Imaging characteristics predicting elevated detrusor pressures in patients with spina bifida.

Purpose: Patients with spina bifida require urologic follow up with assessments of bladder and renal function. The ideal screening protocol for bladder compliance remains controversial. This study assessed associations between bladder end filling pressure (EFP) and detrusor leak point pressure (DLPP) on urodynamic studies (UDS) and findings from renal bladder ultrasounds (RBUS) and voiding cystourethrograms (VCUG).

Methods: Pediatric spina bifida patients who underwent RBUS and/or VCUG within six months of UDS at a single institution from 2015 to 2021 were retrospectively reviewed. Demographics, VCUG and RBUS results, and UDS EFP and DLPP were recorded. Multiple linear regression analyses and Pearson chi-square tests were conducted to correlate RBUS and VCUG findings with DLPP/EFP.

Results: 129 patients were included. In adjusted analyses, moderate to severe hydronephrosis on RBUS was significantly associated with elevations in mean DLPP/EFP (p = 0.006). Patients with round bladders had significantly lower mean DLPP/EFP than patients with elongated or conical bladders (p < 0.0001). The presence of trabeculations was associated with increased mean DLPP/EFP (p < 0.0001) and increases in severity of trabeculations were associated with higher DLPP/EFP (p < 0.0001). The presence of vesicoureteral reflux (VUR) on VCUG was not associated with significant differences in mean DLPP/EFP (p = 0.20).

Conclusions: Abnormal bladder shape and trabeculations on VCUGs in spina bifida patients had significant associations with increased mean bladder pressures on UDS. Assessment of bladder shape and contour by VCUG may be a valuable screening tool in conjunction with routine RBUS in determining the need for further assessment of bladder pressures in patients with spina bifida.