Editor,—Because urethral catheterisation for micturating cystography frequently causes discomfort and embarrassment in children, and is not always successful, we wondered whether suprapubic puncture would provide a suitable alternative,1and began a prospective randomised trial.

All children needing micturating cystography were invited to be randomised to have either suprapubic puncture or urethral catheterisation; the study had ethics committee approval and informed consent. Families received an information pack, were encouraged to contact the study nurse in advance, and met her before the cystogram to discuss their wishes, and for play preparation. Urethral catheterisation or suprapubic puncture were performed in the xray department by a consultant or trainee paediatric radiologist; suprapubic puncture was under ultrasound control2 after using local anaesthetic cream (EMLA), then lignocaine. Urine was tested for blood, and microscoped for bacteria.3

Parents and older children made an assessment of the procedure immediately, and two weeks later. Power calculations indicated it would be necessary to enrol 100 children into each limb to demonstrate whether there was a significant difference between the two procedures, but we stopped the study with just 10 in each limb because families regarded urethral catheterisation as clearly preferable. For the 20 children randomised, suprapubic puncture took a little longer than urethral catheterisation, and scored a little worse for discomfort, and despite thorough preparation, many children having suprapubic puncture appeared frightened by the needle. Eighteen families refused randomisation because of their anxieties that the suprapubic puncture needle would be painful, or would make the procedure ‘too involved’ or ‘more like surgery’. The only two patients strongly enthusiastic about suprapubic puncture were older girls who had been highly embarrassed at the thought of having urethral catheterisation performed.

Though families recognised that urethral catheterisation may be unpleasant, most felt strongly that it seemed safer and preferable to suprapubic puncture, because it followed a ‘natural route’ rather than making a false one.