Antenatal urodynamic studies in the fetal lamb: experimental protocol and preliminary results

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Abstract
Objectives To set up a fetal lamb model for intrauterine fetal urodynamic studies. Methods Fourteen fetal lambs underwent placement of a bladder catheter at a mean gestational age of 87 days. Three fetuses also had a partial urethral obstruction by the simultaneous placement of a peri‐urethral constricting ring. Urodynamic and ultrasound studies were performed weekly by the filling cystometry method. Results Hundred and six voiding cycles were recorded during 25 urodynamic studies between 84‐ and 133‐days gestation. All voiding profiles were biphasic with a mean duration of 4.2 min (range 1–10), a mean voiding pressure of 23 cm of water (range 7–33) and a mean periodicity of 19.2 min (range 11–50). The obstructed animals had bladder overactivity. This correlated with ultrasound and post‐mortem findings of megacystis and bilateral hydroureteronephrosis. The fetal mortality rate was 85.7% and the mean duration of survival post surgery was 45 ± 5.7 days. Conclusion Serial urodynamic studies could be performed in a fetal lamb model. Following partial urethral obstruction, bladder overactivity was observed. Copyright © 2003 John Wiley & Sons, Ltd.