral ratios, is associated with sphincter-detrusor dyscoordination, which causes PDSD and can ultimately result in higher P det. Max in infants.